UPDATE 2-Aggreko warns on 2013 performance

* Revenue to be hit by Afghan military spend, Japan

* Outlook for international power business weakens

* Sees 2012 in line with expectations

* Shares down 16 percent

LONDON, Dec 17 (Reuters) - British group Aggreko

has issued its second profit warning in two months, saying there

would be less need next year for its generators, which provide

temporary power worldwide.

Fewer U.S. troop numbers in Afghanistan, a likely fall in

business in Japan as it recovers from the 2011 earthquake, and

the absence of a summer Olympics would combine to take 100

million pounds ($161 million) off revenue, Aggreko said.

Analysts moved quickly to downgrade their forecasts, and

shares in Aggreko, whose kit powers major events and covers

electricity shortfalls, were down 16 percent to a 12-month low

at 1,793 pence at 1110 GMT on Monday.

"We have got a double whammy going into next year," chief

executive Rupert Soames told Reuters. "We have got a weakening

demand environment in terms of our power projects business ...

the other whammy going on is that we have got about 100 million

pounds of revenue ... that is not going to recur in 2013."

On Oct. 19, Aggreko warned on 2012 profit, saying it would

be hit by bad debt provisions and foreign exchange rates.

JAPAN UNCERTAINTY

Aggreko said it was waiting to learn whether contracts in

Japan will be extended into the second half of 2013, foxing

accurate predictions. "(It) is difficult at this stage to

provide a definitive view of the likely pattern of trading."

Seymour Pierce said it expected the consensus for 2013

pretax profit to come down to about 355 million pounds from

about 400 million. It maintained a "buy" rating on the stock.

"The underlying drivers, namely the continued supply demand

power imbalance in developing countries, remain strong," analyst

Caroline de La Soujeole said. "However, contract awards can be

lumpy."

Aggreko said its 2012 performance was in line with

expectations, and earnings per share should grow at least 15

percent.

Its local business division, which operates mainly in mature

markets, was expected to post underlying revenues around 8

percent higher in the fourth quarter, while underlying margins

on the international side were lower.