Alberta battle over back up for wind
The Alberta Electric System Operator (AESO) and the province's wind producers have launched a study of the variable electrical output from existing and proposed wind power facilities. The initiative was sparked by a recent report commissioned by AESO from ABB, a global power and automation technology company, suggesting a need for high levels of regulating reserves to back-up wind power in the province. The ABB report sent the wind industry scrambling to show the estimates are out of synch with the growing body of experience in other markets.
That ABB study looks at integrating the estimated 1200 MW of wind proposed for Alberta by 2007. It finds that regulating reserves may need to be increased by 120-481 MW, while the contingency reserves may need to increase anywhere from 375-805 MW. At 2003's average price of $31.67/MWh for regulating reserves, ABB states, the added cost to the system could be between C$91,000 and C$370,000 a day. Contingency reserves could add another C$45,000 a day.
The Canadian Wind Energy Association (CanWEA) responded to ABB's claims with strong evidence to the contrary, provided by two independent experts it commissioned to review the ABB report. CanWEA points out that most international studies show the amounts of extra reserve capacity required are in the range of 1-3% of the wind capacity when the wind accounts for 10% of the peak demand. It estimates the cost of extra balancing for 1200 MW of wind on Alberta's system at C$0.30/MWh. The association also calls for a study to give everyone a "realistic indication" of wind energy behaviour in the province -- a suggestion now acted on by AESO and the wind industry.
Wind power producers have agreed to provide data from existing wind farms and from monitoring towers scattered through the southern part of the province, which will be handled on a confidential basis by a third-party consultant. AESO will pay for the study, which is expected to be complete by the end of the year.
"The whole idea is that by looking at wind data from real towers and real prospective wind farm locations, and translating that into what the output from a wind farm would be, you can show the real variability in net generation," explains Vision Quest Windelectric's Jason Edworthy, whose company owns and operates the majority of Alberta's installed wind capacity. "We are confident it will show less variability than the ABB study."
ABB's conclusions were based on data from one week last November that, says Edworthy, was atypical for a variety of reasons, including problems with a 50-year-old breaker at a regional substation that forced the operator to set it on a hair trigger. "It would pop off at any time," he says.
ABB also extrapolated data from wind farms concentrated in a small area, says Edworthy. "Certainly by the time we have 1200 MW in the province we're going to be stretching all the way over to the Saskatchewan border. I think it's clear geographical diversity really evens out those variations."
AESO's Fred Ritter acknowledges more work is needed to understand the volatility question, saying ABB was asked only to take a "high-level" look at the issue as part of a broader wind technical study -- a 1500 page report AESO used to help develop a comprehensive wind interconnection standard for the province. The first draft of that standard, released in June, also sent the industry reeling.
CanWEA says the proposed standard went "far beyond" what is necessary to ensure the grid's reliability. "The costs associated with those requirements for wind energy project developers would threaten C$1.5 billion of potential future investment," the association told AESO. CanWEA also pointed out that a review of the draft by consultant Bob Zavadil of EnerNex found that it laid out many standards for design and performance going "well beyond" those required for wind generation facilities in other parts of North America, in some cases demanding features that, though technically possible, are not yet commercially available.
"I think it shows how, for a lot of the electricity infrastructure providers in Canada, wind is a new idea. Although there is a lot of demonstration from experience in other countries about how wind can be integrated into the grid, we don't have that level of experience here," says CanWEA's Robert Hornung. "There is, unfortunately, going to be a learning curve and probably a bumpy process to get there. One thing that is good about what is happening in Alberta is that it appears to be a somewhat iterative process with some opportunity for discussion, which we appreciate."
Listening to the industry
Indeed, a new draft released last month incorporates feedback from the industry, says Ritter. "What we introduced in June we referred to as a framework for a standard. It was to generate discussion and it certainly did that. We've made adjustments on a number of fronts with the new version," he says. "I'm sure there will be issues, but hopefully those are understood and we can move forward. The objective here, really, is to design a reliable system that will enable a lot more wind to get interconnected."
Edworthy says although there are still some concerns, AESO has come a long way in the right direction. For example, it has deferred a number of requirements related to variability until the study is complete and has lowered its expectations is some areas, such as demands that wind turbines be able to "ride-through" low voltage dips in the network, instead of tripping offline. "Some form of low-voltage ride-through is going to be required, but the requirements within that are now more reasonable," he says. "The fact is we're growing up and we're talking about bigger projects on lines that were meant to serve load. And this is how it is going to be and we just have to recognise that." Edworthy's comment on load refers to lines built to take electricity to the customer, rather than to take electricity from a power plant. AESO expects to have the standard finalised by the end of this month.
In other provinces
Although Alberta is the first jurisdiction in Canada to tackle wind power interconnection issues in a detailed way, it will not be the last. Quebec's energy board has already recommended formation of a utility-industry working group to assess wind interconnection and energy management issues, while in Manitoba, Daniel Brooks of EPRI PEAC Corporation, a global company that grew out of an initiative by the US Electric Power Research Institute two decades ago to provide specialised power system solutions, is in the final stages of a study for Manitoba Hydro. It examines the integration of large scale wind into its system. "Manitoba, with its hydro system, is a net exporter of electricity most of the time, so any additional reserves that they carry obviously have an opportunity cost, so it is a big issue to them," says Brooks.
Meanwhile, with each province and territory in charge of its own electric system, CanWEA is looking at ways to try streamline the process. "There is a fear, always, within Canada that we are going to end up having 12 different discussions," says Hornung. "We have talked with Natural Resources Canada about trying to bring together grid operators from across the country to sit down and have a joint discussion about some of the issues and concerns they have and some of the issues and concerns we have, so we are at least all starting from the same place."
CanWEA has also suggested to the federal and provincial environment ministers that they form a National Wind Interest Group to deal co-operatively with potential barriers to wind power development.