How can biogas do it?

The constituent of the gas makes it a ready alternative for fossil fuels. They behave alike, but its safer than fossil fuel.

Constituent of biogas

Composition of biogas and concentration (by component volume) includes:

Methane                         - 55-60%
Carbon (iv) oxide          - 35-40%
Water                              -  2-7%
Hydrogen sulphide      -   20-20,000ppm
Ammonia                        -  0-0.5%
Nitrogen                          -  0.2%
Oxygen                            -   0.2%
Hydrogen                        -   0.1%

Excerpts from the book simple technique for biogas generation:Easy notes by Ukponmwan Ifueko Oghogho. Get the book from the online store. www.morebooks.de (https://www.morebooks.de/gb/search?utf8=%E2%9C%93&q=Ukponmwan+ifueko+oghogho+) 

Or

amazon.com/author/ifuekoukponmwan