So, how can we tap into the Earths bioenergy cycle?
The energy absorbed by plants on land (and plankton in the seas) is recycled naturally through the process of life on Earth until it is eventually radiated away as low-temperature heat (except perhaps for a small Earth-bound fraction which may very slowly become fossil fuel). If we, the human race, intervene and “capture” some of the biomass at the stage where it is acting as a store of chemical energy, we have a renewable fuel. This has two major implications for the environment. Firstly, by burning biomass fuels we generate no more heat and create no more carbon dioxide than would have been produced in any case by natural processes. Secondly, provided our consumption of biomass does not exceed the natural level of recycling (which is very large), we have a renewable energy source whose use does not substantially disturb the natural biogeochemical cycle on a human time scale.
