Gotland output exceeding demand

Up to ten of the more than 100 turbines on the island of Gotland had to be shut down during some windy nights in the summer when their output exceeded the demand of the island's inhabitants. The excess is not a serious problem yet, but Gotland is likely to double its wind power capacity in the next few years, hastening the search for a solution.

1 October 1997

The 40 MW of installed wind power capacity on the island of Gotland -- the cradle of Swedish wind development -- is producing more electricity than consumers can handle. Up to ten of the more than 100 turbines on the island had to be shut down during some windy nights in the summer when their output exceeded the demand of the island's 56,000 inhabitants. A large cement factory, which usually uses half of Gotland's electricity, was closed for the summer season, sending the island's power consumption to its annual low point.

Gotland, off Sweden's east coast in the Baltic Sea, has an isolated power grid connected to the mainland by a high voltage DC cable, which can only transmit power in one direction -- from the mainland to Gotland. The over production is not a serious problem yet -- stopping a few turbines for a few hours hardly affects economic returns, say the operators. But Gotland is likely to double its wind power capacity in the next few years, hastening the search for a solution.

Local utility GEAB's priority is a grid reinforcement allowing more wind generated electricity, estimated to cost SEK 150 million. Following the summer's wind surplus, the utility has doubled the grid connection fee for wind turbines from SEK 600/kW to SEK 1200/kW as a way to help finance the reinforcement. GEAB reports the fee increase was in response to a complaint from a consumer demanding that reinforcements for wind power be financed solely by wind power producers, not consumers. The utility's Christer Liljengren says he would have preferred a special grid levy on the kWh price of wind output, but current regulations do not allow that.

The Gotland wind power association GVP has reacted strongly to the move. While such fees do not exist on the mainland, the SEK 600/kW grid connection fee had been based on a mutual agreement between the utility and the wind plant operators. Raising the fee without prior consultation with GVP is seen as a move to stop further development without any backing in laws or regulations. The association claims the SEK 1200 will effectively stop further wind development in its tracks.

GEAB is discussing the matter with central authorities, looking for state financing to offset the reinforcement costs, which the small utility says should not be borne by itself alone. Since 1990, GEAB has reinforced the grid twice after wind power development at Gotland's Näsudden site was much faster than expected. And now the country's first offshore wind farm is being built off the Näsudden coast.

The level of grid reinforcement needed to handle wind power development over coming decades is hard to estimate. Today's 32 MW capacity at Näsudden could double within a few years -- and there are plans for groups of several 1.5 MW turbines in other areas of Gotland as well as a series of offshore wind farms of 30-50 MW around the island's coastline.