Lime burning is a now-forgotten industry that sustained many agrarian communities before energy became cheap.
In the nineteenth century, miniature water turbines were connected to the tap and could power any machine that is now driven by electricity
The hydro power installations in use today are less energy efficient than those of earlier centuries.
The trend towards small-scale, decentralised power production means that rope transmission might have a place in our energy system again
Jerker line systems can be used to operate water pumps or sawing machines, to forge iron, to process food or fibres, or to make paper.
Long-distance power transmission predates the invention of electricity by almost four centuries.
A modular system unites the advantages of standardisation (parts can be produced cheaply in large amounts) with the advantages of customisation (a large diversity of unique objects can be made with relatively few parts).
A car with a top speed of 270 km/h can be driven anywhere on Earth, while an electric velomobile with an electric assistance of up to 50 km/h is illegal is most countries.
About a quarter of the existent wind turbines would suffice to power as many electric velomobiles as there are people.
A cargo cycle is at least as fast as a delivery van in the city - and much cheaper to use.
The Spanish botijo is a water bottle that cools itself, without electricity.
Modern research, which combines ancient knowledge with fast computing techniques, shows that passive solar cities are a realistic option, allowing for surprisingly high population densities.