US gas prices power up as winter nears US natural gas prices have doubled from lows reached this year as the coming winter promises to draw down record stocks stored underground. Prices fell below $2 per m British thermal units in April to the cheapest in a decade. On Tuesday Nymex December gas was $3.807 per mBtu, up 2.4 per cent on the day and 100 per cent from the market bottom. Several factors explain gas" turnround. Last week the US Department of Energy reported utilities and other consumers pulled 18bn cubic feet from underground storage facilities in the first withdrawal of the winter heating season. Stocks had this month built to a record 3.93tn cu ft, but did not exceed estimated storage capacity above 4tn cu ft. Fears that traders would be forced to unload gas at any price were not realised. "Over time we have eroded our inventory surplus," said Tim Evans, energy futures specialist at Citi in New York. We have done that based on some warmer-than-normal temperatures through the summer. Gas has also picked up some market share from coal" in firing electric power plants. The US gas industry has struggled to keep supply and demand in balance as output increases from shale regions. After prices fell this year, output growth has slowed. Marketed gas production was up 3.9 per cent on year in August, energy department data show, the slowest annual growth rate in more than a year. Baker Hughes, an oil services group, says the number of rigs drilling for gas in the US has halved in the past year to 417. The impact of less drilling has been blunted by "associated gas" produced at oil wells. Analysts at Goldman Sachs estimate production growth will stall in 2013, acknowledging in a report last week that the "drilling response to the low prices this year has been more aggressive than we previously expected." The bank raised its gas price target to $4.25 per mBtu in 2013. With winter heating needs growing, analysts see underground stocks declining over the next few months, potentially bringing the surplus into line with historical averages. The energy department says a normal winter after last year's record-warm US winter will force households and businesses to burn more gas for heating in 2013. But the agency estimates overall US gas consumption will fall 0.7 per cent next year as power plants put off by higher prices switch back to coal as a fuel.