Big Flows Bring Limits on Non-Hydro Energy
Columbia Basin Bulletin, May 20, 2011
Spill Stirs Gas Levels Potentially Harmful To Fish
With high Columbia-Snake river flows generating an oversupply of hydroelectricity in the middle of the night Tuesday-Wednesday, the Bonneville Power Administration partially and temporarily limited the production of non-hydro energy, including fossil-fuel and other thermal generation and wind energy that was entering its transmission system.
The resulting five-hour non-hydro energy reduction represents the first use of a new policy announced last week that the federal power marketing agency says helps protect salmon and steelhead, maintain the reliability of the power grid and avoid shifting costs to its customers.
Such cutbacks allow the Federal Columbia River Power System to generate at full capacity during such high flow-lower power demand times and send less water through spillgates. Spill stirs up large amounts of total dissolved gas, which at higher levels can be harmful to salmon and other aquatic life. Hydro power generation creates little gas.
The surge in water came as the U.S. Army Corps of Engineers increased river flows to maintain flood control space in upstream reservoirs for further runoff from the largest Northwest snowpack since 1997.
The Columbia River at Vancouver, Wash., was expected to bump up against flood stage – 16 feet elevation – Thursday and then linger within a foot of flood stage for the next 10 days, according to a Northwest River Forecast Center 10-day forecast.
High water and hydroelectric output combined with low night-time energy demand led BPA to temporarily limit other types of generation beginning at 12 a.m. Wednesday. BPA first limited all coal, natural gas and other thermal generation to minimum levels required for transmission grid stability and safety.
The new "environmental redispatch" policy calls for cutting back wind power input to Bonneville's transmission as a last resort. Wednesday morning eventually limited approximately 200 to 350 megawatts of wind power generation until 5 a.m. Wednesday, totaling approximately 1,400 megawatt hours in non-hydro reductions. There are currently more than 3,500 megawatts of wind energy connected to the BPA system, the most of any electricity provider in the nation, according to BPA.
For comparison, 200 to 350 megawatts is about one-third of the generating capacity of Bonneville Dam. The limits were lifted at 5 a.m. Wednesday but reimposed Wednesday-Thursday night. BPA temporarily limited the energy output of regional generators, including wind generators, from 11 p.m. on Wednesday until 5 a.m. May 19. During that six hour period, slightly less than 1,000 megawatts per hour of wind generation, and a total about 5,700 megawatt hours including thermal generation, were impacted.
Further limits may be needed in coming days. The generation limits can be tracked at www.bpa.gov/go/afterhours, where updates will be posed at 9 a.m. and 3 p.m. daily.
"Despite that, most dams are above the 120 percent standard of both states," BPA spokesman Michael Milstein said of total dissolved gas limits imposed by Oregon and Washington for the eight dams on the mainstem Columbia and Snake rivers to protect salmon and steelhead, some of which are listed under the Endangered Species Act.
Flows are managed when possible to keep TDG levels above 115 percent above each dam and 120 percent in the tailrace, though at higher flows that is virtually impossible to accomplish.
TDG 12-hour averages jumped to as high as 132.7 percent Wednesday in Lower Monumental Dam's forebay, 127.5 percent in Little Goose Dam's tailrace and 127 percent in lower Monumental's tailrace. Lower Monumental and Little Goose are on the lower Snake River in southeast Washington. TDG totals were above 124 percent in the John Dan and McNary dam tailraces Wednesday. Both are on the Columbia below its confluence with the Snake.
Dissolved gas levels are available in real time at the U.S. Army Corps of Engineers Water Management Division website at http://www.nwd-wc.usace.army.mil/
Flows jumped from 281,000 cubic feet per second on May 11 to 445 kcfs Wednesday as a daily average at Bonneville Dam, the lowermost hydro project in the Columbia-Snake system. Flows at Lower Granite Dam on the lower Snake rose above 100 kcfs May 9 and sprouted to 203 kcfs Sunday.
"Our biggest concern is that we not wait until it gets significantly above that (the gas caps) for an extended period of time because we know that hurts fish," Milstein said.
Looming high seasonal river flows and hydroelectric generation led the Bonneville to issue an interim decision on the environmental redispatch policy to help cope with runoff from the large snowpack. The Northwest River Forecast Center's most recent forecast, its "midmonth" released Thursday -- predicts runoff past The Dalles Dam on the lower Columbia from April through September will total 125 million acre feet, which would be the fifth highest total in the past 41 years of record.
The conditions could temporarily push generation of hydroelectric power beyond the region's limited spring electricity needs. The interim policy gives BPA the tools to match power generation to demand, which is necessary for dependable operation of the power grid, the federal power marketing agency says.
The interim policy, which will remain in place until March 30, 2012, first limits generation at coal, natural gas and other thermal power plants to keep the supply of power from exceeding demand. Under the policy, BPA will replace any reduced thermal and wind generation from private entities with free hydropower from federal dams on the Columbia River system.
"This was an extremely difficult decision for me. Despite months of searching through a robust public process, there was no good choice here," said Steve Wright, BPA administrator. "I believe we have adopted the option that best preserves reliability, protects salmon and avoids increased costs on average to Northwest ratepayers."
BPA took several earlier steps to avoid need for the interim policy, including:
-- Adjusting non-essential maintenance on transmission lines so that maximum capacity is available to carry large amounts of electric generation to distant markets from Canada to California.
-- Using the plentiful energy to pump water into storage space at Banks Lake, above Grand Coulee Dam, for later use to irrigate crops or generate power.
-- Offering low-cost or free hydropower to help create a market incentive for power producers to substitute it for fossil fuel generation.
Wind energy producers may lose tax credits and other revenues when their wind turbines do not actively generate power. However, BPA will not reimburse wind energy producers for lost tax credits or other revenues because that would shift costs to Northwest ratepayers who do not receive the wind power.
"We're fortunate in the Northwest to have extraordinary renewable hydropower and wind energy resources, but occasionally we have to adjust when nature gives us too much," said Wright. "Wind remains an important part of our clean energy future and is growing quickly. This is an interim step, which appears unavoidable at this point to keep the power grid in balance while the region develops long-term solutions."
BPA earlier this year sought public comment on a draft policy that provides for temporary limits on wind generation when necessary to protect fish and the reliability of the electrical system.
BPA and other agencies will closely monitor river conditions and will lift any limits on power generation as soon as they are no longer needed.
The new interim policy immediately drew criticisms from fish and wind advocates.
"We are extremely disappointed that BPA chose to implement this Record of Decision, but glad that it will be temporary. While we are sympathetic to the impact of Mother Nature's generous snowpack this year, we believe that unilaterally curtailing wind projects with no compensation is an unfair and discriminatory solution to the excess generation issue," according to a statement released by the nonprofit Renewable Northwest Project. "It is also inconsistent with the Northwest's future-forward commitment to deploying clean energy resources, and it will invite litigation. We recommend a diversity of cheaper solutions (e.g., displacing coal, responsible additional spill) that would not create uncertainty for future renewable development in the region."
Renewable Northwest Project is a regional nonprofit advocacy organization promoting responsible development of renewable energy resources in the Northwest.
"It's time for BPA to stop putting its hydro operations and revenue above the needs of the Northwest, both for the sake of our salmon and for the benefit of the renewable energy industry," said Nicole Cordan, Save Our Wild Salmon policy and legal director.
"To suggest that developing clean, renewable wind power and saving endangered salmon are somehow at odds is absurd," said NW Energy Coalition Executive Director Sara Patton. "We know we can build a healthier and more prosperous Northwest while combating climate change and protecting wild salmon; shutting off access to wind power is not the way forward . . . for any of us."
Save Our Wild Salmon is a nationwide coalition of conservation organizations, commercial and sportfishing associations, and taxpayer and clean energy advocates. The NW Energy Coalition is a 30-year-old regional alliance of more than 110 consumer and environmental groups, utilities, businesses, unions and other organizations committed to a clean and affordable energy future.
A May 13 Save Our Wild Salmon press release says that the BPA plan unilaterally changes wind generators' contracts without compensation, which harms the booming alternative energy industry and shortchanges endangered salmon populations.
The coalition said that increased spill, which is generally considered the most benign route of passage, would benefit salmon and steelhead by easing their migration past these dams.
The conservation group noted that U.S. Rep. Ed Markey (D-Mass.) recently sent a letter to Secretary of Energy Steven Chu addressing current issues with BPA and its approach to wind energy production and water spill levels in the Columbia and Snake rivers. In his letter, Rep. Markey writes that he is aware that changes in power systems will present new challenges to energy managers. However, he asks that BPA utilize resources such as the Department of Energy to create sound policies, rather than just shutting off wind.
According to Save Our Wild Salmon, Sen. Jeff Merkley (D-Ore.) and Rep. Earl Blumenauer (D-Ore.) also sent letter to BPA, asking it to reconsider its Record of Decision on the interim policy and expressing their concern that it would "cause significant problems for renewable energy development in our region."
Overgeneration Announcement related to graphic.
To safeguard salmon and steelhead and assure reliable energy delivery during these unusually high seasonal river flows, BPA has taken the following measures, which it took as a last resort and had been working to avoid. BPA will update this site at 9 a.m. and 3 p.m., Monday through Friday.
[May 20, 9 a.m.] BPA temporarily limited the energy output of regional generators, including wind generators, from 11 p.m. May 19 until 5 a.m. May 20. During that six hour period, approximately 600 to 1,200 megawatts per hour of wind generation, totaling about 5,300 megawatt hours, were impacted.
[May 19, 3 p.m.] No current limits on generation
[May 19, 9 a.m.] BPA temporarily limited the energy output of regional generators, including wind generators, from 11 p.m. May 18 until 5 a.m. May 19. During that six hour period, slightly less than 1,000 megawatts per hour of wind generation, totaling about 5,700 megawatt hours, were impacted.
[May 18, 3 p.m.] No current limits on generation
[May 18, 9 a.m.] BPA temporarily limited the energy output of regional generators, including wind generators, from midnight until 5 a.m. May 18. Approximately 200-350 megawatts of wind generation per hour, totaling about 1,400 megawatt hours, were impacted.
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