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?
The Netherlands had 5 times more windmills in 1850 than it has wind turbines today
More than 900 years ago, medieval Europe became the first large civilisation not to be run by human muscle power. Thousands and thousands of windmills and waterwheels, backed up by animal power, transformed industry and society radically. It was an industrial revolution entirely powered by renewable energy – something that we can (and do) only dream of today. Wind and water powered mills were in essence the first real factories in human history. They consisted of a building, a power source, machinery and employees, and out of them came a product.
Water versus wind
Water powered mills were – overall – more important and numerous than windmills. This is logical since they are a simpler and more reliable technology; the flow of a river might change according to the seasons, but generally a river always contains water. Moreover, by making use of canals and sluice gates the flow of water could be precisely controlled to provide the speed or load required by the gearwork inside the factory.
The wind, on the other hand, does not always blow. When it does, wind velocity and direction can change at any moment and windmills had no efficient method to control the strength of the wind – at least not in early medieval times. Water powered mills appeared in Europe in large amounts from the end of the 11th century onwards and only 200 years later almost all available energy in rivers and streams was put to use.
However, not all regions were suited for watermills. The reasons could be that they did not have sufficient water resources (like Spain), that they were too flat and their rivers did not have enough flow (like the Netherlands and the downlands of England) or that rivers generally froze during winter (like in Scandinavia, Russia and parts of Germany). In these countries, windmills appeared in the 13th century, possibly earlier, and spread fast. Later, also regions that had abundant water resources constructed windmills, to relieve the pressure on rivers and streams.
How many windmills?
The amount of windmills in early medieval times remains unknown, because the few inventories that could be studied do not distinguish between water and wind powered mills. For instance, we know that there were between 10,000 and 12,000 mills in the UK in 1300, but we do not know how many of them were wind powered (it must have been a minority). All we have are data on individual windmills, which start to appear at the end of the 1200s. Only in the 1700s and 1800s, when windmill technology really caught on, more accurate inventories appear.
In 1750, there were 6,000 to 8,000 windmills in the Netherlands, in 1850 there were 9,000 of them. For comparison, this is almost 5 times as much as there are wind turbines in the Netherlands today (1,974 turbines as of September 2009). In the UK there were 5,000 to 10,000 windmills in 1820. France had 8,700 windmills (and 37,000 watermills) in 1847.
Read more by Kris De Decker Low-tech Magazine