Alternative fuels are currently in the same trap. In the long run, they are likely to save money, reduce our dependence on foreign producers (many of them with less-than-stable regimes), and do less damage to the environment. But in the short run, they are too expensive—and, in some cases, their net benefits are too uncertain—for private citizens, or very many companies, to take the plunge.

This is where government comes in—where it has always come in.

Biofuels are riskier than solar. Their price may never plunge below the cost of oil (unless, of course, the price of oil skyrockets), and some variants produce their own carbon footprints. But they’re worth a modest experiment; they’re worth a boost in demand, which could spur more firms to take a leap into the market. Also this particular biofuel experiment employs far more promising technologies, based not on growing crops (like corn for ethanol or mustard seeds for an earlier Navy project) but rather on algae and the greases from chicken waste. (One of the companies, Dynamic Fuels, is a division of Tyson Foods.)

The military is very active in this realm, beyond the solar panels in Afghanistan—only sensible, given that the Defense Department spends over $16 billion a year on energy, nearly all of it fossil fuels. The Navy is in a joint project with the Departments of Agriculture and Energy to invest $510 million to convert old factories into bioprocessing plants. The Air Force is experimenting with fueling some of its fighter jets with biofuels.