By Moming Zhou and Mario Parker June 15 (Bloomberg) — The 16 percent jump in natural gas prices in the past month may prompt U.S. power producers to move to coal, as rising temperatures boost air-conditioning demand. Gas surpassed $5 per million British thermal units yesterday in New York for first time in 16 weeks, as Commodity Weather Group, a forecaster based in Bethesda, Maryland, said the hottest areas over the next two weeks will be the Midwest, South and Mid-Atlantic. The price of coal is about $4.58 per million Btu, according to Teri Viswanath , director of commodities research at Credit Suisse Securities USA in Houston. A switch to coal would reduce demand for gas just as power producers enter the busiest season. Gas became cheaper than coal in March, when prices dropped to a six-month low. “Look at the prices and it’s clear that coal will recapture the market share,” said Viswanath, whose coal-price model factors in transportation costs and power-plant efficiency. “It will provide a ceiling for gas prices.” Natural gas for July delivery rose 22.5 cents, or 4.7 percent, to settle at $5.006 per million Btu yesterday on the New York Mercantile Exchange, the highest settlement price since Feb. 19. Gas has been the biggest gainer in the S&P GSCI Index of commodities in the past month. As gas rallied, coal dropped about 1.2 percent. Central Appalachian coal for July delivery fell 35 cents, or 0.6 percent, to $61.82 per ton June 11 on the Nymex. “At $5, no utilities are going to burn gas when they can burn coal,” said Meredith Bandy , an analyst at BMO Capital Inc. in Denver. About 10 percent of power plants, mostly in the Southeastern U.S., can switch between the two fuels, she said. Stronger Demand Demand for gas in April and May was about 11 percent higher than during the same period of 2009 as costs declined, the Energy Department said in its monthly Short-Term Energy Outlook on June 8. Coal averaged $58.47 a ton in April, equal to about $4.38 per million Btu, and the equivalent of $4.58 in May, using Viswanath’s model. Gas futures in New York averaged $4.084 in April and $4.154 in May after falling to $3.842 per million Btu on March 29, the lowest settlement price since Sept. 28, 2009. Stockpiles of coal at utilities dropped 0.4 percent in the week ended June 7 and 5.3 percent from a year earlier, according to an analysis by Genscape Inc. of Louisville, Kentucky. Coal demand fell about 40 million tons last year and should rise about 20 million tons of that consumption back this year, according to estimates by Pearce Hammond , an analyst at Simmons & Co. International Ltd. in Houston. No Oversupply “Utility inventories are higher than normal but I don’t think we’re in an oversupplied market,” Hammond said. “With natural gas at these prices, coal should jump in front of gas.” About 45 percent of U.S. electricity output this year will come from coal plants and 22 percent from gas power facilities, according to the Energy Department. Eastern coal producers closest to power plants with the ability to switch between coal and gas will benefit the most from stronger utility demand, Hammond said. Hammond said Alpha Natural Resources Inc. , the third- largest U.S. coal producer, will be among those to gain. The Abingdon, Virginia-based company has fallen 15 percent this year to $36.76 in New York Stock Exchange composite trading. Patriot Coal Corp. in St. Louis, the fourth-largest eastern U.S. coal producer, which has risen 9 percent this year, and James River Coal Co. , a Richmond, Virginia-based coal company, which is down 8 percent, may also benefit, Hammond said. Gas prices at the Henry Hub in Erath, Louisiana, where New York futures contracts are delivered, will average $4.49 per million Btu in 2010 and $5.06 in 2011, the department estimated in the monthly outlook. Gas at the hub yesterday traded at $4.9389, the highest price since Feb. 19, according to data compiled by Bloomberg. “We’ve had a significant percentage increase in natural gas and certainly we are going to start to hear squealing that gas is getting a little dear at this time,” said Stephen Schork , president of Schork Group Inc., a consulting company in Villanova, Pennsylvania. To contact the reporters on this story: Moming Zhou in New York at Mzhou29@bloomberg.net ; Mario Parker in Chicago at mparker22@bloomberg.net ;