$5 on your system component costs.
This rule is applicable for mega-utility nuclear plants or your own renewable energy home power station. The logic is quite simple. The problem is the first question most people ask when pondering a renewable energy system: “How much does it cost?”
The answer is always “too much”. But think about the DOE’s statistics. It will cost less to optimize energy consumption in your home than to source for a larger power station, regardless of the type of energy sources. And don’t worry – you won’t be using coal-oil lamps or a black and white TV with a coat-hanger antenna!