Stockholm — Swedish utilities and power generators have already installed so many wind turbines that the Nordic nation is on course to reach its 2030 renewable energy target late this year.

By December, Sweden will have 3,681 wind turbines installed, lobby group Swedish Wind Energy Association estimates. Together with second-half investment decisions, this will be more than enough capacity to meet a target to add 18 terawatt-hours of new, renewable energy output by the end of next decade. Some new plants will be built by Norway, with which Sweden shares a renewable certificates market.

The surge in new installations and investment decisions has become a concern for existing power producers, who rely on subsidies to make their projects financially viable. Forward prices in the renewable certificate market are 70% lower for 2021 than a year earlier because of all the new installations.

"For Sweden to remain interesting for investors ahead of markets with higher revenues but greater political risks, it is important for policy makers to show that they care about past investments," Mattias Wondollek, a spokesman for Swedish Wind Energy Association, said in a statement. "This is done best by introducing a volume-based stop rule."

Such a rule would mean that once the 2030 target is reached, new investors would not be able to get subsidies.

Final investment decisions for as many as 840MW were taken in the second quarter, according to the lobby group estimates and a total of 7,506MW of wind capacity will be installed by December.

Most of the new capacity will be on land. A total of 2,609MW of on-shore wind capacity will be added in 2018 and 2019, according to the latest forecast from the lobby group. This compares with 970MW for the same period in the report a year earlier.