(Reuters) - The Obama administration proposed on Tuesday the first ever standards to cut carbon dioxide emissions from new power plants, a move likely to be hotly contested by Republicans and industry in an election year. The Environmental Protection Agency proposed the long-delayed rules that limit emissions from all new U.S. power stations, which would effectively bar the building of any new coal plants. While the rules do not dictate which fuels a plant can burn, they would require any new coal plants essentially to halve carbon dioxide emissions to match those of efficient gas plants. "We're putting in place...