According to Xcel Energy, 9 percent of all the power it provides comes from wind power, and by 2020, it projects that this will grow to about 20 percent. However, at certain times of the day, the wind farms supplying energy to Xcel achieve a far higher share of its energy mix.
This was the case early on the morning of 6 October, when 55.6 percent of the electricity consumed by the company’s 1 million customers came from wind farms in Colorado. The achievement was, says the American Wind Energy Association, a new world record for the share of electricity generated by wind power. A combination of low electricity demand, with most of the state’s citizens still asleep and businesses closed, and a high output made the record possible.
"That is the highest recorded wind penetration record in the world for a utility system, as best we know," Michael Goggin, manager of transmission for policy for the American Wind Energy Association, told the Denver Post.
"We're proud of that and believe it shows that wind is an important part of the portfolio," said Michelle Aguayo, an Xcel spokeswoman told the local newspaper. Minneapolis-based Xcel, which handles 3.4 gigawatts of wind power across its eight-state service area, has been providing customers with the option to choose renewable energy for more than a decade.
The company’s Windsource program, launched in 1998 to Colorado customers, has grown to be one of the largest voluntary green-energy programs in the United States. Customers now in Colorado, New Mexico, Minnesota and Wisconsin can designate that part or all of their electricity comes from a renewable energy source through participation in Windsource.
The company currently owns and operates three wind farms – the Grand Meadow and Nobles wind farms in Minnesota and the Ponnequin wind farm in Colorado. It is also working with the National Center for Atmospheric Research and its high-resolution wind energy forecasting system, which combines real-time, wind turbine-level operating data with weather prediction models and sophisticated algorithms to forecast wind energy out for 72 hours. The forecasts help system operators make decisions about powering down coal- and natural gas-fired power plants when sufficient winds are predicted.
Battery storage
In 2008, Xcel also began testing a 1-megawatt battery-storage technology in Luverne, Minn., to demonstrate the ability to store wind energy in batteries and move it to the electricity grid when needed. The battery installation is connected to a nearby 11-megawatt wind farm owned by Minwind Energy.
According to the Denver Post, Xcel is appearing before the Colorado Public Utilities Commission on 21 November to request permission to add another 200 megawatts of wind from NextEra Energy to its portfolio.
The previous record for wind's contribution to the energy mix of 53 percent was set in in 2009 in Spain, although in that case, the achievement was all the more impressive, as it was set for the entire power system. According to the Spanish grid operator, Red Eléctrica Española, wind power covered 10,170 MW of the country's total demand for power in the dawn of 8 November 2009. Furthermore, during the first nine days of that month, wind turbines generated more power than any other source, with an output of 1,770,486 MWh, ahead of Spain’s combined cycle plants with 1,369,955 MWh and nuclear facilities with 1,223,350 MWh.
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