* Lawmakers worry more exports could push up U.S. prices * Energy Dept has role in approving natural gas exports * Two studies due in Q1 2012 * South Korea trade deal opens up large market-analyst By Roberta Rampton WASHINGTON, Nov 8 (Reuters) - U.S. lawmakers urged the Obama administration to weigh the risk of rising domestic natural gas prices as it considers allowing more exports, putting liquefied natural gas in the political spotlight for the first time in six years. The Energy Department last month approved Cheniere Energy's $8 billion, 20-year deal to sell liquefied natural gas to Britain's BG Group -- the first of several large projects designed to ship part of the bounty of cheap U.S. gas into higher-priced Asian markets. The Senate Energy Committee held its first hearing on liquefied natural gas since 2005 on Tuesday. In that time, the United States has gone from contemplating large imports of the fuel to now considering exports, a dramatic about face. At the hearing, Democratic Senator Ron Wyden held up a chart showing the gap between Asian and U.S. natural gas prices, and said he worries prices for U.S. consumers will jump as exports rise. "I'm trying to get my arms around where the department is going to draw the line," Wyden said.WHERE TO DRAW THE LINE? Advanced drilling techniques such as hydraulic fracturing, or fracking, have unlocked vast U.S. natural gas reserves, driving down domestic prices and leading to requests for exports to Asia, where prices are four times higher. It's critical to understand how exports will affect domestic prices, said Jeff Bingaman, the chairman of the Senate committee. "U.S. energy security requires reliable and affordable energy prices, not just reliable supplies," Bingaman said. The Energy Department must approve export applications under U.S. law, but it cannot deny exports to 15 countries that have bilateral free trade agreements with the United States -- a list soon set to expand when FTAs with South Korea, Colombia and Panama take effect. "If it's a free-trade country, it's a rubber stamp," said Kenneth Medlock, an energy fellow at the Baker Institute at Rice University in Houston. South Korea is a major LNG importer, and that free trade deal will open the door to new export opportunities, Medlock told Reuters. Still, prospects for export licenses could be affected by resource nationalism and environmental concerns, said Kevin Book, an analyst with ClearView Energy Partners LLC. "We remind clients how dramatically sentiment could shift should the issue gather emotional momentum in the wake of a price spike," Book said in a research note. STUDIES LOOK AT PRICE IMPACTS Exports contemplated by Cheniere Energy's project would amount to about 3.3 percent of current U.S. domestic consumption, a senior Energy Department official told senators. But the Energy Department is also considering four other applications. Together, the five export projects would account for the equivalent of about 10 percent of current U.S. natural gas use, said Christopher Smith, Energy Department deputy assistant secretary for oil and natural gas. "It becomes a larger and more detailed and more complicated question," Smith told senators. The Energy Department has commissioned the Energy Information Administration to examine how exports affect prices, and an external study to weigh the net impact on jobs and the economy, Smith said. The studies, due in the first quarter of 2012, will help determine whether exports to countries outside of free trade agreements are in the national interest, Smith said.