Energy

Making fire without matches. Friction fire, flint and steel, and fire management.

Converting wood to charcoal for metalworking and cooking efficiency.

Orienting and shaping buildings to capture heat in winter and stay cool in summer.

Working with oxen, horses, and donkeys for ploughing, hauling, and grinding.

Harnessing river flow for mechanical power — grinding, sawing, pumping.

Building basic windmills from available materials for water pumping.

Producing methane from animal waste for cooking and lighting.

Low-tech solar water heating and cooking without photovoltaics.

Rendering animal fats and pressing plant oils for reliable lighting without electricity.

Converting wood into combustible gas for cooking and eventually engines.

Simple generators from salvaged motors. Storing and distributing electricity.

Building basic steam engines from metal. Safety, efficiency, and practical applications.