What are some Alternate Car fuels?

* biogas (methane produced from decomposing organic matter - pig farms)
* biodiesel (oil made from organic material)
* ethanol (alcohol made from vegetation) * hydrogen (but it's difficult to store and expensive to produce) * electricity (but we need more efficient batteries) * compressed air (but it uses electricity to compress it) * pedal power (all the passengers pedalling at once might work)