Similarly for biofuels, there could be refineries that are supplied by the lands within a certain radius of the plant. While were subsidizing ethanol, why not subsidize the return of the nutrients back to those lands? It could be carried on the return trip of the empty supply trucks.

Getting politicos to pay attention is a hard one. First, we have to get them to listen to scientists in the first place..!

I think I would have made the same points as back40; it has always been possible to close the loops, not entirely, but enough, on farms. Just that with increased specialisation and concentration, it hasn’t been worth it. Let “society” deal with a lagoon of pig slurry. On a small, mixed farm, biomass such as wheat straw might have gone for bedding, which would then have been spread with its load of manure, onto the fields. Big bioenergy plants — no matter what the feedstock — are going to have problems returning their nutrients to the place where the feedstocks grew. If they’re aware of that, and deal with it, good. But maybe I’m just too cynical. I don’t believe they will.

Karl’s other point about municipal water is great. And yes, willow beds have been used to polish grey water and supply willow chips for fuel. But the municipal water is in towns. And while towns need energy, they also need food. So which is better to have around a town, farms growing perishable foods or farms growing biofuels? There’s another problem with municipal waste, at least in some parts of the world. It concentrates heavy metals. I seem to recall a study of this that looked at the uptake into willow, but I cannot now find it.

In the end, I believe that small scale and local use of biofuels to deliver heat and power, especially via gasifiers or direct burning, may have something to be said for it. As a substitute for gasoline, in temperate climates, I don’t think it is going to work.

To take up back40′s point, we may be watching, but the politicos seem to have averted their gaze; how do we help them to focus?