Have Biofuels been used in aeroplanes/helicopters ? Any info. in this regard welcome.

Vijay

None are comparable in energy density or cheapness (EROEI - "energy return on energy invested"), so my guess is, probably not yet. Because biofuels are subsidized either by governments or by the destruction of ecosystems, we aren't seeing the true costs. I imagine in a future of extremely expensive fossil fuels, biofuels may be used for special transportation, but not for everyday use. But I haven't found anything about current use of biofuels for airplanes.

But I haven't found anything about current use of biofuels for airplanes.search and you shall find, a few scant articles mostly. biodiesel also has the problem of not staying liquid at low temperatures but the advantage of not being flammable at regular pressures. but basically you're right, low energy density, high cost (unlike cars, they don't tax aviation fuel).

energy density is a big issue in aviation, jet fuel is kerosine which lies somewhere between gasoline and diesel in energy density and the refining process. there have even been experimental fuels including boron just to get better energy density.