Iberian spot power jumps on sluggish wind parks

* Spain day-ahead 37.32 euros ($55.05)/MWh, up 1.80

* Cal-10 up 0.27 to 40.15 euros/MWh (exchange)

MADRID, Dec 9 (Reuters) - Iberian spot power prices rose by nearly 2 euros on Wednesday due to a lack of relatively cheap wind and nuclear power which required ramping up output from gas-fired plants.

Spanish wind farms -- the third-most powerful in the world -- were generating 2,291 megawatts by mid-afternoon, or 6.4 percent of demand, down from 4,000 MW earleir in the day.

Wind power was expected to remain low at about 2,000 MW on Thursday and Friday, a factor which often props up the benchmark day-ahead price.

Spain's grid is also short of 2,000 MW of nuclear power at the moment because the Almaraz I plant is refuelling and not due back until next week, and the Asco I reactor is offline for maintenance and not expected back this week, at least.

The remaining six nuclear plants were producing 5,276 MW, or 14.8 percent of the generating mix, according to data from the national grid operator REE (REE.MC). Benchmark forward contracts rose above the 40-euro mark for the first time in more than a week, but were still close to year-lows and below countrparts in France and Germany.

Baseload calendar-year 2010, the benchmark forwards contract, traded up 0.37 euros/MWh on the Omip forwards exchange to 40.15.

All Spanish power stations were emitting an unusually high 10,324 tonnes per hour of carbon dioxide. (Reporting by Martin Roberts)