President Obama and his EPA are now taking public comments on the Clean Power Plan – the proposal to reduce carbon dioxide emissions on existing coal-fired power plants by motivating investments in new technologies or entering into regional cap-and-trade programs. It's a rule-making that has raised the ire of Republicans, who feel the Democratic administration has gone too far. But it's one that raises the hopes of others, who say that it will spur utilities to build or invest in cleaner alternatives. Just what fuels benefit from this? Natural gas is obvious winner, although nuclear and renewables are also fighting for a greater slice of the electric generation pie.