U.S. Senate Majority Leader Harry Reid of Nevada sent a letter this week to four companies telling them not to build planned coal-burning power plants in his state.

Reid's letter, dated Monday, was addressed to the corporate leaders of the Sierra Pacific Resources, private equity LS Power Group, Dynegy Inc. and Sithe Global Power LLC. A copy of the letter was obtained by Reuters on Thursday.

I am writing to each of you regarding your company's proposal to build new coal-fired power plants in eastern Nevada and to express my strong opposition to those plants, Reid wrote.

The Democratic senator said he will use his influential post in Congress to keep coal plants out of Nevada.

Because I believe that developing renewable energy in Nevada is far preferable to coal for the sake of our economy, public health and the environment, I will use every means at my disposal to prevent the construction of new coal-fired power plants in Nevada that do not capture and permanently store greenhouse gas emissions, Reid wrote.

Reid said he'd rather have the state focus on renewable power and energy efficiency. He also opposes nuclear power for Nevada and the Yucca Mountain site in the state for storage of nuclear waste.

Reid said the state's demand for energy can be met largely through new renewable energy, energy efficiency and demand-side management.

That's just unrealistic in a fast-growing state where power use is on the rise, particularly in the Las Vegas metropolitan area, said Frank Maisano of energy company advocate Bracewell & Giuliani LLP.

Given the massive growth in the region, (Reid's letter) is probably not reflective of reality to say we are not going to build any new coal plants, said Maisano, acting as spokesman for Sithe Global, which is owned by the Blackstone Group's Blackstone Capital Partners (80 percent) and Reservoir Capital Group (20 percent.

Senator Reid is also opposed to nuclear power, so I don't know how they are going to meet Nevada's growing power needs, Maisano said.

About 70 percent of the power generated in Nevada is from natural gas-fired plants and 13 percent by coal-fired plants, according to the federal Energy Information Administration. There are no nuclear power plants in Nevada.

Coal-fired plants account for 50 percent of U.S. electricity generation, nuclear power for 20 percent, and natural gas-fired plants for 18 percent.