Recent news articles [1,2] have highlighted some of the challenges faced by renewable energy sources in the Pacific Northwest as wind turbine farms grow larger. By far, the majority of electricity produced in Washington, Oregon and Idaho comes from hydroelectric dams on the Columbia and Snake Rivers, with some contribution from nuclear and coal and natural gas plants . Total wind turbine installations in Washington and Oregon are approaching 4000 MW in nameplate capacity, however , which represents a non-trivial fraction of total generation.
Snowmelt in the Northwest can vary significantly from year to year, and during spring and summer seasons following a heavy snowpack buildup, flow down the Columbia River can increase substantially. This excess water is spilled over the dams if the turbines are operating at capacity.
However, the article from Fox News points out that added wind generation capacity has, in effect, increased the amount of water spilled over the dams since the hydroelectric turbines begin to throttle down to accommodate the wind. The Bonneville Power Administration, which is responsible for hydroelectric generation and distribution of much of the electricity in the NW, says it is concerned that this increased spillage will endanger salmon runs, due to the higher oxygen content of the river water after spilling. Alternatively, wind turbine farms can be forced to shut down in this scenario, relieving pressure on the grid but also resulting in lost revenue for the farm owners. The BPA has been compensating some of the owners for their downtime, but this increases the cost of the electricity to the consumer. From a public relations standpoint, this situation is awkward for the BPA since they get into the absurd position of paying federally-subsidized wind farms regardless of their production.
It appears that the installation of wind turbine farms in the PNW has gotten ahead of the grid’s ability to dispose of the increased generating capacity. Needed for continued wind installation is increased transmission line capacity to move the electricity to markets where it is needed, but this is expensive and take considerable time to build, and it is probably cheaper for BPA to pay off wind farm owners than expand grid infrastructure (for the time being). Meanwhile, a moratorium on wind farm construction would be politically risky in Washington and Oregon, which seek to increase their use of renewables in their fuel mix (hydropower, interestingly, does not seem to be a renewable resource like wind and solar are in current Washington State law). Some new transmission lines and substations are under construction to ameliorate some of the glut of wind capacity, but more will be needed .
This problem illustrates some of the challenges of bringing more and more renewable resources online before adequate infrastructure is in place. Increasing wind capacity will reduce the amount of snowmelt that necessitates opening the spillways, exacerbating the problem. Wind and solar are obviously weather-dependent, and accurate weather forecasting can be difficult in the Northwest. Some utility-owed wind farms are supplemented by natural gas powerplants, such as those installed by Puget Sound Energy. This allows the utility to manage minute-by-minute changes in the wind resource without disrupting other grid activities. However, the majority of wind capacity is not backed up by any other fuel source, and therefore the BPA must manage the excess electricity. This would seem to be a prime example of a politically-driven enterprise creating additional problems that were unanticipated at the outset. While there is nothing wrong with increasing our use of renewable energy, it must be done in a way that is not disruptive to the existing infrastructure, and requires careful management and coordination.