HOUSTON, Dec 22 (Reuters) - Coal stockpiles at U.S. power plants fell 2.7 percent this week from last week as power demand rose due to cold weather and coal supply fell as shippers held back deliveries, Genscape said Tuesday.
Total coal inventory as of Tuesday was 7 percent more than the same week of 2008, the power industry data provider said.
Power generators had 176.5 million tons of coal on hand as of Tuesday, down from 181.4 million tons last Tuesday but up from 165 million tons the same week last year, Genscape said.
As of Tuesday, U.S. generators, which rely on coal to fuel about half of U.S. electricity production, had an average of 67 days' supply of coal on hand, assuming typical burn rates, down from 70 days the previous week, Genscape said.
Power companies as of Tuesday averaged four more days' of coal stockpiled than the same week last year, down two days from last week's cushion over 2008 stockpiles, data showed.
"Cold weather along the East Coast of course contributed to heavy energy use," Genscape said. "Producer discipline, holding (coal) deliveries steady essentially since the spring, also contributed."
Average weekly stockpile draws for the past month have been about 2 million tons compared with 200,000 tons weekly at the end of 2008, the data provider reported.
Inventories typically grow in spring and fall when demand for heating and cooling drops. Stockpiles shrink during summer and winter when demand rises for climate control in homes, stores and factories.
Due to the economic slowdown, coal inventory at the end of summer 2009 was unusually high. In mid-July, stockpiles were 28 percent greater than the same week of 2008 and were still 12 percent greater as of Dec. 1.
Mathematical rounding sometimes affects the results, overstating some changes and understating others, Genscape has said. (Reporting by Bruce Nichols; Editing by Lisa Shumaker)