* Q4 loss 53 mln dhs vs 380 mln dhs in Q4 2011 - Reuters
* Full year profit 640 mln dhs vs 744 mln dhs - statement
* Lower gas prices, charge on decommissioning spend hit (Adds details, context)
ABU DHABI, Feb 6 Abu Dhabi National Energy Co (TAQA) posted its second-successive drop in full-year net profit on Wednesday as charges against its business in the North Sea and lower gas prices in North America affected its earnings.
The state-owned utility said in a bourse filing that net profit for 2012 fell 14 percent to 640 million dirhams ($174.2 million) from 744 million dirhams a year ago.
TAQA did not provide quarterly figures but, according to a Reuters calculation, the company recorded a narrower loss in the fourth quarter of 53 million dirhams versus a loss of 380 million dirhams in 2011.
TAQA attributed the drop in annual profit due to a one-off charge which restricted tax relief on decommissioning spending in the North Sea as well as lower North American gas prices.
The company, which is 75-percent owned by the Abu Dhabi government, said in November it would cut spending in North America by 30 percent in 2013 to weather a downturn in commodity prices, including a 40 percent year-on-year drop in natural gas prices.
No details were provided on how much the North Sea charge affected results, although it is the second year in a row that tax issues have hit profitability. TAQA's 2011 results said its income tax expense for the United Kingdom was 1.59 billion dirhams more that year than in 2010.
In November, TAQA agreed to buy a number of BP's North Sea assets for over $1.3 billion, a deal interpreted at the time as a sign of improving relations between Britain and the Gulf emirate.
TAQA also cited on Wednesday lower aluminium prices, a lower margin on back-up fuel and higher funding costs for the decline in profit, although a gain on divestments and lower impairment charges in North America partially offset the fall.
Revenue in 2012 increased to 27.5 billion dirhams from 24.2 billion dirhams in the previous year.
TAQA said last month it sealed a $1.4 billion financing for expansion of the Jorf Lasfar power plant in Morocco.
Shares in TAQA were flat at 0730 GMT against a 0.07 percent decline in the wider Abu Dhabi market. ($1 = 3.6730 UAE dirhams) (Reporting by Stanley Carvalho; Editing by David French)