It’s springtime in the Northwest, meaning rain, warmer temperatures, snow melt and blustery wind. Occasionally, it also means more hydro and wind electricity is pulsing into the grid than anyone can use.
That’s a major problem for wind farm owners, for whom spring has become the season of curtailments, when BPA can suddenly shut down their output to prevent “over-generation.” The cutoffs can mean millions of dollars in lost revenue, and put a cloud over further wind development in the Northwest.
The season just started. No one knows what it will bring. Dispatchers are standing by.
When the situation gets critical, “that thing makes a really obnoxious alarm and we have to scramble,” Blair said, pointing to a display on a flat panel. “We get charged $1,000 a megawatt hour if we generate more than they tell us to. They don’t give us any indication, and suddenly they need 500 megawatts” less wind.
While the output of the Columbia hydro system is awe-inspiring, “over-generation” hasn’t been a problem since the federal government built dams and a slew of industrial customers – shipbuilders, aluminum smelters, semiconductor makers – migrated to the Northwest for cheap power. But many of those energy hogs are gone, only partially replaced by the new data centers east of the Cascades.
Meanwhile, a wind farm boom to satisfy state renewable power mandates plugged 4,400 new megawatts of intermittent generation into BPA’s transmission system. When the windmills go full throttle, they generate enough power for 3.5 million homes.
The problem blew up last year, when wind reached a critical mass and the region faced an unusually high snow pack and runoff. BPA responded by instituting “environmental redispatch,” a protocol to cut off wind farms’ transmission during over-generation and substitute free hydropower to satisfy scheduled deliveries to customers.
BPA says it has no choice. During extreme runoff events, it says it can’t reduce hydro generation by shutting off turbines and spilling excess water over the dams. Resulting turbulence would increase dissolved gases in the river beyond mandated levels set to protect migrating fish.
Fish advocates actually say more flow over the dams would be good for salmon. But BPA says it needs to stick to legal limits. Likewise, BPA says it needs to protect the reliability of the grid by ensuring electricity supply is always perfectly in synch with demand. The largely automated process is complicated with the addition of so much variable capacity from wind farms.
Wind developers acknowledge the problem, up to a point. But they say the real issue is too much hydro, and not enough demand. Last year, federal regulators agreed that BPA’s solution — unilaterally cutting off winds farms’ transmission contracts and substituting hydro without full compensation for lost revenues — illegally discriminated against wind farms.
BPA came up with a cost-sharing mechanism this year, agreeing to split lost revenue with wind farms. But renewables advocates say the new transmission tariff BPA was required to file with federal regulators last month didn’t solve the problem. It leaves BPA with discretion to discriminate when conditions dictate and protect its own power sales at wind farms expense, they say.
That argument will play out in coming months. Meanwhile, spring has sprung.