> Energy accounting method showed quantitatively that biofuels are not renewable energy sources
That's essentially the same as the argument that electric cars aren't green because they're charged from a grid powered by non-renewable sources.
It's true, as long as the energy input to either system comes from non-renewable sources, neither is really green. But it's not inevitable.
That paper also says the energy yield ratio for biofuels is around 1.5, so it should be possible to make closed loop, renewable production of biofuels using biofuels as energy input.
That's essentially the same as the argument that electric cars aren't green because they're charged from a grid powered by non-renewable sources.
It's true, as long as the energy input to either system comes from non-renewable sources, neither is really green. But it's not inevitable.
That paper also says the energy yield ratio for biofuels is around 1.5, so it should be possible to make closed loop, renewable production of biofuels using biofuels as energy input.