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.

Too Much Combustion, Too Little Fire

The fire – which we have used in our homes for over 400,000 years – remains the most versatile and sustainable household technology that humanity has ever known. The fire alone provided what we now get through a combination of modern appliances such as the oven and cooking hob, heating system, lights, refrigerator, freezer, hot water boiler, tumble dryer, and television. Unlike these newer technologies, the fire had no need for a central infrastructure to make it work, and it could be built locally from readily available materials.

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.

How (Not) to Run a Modern Society on Solar and Wind Power Alone

While the potential of wind and solar energy is more than sufficient to supply the electricity demand of industrial societies, these resources are only available intermittently. To ensure that supply always meets demand, a renewable power grid needs an oversized power generation and transmission capacity of up to ten times the peak demand. It also requires a balancing capacity of fossil fuel power plants, or its equivalent in energy storage. 

Consequently, matching supply to demand at all times makes renewable power production a complex, slow, expensive and unsustainable undertaking. Yet, if we would adjust energy demand to the variable supply of solar and wind energy, a renewable power grid could be much more advantageous. Using wind and solar energy only when they're available is a traditional concept that modern technology can improve upon significantly.