BPA Plan Seeks to Balance Wind and Water

The Bonneville Power Administration, which markets the energy produced by 31 hydroelectric dams and a nuclear plant, daily faces the challenges of accommodating over 2000 megawatts of new wind capacity on its aging grid.

That 2000 MW is twice the amount that was on the grid less than two years ago. And the agency estimates indicate that wind capacity on the agency’s 15,238-mile grid could jump to 6000 MW in the next four years, reported the Yakima Herald-Republic.

On the one hand, the BPA’s extensive hydro system is ideally suited to integrate with wind, as reservoirs represent large quantities of stored energy which can quickly be ramped up or down to balance out changing levels of wind production.

On the other, when wind speeds change more dramatically than forecast by operators, the BPA finds itself forced to walk a tenuous line between system reliability and environmental stewardship.

Holding water behind dams to accommodate wind power surges can harm fish, which need flowing water. Equally damaging is spilling water too quickly when wind power dies down.

Because the wind farms are all located near each other at the east end of the Columbia River Gorge, a change in the wind produces a dramatic change in the power being sent to the grid in one particular spot.

In July the agency released a 541-page order for setting future rates to public and private utilities. Its struggle to integrate wind resources was reflected in a section of that order concerning how much the BPA will charge wind producers to help buffer the grid against wind’s intermittencies.

In October of 2008, the BPA implemented its first “wind integration rate,” which forced wind producers to help with the cost of accommodating, absorbing and backing up wind power. This year’s proposed rate increase was about 90 percent—large, but substantially less than a 300 percent increase the agency proposed earlier this year.

The agency attributed the lower rate increase to efforts among wind power producers to improve forecasting and operational practices, which in turn enabled the hydro system to operate with lower emergency reserves.

The agency has also drawn up a timetable for several initiatives designed to assist operations on a grid under increasing pressure from intermittent resources, according to The Oregonian.

Plans are in place to install 16 wind stations throughout the region to provide wind speed and direction data to wind operators at five-minute intervals. BPA aims to have an in-house wind forecasting desk by mid-2010.

By October, the agency will implement a system that will knock wind producers off the grid when they are operating dangerously outside their scheduled output.

Another proposed element in the plan could enable wind generators to pay coal or natural gas-fired plants to curtail generation when their own output was high, and to purchase reserves from non-BPA suppliers when needed.

Return to August 2009 Western Energy News

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