we still use petrol because there is so much investment in...

we still use petrol because there is so much investment in petrol, though vehicle manufacturers could switch relatively easily to biodiesel and gas if they thought the market was there. Maybe consumers need to show them.

btw, what's the whole equation for biomass fuels? if you take land utilisation etc into account, are biomass fuels less environmentally damaging and are they more economic than the current petrol economy?

I think it's not an easy problem. The real solution is to use less of everything - but I'll be a blue-assed ape before that happens.