Bio-fuel: Combustible fuels generated from contemporary biological process that convert biomass into fuels that are in solid, liquid or gas forms. So much biomass around the world is wasted. There are still so many countries that rely on firewood for cooking. Even in the U.S.A., we chop down trees and turn them into charcoal. All over the world trees are wastefully cut down for fuel.
This design will help prevent the waste of trees. Tree trimmings can be turned into charcoal. Any type of biomass (even grass) can be turned into charcoal while collecting methane in the process. Charcoal making machines powered by methane can be operated to turn the charcoal dust into any charcoal form salable in the market.
The design may be further modified to generate electricity in the process. Coils filled with water can be wrapped around the drum. The heated water will generate steam which will be directed to a steam electric generator. The same principle of steam electric generators will apply except the fuel to create the steam comes from the sun via the drum that creates, charcoal and methane.
Bio-Fuel, burning of firewood, burning of grass and straws do not cause the greenhouse effect. Farmers need not be restricted from burning. It does not highly contribute to the high CO2 in our atmosphere. Fossil fuels create the pollution. The carbon expelled from the burning of fossil fuels is from millions of years ago. On the other hand the burning of bio-mass expels only carbon mostly accumulated from within 10 years prior to burning. Very small quantity from over 100 to 200 years ago. Mother earth can easily recycle CO2 from biomass. But it is not prepared to recycle the CO2 expelled from fossil fuels which was originally absorbed from over a million years ago.
Making it illegal to burn firewood is strictly political-bias. Laws created to propagate the fossil fuel industry.