UPDATE 1-German grid operator TenneT's cross-border capacity under EU microscope

(Adds Vestager quotes, TenneT statement, Danish lobby group)

BRUSSELS/COPENHAGEN, March 19 (Reuters) - EU antitrust authorities are investigating whether limits placed by German grid operator TenneT on cross-border electricity capacity with Denmark breaches EU antitrust rules.

The European Commission said it has "constructive dialogue" with German transmission system company TenneT, a subsidiary of TenneT Holding IPO-TTH.AS, the Dutch government-owned operator of electrical grids in the Netherlands and Germany.

“We’ve had several complaints from Danish producers who say they want to supply power to our neighbours but cannot get access,” Europe’s antitrust Commissioner Margrethe Vestager said at a press briefing in Copenhagen on Monday.

“We suspect that access is deliberately decreased when too much power is produced.”

TenneT controls 40 percent of the cross-border network capacity of 1800 MW. Vestager added.

TenneT responded with a statement saying that the German-Danish border suffered from transmission bottlenecks, adding that transmission capacities were stretched to the limit because of market liberalisation and the transition to renewable energy. The company said the EU investigation will include calculations on whether capacities approved under European law put foreign providers at an unfair disadvantage.

“The examination can therefore set a precedent for all border connections in Europe,” it added.

Power producers in Denmark, Sweden and Norway have long complained of limited access to the power link between Western Denmark and Northern Germany, according to lobby group Danish Energy.

“Germany has for years prevented Danish, Swedish and Norwegian producers in supplying green energy to the rest of Europe,” said Anders Stouge, deputy director of Danish Energy.

In 2016, when access was limited to 200 MW, lost revenue for Nordic power producers amounted to about 500 million Danish crowns ($82.44 million), Stouge said.

A temporary solution was found last year, gradually raising access to 60 percent of capacity until 2020.

“We are pleased that the Commission is looking into this but hope that this won’t be used as a chance to quit the temporary solution agreed last year,” he said.

TenneT said it will submit concrete solutions on Monday, including an extension of the temporary solution agreed last year.

Danish state-owned power transmission company was not immediately available for comment. ($1 = 6.0653 Danish crowns) (Reporting by Alissa de Carbonnel, Teis Jensen and Jacob Gronholt-Pedersen Editing by Foo Yun Chee and David Goodman)