* Spain day-ahead euros 35.56 euros ($53.25)/MWh, down 0.40
* Portugal “pool” rises 0.39 to 36.30 euros/MWh
MADRID, Oct 20 (Reuters) - Iberian wholesale power prices for prompt delivery mostly extended prior falls on Tuesday as strong winds boosting cheaper electricity supplies were expected to blow harder.
Prices bucked the trend with a mild rise in Portugal, which is a net importer of power.
Producers predicted that wind parks in Spain, the world’s third biggest, would rise to a peak of nearly 8,000 megawatts on Wednesday, up from 6,630 MW on Tuesday afternoon.
Wind power was forecast to slip again on Thursday, which may bolster prompt prices on Wednesday. But an additional 1,000 MW of relative cheap nuclear power may undercut prices if the Cofrentes plant finishes refuelling on schedule.
Benchmark curve prices were little traded and posted a limited response to crude oil hitting a one-year high, as they have done since Brent topped $70 last week.
Usually, higher oil prices haul up forwards because they herald more expensive generating costs in the months ahead at power plants burning crude-indexed gas and coal.
Traders across Europe do not believe economic activity is strong enough to sustain crude at current levels, and say a change of $1 in the oil price affects power prices less than a year or two ago.
They add that the outlook for industrial activity in Europe remains weak and current demand for electricity can be met with more efficient plant than two years ago.
Baseload Cal-10 was quoted at 38.60/38.65 euros/MWh in late over-the-counter trading, compared to 38.00/38.65 on Monday.
Data from the CSN nuclear regulator and national grid operator REE REE.MC showed five of Spain's eight nuclear power stations were running normally and generating 4,317 MW between them, or 12.3 percent of total demand.
The Asco I and Asco II nuclear plants have both halted to allow repair work on back-up generators, while the Cofrentes reactor is currently refuelling. All three plants produce 1,000 MW when up and running.
Spanish power stations were meanwhile emitting 9.959 tonnes per hour of carbon dioxide.
In other news, Spain’s hydropower reserves fell again due to drought last week, and now stand at 7,869 gigawatt-hours, or enough to meet demand for about 11.3 days. (Reporting by Martin Roberts, editing by Anthony Barker)
Our Standards: The Thomson Reuters Trust Principles.