LOW-TECH MAGAZINE

How to design a sailing ship for the 21st century?

It is surprisingly difficult to build a carbon neutral sailing ship. This is even more the case today, because our standards for safety, health, hygiene, comfort, and convenience have changed profoundly since the Age of Sail.

How to Make Wind Power Sustainable Again

For more than two thousand years, windmills were built from recyclable or reusable materials: wood, stone, brick, canvas, metal. When – electricity producing – wind turbines appeared in the 1880s, the materials didn’t change.

It’s only since the arrival of plastic composite blades in the 1980s that wind power has become the source of a toxic waste product that ends up in landfills.

New wood production technology and design makes it possible to build larger wind turbines almost entirely out of wood again – not just the blades, but also the rest of the structure. This would solve the waste issue and make the manufacturing of wind turbines largely independent of fossil fuels and mined materials. A forest planted in between the wind turbines could provide the wood for the next generation of wind turbines.

Reinventing the Small Wind Turbine

Many commercially available small wind turbines with plastic blades and steel towers are infamous for their low reliability, high embodied energy, and limited power output.

Building them out of wood can address these issues. Because of their aesthetic appeal, and thanks to the ability to produce them locally, small wooden wind turbines can also improve the public acceptance of wind power.

Furthermore, innovation in tower design facilitates the installation of small wind turbines, reducing the need for concrete foundations and heavy machinery. 

Image: A wind turbine with wooden blades. Source: EAZ Wind.

Heat your House with a Mechanical Windmill

Renewable energy production is almost entirely aimed at the generation of electricity. However, we use more energy in the form of heat, which solar panels and wind turbines can produce only indirectly and relatively inefficiently. 

A solar thermal collector skips the conversion to electricity and supplies renewable thermal energy in a direct and more efficient way.

Much less known is that a mechanical windmill can do the same in a windy climate -- by oversizing its brake system, a windmill can generate lots of direct heat through friction. A mechanical  windmill can also be coupled to a mechanical heat pump, which can be cheaper than using a gas boiler or an electric heat pump driven by a wind turbine.

Ditch the Batteries: Off-Grid Compressed Air Energy Storage

Going off-grid? Think twice before you invest in a battery system. Compressed air energy storage is the sustainable and resilient alternative to batteries, with much longer life expectancy, lower life cycle costs, technical simplicity, and low maintenance. Designing a compressed air energy storage system that combines high efficiency with small storage size is not self-explanatory, but a growing number of researchers show that it can be done.

History and Future of the Compressed Air Economy

Compressed air energy storage (CAES) is considered to be an important component of a renewable power grid, because it could store surplus power from wind turbines and solar panels on a large scale. However, in its present form, the technology suffers from large energy losses and depends on natural gas to operate.

A look at the 4,000 year long history of compressed air makes clear that this is not unavoidable. Although our ancestors were dependent on less energy efficient technology, they used compressed air in more intelligent configurations that had fewer energy conversion losses and were independent of fossil fuels.

These historical systems hold the key to the design of a low-tech, low-cost, robust, sustainable and relatively energy efficient energy storage medium. The compressed air economy could be the practical and realistic alternative to the hydrogen or all-electric utopias.