The six-month pilot began in early May and involves two wind farms owned by Calgary-based TransAlta Corporation, the largest wind producer in Alberta. The company receives wind forecasts from the Alberta Electric System Operator (AESO) and uses the data to make price and volume bids that will determine whether generation from its wind farms is dispatched.
The test is a significant change from the status quo, under which all wind generation bids into the market at C$0/MWh and is automatically taken onto the grid whenever the turbines are producing. The lower the generator bids, the higher its chance of its power generation being dispatched. Generators that succeed are all paid the same price, which is arrived at by taking the bid of the last generator dispatched to meet demand. But as wind becomes a bigger part of the system mix that is increasingly hard to manage, explained Jacques Duchesne, manager of wind integration at AESO.
Alberta currently has 891MW of wind capacity, about 6% of the province's total installed generation base. Wind will reach about 1.1GW this autumn and by the time it gets to 1.5GW - expected next year - the system operator is going to need a longer-term strategy in place, said Duchesne. "There are a few options we are exploring and one of them is to have wind participate in the market like any other generator," he said. "This is a good time to test that using real live assets."
Setting dispatch limits for wind facilities will reduce variability, Duchesne said. That in turn should reduce the need for backup resources and allow more wind to come online, added Jason Edworthy, TransAlta's director of communications. "If we can reduce the cost of being part of the system, have some confidence that we can grow as an industry and make the system controllers much more comfortable, those are really positive things."
There could be other positives as well. Because most of Alberta's wind generation is concentrated in the same wind regime, it is usually all on or all off at the same time. When it is operating, it tends to pull down the wholesale market price because less higher-priced generation needs to be dispatched. When it is not operating, the price goes up, but wind producers are not there to benefit.
In 2011, the average spot market price was C$72/MWh but wind producers only earned an average of C$50/MWh. Allowing wind producers to price their product could help earn them more money, said Duchesne.