Sept. 8 (Bloomberg) -- Tenaris Chief Executive Officer Paolo Rocca said U.S. power generators will switch from coal to natural gas next year, boosting sales for the world’s largest maker of steel pipe for the oil and natural gas industries. Natural gas prices close to a seven-year low will prompt industrial users to switch fuels in the first half of 2010, Rocca, whose family controls the company, said yesterday in an interview in London. “There will be renewed interest for investment in gas,” Rocca said. “There will be substitution of coal and fuel oil in the production of power.” Tenaris gets almost half of its revenue from selling steel tubes in North America. The company, which is based in Luxembourg, spent $4.8 billion to acquire Chesterfield, Missouri-based Maverick Tube Corp. and Houston-based Hydril in 2006 and 2007. Sales in North America fell 33 percent in the second quarter to $661 million. Natural gas for October delivery rose 8 cents, or 2.9 percent, to $2.808 per million British thermal units at 11:53 a.m. on the New York Mercantile Exchange. Gas dropped to $2.409 in intraday trading Sept. 4, the lowest since March 4, 2002. Tenaris rose $1.87, or 6.4 percent, to $31.14 on the in New York Stock Exchange. The stock has gained 48 percent this year. http://www.bloomberg.com/apps/news?pid=20602099&sid=avjxvlofdV7E