GOOGLE IS CONVERTING ITS HEADQUARTERS to solar power.

And in other alternative-energy news, Popular Mechanics crunches the numbers on the hydrogen economy, and discovers that it’s not all it’s cracked up to be: “At first glance, hydrogen would seem an ideal substitute for these problematic fuels. Pound for pound, hydrogen contains almost three times as much energy as natural gas, and when consumed its only emission is pure, plain water. But unlike oil and gas, hydrogen is not a fuel. It is a way of storing or transporting energy. You have to make it before you can use it — generally by extracting hydrogen from fossil fuels, or by using electricity to split it from water.”

The news isn’t all bad, though.