Denmark has a problem — it’s generating too much power from the wind. Currently, Denmark gets about 20% of its total electrical power from wind. On windy days, that percentage can double. The ups and downs of wind power can strain an electricity grid. In western Denmark, the price of electricity can drop to zero on a windy day, leaving utilities scrambling to offload excess power or take a financial hit. To solve this problem, the Danish utility company Dong Energy plans to build a nationwide system to charge electric cars with the surplus wind power.
They are partnering with a start-up company in California, Project Better Place, and they are planning by 2010 to build the infrastructure to support a countrywide electric-car system, with charging spots and battery-exchange locations across Denmark.
“Cars are the perfect match for wind power,” said Shai Agassi, chief executive of Better, which is rolling out a similar network in Israel and has a deal with Renault and Nissan to build fully electric mass-market cars that run on lithium-ion batteries. “They charge sitting in the garage at night when there is little other demand for electricity.”
Dong, which has dealt with wind “intermittency” for years, has its hands full with the Danish government’s pledge to raise its share of electricity from renewable sources to 30% by 2025. “It’s an increasingly difficult challenge for us,” said Dong CEO Anders Eldrup. “We have to make our traditional fossil-fuel plants more flexible. That way we can turn power plants down, or even off, when the wind is blowing.”
In addition to revamping old plants, Denmark has built stronger connections to nearby Germany, Sweden and Norway so it can sell excess electricity on windy days. When it is windy in Denmark, countries like Norway buy cheap power to supplement their own hydropower resources. On very windy days about half of wind power is exported to Norway and Sweden, where many homes are heated with electricity.
“We have to keep investing heavily in the grid to make sure we can transport the electricity from wind when and where it is most needed,” said Peter Jorgensen, vice president at Energinet.dk, the nonprofit, state-owned company that runs Denmark’s grid.