The Columbia River system could see more runoff this spring than it has in a decade. It will also likely see more wind generation than it has ever seen before.
Bonneville Power Administration officials say such a situation could pose unique challenges for dam operators, whose goal is to operate the hydro system reliably and keep water conditions safe for fish.
BPA says it is taking steps now to help it achieve these goals, should the forecasts prove accurate.
Depending on when and how quickly the snowpack melts, BPA could at times end up with more water for the hydro system than it needs. Power systems rely on a constant balance of energy production and consumption. So when faced with a surplus, BPA must either reduce generation or find consumers to absorb the extra power. .
At the same time, BPA’s integration of renewable resources has greatly increased the amount of generation that may be online during high runoff, increasing the frequency and magnitude of “overgeneration” conditions.
Spill is one tool BPA uses to balance generation and consumption – and spill often helps young fish migrate downriver. But too much spill can lead to excessive levels of dissolved gas in the rivers, which can harm fish.
So BPA officials says the agency is taking additional measures.
Since spring runoff began April 1, BPA has:
-- Adjusted non-essential maintenance on transmission lines so that maximum capacity is available to carry large amounts of power to consumers.
-- Deferred non-essential hydro generation outages and maintenance activities.
-- Executed contracts with other power producers to sell low-cost federal hydroelectric power.
-- Implemented spill at federal hydro projects within prevailing water quality standards.
-- Operated Grand Coulee Dam inefficiently at night when power consumption is lowest.
-- Asked Energy Northwest to begin a refueling outage of Columbia Generating Station – the region’s only nuclear plant – several days earlier than planned, reducing the generation feeding BPA’s transmission system by about 1,000 megawatts.
-- Sold significant amounts of energy at zero cost.
BPA says it has worked with thermal generators to reduce fossil-fuel generation when necessary to avoid excess power. But given the amount of snowpack this year, the agency may have to reduce wind generation as well.
In February, BPA sought public comment on a proposal to protect fish and maintain system reliability during high runoff by temporarily replacing non-federal generation in the region with free federal hydropower. Because wind producers may lose production tax credits or renewable energy credits when wind power is replaced with federal hydropower, BPA has not yet announced a decision on the proposal.
The agency received significant comment on its proposal and says it is determining the appropriate course of action. In the interim, officials say the agency continues to do what it can and consult with other regional utility leaders to minimize the risk of excess generation. .