Guardian: The offers are tempting for any self-respecting green. For a small premium, or sometimes no premium at all, you can make sure that only clean, green, renewable electricity comes down the grid into your home. But what do you get for your money? Does the planet really benefit? Is this greenwash? Most of us are not foolish enough to suppose that our electricity supplier specially packages up “green energy” for us, and shoves it down the wires. We just get regular electricity, of course. …