MADRID/PARIS/STOCKHOLM, March 2 (Reuters) - France and Spain are poised to announce a breakthrough this week in a long-running impasse over hefty costs of what would be their first undersea electricity link, a minister and sources in both countries told Reuters. That was due to unforeseen seabed instability on the French side that required costly re-routing, and rising costs of raw materials. Spain is a growing producer of renewable energy that it exports to France and it wants its neighbour to pay most of the extra costs. That had led to disagreement amid wider tensions between them about pipeline connections and protectionism. Spanish sources said the go-ahead would likely mean that France, whose nuclear power industry has been beset by problems, finally agreed to pay more.

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