Power is every bit as big a business as telecoms. America's $220 billion electricity market is larger than those for cellular and long-distance telephony combined. The secret to this revolution lies in "micropower", the generation of electricity by small-scale fuel cells and gas turbines. The technology is not exactly new: most of it is, indeed, over a century old. But, thanks in good part to a huge inflow of venture capital into the business, it has in the past few years moved far closer to commercial reality.