The diagram below shows a possible future means of home energy production

The diagram shows a process for producing electricity for home use. The equipment consists of a large tank, boxes and pipes that would be able to fit into a garage-sized room.
Electricity is produced using methane gas, generated from a mix of compost and water in a large steel tank. The tank is about the same height as a person and about twice as wide. Methane rises to the top of the tank and is collected and stored in a gas storage system. The stored gas is the fuel source used in the energy conversions that happen next.
Once compressed in a gas compressor, the methane fuels a combustion engine, which in turn produces mechanical energy. Having been transferred to a generator, the mechanical energy is then transformed into electrical energy, which is then stored in a battery. At this stage the electricity is ready for home use.