Fuel

Wood was once an important fuel, and still is in some parts
of the world. All fossil fuels (coal, gas and petroleum) are the product
of photosynthesis that took place several hundred million years ago.
The problem with using fossil fuels today is that this releases carbon
back into the atmosphere that has been stored as organic compounds
all this time. Plants are often mentioned in long-range plans to help
mitigate the energy crisis because they are a “renewable resource,”
unlike the fossil fuels. Biofuels and biodiesels from a variety of
plant sources such as soybeans, grains, vegetable oil, sugar cane,
and grasses may prove to be important alternatives to petroleum products.