Gas engines are highly efficient at providing the stimulus for the growth of plants, whilst in parallel providing a flexible supply of electrical power. Heat, light and carbon dioxide (CO2) all promote plant growth. Gas engines provide electrical power at the alternator and when in a cogeneration configuration can also recover useful heat. Carbon dioxide is released in the exhaust gases of the engine as a by-product of the combustion of the fuel gas. Electrical power can be used to provide energy for lighting or can be exported to the grid, heat can be stored as hot water for use when needed and finally the CO2 can be scrubbed and used to promote plant growth.