Bedazzled by Energy Efficiency

 últim editat: Sun, 07 Jan 2018 23:03:02 +0100  
Bedazzled by Energy Efficiency


To focus on energy efficiency is to make present ways of life non-negotiable. However, transforming present ways of life is key to mitigating climate change and decreasing our dependence on fossil fuels.

Energy efficiency policy
Energy efficiency is a cornerstone of policies to reduce carbon emissions and fossil fuel dependence in the industrialised world. For example, the European Union (EU) has set a target of achieving 20% energy savings through improvements in energy efficiency by 2020, and 30% by 2030. Measures to achieve these EU goals include mandatory energy efficiency certificates for buildings, minimum efficiency standards and labelling for a variety of products such as boilers, household appliances, lighting and televisions, and emissions performance standards for cars. [1]

The EU has the world’s most progressive energy efficiency policy, but similar measures are now applied in many other industrialised countries, including China. On a global scale, the International Energy Agency (IEA) asserts that “energy efficiency is the key to ensuring a safe, reliable, affordable and sustainable energy system for the future”. [2] In 2011, the organisation launched its 450 scenario, which aims to limit the concentration of CO2 in the atmosphere to 450 parts per million. Improved energy efficiency accounts for 71% of projected carbon reductions in the period to 2020, and 48% in the period to 2035. [2] [3]

What are the results?
Do improvements in energy efficiency actually lead to energy savings? At first sight, the advantages of efficiency seem to be impressive. For example, the energy efficiency of a range of domestic appliances covered by the EU directives has improved significantly over the last 15 years. Between 1998 and 2012, fridges and freezers became 75% more energy efficient, washing machines 63%, laundry dryers 72%, and dishwashers 50%. [4]

However, energy use in the EU-28 in 2015 was only slightly below the energy use in 2000 (1,627 Mtoe compared to 1.730 Mtoe, or million tonnes of oil equivalents). Furthermore, there are several other factors that may explain the (limited) decrease in energy use, like the 2007 economic crisis. Indeed, after decades of continuous growth, energy use in the EU decreased slightly between 2007 and 2014, only to go up again in 2015 and 2016 when economic growth returned. [1]

On a global level, energy use keeps rising at an average rate of 2.4% per year. [3] This is double the rate of population growth, while close to half of the global population has limited or no access to modern energy sources. [5] In industrialised (OECD) countries, energy use per head of the population doubled between 1960 and 2007. [6]

Rebound effects?
Why is it that advances in energy efficiency do not result in a reduction of energy demand? Most critics focus on so-called “rebound effects”, which have been described since the nineteenth century. [7] According to the rebound argument, improvements in energy efficiency often encourage greater use of the services which energy helps to provide. [8] For example, the advance of solid state lighting (LED), which is six times more energy efficient than old-fashioned incandescent lighting, has not led to a decrease in energy demand for lighting. Instead, it resulted in six times more light. [9]

In some cases, rebound effects may be sufficiently large to lead to an overall increase in energy use. [8] For example, the improved efficiency of microchips has accelerated the use of computers, whose total energy use now exceeds the total energy use of earlier generations of computers which had less energy efficient microchips. Energy efficiency advances in one product category can also lead to increased energy use in other product categories, or lead to the creation of an entirely new product category.

For example, LED-screens are more energy efficient than LCD-screens, and could therefore reduce the energy use of televisions. However, they also led to the arrival of digital billboards, which are enormous power hogs in spite of their energy efficient components. [10] Finally, money saved through improvements in energy efficiency can also be spent on other energy-intensive goods and services, which is a possibility usually referred to as an indirect rebound effect.

Beyond the rebound argument
Rebound effects are ignored by the EU and the IEA, and this might partly explain why the results fall short of the projections. Among academics, the magnitude of the rebound effect is hotly debated. While some argue that “rebound effects frequently offset or even eliminate the energy savings from improved efficiency” [3], others maintain that rebound effects “have become a distraction” because they are relatively small: “behavioural responses shave 5-30% of intended energy savings, reaching no more than 60% when combined with macro-economic effects – energy efficiency does save energy”. [11]

Those who downplay rebound effects attribute the lack of results to the fact that we don’t try hard enough: “many opportunities for improving energy efficiency still go wasted”. [11] Others are driven by the goal of improving energy efficiency policy. One response is to suggest that the frame of reference be expanded and that analysts should consider the efficiency not of individual products but of entire systems or societies. In this view, energy efficiency is not framed holistically enough, nor given sufficient context. [12] [13]

However, a few critics go one step further. In their view, energy efficiency policy cannot be fixed. The problem with energy efficiency, they argue, is that it establishes and reproduces ways of life that are not sustainable in the long run. [12][14]

A parellel universe
Rebound effects are often presented as “unintended” consequences, but they are the logical outcome of the abstraction that is required to define and measure energy efficiency. According to Loren Lutzenhiser, a researcher at Portland State University in the US, energy efficiency policy is so abstracted from the everyday dynamics of energy use that it operates in a “parallel universe”. [14] In a more recent paper, What is wrong with energy efficiency?, UK researcher Elizabeth Shove unravels this “parallel universe”, concluding that efficiency policies are “counter-productive” and “part of the problem”. [12]
According to some critics, efficiency policies are "counter-productive" and "part of the problem".

To start with, the parallel universe of energy efficiency interprets “energy savings” in a peculiar way. When the EU states that it will achieve 20% “energy savings” by 2020, “energy savings” are not defined as a reduction in actual energy consumption compared to present or historical figures. Indeed, such a definition would show that energy efficiency doesn’t reduce energy use at all. Instead, the “energy savings” are defined as reductions compared to the projected energy use in 2020. These reductions are measured by quantifying “avoided energy” – the energy resources not used because of advances in energy efficiency.

Even if the projected “energy savings” were to be fully realised, they would not result in an absolute reduction in energy demand. The EU argues that advances in energy efficiency will be “roughly equivalent to turning off 400 power stations”, but in reality no single power station will be turned off in 2020 because of advances in energy efficiency. Instead, the reasoning is that Europe would have needed to build an extra 400 power stations by 2020, were it not for the increases in energy efficiency.

In taking this approach, the EU treats energy efficiency as a fuel, “a source of energy in its own right”. [15] The IEA goes even further when it claims that “energy avoided by IEA member countries in 2010 (generated from investments over the preceding 1974 to 2010 period), was larger than actual demand met by any other supply side resource, including oil, gas, coal and electricity”, thus making energy efficiency “the largest or first fuel”. [16] [12]

Measuring something that doesn’t exist
Treating energy efficiency as a fuel and measuring its success in terms of “avoided energy” is pretty weird. For one thing, it is about not using a fuel that does not exist. [14] Furthermore, the higher the projected energy use in 2030, the larger the “avoided energy” would be. On the other hand, if the projected energy use in 2030 were to be lower than present-day energy use (we reduce energy demand), the “avoided energy” becomes negative.

An energy policy that seeks to reduce greenhouse gas emissions and fossil fuel dependency must measure its success in terms of lower fossil fuel consumption. [17] However, by measuring “avoided energy”, energy efficiency policy does exactly the opposite. Because projected energy use is higher than present energy use, energy efficiency policy takes for granted that total energy consumption will keep rising.

That other pillar of climate change policy – the decarbonisation of the energy supply by encouraging the use of renewable energy power plants – suffers from similar defects. Because the increase in total energy demand outpaces the growth in renewable energy, solar and wind power plants are in fact not decarbonising the energy supply. They are not replacing fossil fuel power plants, but are helping to accommodate the ever growing demand for energy. Only by introducing the concept of “avoided emissions” can renewables be presented as having something of the desired effect. [18]

What is it that is efficient?
In What is wrong with energy efficiency?, Elizabeth Shove demonstrates that the concept of energy efficiency is just as abstract as the concept of “avoided energy”. Efficiency is about delivering more services (heat, light, transportation,…) for the same energy input, or the same services for less energy input. Consequently, a first step in identifying improvements depends on specifying “service” (what is it that is efficient?) and on quantifying the amount of energy involved (how is “less energy” known?). Setting a reference against which “energy savings” are measured also involves specifying temporal boundaries (where does efficiency start and end?). [12]

Shove’s main argument is that setting temporal boundaries (where does efficiency start and end?) automatically specifies the “service” (what is it that is efficient?), and the other way around. That’s because energy efficiency can only be defined and measured if it is based on equivalence of service. Shove focuses on home heating, but her point is valid for all other technology. For example, in 1985, the average passenger plane used 8 litres of fuel to transport one passenger over a distance of 100 km, a figure that came down to 3.7 litres today.

Consequently, we are told that airplanes have become twice as efficient. However, if we make a comparison in fuel use between today and 1950, instead of 1985, airplanes do not use less energy at all. In the 1960s, propeller aircraft were replaced by jet aircraft, which are twice as fast but initially consumed twice as much fuel. Only fifty years later, the jet airplane became as “energy efficient” as the last propeller planes from the 1950s. [19]
If viewed in a larger historical context, the concept of energy efficiency completely disintegrates.

What then is a meaningful timespan over which to compare efficiencies? Should propeller planes be taken into account, or should they be ignored? The answer depends on the definition of equivalent service. If the service is defined as “flying”, then propeller planes should be included. But, if the energy service is defined as “flying at a speed of roughly 1,000 km/h”, we can discard propellers and focus on jet engines. However, the latter definition assumes a more energy-intensive service.

If we go back even further in time, for example to the early twentieth century, people didn’t fly at all and there’s no sense in comparing fuel use per passenger per kilometre. Similar observations can be made for many other technologies or services that have become “more energy efficient”. If they are viewed in a larger historical context, the concept of energy efficiency completely disintegrates because the services are not at all equivalent.

Often, it’s not necessary to go back very far to prove this. For example, when the energy efficiency of smartphones is calculated, the earlier generation of much less energy demanding “dumbphones” is not taken into account, although they were common less than a decade ago.

How efficient is a clothesline?
Because of the need to compare 'like with like' and establish equivalent of service, energy efficiency policy ignores many low energy alternatives that often have a long history but are still relevant in the context of climate change.

For example, the EU has calculated that energy labels for tumble driers will be able to “save up to 3.3 Twh of electricity by 2020, equivalent to the annual energy consumption of Malta”. [20]. But how much energy use would be avoided if by 2020 every European would use a clothesline instead of a tumble drier? Don’t ask the EU, because it has not calculated the avoided energy use of clotheslines.


Neither do the EU or the IEA measure the energy efficiency and avoided energy of bicycles, hand powered drills, or thermal underwear. Nevertheless, if clotheslines would be taken seriously as an alternative, then the projected 3.3 TWh of energy “saved” by more energy efficient tumble driers can no longer be considered “avoided energy”, let alone a fuel. In a similar way, bicycles and clothing undermine the very idea of calculating the “avoided energy” of more energy efficient cars and central heating boilers.

Unsustainable concepts of service
The problem with energy efficiency policies, then, is that they are very effective in reproducing and stabilising essentially unsustainable concepts of service. [12] Measuring the energy efficiency of cars and tumble driers, but not of bicycles and clotheslines, makes fast but energy-intensive ways of travel or clothes drying non-negotiable, and marginalises much more sustainable alternatives. According to Shove:
“Programmes of energy efficiency are politically uncontroversial precisely because they take current interpretations of ‘service’ for granted… The unreflexive pursuit of efficiency is problematic not because it doesn’t work or because the benefits are absorbed elsewhere, as the rebound effect suggests, but because it does work – via the necessary concept of equivalence of services – to sustain, perhaps escalate, but never undermine… increasingly energy intensive ways of life.” [12]

Indeed, the concept of energy efficiency easily accommodates further growth of energy services. All future novelties can be subjected to an efficiency approach. For example, if patio heaters and monsoon showers become “normal”, they could be incorporated in existing energy efficiency policy – and when that happens, the problem of their energy use is considered to be under control. At the same time, defining, measuring and comparing the efficiency of patio heaters and monsoon showers helps make them more “normal”. As a bonus, adding new products to the mix will only increase the energy use that is “avoided” through energy efficiency.

In short, neither the EU nor the IEA capture the “avoided energy” generated by doing things differently, or by not doing them at all – while these arguably have the largest potential to reduce energy demand. [12] Since the start of the Industrial Revolution, there has been a massive expansion in the uses of energy and in the delegation of human to mechanical forms of power. But although these trends are driving the continuing increase in energy demand, they cannot be measured through the concept of energy efficiency.

As Shove demonstrates, this problem cannot be solved, because energy efficiency can only be measured on the basis of equivalent service. Instead, she argues that the challenge is “to debate and extend meanings of service and explicitly engage with the ways in which these evolve”. [12]

Towards an energy inefficiency policy?
There are several ways to escape from the parallel universe of energy efficiency. First, while energy efficiency hinders significant long term reduction in energy demand through the need for equivalence of service, the opposite also holds true – making everything less energy efficient would reverse the growth in energy services and reduce energy demand.

For example, if we were to install 1960s internal combustion engines into modern SUVs, fuel use per kilometre driven would be much higher than it is today. Few people would be able or willing to afford to drive such cars, and they would have no other choice but to switch to a much lighter, smaller and less powerful vehicle, or to drive less.
Making everything less energy efficient would reverse the growth in energy services and reduce energy demand.

Likewise, if an “energy inefficiency policy” were to mandate the use of inefficient central heating boilers, heating large homes to present-day comfort standards would be unaffordable for most people. They would be forced to find alternative solutions to achieve thermal comfort, for instance heating only one room, dressing more warmly, using personal heating devices, or moving to a smaller home.

Recent research into the heating of buildings confirms that inefficiency can save energy. A German study examined the calculated energy performance ratings of 3,400 homes and compared these with the actual measured consumption. [21] In line with the rebound argument, the researchers found that residents of the most energy efficient homes (75 kWh/m2/yr) use on average 30% more energy than the calculated rating. However, for less energy efficient homes, the opposite – “pre-bound” – effect was observed: people use less energy than the models had calculated, and the more inefficient the dwelling is, the larger this gap becomes. In the most energy inefficient dwellings (500 kWh/m2/yr), energy use was 60% below the predicted level.

From efficiency to sufficiency?
However, while abandoning – or reversing – energy efficiency policy would arguably bring more energy savings than continuing it, there is another option that’s more attractive and could bring even larger energy savings. For an effective policy approach, efficiency can be complemented by or perhaps woven into a “sufficiency” strategy. Energy efficiency aims to increase the ratio of service output to energy input while holding the output at least constant. Energy sufficiency, by contrast, is a strategy that aims to reduce the growth in energy services. [4] In essence, this is a return to the “conservation” policies of the 1970s. [14]

Sufficiency can involve a reduction of services (less light, less travelling, less speed, lower indoor temperatures, smaller houses), or a substitution of services (a bicycle instead of a car, a clothesline instead of a tumble drier, thermal underclothing instead of central heating). Unlike energy efficiency, the policy objectives of sufficiency cannot be expressed in relative variables (like kWh/m2/year). Instead, the focus is on absolute variables, such as reductions in carbon emissions, fossil fuel use, or oil imports. [17] Unlike energy efficiency, sufficiency cannot be defined and measured by examining a single product type, because sufficiency can involve various forms of substitution. [22] Instead, a sufficiency policy is defined and measured by looking at what people actually do.

A sufficiency policy could be developed without a parallel efficiency policy, but combining them could bring larger energy savings. The key step here is to think of energy efficiency as a means rather than an end in itself, argues Shove. [12] For example, imagine how much energy could be saved if we would use an energy efficient boiler to heat just one room to 16 degrees, if we install an energy efficient engine in a much lighter vehicle, or if we combine an energy saving shower design with fewer and shorter showers. Nevertheless, while energy efficiency is considered to be a win-win strategy, to develop the concept of sufficiency as a significant force in policy is to make normative judgments: so much consumption is enough, so much is too much. [23] This is sure to be controversial, and it risks being authoritarian, at least as long as there is a cheap supply of fossil fuels.

Kris De Decker

Illustrations by Diego Marmolejo.

[1] "Energy Efficiency", European Commission.

[2] "Energy Efficiency", International Energy Association (IEA).

[3] Sorrell, Steve. "Reducing energy demand: A review of issues, challenges and approaches." Renewable and Sustainable Energy Reviews 47 (2015): 74-82.

[4] Brischke, Lars-Arvid, et al. Energy sufficiency in private households enabled by adequate appliances. Wuppertal Institut für Klima, Umwelt, Energie, 2015.

[5] "Poor people's Energy Outlook 2016", Practical Action, 2016.

[6] "Energy use (kg of oil equivalent per capita)", World Bank, 2014.

[7] Alcott, Blake. "Jevons' paradox." Ecological economics 54.1 (2005): 9-21.

[8] Sorrell, Steve. "The Rebound Effect: an assessment of the evidence for economy-wide energy savings from improved energy efficiency." (2007).

[9] Kyba, Christopher CM, et al. "Artificially lit surface of Earth at night increasing in radiance and extent." Science advances 3.11 (2017): e1701528.; Tsao, Jeffrey Y., et al. "Solid-state lighting: an energy-economics perspective." Journal of Physics D: Applied Physics 43.35 (2010): 354001.

[10] Young, Gregory. "Illuminating the Issues." (2013).

[11] Gillingham, Kenneth, et al. "Energy policy: The rebound effect is overplayed." Nature 493.7433 (2013): 475-476.

[12] Shove, Elizabeth. "What is wrong with energy efficiency?." Building Research & Information (2017): 1-11.

[13] Calwell, Is efficient sufficient? Report for the European Council for an Energy Efficient Economy.

[14] Lutzenhiser, Loren. "Through the energy efficiency looking glass." Energy Research & Social Science 1 (2014): 141-151.

[15] Good Practice in Energy Efficiency: for a sustainable, safer and more competitive Europe. European Commission, 2017.

[16] Capturing the Multiple Benefits of Energy Efficiency. IEA, 2014.

[17] Harris, Jeffrey, et al. "Towards a sustainable energy balance: progressive efficiency and the return of energy conservation." Energy efficiency 1.3 (2008): 175-188.

[18] How (not) to resolve the energy crisis, Low-tech Magazine, Kris De Decker, 2009.

[19] Peeters, Paul, J. Middel, and A. Hoolhorst. "Fuel efficiency of commercial aircraft." An overview of historical and future trends (2005).

[20] Household Tumble Driers, European Commission.

[21] Sunikka-Blank, Minna, and Ray Galvin. "Introducing the prebound effect: the gap between performance and actual energy consumption." Building Research & Information 40.3 (2012): 260-273.

[22] Thomas, Stefan, et al. Energy sufficiency policy: an evolution of energy efficiency policy or radically new approaches?. Wuppertal Institut für Klima, Umwelt, Energie, 2015.

[23] Darby, Sarah. "Enough is as good as a feast–sufficiency as policy." Proceedings, European Council for an Energy-Efficient Economy. La Colle sur Loup, 2007.
Imatge/foto Imatge/foto Imatge/foto Imatge/foto Imatge/foto Imatge/foto
 Energy consumption  Cover story  Energy efficiency paradox  Energy Efficiency  LowTechMagazine  energy efficiency
Slow Travel: Crossing Europe with a Giant Land Ship

Slow Travel: Crossing Europe with a Giant Land Ship


Belgian art collective Time Circus built their first prototype of a giant Land Ship that will travel through Europe. Like a modern-day galley, the land ship will be propelled by the muscle power of the participating travelers. The journey is understood as a 21st century pilgrimage and will take an estimated 10 years.



The Journey
Along the journey, people can board the land ship and travel along for as long as they want to. Longer stops will be made in Marseille (France), Novisad (Serbia), Timisoara (Romania) and Elefsina (Greece).

In 2018, land ship terminals will be built in these cities. Like bus stops, these will show how long it takes before the vehicle arrives. The start of the journey is planned for 2020.

The Ship
When we talked to one of the makers earlier this month in Antwerp, he said it was not yet clear whether the final vehicle would be a single monstrous land ship of 50 metres long, or a caravan of ‘small’ ones the size of the first prototype, which is 13 metres long.

He said they were also contemplating the use of draft animals or sails — reminiscent of the ancient Chinese wheelbarrow. The vehicle or vehicles will be equipped with sleeping accommodation for at least 50 people.



Confronting Bureaucracy
Either way, the trip will be challenging, not only because of the physical effort involved, but also because of many other obstacles, from bridges over telephone lines to rules and regulations. Time Circus wants to “obtain freedom of movement by gently opposing regulations with inventiveness and the use of the grey areas of the law, confronting the bureaucracy in a playful and witty way.”

The slowness of the journey gives ample space for meetings and interaction along the road. The main message of the project is to demonstrate that “unexpected forces can develop through cooperation”. It also wants to “encourage the imaginative forces in the world, introducing alternatives that lie dormant”.


More info: Time Circus. There’s also a video (in Dutch).
 Animal power  Art  Chariots  Human power  Public transport  Random  Travel  Walking  Wheelbarrows  NoTechMagazine
Low tech? Wild tech!

Low tech? Wild tech!


The French scientific magazine Techniques et Culture has published an entire volume about alternative forms of technology: “Low-tech? Wild tech!“. The 300-page issue explores the differences and conflicts between high-tech and low-tech, with a focus on all the forms of technology which are in between these extremes.

The authors argue for a more sophisticated view of technological evolution, which is now usually seen as linear progress towards ever increasing complexity and perfection. The contributions show that reality is much more complicated, and much more interesting.

The issue is the fruit of a three-day discussion in Paris in 2012, in which I participated. The volume features a translated article from Low-tech Magazine: “How to build a low-tech Internet?”. “Low tech? Wild tech!” will be presented and discussed in Paris on December 9, 2017.
 Books  Random  Technology  NoTechMagazine
How to Run the Economy on the Weather

 últim editat: Thu, 21 Sep 2017 16:00:52 +0200  
How to Run the Economy on the Weather


Before the Industrial Revolution, people adjusted their energy demand to a variable energy supply. Our global trade and transport system -- which relied on sail boats -- operated only when the wind blew, as did the mills that supplied our food and powered many manufacturing processes.

The same approach could be very useful today, especially when improved by modern technology. In particular, factories and cargo transportation -- such as ships and even trains -- could be operated only when renewable energy is available. Adjusting energy demand to supply would make switching to renewable energy much more realistic than it is today.

Stoneferry (detail), a painting by John Ward of Hull.

Renewable Energy in Pre-Industrial Times

Before the Industrial Revolution, both industry and transportation were largely dependent on intermittent renewable energy sources. Water mills, windmills and sailing boats have been in use since Antiquity, but the Europeans brought these technologies to full development from the 1400s onwards.

At their peak, right before the Industrial Revolution took off, there were an estimated 200,000 wind powered mills and 500,000 water powered mills in Europe. Initially, water mills and windmills were mainly used for grinding grain, a laborious task that had been done by hand for many centuries, first with the aid of stones and later with a rotary hand mill.


"Een zomers landschap" ("A summer landscape"), a painting by Jan van Os.

However, soon water and wind powered mills were adapted to industrial processes like sawing wood, polishing glass, making paper, boring pipes, cutting marble, slitting metal, sharpening knives, crushing chalk, grinding mortar, making gunpowder, minting coins, and so on. [1-3] Wind- and water mills also processed a host of agricultural products. They were pressing olives, hulling barley and rice, grinding spices and tobacco, and crushing linseed, rapeseed and hempseed for cooking and lighting.
Even though it relied on intermittent wind sources, international trade was crucial to many European economies before the Industrial Revolution.

So-called 'industrial water mills' had been used in Antiquity and were widely adopted in Europe by the fifteenth century, but 'industrial windmills' appeared only in the 1600s in the Netherlands, a country that took wind power to the extreme. The Dutch even applied wind power to reclaim land from the sea, and the whole country was kept dry by intermittently operating wind mills until 1850. [1-3]


Abraham Storck: A river landscape with fishermen in rowing boats, 1679.

The use of wind power for transportation – in the form of the sailboat – also boomed from the 1500s onwards, when Europeans 'discovered' new lands. Wind powered transportation supported a robust, diverse and ever expanding international trading system in both bulk goods (such as grain, wine, wood, metals, ceramics, and preserved fish), luxury items (such as precious metals, furs, spices, ivory, silks, and medicin) and human slaves. [4]

Even though it relied on intermittent wind sources, international trade was crucial to many European economies. For example, the Dutch shipbuilding industry, which was centred around some 450 wind-powered saw mills, imported virtually all its naval stores from the Baltic: wood, tar, iron, hemp and flax. Even the food supply could depend on wind-powered transportation. Towards the end of the 1500s, the Dutch imported two thousand shiploads of grain per year from Gdansk. [4] Sailboats were also important for fishing.

Dealing with Intermittency in Pre-Industrial Times

Although variable renewable energy sources were critical to European society for some 500 years before fossil fuels took over, there were no chemical batteries, no electric transmission lines, and no balancing capacity of fossil fuel power plants to deal with the variable energy output of wind and water power. So, how did our ancestors deal with the large variability of renewable power sources?

To some extent, they were counting on technological solutions to match energy supply to energy demand, just as we do today. The water level in a river depends on the weather and the seasons. Boat mills and bridge mills were among the earliest technological fixes to this problem. They went up and down with the water level, which allowed them to maintain a more predictable operating regime. [1-2]
To some extent, our ancestors were counting on technological solutions to match energy supply to energy demand, just as we do today.

However, water power could also be stored for later use. Starting in the middle ages, dams were built to create mill ponds, a form of energy storage that's similar to today's hydropower reservoirs. The storage reservoirs evened out the flow of streams and insured that water was available when it was needed. [2] [5]

Imatge/fotoThe Horse Mill, a painting by James Herring. Ca. 1850.

But rivers could still dry out or freeze over for prolonged periods, rendering dams and adjustable water wheels useless. Furthermore, when one counted on windmills, no such technological fixes were available. [3] [6-7]

A technological solution to the intermittency of both water and wind power was the 'beast mill' or 'horse mill'. [8] In contrast to wind and water power, horses, donkeys or oxen could be counted on to supply power whenever it was required. However, beast mills were expensive and energy inefficient to operate: feeding a horse required a land area capable of feeding eight humans. [9] Consequently, the use of animal power in large-scale manufacturing processes was rare. Beast mills were mostly used for the milling of grain or as a power source in small workshop settings, using draft animals. [1]

Obviously, beast mills were not a viable backup power source for sailing ships either. In principle, sailing boats could revert to human power when wind was not available. However, a sufficiently large rowing crew needed extra water and food, which would have limited the range of the ship, or its cargo capacity. Therefore, rowing was mainly restricted to battleships and smaller boats.

Adjusting Demand to Supply: Factories

Because of their limited technological options for dealing with the variability of renewable energy sources, our ancestors mainly resorted to a strategy that we have largely forgotten about: they adapted their energy demand to the variable energy supply. In other words, they accepted that renewable energy was not always available and acted accordingly. For example, windmills and sailboats were simply not operated when there was no wind.


Painting: Mills in the Westzijderveld near Zaandam, a painting by Claude Monet.

In industrial windmills, work was done whenever the wind blew, even if that meant that the miller had to work night and day, taking only short naps. For example, a document reveals that at the Union Mill in Cranbrook, England, the miller once had only three hours sleep during a windy period lasting 60 hours. [3] A 1957 book about windmills, partly based on interviews with the last surviving millers, reveals the urgency of using wind when it was available:

Often enough when the wind blew in autumn, the miller would work from Sunday midnight to Tuesday evening, Wednesday morning to Thursday night, and Friday morning to Saturday midnight, taking only a few snatches of sleep; and a good windmiller always woke up in bed when the wind rose, getting up in the middle of the night to set the mill going, because the wind was his taskmaster and must be taken advantage of whenever it blew. Many a village has at times gone short of wheaten bread because the local mill was becalmed in a waterless district before the invention of the steam engine; and barley-meal bread or even potato bread had to suffice in the crisis of a windless autumn. [10]

In earlier, more conservative times, the miller was punished for working on Sunday, but he didn't always care. When a protest against Sunday work was made to Mr. Wade of Wicklewood towermill, Norfolk, he retorted: "If the Lord is good enough to send me wind on a Sunday, I'm going to use it". [11] On the other hand, when there was no wind, millers did other work, like maintaining their machinery, or took time off. Noah Edwards, the last miller of Arkley tower mill, Hertfordshire, would “sit on the fan stage of a fine evening and play his fiddle”. [11]

Adjusting Demand to Supply: Sailboats

A similar approach existed for overseas travel, using sail boats. When there was no wind, sailors stayed ashore, maintained and repaired their ships, or did other things. They planned their trips according to the seasons, making use of favourable seasonal winds and currents. Winds at sea are not only much stronger than those over land, but also more predictable.
Sailors planned their trips according to the seasons, making use of favourable seasonal winds and currents.

The lower atmosphere of the planet is encircled by six major wind belts, three in each hemisphere. From Equator to poles these 'prevailing winds' are the trade winds, the westerlies, and the easterlies. The six wind belts move north in the northern summer and south in the northern winter. Five major sea current gyres are correlated with the dominant wind flows.


The Maas at Dordrecht, a painting by Aelbert Cuyp, 1660.

Gradually, European sailors deciphered the global pattern of winds and currents and took full advantage of them to establish new sea routes all over the world. By the 1500s, Christopher Columbus had figured out that the combination of trade winds and westerlies enabled a round-trip route for sailing ships crossing the Atlantic Ocean.

The trade winds reach their northernmost latitude at or after the end of the northern summer, bringing them in reach of Spain and Portugal. These summer trade winds made it easy to sail from Southern Europe to the Caribbean and South America, because the wind was blowing in that direction along the route.


Wind map of the Atlantic, September 9, 2017. Source: Windy.

Taking the same route back would be nearly impossible. However, Iberian sailors first sailed north to catch the westerlies, which reach their southernmost location at or after the end of winter and carried the sailors straight back to Southern Europe. In the 1560s, Basque explorer Andrés de Urdaneta discovered a similar round-trip route in the Pacific Ocean. [12]
The use of favourable winds made travel times of sailboats relatively reliable. The fastest Atlantic crossing was 21 days, the slowest 29 days.

The use of favourable winds made the travel times of sailboats relatively predictable. Ocean Passages for the World mentions that typical passage times from New York to the English Channel for a mid-19th to early 20th century sailing vessel was 25 to 30 days. From 1818 to 1832, the fastest crossing was 21 days, the slowest 29 days. [13]

The journey from the English Channel to New York took 35-40 days in winter and 40-50 days in summer. To Cape Town, Melbourne, and Calcutta took 50-60 days, 80-90 days, and 100-120 days, respectively. [13] These travel times are double to triple those of today's container ships, which vary their speed based on oil prices and economic demand.

Old Approach, New Technology

As a strategy to deal with variable energy sources, adjusting energy demand to renewable energy supply is just as valuable a solution today as it was in pre-industrial times. However, this does not mean that we need to go back to pre-industrial means. We have better technology available, which makes it much easier to synchronise the economic demands with the vagaries of the weather.


Shipping in a calm, a painting by Charles Brooking, first half 18th century.

In the following paragraphs, I investigate in more detail how industry and transportation could be operated on variable energy sources alone, and demonstrate how new technologies open new possibilities. I then conclude by analysing the effects on consumers, workers, and economic growth.

Industrial Manufacturing

On a global scale, industrial manufacturing accounts for nearly half of all energy end use. Many mechanical processes that were run by windmills are still important today, such as sawing, cutting, boring, drilling, crushing, hammering, sharpening, polishing, milling, turning, and so on. All these production processes can be run with an intermittent power supply.

The same goes for food production processes (mincing, grinding or hulling grains, pressing olives and seeds), mining and excavation (picking and shovelling, rock and ore crushing), or textile production (fulling cloth, preparing fibres, knitting and weaving). In all these examples, intermittent energy input does not affect the quality of the production process, only the production speed.
Many production processes are not strongly disadvantaged by an intermittent power supply.

Running these processes on variable power sources has become a lot easier than it was in earlier times. For one thing, wind power plants are now completely automated, while the traditional windmill required constant attention. [14]


Image: “Travailler au moulin / Werken met molens”, Jean Bruggeman, 1996.

However, not only are wind turbines (and water turbines) more practical and powerful than in earlier times, we can now make use of solar energy to produce mechanical energy. This is usually done with solar photovoltaic (PV) panels, which convert sunlight into electricity to run an electric motor.

Consequently, a factory that requires mechanical energy can be run on a combination of wind and solar power, which increases the chances that there's sufficient energy to run its machinery. The ability to harvest solar energy is important because it's by far the most widely available renewable power source. Most of the potential capacity for water power is already taken. [15]

Thermal Energy

Another crucial difference with pre-industrial times is that we can apply the same strategy to basic industrial processes that require thermal energy instead of mechanical energy. Heat dominates industrial energy use, for instance, in the making of chemicals or microchips, or in the smelting of metals.

In pre-industrial times, manufacturing processes that required thermal energy were powered by the burning of biomass, peat and/or coal. The use of these energy sources caused grave problems, such as large-scale deforestation, loss of land, and air pollution. Although solar energy was used in earlier times, for instance, to evaporate salt along seashores, to dry crops for preservation, or to sunbake clay bricks, its use was limited to processes that required relatively low temperatures.
We can apply the same strategy to basic industrial processes that require thermal energy instead of mechanical energy, which was not possible before the Industrial Revolution.

Today, renewable energy other than biomass can be used to produce thermal energy in two ways. First, we can use wind turbines, water turbines or solar PV panels to produce electricity, which can then be used to produce heat by electrical resistance. This was not possible in pre-industrial times, because there was no electricity.


Augustin Mouchot's solar powered printing press, 1882.

Second, we can apply solar heat directly, using water-based flat plate collectors or evacuated tube collectors, which collect solar radiation from all directions and can reach temperatures of 120 degrees celsius. We also have solar concentrator collectors, which track the sun, concentrate its radiation, and can generate temperatures high enough to melt metals or produce microchips and solar cells. These solar technologies only became available in the late 19th century, following advances in the manufacturing of glass and mirrors.

Limited Energy Storage

Running factories on variable power sources doesn't exclude the use of energy storage or a backup of dispatchable power plants. Adjusting demand to supply should take priority, but other strategies can play a supportive role. First, energy storage or backup power generation capacity could be useful for critical production processes that can't be halted for prolonged periods, such as food production.

Second, short-term energy storage is also useful to run production processes that are disadvantaged by an intermittent power supply. [16] Third, short-term energy storage is crucial for computer-controlled manufacturing processes, allowing these to continue operating during short interruptions in the power supply, and to shut down safely in case of longer power cuts. [17]


Binnenshaven Rotterdam, a painting by Jongkind Johan Berthold (1857)

Compared to pre-industrial times, we now have more and better energy storage options available. For example, we can use biomass as a backup power source for mechanical energy production, something pre-industrial millers could not do – before the arrival of the steam engine, there was no way of converting biomass into mechanical energy.
Before the arrival of the steam engine, there was no way of converting biomass into mechanical energy.

We also have chemical batteries, and we have low-tech systems like flywheels, compressed air storage, hydraulic accumulators, and pumped storage plants. Heat energy can be stored in well-insulated water reservoirs (up to 100 degrees) or in salt, oil or ceramics (for much higher temperatures). All these storage solutions would fail for some reason or another if they were tasked with storing a large share of renewable energy production. However, they can be very useful on a smaller scale in support of demand adjustment.

The New Age of Sail

Cargo transportation is another candidate for using renewable power when it's available. This is most obvious for shipping. Ships still carry about 90 percent of the world's trade, and although shipping is the most energy efficient way of transportation per tonne-kilometre, total energy use is high and today's oil powered vessels are extremely polluting.


Image by Arne List [CC BY-SA 2.0], via Wikimedia Commons

A common high-tech idea is to install wind turbines off-shore, convert the electricity they generate into hydrogen, and then use that hydrogen to power seagoing vessels. However, it's much more practical and energy efficient to use wind to power ships directly, like we have done for thousands of years. Furthermore, oil powered cargo ships often float idle for days or even weeks before they can enter a port or leave it, which makes the relative unpredictability of sailboats less problematic.
It's much more practical and energy efficient to use wind to power ships directly.

As with industrial manufacturing, we now have much better technology and knowledge available to base a worldwide shipping industry on wind power alone. We have new materials to build better and longer-lasting ships and sails, we have more accurate navigation and communication instruments, we have more predictable weather forecasts, we can make use of solar panels for backup engine power, and we have more detailed knowledge about winds and currents.


Thomas W. Lawson was a seven-masted, stell-hulled schooner built in 1902 for the Pacific trade. It had a crew of 18.

In fact, the global wind and current patterns were only fully understood when the age of sail was almost over. Between 1842 and 1861, American navigator Matthew Fontaine Maury collected an extensive array of ship logs which enabled him to chart prevailing winds and sea currents, as well as their seasonal variations. [18]

Maury's work enabled seafarers to shorten sailing time considerably, by simply taking better advantage of prevailing winds and sea currents. For instance, a journey from New York to Rio de Janeiro was reduced from 55 to 23 days, while the duration of a trip from Melbourne to Liverpool was halved, from 126 to 63 days. [18]

More recently, yacht racing has generated many innovations that have never been applied to commercial shipping. For example, in the 2017 America's Cup, the Emirates Team New Zealand introduced stationary bikes instead of hand cranks to power the hydraulic system that steers the boat. Because our legs are stronger than our arms, pedal powered 'grinding' allows for quicker tacking and gybing in a race, but it could also be useful to reduce the required manpower for commercial sailing ships. [19]


Speed sailing records are also telling. The fastest sailboat in 1972 did not even reach 50 km/h, while the current record holder -- the Vestas Sailrocket 2 -- sailed at 121 km/h in 2012. While these types of ships are not practical to carry cargo, they could inspire other designs that are.

Wind & Solar Powered Trains

We could follow a similar approach for land-based transportation, in the form of wind and solar powered trains. Like sailing boats, trains could be running whenever there is renewable energy available. Not by putting sails on trains, of course, but by running them on electricity made by solar PV panels or wind turbines along the tracks. This would be an entirely new application of a centuries-old strategy to deal with variable energy sources, only made possible by the invention of electricity.
Wind and solar powered trains would be an entirely new application of a centuries-old strategy to deal with variable energy sources.

Running cargo trains on renewable energy is a great use of intermittent wind power because they are usually operated at night, when wind power is often at its best and energy demand is at its lowest. Furthermore, just like cargo ships, cargo trains already have unreliable schedules because they often sit stationary in train-yards for days, waiting to become fully loaded.


Cardiff Docks, a painting by Lionel Walden, 1894

Even the speed of the trains could be regulated by the amount of renewable energy that is available, just as the wind speed determines the speed of a sailing ship. A similar approach could also work with other electrical transportation systems, such as trolleytrucks, trolleyboats or aerial ropeways.

Combining solar and wind powered cargo trains with solar and wind powered factories creates extra possibilities. For example, at first sight, solar or wind powered passenger trains appear to be impossible, because people are less flexible than goods. If a solar powered train is not running or is running too slow, an appointment may have to be rescheduled at the last minute. Likewise, on cloudy days, few people would make it to the office.


Solar PV panels cover a railway in Belgium, 2016. Image: Infrabel.

However, this could be solved by using the same renewable power sources for factories and passenger trains. Solar panels along the railway lines could be sized for cloudy days, and thus guarantee a minimum level of energy for a minimum service of passenger trains (but no industrial production). During sunny days, the extra solar power could be used to run the factories along the railway line, or to run extra passenger (or cargo) trains.

Consequences for Society: Consumption & Production

As we've seen, if industrial production and cargo transportation became dependent on the availability of renewable energy, we would still be able to produce a diverse range of consumer goods, and transport them all over the globe. However, not all products would be available all the time. If I want to buy new shoes, I might have to wait for the right season to get them manufactured and delivered.

Production and consumption would depend on the weather and the seasons. Solar powered factories would have higher production rates in the summer months, while wind powered factories would have higher production rates in the winter months. Sailing seasons also need to be taken into account.
If I want to buy new shoes, I might have to wait for the right season to get them manufactured and delivered.

But running an economy on the rhythms of the weather doesn't necessarily mean that production and consumption rates would go down. If factories and cargo transportation adjust their energy use to the weather, they can use the full annual power production of wind turbines and solar panels.


A Windmill at Zaandam, a painting by Claude Monet, 1871.

Manufacturers could counter seasonal production shortages by producing items 'in season' and then stocking it close to consumers for sale during low energy periods. In fact, the products themselves would become 'energy storage' in this scenario. Instead of storing energy to manufacture products in the future, we would manufacture products whenever there is energy available, and store the products for later sale instead.

However, seasonal production may well lead to lower production and consumption rates. Overproducing in high energy times requires large production facilities and warehouses, which would be underused for the rest of the year. To produce cost-efficiently, manufacturers will need to make compromises. From time to time, these compromises will lead to product shortages, which in turn could encourage people to consider other solutions, such as repair and re-use of existing products, crafted products, DIY, or exchanging and sharing goods.

Consequences for the Workforce

Adjusting energy demand to energy supply also implies that the workforce adapts to the weather. If a factory runs on solar power, then the availability of power corresponds very well with human rhythms. The only downside is that workers would be free from work especially in winter and on cloudy days.

However, if a factory or a cargo train runs on wind power, then people will also have to work during the night, which is considered unhealthy. The upside is that they would have holidays in summer and on good weather days.


Nachtelijk werk in de dokken (Night work at the docks), a painting by Henri Adolphe Schaep, 1856.

If a factory or a transportation system is operated by wind or solar energy alone, workers would also have to deal with uncertainty about their work schedules. Although we have much better weather forecasts than in pre-industrial times, it remains difficult to make accurate predictions more than a few days ahead.

However, it is not only renewable power plants that are now completely automated. The same goes for factories. The last century has seen increasing automation of production processes, based on computers and robots. So-called “dark factories” are already completely automated (they need no lights because there is nobody there).
It's not only renewable power plants that are now completely automated. The same goes for factories.

If a factory has no workers, it doesn't matter when it's running. Furthermore, many factories already run for 24 hours per day, partly operated by millions of night shift workers. In these cases, night work would actually decrease because these factories will only run through the night if it's windy.

Finally, we could also limit the main share of industrial manufacturing and railway transportation to normal working hours, and curtail the oversupply during the night. In this scenario, we would simply have less material goods and more holidays. On the other hand, there would be an increased need for other types of jobs, like craftsmanship and sailing.

What About the Internet?

In conclusion, industrial manufacturing and cargo transportation -- both over land and over sea -- could be run almost entirely on variable renewable power sources, with little need for energy storage, transmission networks, balancing capacity or overbuilding renewable power plants. In contrast, the modern high-tech approach of matching energy supply to energy demand at all times requires a lot of extra infrastructure which makes renewable power production a complex, slow, expensive and unsustainable undertaking.

Adjusting energy demand to supply would make switching to renewable energy much more realistic than it is today. There would be no curtailment of energy, and no storage and transmission losses. All the energy produced by solar panels and wind turbines would be used on the spot and nothing would go to waste.


Marina, a painting by Carol Popp de Szathmary, 1800s.

Admittedly, adjusting energy demand to energy supply can be less straightforward in other sectors. Although the internet could be entirely operated on variable power sources -- using asynchronous networks and delay-tolerant software -- many newer internet applications would then disappear.

At home, we probably can’t expect people to sit in the dark or not to cook meals when there is no renewable energy. Likewise, people will not come to hospitals only on sunny days. In such instances, there is a larger need for energy storage or other measures to counter an intermittent power supply. That's for a next post.

Kris De Decker. Edited by Jenna Collett.

Part of the research for this article happened during a fellowship at the Demand Centre, Lancaster, UK.
Related articles:

[1] Lucas, Adam. Wind, Water, Work: Ancient and Medieval Milling Technology. Vol. 8. Brill, 2006.

[2] Reynolds, Terry S. Stronger than a hundred men: a history of the vertical water wheel. Vol. 7. JHU Press, 2002.

[3] Hills, Richard Leslie. Power from wind: a history of windmill technology. Cambridge University Press, 1996.

[4] Paine, Lincoln. The sea and civilization: a maritime history of the world. Atlantic Books Ltd, 2014.

[5] One of the earliest large hydropower dams was the Cento dam in Italy (1450), which was 71 m long and almost 6 m high. By the 18th century, the largest dams were up to 260 m long and 25 m high, with power canals leading to dozens of water wheels. [2]

[6] Although windmills had all kinds of internal mechanisms to adapt to sudden changes in wind speed and wind direction, wind power had no counterpart for the dam in water power.

[7] This explains why windmills became especially important in regions with dry climates, in flat countries, or in very cold areas, where water power was not available. In countries with good water resources, windmills only appeared when the increased demand for power created a crisis because the best waterpower sites were already occupied.

[8] Tide mills were technically similar to water mills, but they were more reliable because the sea is less prone to dry out, freeze over, or change its water level than a river.

[9] Sieferle, Rolf Peter, and Michael P. Osman. The subterranean forest: energy systems and the industrial revolution. Cambridge: White Horse Press, 2001.

[10] Freese, Stanley. Windmills and millwrighting. Cambridge University Press, 1957

[11] Wailes, Rex. The English windmill. London, Routledge & K. Paul, 1954

[12] The global wind pattern is complemented by regional wind patterns, such as land and sea breezes. The Northern Indian Ocean has semi-annually reversing Monsoon winds. These blow from the southwest from June to November, and from the northeast from December to May. Maritime trade in the Indian Ocean started earlier than in other seas, and the established trade routes were entirely dependent on the season.

[13] Jenkins, H. L. C. "Ocean passages for the world." The Royal Navy, Somerset (1973).

[14] Windmillers had to be alert to keep the gap between the stones constant however choppy the wind, and before the days of the centrifugal governor this was done by hand. The miller had to watch the power of the wind, to judge how much sail cloth to spread, and to be prepared  to stop the mill under sail and either take in or let out more cloth, for there were no patent sails. And before the fantail came into use, he had to watch the direction of the wind as well and keep the sails square into the wind's eye. [11]

[15] Apart from electricity, the Industrial Revolution also brought us compressed air, water under pressure, and improved mechanical power transmission, which can all be valuable alternatives for electricity in certain applications.

[16] A similar distinction was made in the old days. For example, when spinning cloth, a constant speed was required to avoid gearwheels hunting and causing the machines to deliver thick and thin parts in rovings or yarns. [3] That's why spinning was only mechanised using water power, which could be stored to guarantee a more regular power supply, and not wind power. Wind power was also unsuited for processes like papermaking, mine haulage, or operating blast furnace bellows in ironworks.

[17] Very short-term energy storage is required for many mechanical production processes running on variable power sources, in order to smooth out small and sudden variations in energy supply. Such mechanical systems were already used in pre-industrial windmills.

[18] Leighly, J. (ed) (1963) The Physical Geography of the Sea and its Meteorology by Matthew Fontaine Maury, 8th Edition, Cambridge, MA: Belknap Press. Cited by Knowles, R.D. (2006) "Transport shaping space: the differential collapse of time/space", Journal of Transport Geography, 14(6), pp. 407-425.

[19] Rival teams rejected pedal power because they feared radical change, says Team New Zealand designer. The Telegraph, May 24, 2017.
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Restore the Night Trains in Europe

Restore the Night Trains in Europe


The French passenger association “Oui au train de nuit” (“Night trains yes!”) has compiled a report about European night trains: “Put the night trains back on track“. During the last five years, most of Europe’s night trains have disappeared, although they are popular with travelers and the only alternative to the airplane.

* The report was brought to our attention by Back on Track, a European coalition that supports cross-border rail and brings the latest news about international passenger travel in Europe. * Previously: High speed trains are killing the European railway network. * Picture taken from the back window of the night train Madrid – PortBou in 2013.
 Trains  NoTechMagazine
Non-Electric Hearing Aids Outperform Modern Devices

Non-Electric Hearing Aids Outperform Modern Devices


Most people with hearing problems are not using hearing aids, mainly because the electronic devices often do not provide enough benefit. Research shows that non-electric hearing aids from earlier centuries are performing significantly better.

Digital Hearing Aids
Roughly 40% of people between the ages of 55 to 74 suffer hearing loss. Eighty percent of them do not wear a hearing aid, even though their disability often has a negative impact on their quality of life as well as others around them. According to a 2013 research paper, the main reason is the limited performance of the devices.

Interestingly, these results are in line with those of studies performed at the end of the twentieth century, meaning that the introduction of digital hearing aids has had no positive effect on the popularity of the technology. Electric hearing aids consist of a battery, a microphone, an amplifier and a speaker. The more compact electronic hearing aids also contain a microchip.

An additional obstacle in poorer countries is the cost of the technology, which concerns the device as well as the batteries, which need to be replaced regularly. Worldwide, roughly 1 billion people suffer from hearing loss. According to the World Health Organisation, only one fifth of them wears a hearing aid.

Ear Trumpets & Speaking Tubes
From the seventeenth century onwards, several types of non-electric hearing aids were developed, based on different acoustical principles. The most important devices were ear trumpets and speaking tubes.

An ear trumpet

In the ear trumpet, sound from a funnel-shaped metal tube was conducted to a small opening that was inserted in the listener’s ear. Ear trumpets were often slighty curved at one end so that they could be aimed at the sound source more easily. Some models were collapsible for easy carrying.

The speaking tube consisted of a flexible tube with a funnel-shaped opening on one end through which the speaker could talk, while the other end of the tube was put in the ear of the listener.

Stationary Hearing Aids
Speaking tubes and ear trumpets were also combined, especially in stationary hearing aids such as the acoustical chair. This seating had a pair of large trumpets on each side, which amplified the sound and led it through flexible tubes to the listener’s ears.

Similar technology could also be hidden in objects like vases. This was meant for several speakers and listeners gathering around a table. In the days before the telephone, speaking tubes were also used by people with normal hearing to communicate between floors of a building or a ship.

Sound Amplification
Measurements from the late twentieth century show that these devices perform better than today’s high-tech hearing aids. Ear trumpets and speaking tubes not only yielded a sound amplification of 10 to 25 decibels, they also suppressed sounds that came from other directions, further improving their workings. The speaking tube also reduced the noise reduction between speaker and listener.

A speaking tube

Another important advantage was that both devices were very visible and thus encouraged the speaker to talk slower and more clearly. However, this visibility was also considered to be a problem: well-functioning, non-electric hearing aids are laughable.

From the nineteenth century onwards, the development of hearing aids took another direction: much smaller ear trumpets and speaking tubes were now hidden in clothing and accessories.

The most popular models were worn as a kind of headband, with small trumpets hidden behind the ears, in hats, wigs, beards or scarfs. An extra advantage was that these devices could be operated hands free. Unfortunately, these hearing aids had poor performance compared to earlier models, and sometimes even impaired hearing.

However, a new trend was set. Since the nineteenth century, the main criterium for a hearing aid is no longer its effectivity but its discretion and compactness. Nevertheless, those who can overcome their vanity can revert to technology that has proven to work.

A large collection of images showing non-electric hearing aids can be found at the Bernard Becker Medical Library Image Gallery.

 Health  Random  NoTechMagazine
Vietnam's Low-tech Food System Takes Advantage of Decay

Low Tech Magazine
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Vietnam's Low-tech Food System Takes Advantage of Decay
Vietnam's Low-tech Food System Takes Advantage of Decay

Imatge/fotoThe food system in the industrialised world is based on mass-production, global distribution, and constant refrigeration. It requires many resources and produces a lot of food waste.

Aaron Vansintjan takes to the streets of Hanoi, where the Vietnamese practice a food culture based largely on fermentation.

Although food spoils much faster in a tropical climate, the Vietnamese will often store it without refrigeration, and instead take advantage of controlled decay. Vietnam's decentralised food system has low energy inputs and reduced food waste, giving us a glimpse of what an alternative food system might look like.

Picture: Street food in Hanoi, Vietnam. Maxime Guilbot.
In a tropical climate, everything decays faster. Bread gets soft and mushy, milk spoils, the walls get moldy just months after a layer of fresh paint. Food poisoning is a constant concern. The heat and moisture make for an ideal breeding ground for bacteria and fungi. In this environment, you’d think people would be wary of any food product that smells funny. But in tropical Vietnam, food can get pretty pungent.

Take mắm tôm, a purplish paste made of fermented pureed shrimp. Cracking open a jar will result in a distinct smell of ‘there’s something wrong here’ with hints of marmite to whelm through the whole room. You have chao, a stinky fermented tofu, which was so rank that the smallest bite shot up my nose and incinerated my taste buds for an hour (‘Clears the palate!’ said the waiter encouragingly).

Consider rượu nếp, which is sticky rice mixed with yeast and left to ferment for several days ‘in a warm place’ — i.e. the counter. The result is a funky-smelling desert—literally rice left to rot until it turns in to a sweet wine pudding. On the 5th of May of the lunar calendar, Vietnamese people will eat rượu nếp in the morning to celebrate ‘inner parasite killing day’. Bonus: day-drunk by the time you arrive at work.

We shouldn’t forget Vietnam’s world-famous fish sauce — nước mắm — made from diluted fermented fish, a flavour that many people around the world continue to find totally intolerable.

Imatge/fotoA stall selling homemade dưa chua in a Hanoi market. Picture: Aaron Vansintjan.

In Vietnam, putrefaction is accepted as a part of life, even encouraged. But fermentation in Vietnam isn’t just an odd quirk in a tropical diet. To understand why fermentation is so integral to Vietnamese culture, you have to consider how it is embedded within people’s livelihoods, local agricultural systems, food safety practices, and a culture obsessed with gastronomy; where food is seen as a social glue. And when you bring together all these different puzzle pieces, an enchanting picture emerges: one in which fermentation can be a fundamental component of a sustainable food system.

Unlike many high-tech proposals like ‘smart’ food recycling apps, highly efficient logistics systems, and food packaging innovations, fermentation is both low-tech and democratic—anyone can do it. What’s more, it has low energy inputs, brings people together, is hygienic and healthy, and can reduce food waste.

Rotting Food can be Safe and Healthy
At the entrance of a market in Hanoi, a woman with a dưa chua stand tells us that making ‘sour vegetables’ is easy: you just add salt to some cabbage and let it sit for a couple of days. As we talk, several customers come by, eager to scoop some brine and cabbage into a plastic bag. Worried that we’re discouraging her customers, she shoos us away. She isn’t lacking business.

Is fermentation really so effortless? The short answer is yes. Many recipes will call for two things: water and salt. At just a 1:50 ratio (2%) of salt to food, you can create an environment undesireable for all the bad bacteria and encourage all the good ones. Sauerkraut, kimchi, fish sauce, sriracha, and kosher dill pickles—are all made according to this principle.

Yet other types of fermentation are a bit more complicated. They call for sugar (e.g. wild fermented alcohol like ethiopian honey wine), yeast starters (rượu nếp, most wines and beers), special fungi (tempeh, miso), or some kind of combination of fungi, bacteria, salt, or sugar (kombucha). Yet others are simpler: to make cooking vinegar, just let that bottle of bad wine sit for a couple of days, and to make sourdough, just mix water and flour and leave it on your counter.
Fermentation is both low-tech and democratic. It can be a fundamental component of a sustainable food system

All in all, fermentation is just controlled decay: your most important ingredient is time. This can sound like a bit too much, too fast. Take the woman I met at the entrance of the market. Her dưa chua, while in great demand, looks like wilted cabbage, soppy, floating in murky brine. Some bubbles are forming on the edges of the plastic container—for the trained eye a sign of an active fermentation process, but for the uninitiated, an alarm bell.

There’s no use beating about the bush. That dưa chua is in fact rotting in a very similar way that a peat swamp is constantly rotting, belching large doses of methane into the world. What’s happening is an anaerobic fermentation—that is, without significant amounts of oxygen. This absence of oxygen and the high levels of salt creates an environment supportive to several bacteria that also find their home in our own digestive systems.

Those bubbles forming in the container are by-products of these bacteria: CO2 and methane. The bacteria also lower the pH and start breaking down raw food—essentially pre-digesting it for you. And, once the pH goes down even lower, you’ve created a monster so voracious that no other fungus, bacteria, or parasite with bad intentions will dare to enter its domain. So yes, it’s rotting just like a stinky swamp, and that’s a good thing.

Imatge/fotoA woman sells nem chua—raw fermented pork—outside her house. Picture: Aaron Vansintjan

It’s a good thing especially in a climate like that of Vietnam. Every fermentation is a small victory against the constant war against heat and humidity, which destroys all edibles in its path. Instead of eating raw cabbage and risking death by a thousand E. Coli, you can eat fermented cabbage and know, for a fact, that it won’t have you hunkering by the toilet bowl any time soon.

Not only that, but eating fermented food has significant health benefits. You might’ve noticed the new fad of ‘pro-biotic’—well all that really means is that the product contains some kind of active bacterial culture that looks like the flora in your own stomach. That would include, not just Go-gurt, Yoplait, Chobani, and Danone, but also several kinds of cheese, pickles, beer, and just about any other fermented product.

Eat about a tablespoon of any of these at the end of every meal, and you inoculate your stomach with a fresh batch of microbes that help you digest—all the more necessary when we eat antibiotics in our meat and bland diets of white bread and peanut butter, and drink chlorine in most municipal water systems.

Further, products like fish sauce and shrimp paste provide many impoverished Vietnamese with micro-nutrients, B-12 vitamin, proteins, and omega 3 fatty acids—comprising a significant part of people’s nutritional requirements. For a country that still remembers hunger and starvation, this is no small fry.

A Diverse Food System
In the same market we talk to a vegetable vendor. Real estate in the neighborhood is getting more expensive, rents are going up. She’s having a hard time making ends meet. On her street many elderly have sold their farmland—which they used to grow vegetables and decorative flowers—and now, unemployed, they spend their time selling home-made fermented vegetables out of their front door.

In the same neighborhood, we meet Tuan, an elderly woman growing vegetables in the banks of a drained pond. She rarely goes to the market—she can grow much of her own food in this little patch. We ask her if she ever ferments her vegetables. Of course, but she doesn’t sell them—they’re just for herself and her family.
If you want a localised food system, you need to be able to store your food for long periods. Fermentation makes that possible.

After several months of studying Hanoi’s food system and the people who make their living off of it, Vân (my Vietnamese collaborator) and I are starting to see some patterns. In Western countries, the food system is shaped a bit like an hourglass: industrial farmers send their food to a supplier, who then engages with a handful of supermarket companies, who then sell to consumers.

In Vietnam, on the other hand, it looks more like an intricate web: wholesale night markets, mobile street vendors, covered markets, food baskets organized by office workers with family connections to farmers, guerilla gardening on vacant land. Food is grown, sold, and bought all over the place, and supermarkets are just a small (albeit growing) node in the complex latticework. Most people still get food at the market, but many also source their food from family connections.

Imatge/fotoA restaurant offers homebrewed rượu men, Vietnamese rice wine. Picture: Aaron Vansintjan

In Vietnam, many people might have one ‘profession’, but when you ask a bit more questions it’ll turn out that they have half a dozen other jobs for ‘extra income’. There’s a generalised ‘hustle’: everyone is a bit of an entrepreneur. After talking with Tuan for several hours, we learned that she has, throughout her long life, fished, grown vegetables, corn, and fruit trees, sold rice noodles, bread, ice cream, roses, and silk worms. Now, aged 68, she grows decorative peach trees and grows vegetables when she can.

With an economy just decades shy of a highly regulated communist regime where the only food you could get was through rations, and the memory of famine still fresh in people’s mind, this is entirely understandable: with a finger in every pot, you can just about manage to survive. These two factors, a highly distributed food system and diversified livelihoods, make for a fertile environment for fermentation practices. With easy access to wholesale produce, many can turn to small-scale fermentation to compliment their income—or, in the case of Tuan, to spend less on food at the market.

Preserving the Harvest, Bringing People Together
Vietnam hosts both the Red River delta and the Mekong delta—two of the most productive agricultural regions in the world. The heat and the vast water supply allow some areas of Vietnam to have three full growing seasons. That means three harvests, and that means lots of food at peak times, and sometimes so much that you can’t eat it all. That’s another bonus of fermentation: if your food system is local, you’re bound to stick to seasonal consumption. But by fermenting your harvest you can eat it slowly, over a long time period. It’s this principle that underlies much of fermentation culture in East Asia.

Take kim chi, a spicy fermented cabbage from Korea. Traditionally, the whole village would come together to chop, soak, salt, and spice the cabbage harvest every year. Then, these mass quantities of salted spicy cabbage were stored in large earthenware pots underground—where cooler temperatures lead to a more stable fermentation process. As a result, you can have your cabbage all year. If you want a localised food system, you need to be able to store your food for long periods. Fermentation makes that possible.
Food fermentation is a strange thing: it inverts what many regard as waste and turns it into a social, living, edible object.

Fermentation is also social. Fermenting large batches of summer’s bounty typically requires hours of chopping—the more the merrier. And chopping is the perfect time for sharing cooking tips, family news, and the latest gossip. In South Korea, now that kim chi production has been largely industrialized, people try to relive the social aspect of making it through massive kim chi parties in public spaces.

Imatge/fotoCutting open nem chua a week later. I’m not dead yet. Picture: Aaron Vansintjan

In a country like Vietnam, where a traditional food system still exists for a large part, fermentation remains embedded in social relations. Relatives and neighbors constantly gift each other fermented vegetables, and many dinners end with a batch of someone’s homebrewed rice wine—rượu men. Fermentation lends itself well to a gift economy: there is pride in your own creation, but there is also no shame in re-gifting. And because of its low costs, anyone can take part in it.

Gastronomy, Tested with Time
It is a bit disingenuous to caricature Vietnam’s food culture as obsessed with rotting, and suggest that this is largely the result of a tropical climate. Rather, what we’re dealing here is difference in taste: what may seem strange and pungent to one culture is highly appreciated in another. In fact, one of the greatest impressions I have of Vietnamese culture is its deep appreciation for gastronomy: subtle, complex flavours, considered textures, modest spicing and well-balanced contrasts define Vietnamese cuisine.

Fermentation is a crucial part of this culture: the art of fermentation requires paying attention to how flavours change as food transforms, understanding these chemical shifts and using them to achieve a desired affect. It’s also clear that Vietnamese gastronomy is popular: it takes place in street food stalls, run by enterprising matriarchs, constantly experimenting with modern products and traditional flavors. It is cheap and, to ensure customer loyalty, it is surprisingly hygienic.

Street vendors rarely have fridges, nor do they have large cooking surfaces, dishwashing machines, or ovens. By and large, they make do with some knives, two bowls to wash fresh vegetables in, a large pot, a frying pan, coals or gas burners and — for products that may go bad during the day — fermentation. Having limited access to capital and consumer electronics, these vendors — most often women — ply their trade in a way that has stood the test of time.

They know the rules of hygiene and food safety, and, because they have to be careful with their money, they know exactly what kinds of food will go bad, and what kinds of food can be preserved. In doing so, they practice a food culture that has been passed down through generations—to a time before fridges, a global food system powered by container shipping, factory trawlers, and produce delivered to far-off markets by airplane.

Imatge/fotoFresh dưa chua at a street stall, sold next to fermented garlic and figs. Picture: Aaron Vansintjan

While modern technology has provided many benefits for our diets, there are many innovations from the past that have been abandoned as the global food system was transformed by the availability of cheap fuel. One such innovation was the fish sauce industry that flourished during Ancient Roman times. For Romans, fermenting fish was a crucial aspect of a low-tech and seasonally-bound food system. In fact, it so happens that research now suggests Vietnamese fish sauce may actually have its origins in the Roman variant produced over 2,000 years ago.

Today, however, fermentation doesn’t fit so easily within the global food system. Harold McGee at Lucky Peach tells the story of how canned products were notoriously difficult to transport in the newly industrialized food system of the 19th century. Apparently, until the 20th century, metal cans would regularly explode, sending shrapnel and preserved tuna flying through the decks of transport ships. This was due to heat-resistant bacteria, which continued fermenting the product long after it was heat-treated.
Fermented food has to be produced locally: transporting it will risk explosions on the high seas

The solution was to subject the canned product to high temperatures over a long period of time, killing all remaining cultures, in turn changing their flavor. But in the case of fermented food, the problem has not gone away: if you want it to be actively fermenting, transporting it will risk explosions on the high seas. But heating stops the fermentation process, and kills its unique flavor.

It’s for this reason that products like kim chi, kombucha, and sauerkraut often have to be produced locally, despite increasing global demand. In some way, fermentation belies the industrial food system: the fact that it is alive means that it doesn’t quite fit in. You either have to kill it, thereby change it, or it will keep bubbling through the cracks.

A Low-tech Food System is Possible
Fermentation cultures in Vietnam give us a glimpse of what an alternative food system might look like, one that is both decentralized and doesn’t depend on high inputs of fossil fuel energy to preserve food, high waste, and high-tech. Why does this matter? Well, in a world facing climate change, we need a low-impact food system, and fast.

But there are other reasons: with increasing concern over the health side effects of common chemicals such as BPA, found in almost all cans and pasta sauce jars, people are looking to safer kinds of preservation, which aren’t killing them and their families slowly. And with the rise of the local food and food sovereignty movements, many are realising that we need food systems that support everyone: from small farmers to low-income families.

Because of its low investment costs, fermentation lends itself well to supporting small businesses, allowing them to take advantage of seasonality while practicing a time-tested low-tech method of food preparation. Today, in response to increasing food insecurity, we are hearing increasing calls for a smarter, more efficient food system. Proposals such as intensive hydroponic and vertical farming, big data-powered logistics systems, smart agriculture technologies, and food waste recycling apps clog the news.

But we already have a low-tech innovation that works very well. Fermentation, because it is accessible to everyone, because of its low energy requirements, and because it fits right in to a more sustainable food system, should not be abandoned in the search for global food security.

Imatge/fotoA fish sauce factory in Vietnam. Source: Mui Ne info & events.

It’s easy to get the impression that we live in a world of scarcity, where there just isn’t enough food to go around, and food production all around the world is limited by technological backwardness. On the other hand, many of us are more and more concerned with the increasing problem of food waste in Western food systems. We seem to live in a world of both scarcity and abundance at the same time.

Food fermentation is a strange thing: it inverts what many regard as waste and turns it into a social, living, edible object. As a friend of mine once said, if you have too many grapes, you make wine. If you have too much wine, you throw a party. If you still have too much wine, you make vinegar. Fermentation turns scarcity and abundance on its head, belying easy categories of what is waste and what is too much.

Sustainability advocates worry a lot about making the ‘supply chain’ more ‘efficient’ — that is, increasing profits margins while making sure all food reaching consumers in a perfectly fresh state. Instead, we could consider taking advantage of decay. This isn’t hard: you just have to add some salt and water. We’ve done it for thousands of years, and, if we follow the example of food cultures like those in Vietnam, we can do it again.

Aaron Vansintjan
Related articles:
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#Agriculture #Cooking #Cover story  #Gardening  #Low-tech solutions
Heat Storage Hypocausts: Air Heating in the Middle Ages

Low Tech Magazine
  últim editat: Mon, 31 Jul 2017 12:51:14 +0200  
LOW-TECH MAGAZINELOW-TECH MAGAZINE va escriure el següent entrada Tue, 07 Mar 2017 15:25:13 +0100
Heat Storage Hypocausts: Air Heating in the Middle Ages
Heat Storage Hypocausts: Air Heating in the Middle Ages

Hot air vents in the floor of the Maulbronn monastery. Source: "Das Kloster Maulbronn. Geschichte und Baugeschichte.", Ulrick Knapp, 1997 / Via Spiegel 2016.

The Romans are credited with the invention of the first smoke-free heating system in Western Europe: the hypocaust. Until recently, historians had assumed that its technology was largely lost after the collapse of the Roman Empire. In fact, however, it lived on in large parts of Europe, and was further developed into the “heat storage hypocaust”, an underground furnace on top of which granite stones would be piled, to then release hot air through vents in the floor. By this means, a room could be kept warm for days with just one firing of the hypocaust's furnace.

Hypocausts were heating systems that distributed the heat from an underground fire throughout a space beneath the floor. The heat was absorbed by the floor and then radiated into the room above. The effect on thermal comfort must have been similar to that of a modern-day hot water or electricity-based radiant floor heating system. The Roman hypocaust was characterised by its under-floor flue passages, created by small pillars bearing the floor's paving slabs. Sometimes, the heat was also fed through cavities in the walls before escaping from the building, thereby warming up the walls, too.

The Romans were not the first to develop a heating system in which the heat from a fire was fed under the floor from one side of a room to the other. The Chinese kang and dikang, the Korean ondol and the Afghan tawakhaneh were based on similar principles and date back to even earlier times. What's more, the Romans probably learned the technology from the Greeks. Nevertheless, it was the Romans who developed the hypocaust into a more sophisticated heating system, especially in their public bath houses, which were built all across Europe and around the Mediterranean.

Imatge/fotoRemains of a Roman hypocaust. Wikipedia Commons.

For a long time, historians believed that the fall of the Roman Empire in around 500 AD marked the start of a hiatus in Europe's use of smoke-free heating. Nevertheless, although most public baths fell into disrepair in the Western Roman Empire, hypocausts continued to be built and used in the Early Middles Ages, especially in monasteries. The technology also lived on in the Eastern Roman (Byzantine) Empire and was adopted in the hammams of the Arabs, who reintroduced the hypocaust to Western Europe when they built the Alhambra palace in the 13th century. [1]

Smaller and cheaper systems, using ducts instead of pillars, also continued to be used, especially in smaller buildings. These hypocausts only heated part of the floor, but were much easier to build. We found just such a hypocaust in a remote village in Spain, which is still in use today.

Heat Storage Hypocausts

With the spread of Christianity and its monasteries to Northern Europe, the Roman hypocaust proved too inefficient for the region's colder climes. The first half of the 14th century, or possibly even earlier, saw the start of the practice of piling up granite stones on the top of the furnace vault to accumulate heat. [1, 2] Far from a simplified medieval imitation, the heat storage hypocaust represented a further stage in the development of this ancient technology. [3]
When the firing was complete, the vents in the hot plate were opened and hot air rose from the pile of stones into the room to be heated.

Unlike the Roman hypocaust, which was based on radiant heating, the heat storage hypocaust provided convective heating. The room to be heated featured a perforated “hot plate” above the pile of granite stones. Its perforations remained closed while the fire was burning, so that the smoke was kept out of the room and could escape through the chimney or a cavity in the wall. When the firing was complete and the furnace had been cleaned, the smoke flue was closed by means of a damper, the vents in the hot plate were opened and hot air rose from the pile of stones into the room. [2, 3]

Imatge/fotoA heat storage hypocaust. Source: K. Bingenheimer, 1998

Imatge/fotoAir vents in the floor of the Malbork castle in Poland. Picture: Robert Young. The hot air vents were usually round in shape and 10 to 12 cm in diameter.

Because of their poor heat storage capacity, Roman hypocausts had to be fired continuously. Adding a stone chamber to create the heat storage hypocaust made it easier to accumulate heat, meaning it was no longer necessary to keep the furnace constantly lit. In 1822, a number of experiments were conducted to establish the effectiveness of a then 400 year-old heat storage hypocaust in Poland's Malbork Castle. One such experiment involved heating the castle's 850 square-metre banqueting hall. [1-3]

A Weekly Fire

On 3 April, a cold furnace was lit for three and a half hours using 0.7 cubic metres of spruce wood. When the vents in the hot plate were opened, hot (200 ºC) air rushed into the banqueting hall, raising its temperature from 6 to 22.5°C in just 20 minutes. The air vents were then closed. By the following morning (4 April), the room's air temperature had fallen to 14°C. The air vents were opened and the temperature rose to 19°C in one hour–without any additional fire being lit.
A full six days after the fire was extinguished, the air rising from the vents had a temperature of 46°C

On 5 April, the temperature of the air escaping through the vents was 94°C and the room temperature rose from 10 to 16°C in half an hour. On 6 April, three days after the fire was extinguished, the air was still hot enough to raise the room's temperature from 10 to 12°C. Even on 9 April, a full six days later, the warm (46°C) air rising from the vents managed to lift the temperature in the hall from 8 to 10°C.

During his 1438 trip through Europe, the Spanish traveller Pero Tafur wrote that people placed "seats above the holes, also with holes in them. The people then sit down on those seats and unstop the holes and the heat rises between the legs to each one". [3] This is reminiscent of the footstoves used in Northern Europe during the Middle Ages.


Above: The heat storage hypocaust in the Malbork castle in Poland. Source: J. Kacperska.

Imatge/fotoA heat storage hypocaust in Tallinn's town hall. Source: Kaarel Truu, 2016.

Baltic Sea Region

The heat storage hypocaust was mainly used in the Baltic Region–Northern Germany, Denmark, Sweden, Finland, Estonia, Latvia, Lithuania, and Poland. To a lesser extent, they have been found further to the south and east, in places such as Western and Southern Germany, Switzerland, Austria, the Czech Republic, Hungary and Russia. Most were built in the 1400s and 1500s. [1]

Research into the history of heat storage hypocausts continues today. In his groundbreaking 1998 study, Klaus Bingenheimer estimated that Medieval Europe boasted a total of 500 hypocausts, of which 154 were of the heat storage variety. [4] Since then, however, many more have been discovered. For example, while Bingenheimer had evidence for only two heat storage hypocausts in Estonia, a 2009 paper by Andres Tvauri listed 95 heat storage hypocausts, either still standing or whose location had been documented. [2]
According to the latest estimates, there must have been at least 800-1,000 heat storage hypocausts around the Baltic Sea

In total, around 500 heat storage hypocausts have now been documented in the Baltic Region and, according to the latest estimates, there must have been at least 800-1,000 of them by the end of the 15th century [1], their use spreading from monasteries and castles to other public buildings, such as almshouses, town halls, guildhalls and hospitals. In Old Livonia, which covered present-day Estonia and Latvia, the technology also found its way into private homes. In Tallinn, Estonia's capital, a heat storage hypocaust was not the exception, but the rule, and at least 54 such systems have been discovered there. [2]

Hypocausts in Tallinn

Andres Tvauri's overview of the heat storage hypocaust in Estonia, one of the few available resources in English language, provides a wealth of technical details. Special covers or plugs, made of metal, stone or fired clay, were made to seal the hot air vents in the floor's “hot plates”. Small ceramic dishes have been found, placed on the hot stones directly under these venting holes. It is assumed that water was poured on them, to produce steam and thereby increase the air humidity level. [2]



Remains of heat storage hypocausts in Tallinn, Estonia. Source: [5] Kaarel Truu, 2016. In Tallinn's homes, the subterranean stoker's room of the hypocaust and the heated bedroom on the ground floor were usually connected by a flight of stairs.

The furnace was covered with a barrel vault on which the stones, with diameters of 40 to 50 cm, were piled to accumulate heat. The vault's bricks were laid to form three or four arches, with intervals of about 20 cm between them and medieval builders probably used an old vat in helping to shape the arches of the vault. When the furnace was completed, a fire was built in the vat.

A furnace's dimensions would depend on the size of the room to be heated. In private homes, where only the bedroom was heated, it would be one to two metres long, a little more than a metre wide and 50 to 60 cm high. In public buildings and monasteries, where large halls and rooms had to be heated, the furnaces would be much larger.

Tile Stoves

Heat storage hypocausts were only used for a fairly short period of time. By the fifteenth century, glazed tile stoves were already spreading through the Baltic countries. The tile stove is a radiant heating system with an interior maze of brick or stone channels designed to accumulate a fire's heat. It was more convenient to use and to build than the hypocaust, not to mention more energy efficient, as it takes less energy to heat people than to heat spaces.

Although it was possible to heat at least two separate rooms by means of one furnace, as a rule, the hypocaust was located under the heated room or rooms, which were always on the ground floor. Tile stoves could be built anywhere, even on a building's upper floors. Over the course of the 16th century, Old Livonia stopped using the heat storage hypocaust, which was replaced by a glazed tile stove, often built exactly where the hypocaust's furnace had previously stood. Elsewhere, in Poland for example, some heat storage hypocausts remained in use until the 18th and 19th centuries.

Kris De Decker. Edited by Roly Osborne.

[1] Spiegel, T. "Die mittelalteriche Luftheizung der Zisterzeiner-Klosters Doberan im Kontext der Entwicklung der vormodernen Heiztechnik", 2016

[2] Tvauri, A. "Late Medieval Hypocausts with Heat Storage in Estonia. Andres Tvauri. 2009. Baltic Journal of Art History", 2009.

[3] Atzbach, R. "The ‘Stube’and its Heating. Archaeological Evidence for a Smoke-Free Living Room between Alps and North Sea". Svart Kristiansen, M. & Giles, K.(red.)." Dwellings, Identities and Homes. European Housing Culture from the Viking Age to the Renaissance (2014).

[4] Bingenheimer K. "Die Luftheizungen des Mittelalters. Zur Typologie und Entwicklung eines Technikgeschichtlichen Phänomens", 1998

[5] Truu, K. "Keskaegsed kerishüpokaustid Tallinna vanalinnas", 2016

Imatge/foto Imatge/foto Imatge/foto Imatge/foto Imatge/foto Imatge/foto
Hello Zot World and Fediverse!

Low Tech Magazine
This is an authorized republish of the two online magazines Low Tech Magazine and No Tech Magazine. The first one publishes extensive research on degrowth and ancient technologies, from power sources to transportation, from Ancient Chine to today's Netherlands. The second one publishes more often but with shorter stories, news or thoughts.

This is all work from Kris de Decker, which is not "me".

So, from now on, this channel will automatically republish the posts from both websites, and from time to time I will share older posts, which don't get reposted alone. For instance, the first post, "Digital colonialism", is an automatic republish. On the other hand, "Could we Run Modern Society on Human Power Alone?" is an older post republished manually. Therefore, don't expect linear chronology.

Have a good reading!
Could We Run Modern Society on Human Power Alone?

Low Tech Magazine
LOW-TECH MAGAZINELOW-TECH MAGAZINE va escriure el següent entrada Sun, 28 May 2017 19:18:19 +0200
Could We Run Modern Society on Human Power Alone?
Could We Run Modern Society on Human Power Alone?


Unlike solar and wind energy, human power is always available, no matter the season or time of day. Unlike fossil fuels, human power can be a clean energy source, and its potential increases as the human population grows. In the Human Power Plant, Low-tech Magazine and artist Melle Smets investigate the feasibility of human energy production in the 21st century.

To find out if human power can sustain a modern lifestyle, we are designing plans to convert a 22 floors vacant tower building on the campus of Utrecht University in the Netherlands into an entirely human powered student community for 750 people. We're also constructing a working prototype of the human power plant that supplies the community with energy.

The Human Power Plant is both a technical and a social challenge. A technical challenge, because there's a lack of scientific and technological research into human power production. A social challenge, because unlike a wind turbine, a solar panel or an oil barrel, a human needs to be motivated in order to produce energy.

Image: A human powered student room. Golnar Abbasi.
The Rise and Fall of Human Power
Throughout most of history, humans have been the most important source of mechanical energy. Building cities, digging canals, producing food, washing clothes, communication and transportation: it all happened with human muscle power as the main source of energy. Human power was complemented with animal power, and windmills and watermills became increasingly important from the middle ages onwards. Most work, however, we carried out ourselves.

These days, human power plays virtually no role anymore. We have automated and motorised even the smallest physical efforts. Mechanical energy is now largely provided by fossil fuels, either as a primary fuel or converted to electricity. This 'progress' comes at a price. Industrial society is totally dependent on a steady supply of fossil fuels and electricity, which makes it very vulnerable to an interruption in this supply.

Imatge/fotoDigging the Panama Canal. Picture: National Archives.

Furthermore, fossil fuels are not infinitely available and their large-scale use causes a host of other problems. On the other hand, renewable energy sources such as wind and solar power are not always available, and their manufacturing is also dependent on fossil fuels. Meanwhile, in order to keep in shape and stay healthy, people go to the gym to exercise, generating energy that's wasted. The Human Power Plant wants to restore the connection between energy demand and energy supply.

Why Human Power?
Compared with fossil fuels and renewable energy sources, human power has a lot of advantages. A human can generate at least as much power as a 1 m2 solar PV panel on a sunny day -- and as much as 10 m2 of solar PV panels on a heavy overcast day. Human power is a dispatchable energy source, just like fossil fuels. Its power output is not dependent on the season, the weather or the time of the day. In fact, humans can be considered renewable energy sources and batteries at the same time.

Unlike fossil fuels, human power can be a clean energy source, which produces little or no air pollution and soil contamination. Moreover, the potential of human power increases as the human population grows, while all other energy sources need to be shared among an ever-growing amount of people. Furthermore, unlike solar panels, wind turbines, and batteries, humans don't need to be manufactured in a factory. In combination with the right diet, human power is carbon neutral.

The potential of human power increases as the human population grows, while all other energy sources need to be shared among an ever-growing amount of people.

Finally, humans are all-round power sources, just like fossil fuels. They not only supply muscle power that can be converted to mechanical energy or electricity, but also thermal energy, especially during exercise: a physically active human being can generate up to 500 watts of body heat. Furthermore, human waste can be converted to biogas and fertiliser. Arguably, human power is the most versatile and most sustainable power source on Earth.

Imatge/fotoDetail from the communal shower and laundry floor. Image: Golnar Abbasi.

Modern technology has greatly improved the potential of human power production. On the one hand, many electric devices have become very energy efficient. For example, solid state lighting consumes roughly ten times less power than old-fashioned lightbulbs, so that a quick workout can supply many hours of light. On the other hand, we now have much better technology for human power production, ranging from sophisticated exercise machines to biogas power plants.

Lessons from the Gym
The power output of a human being is determined by three factors: the person, the duration of the effort, and the mechanical device that is used to convert human power into useful energy -- human power generation is often a symbiosis between man and tool or machine. Our legs are roughly four times stronger than our arms, which means that a human on a stationary bicycle machine can produce more power (75 to 100 watts) than a human operating a small hand crank (10 to 30 watts).

During shorter efforts, the mechanical power output of a human being can increase substantially: up to 500 watts on a bicycle and up to 150 watts while operating a hand crank over a period of one minute. However, age, gender and fitness also play an important role. Athletes can generate more power for a longer period of time -- up to 2,000 watts during three seconds, or up to 400 watts during one hour. So far the theory, which is far from complete.
Exercise machines for strength training are an interesting addition to stationary cycling machines for human power production.

During the research phase for the Human Power Plant, we followed a fitness programme to become better human power sources. This was a very instructive experience. One of the first things we learned is that there are important differences between individuals, even if they have similar age, gender and fitness.


Melle, the powerhouse in our team, could lift a heavier weight on almost any exercise machine. Kris, on the other hand, appeared to have better endurance, and could beat Melle with triceps and shoulder exercises. Such differences should be taken into account in order to achieve optimal energy production - there is no ready-made solution.

We also found out that exercise machines for strength training can produce a lot of power in a very short time, making them an interesting addition to stationary cycling machines for human power production. A five minute workout (including two breaks of one minute each) can supply more than 15 Wh of electricity, enough to charge a quarter of a laptop's battery or to power a desk lamp for 3 hours.

Finally, we quickly discovered that gyms are pretty boring places. The exercise equipment is often positioned in such a way that people all look in the same direction, which excludes all but the most primitive communication. And, while a stationary bicycle is considered to be the most energy-efficient human power machine, we found out that stationary cycling is no fun at all.

How to Motivate Human Power?
The last point deserves extra attention. Unlike a windmill, a solar panel or an oil barrel, human power needs to be motivated in order to produce energy. If we make a switch to human power production, would everybody generate their own power for the sake of sustainability? Would people pay others to do it for them? Or, would people force others to do it for them?


A financial reward won’t do the trick, because at the current energy prices in the Netherlands, a human generating electricity would earn only 0.015€ per hour. Consequently, unless environmental awareness increases dramatically, the use of human power could open the door to new forms of slavery. Is such slavery justified for a reduction in CO2-emissions? Could we force refugees or criminals to produce power?
At the current energy prices in the Netherlands, a human generating electricity would earn only 0.015€ per hour.

These are disturbing questions, because the history of human power is -- broadly -- also the history of slavery. These days we import oil, coal and uranium, in the past we imported slaves. Luckily, there may be a third possibility. We can try and motivate people by making human energy production more fun, social, and exciting.

The few commercially available devices for human energy production are entirely focused on energy efficiency -- there's no attention to fun or motivation. They are also designed for emergency purposes, not for prolonged and daily use. For example, most hand cranks are made as compact as possible, while a larger device would be much more comfortable to use.

Designing the Prototype
For the design of our prototype human power plant, we wanted to address these issues. We teamed up with makers and sports coaches to develop fitness machines that are suited for different types of human power sources, are fun too use, and produce a maximum amount of power.

Imatge/fotoVarious components of the prototype Human Power Plant. Illustration: Melle Smets.

To make power production more social, we decided that power producers should be able to talk to each other. They can even bring their pets to help with power production, creating a cosy and home-like atmosphere. This is not a new idea: dogs were commonly used as a source of mechanical power in pre-industrial times, and also provided their owners with a source of warmth.

Water Under Pressure

For extra motivation, all exercise machines in our prototype human power plant are facing a jacuzzi & shower where girls are invited to encourage the boys to flex their muscles and generate more power. Of course, the gender roles could be reversed, but during the first experiments we discovered that this is less energy-efficient. Girls don't seem to get motivated by guys in jacuzzis, at least not to the extent that guys get motivated by girls in jacuzzis.

Imatge/fotoThe prototype Human Power Plant under construction.

The jacuzzi is not a gimmick, but an essential part of the prototype human power plant. That's because we opted for water under pressure as the energy carrier. The kinetic energy produced by humans and their pets is pumped into a pressure vessel, which produces water under pressure that is led to water turbines which supply mechanical energy and electricity. The jacuzzi is the receiving reservoir of this closed system.

With the choice for water under pressure, we want to make energy more visible and audible. More importantly, however, it allows us to produce electricity without the use of batteries and electronics -- which are not sustainable components. In our human power plant, the hydraulic accumulator takes the place of the battery and the voltage regulator. Small variations in human power production can be smoothed out, keeping the voltage constant. Longer term energy storage is provided by the humans themselves.

For Rent: 750 Human Powered Student Rooms
To find out if we could sustain a modern lifestyle with human power alone, we teamed up with architects to design plans for the conversion of a 22 floors tower building into an entirely human powered student community of 750 people.

The Willem C. Van Unnik building is the tallest building on the campus of Utrecht University. The concrete, steel and glass monolith, which occupies a central position on the campus, was built in the late 1960s and has been mostly empty for years. Maintaining it is an important cost for the university, who owns the building.
A time schedule tells the students when they have to produce elelectricity and heat, and when to perform other services for the community.

Because the university has the ambition to become carbon neutral in 2030, we propose to turn a problem into an opportunity. The ecological footprint of the human powered Van Unnik student community will be close to zero, and the building is already there.


Each student in the human powered Van Unnik student building is responsible for generating the electricity that’s used in his or her individual room. The lower floors of the building are reserved for communal energy production, providing both electricity and warmth. This energy is used to heat the building, prepare food, wash clothes, take showers, and so on.

More energy is supplied by a biogas plant, which is operated by the students and runs on their food waste and excrements. A time schedule tells every student when he or she has to produce electricity and heat, and when to perform other services for the community.

Power Generation Schedule
According to our preliminary calculations, an entirely human powered student building is achievable. The students would maintain a modern lifestyle, including hot showers, computers, and washing machines. On the other hand, they would have to produce energy for 2 to 6 hours per day, depending on the season and their individual and communal preferences.

Imatge/fotoClothes drying. Image: Golnar Abbasi.

A human powered student community has enormous potential for a reduction in energy use. If students have to generate their own power, they are much less likely to waste it. How far would students go to reduce their efforts? Would hot showers go out of fashion? Would salads be the next culinary trend? Would typewriters make a comeback?

Energy use is also lowered by encouraging the communal organisation of daily household tasks, just like in the old days. Finally, the human powered student community applies low-tech solutions, such as fireless cookers, thermal underclothing, and heat exchange showers, which all maximize comfort in the context of a limited energy supply.

The design of the building and the construction of the prototype human power plant is documented on a separate blog: Human Power Plant. It's a work-in-progress, and comments are welcome. Once the project is complete, we will post an update on Low-tech Magazine.

Kris De Decker & Melle Smets.

The Human Power Plant is part of the Zero Footprint Campus project, for which 12 artists examine sustainability.
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Digital Colonialism

Digital Colonialism

Imatge/fotoFree Basics, Facebook’s free, limited internet service for developing markets, is neither serving local needs nor achieving its objective of bringing people online for the first time.

“Facebook is not introducing people to open internet where you can learn, create and build things,” said Ellery Biddle, advocacy director of Global Voices. “It’s building this little web that turns the user into a mostly passive consumer of mostly western corporate content. That’s digital colonialism.”

Read more: How Facebook’s free internet service has failed its users.
Previously: How to build a low-tech internet.
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