The Bonneville Power Administration (BPA) curtailed wind power generation again during the early morning hours of April 29 and 30, when rising runoff and high wind caused oversupply on BPA's system.
BPA displaced about 4.3 GWh of wind energy generation for several hours on the morning of April 29, and about 5.8 GWh on the morning of April 30.
The agency says it applied its new oversupply management protocol for the first time, temporarily replacing the output of thermal and wind power generators in its balancing area with hydropower.
The protocol states that BPA will reimburse generators for the value of lost production tax credits and renewable energy credits and certain costs related to contracts. Under the protocol, generators with the lowest cost are displaced first.
The agency tells NAW it is taking a number of measures to avoid impacts on wind energy generators, including the following:
Curtailing available thermal generation first. Thermal generation will be curtailed before any wind energy generation is ordered to stop producing.
Using a new product called "capacity recallable energy." This tool is designed to manage the large seasonal amounts of energy sometimes caused by the combination of high water and high wind. The product allows BPA to have another utility or power producer in another system to provide balancing reserves that offset the ups and downs of wind energy, maintaining the critical balance between electricity supply and demand. That, in turn, lets BPA produce hydroelectricity that otherwise would be held in reserve and helps it control dissolved gases without asking a thermal or renewable energy source to reduce or cut its output.
Engaging in "spill exchanges" involving the federal hydroelectric system and other partners. According to BPA, these exchanges have helped reduce the risk of oversupply and potential impacts on wind generators. BPA says it has acquired 61.5 GWh under the Mid-Columbia Spill Exchange agreement, which allows more spill at the Mid-C dams and more generation at the Grand Coulee and Chief Joseph dams. It has also coordinated spill on the Willamette hydro projects for additional relief.
Reducing the region's only nuclear plant's output by up to 85%. According to BPA, this is the lowest level that still maintains grid reliability.
Still work to be done
Despite these measures, wind energy generators are disappointed with BPA's actions. The Renewable Northwest Project (RNP), a coalition that represents wind power generators in the matter, maintains that BPA's decision to curtail wind power is a violation of the Federal Energy Regulatory Commission's (FERC) open-access transmission policy.
"Given a full year to plan ahead, we are disappointed that BPA is choosing to curtail wind energy, despite more equitable solutions within reach," says Rachel Shimshak, executive director of RNP. "This practice wastes clean and affordable energy while power plants continue to burn coal around the region. BPA's dismissal of FERC's open-access transmission policy – that all generators should be treated equitably – undermines the long-term policy certainty necessary to attract continued investment in renewable energy in the Northwest."
Although RNP recognizes BPA's efforts in trying to resolve the issue, the coalition is advocating for other methods of doing so, such as a non-treaty storage agreement with Canada, an irrigation-pump aquifer recharging pilot and the sale of hydropower in advance of oversupply events.
"While these are positive steps in the right direction, they are not currently being deployed at a sufficient scale," Shimshak says.
Shimshak recommends that BPA work to power down the nuclear plant for refueling each spring, collaborate with fish experts on additional responsible spill, and pay the prevailing market price, which sometimes goes negative and is a common practice in most electricity markets across the country.
BPA could also better pursue advance agreements with coal generators beyond its balancing area to share the Northwest's abundant renewable energy, RNP adds.