Results tagged “Total Dissolved Gas” from GTH Energy & Natural Resources Law Blog

Wind War Subplot: Challenge to Washington Gas Limits Fails, Barrier to Increased Spill Remains in Place

December 11, 2012

Washington State's Court of Appeals recently upheld the Washington Department of Ecology's decision to retain existing water quality standards limiting dissolved gases at hydroelectric dams. The decision carries significance well beyond the specific dispute resolved by the court because it limits one avenue -- increased spill -- that may have relieved some of the pressure on the Bonneville Power Administration ("BPA") to integrate increasing amounts of variable wind generation into the regional grid. As we have previously reported, BPA's decision to require curtailments of wind generation during high-wind/high-water events has produced contentious litigation, pitting the Northwest's wind generators against BPA and its public power customers. Although it does not directly address the issues involved in that litigation, the Court of Appeals decision nonetheless has significant bearing on the BPA litigation because it means that BPA's non-curtailment options will continue to be limited.

The Court of Appeals case, Northwest Sportfishing Industry Association v. Department of Ecology, arose from a petition filed by a group of fisheries and environmental advocates asking the Department of Ecology to raise its Total Dissolved Gas ("TDG") standards to accommodate greater flows over the dams. TDG standards are aimed at preventing damage to fish and other aquatic species from gas-bubble trauma. Gas-bubble trauma occurs when excessive levels of atmospheric gases in the water column are absorbed by aquatic creatures and then released in their tissues as gas bubbles, much like "the bends" in a human diver. Gas-bubble trauma can cause significant physiological damage or even death, and is therefore of concern for the Columbia Basin's salmon and steelhead runs, including several listed under the Endangered Species Act. The fisheries advocates who filed the petition believe that TDG limits can be raised by the Department of Ecology without threatening significantly greater damage to fisheries from gas-bubble trauma, and that higher TDG limits will accommodate greater spill over the Columbia Basin's dams, leading to an improvement in the survival of salmon smolts migrating downstream.

Greater latitude for spill would also give BPA some additional flexibility to manage springtime conditions, in which high run-off in the river system often coincides with high winds and high power production from the region's wind fleet. In such conditions, BPA has sometimes curtailed production from wind generators because generation during periods of high wind combined with production from federal dams in the region exceeded the demand during that period. An additional margin for spill would allow BPA to spill additional water over the Columbia Basin's dams rather than running it through turbines (which produces significantly lower concentrations of dissolved gas but also power when it is not always needed). Because less power would then be produced by hydroelectric turbines, there would be a greater margin for allowing wind generators to produce without curtailments.

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