Alta. doubling wind power capacity .................................................
Unpredictable winds keep supply unreliable
Gordon Jaremko, The Edmonton Journal
Saturday, May 27, 2006
EDMONTON - Wind power capacity will nearly double in Alberta over the next 18 months, then keep on growing, an electricity supply and reliability watchdog predicted Friday.
Turbines under construction will add 244 megawatts by the end of 2007 to the 297 MW of wind power currently operating, said Kevin Willerton, market services director of the Alberta Electric System Operator. The renewable energy source could then grow by an additional 360 MW before hitting a natural limit on its size, the AESO estimates.
Wind power has to remain less than 10 per cent of Alberta's electricity supply because it is unpredictable, said Willerton, who worked in the field before joining the watchdog agency.
Peak provincial demand, at the busiest time on the coldest day of the year, is about 9,600 MW.
Wind turbines do well if they run 30 to 35 per cent of the time, on average over a year. At any given moment sudden changes in wind speed and direction turn the towering machinery on or off unpredictably in a matter of minutes.
"You're never quite sure what you're going to get," Willerton told the Economics Society of Northern Alberta.
While encouraging renewable energy development, AESO still has primary responsibility for ensuring power supplies match requirements around the clock, he said.
The role includes minute-by-minute "dispatching," or switching on coal-fired and natural gas-fired power stations, as well as wind and hydroelectric generators, as demand fluctuates. Few plants can turn on or off rapidly enough to make up for wind power's trademark sudden changes in strength.
The Alberta electric system's ability to use wind power could eventually increase beyond 10 per cent if its range of supplies grows, Willerton said in an interview. Improved connections with other grids in Canada and the United States would help, he said. Wind turbines could become a more reliable power source if larger numbers of them were spread over wider geographical areas with varying weather conditions, he added.
Wind power stations to date are concentrated in the southwestern Alberta chinook belt near the Rocky Mountains.
But new projects are spreading development east onto windswept plains between Lethbridge and Medicine Hat, Willerton said.
Turbines could be erected eventually in breezy locations north of Edmonton under confidential schemes discussed by AESO and wind power entrepreneurs, he added.
More than enough projects are lined up to build all the wind generators Alberta can handle. Proposals to build 2,240 MW of wind power, in addition to the 541 MW now operating or under construction, are seeking AESO support to hook up to the provincial grid, Willerton said.
Competition, environmental concerns aroused by mammoth turbine generators and high price tags on new projects will pare down the lineup to the hardiest economic survivors, he predicted.
Wind power construction costs average $2 million per MW, or about the same as coal-fired plants. That makes wind generators about three times as expensive because they run only one-third of the time while coal stations run virtually flat out around the clock all year, Willerton said.
Gas-fired stations are cheaper to build at $700,000 per MW, but their low construction costs are offset by high fuel prices. |
