Low-tech Magazine

Medieval smokestacks: fossil fuels in pre-industrial times

The history of energy use in human civilisation is generally summarised as follows: from Antiquity until the start of the Industrial Revolution, people made use of the manual labour of both animals and humans, as well as biomass, sun, water and wind.

Next, all these renewable energy sources were replaced by fossil fuels: first coal, and later oil and gas. Uranium completed the picture in the second half of the twentieth century.

While this historical summary is basically correct, there were some - rather important - exceptions. Almost all of the leading economies in Western Europe during the last millenium relied on a large-scale use of fossil fuels such as peat and coal.

The bright future of solar powered factories

Most of the talk about renewable energy is aimed at electricity production. However, most of the energy we need is heat, which solar panels and wind turbines cannot produce efficiently. To power industrial processes like the making of chemicals, the smelting of metals or the production of microchips, we need a renewable source of thermal energy. Direct use of solar energy can be the solution, and it creates the possibility to produce renewable energy plants using only renewable energy plants, paving the way for a truly sustainable industrial civilization.

Pedal powered farms and factories: the forgotten future of the stationary bicycle

If we boost the research on pedal powered technology - trying to make up for seven decades of lost opportunities - and steer it in the right direction, pedals and cranks could make an important contribution to running a post-carbon society that maintains many of the comforts of a modern life. The possibilities of pedal power largely exceed the use of the bicycle.

Bike powered electricity generators are not sustainable

Pedalling a modern stationary bicycle to produce electricity might be a great work-out, but in many cases, it is not sustainable. While humans are rather inefficient engines converting food into work, this is not the problem we want to address here; people have to move in order to stay healthy, so we might as well use that energy to operate machinery. The trouble is that the present approach to pedal power results in highly inefficient machines.

Boat mills: water powered, floating factories

The waterwheel was seen as the most important power source in the world, from the Middle Ages to the end of the nineteenth century. When smaller streams became saturated, medieval engineers turned their attention to larger rivers, eventually leading to the development of the hydropower dams that still exists today. Lesser known are the intermediate steps toward that technology: boat mills, bridge mills and hanging mills. Boat mills had already appeared in 6th century Italy and spread all over the world. Most of them remained in use up until the end of the 1800s, with some of them surviving well into the 1900s.

How (not) to resolve the energy crisis

Increasing the share of renewable energy will not make us any less dependent on fossil fuels as long as total energy consumption keeps rising. Renewable energy sources do not replace coal, oil or gas plants, they only meet (part of) the growing demand. 

Wind powered factories: history (and future) of industrial windmills

In the 1930s and 1940s, decades after steam engines had made wind power obsolete, Dutch researchers obstinately kept improving the – already very sophisticated – traditional windmill.

The results were spectacular, and there is no doubt that today an army of ecogeeks could improve them even further. Would it make sense to revive the industrial windmill and again convert kinetic energy directly into mechanical energy?

Small windmills put to the test

A real-world test performed by the Dutch province of Zeeland (a very windy place) confirms our earlier analysis that small windmills are a fundamentally flawed technology (test results here, pdf in Dutch). Twelve of these much hyped machines were placed in a row on an open plain (picture above). Their energy yield was measured over a period of one year (April 1, 2008 - March 31, 2009), the average wind velocity during these 12 months was 3.8 meters per second (note: update on the wind speed ). Three windmills broke. Find the disappointing results of the others below.

Urban windmills harm the environment

A small windmill on your roof or in the garden is an attractive idea. Unfortunately, micro wind turbines deliver hardly enough energy to power a light bulb. Their financial payback time is much longer than their life expectancy and in urban areas they will not even deliver as much energy as was needed to produce them. Sad, but true.

Carbon sequestration: bury the idea, not the CO2

Why introduce yet another expensive, energy-intensive and risky technology if there are so many other and better ways of fighting global warming? 

Capturing CO2 from the smokestacks of power stations with the intention of storing it in underground reservoirs, oceans, rocks, consumer products, chemicals or fuels has gained a lot of credibility recently. Many experts believe that we will burn the world's remaining fossil fuels anyway, and we should therefore try to lower the impact if we are to prevent a catastrophic climate change. Yet capturing, transporting and storing carbon dioxide raises energy consumption considerably and brings with it serious health and environmental problems. The benefits, on the other hand, are shadowed in doubt.