The Pacific Northwest's delicate balance between wind power, hydro power and fish survived the potential for serious problems when unexpectedly high winds led to more wind generation than allowed for early last month, forcing river managers to spill water over dams, putting the lives of migrating salmon at risk. The Bonneville Power Administration (BPA), a federal agency that manages regional wind integration, initiated calls to wind farm operators requesting them to dump wind generation in excess to demand. But, largely due to miscommunication and an untested emergency plan, much of the wind stayed online, forcing large quantities of water to be spilled. "We had a significant wind-ramp event where wind output was going beyond what was scheduled with us on the evening of June 30," says BPA's Scott Simms. "So, for about a five-hour, period we saw a deviation from schedule -- that's really the crucial point -- of between three to five hundred megawatt." When unscheduled generation comes into the system, automatic control units throttle back the hydro turbines, forcing more water through spillways and creating gas bubbles. Some bubbles are healthy for the fish, but past a certain point they are lethal. Of ten wind generators online that night, five were holding to schedule. BPA tried to reach the other five, but in several cases machines rather than humans answered the phones. "You've basically got a time equation with so much water and only so much pipe to force it through," Simms says. "Sooner or later you have to spill in vast quantities. But we had no reliability impacts, no fish impacts and we greatly learned from the experience. We're ready for next time." According to Rachel Shimshak of Renewable Northwest Project, the whole region needs to work together and not just depend on the BPA. "It's lucky that there weren't any serious impacts," Shimshak says. "It underscored the need for a specific protocol. I think everybody learned a good lesson."
Windpower Monthly Events
Senior Renewable Energy Analyst (WindGEMINI Product Lead) DNV GL Bristol (City Centre), City of Bristol