BPA sees volatility in wind, wind generation

After curtailing generation on four consecutive days to curb oversupply in the Northwest, the Bonneville Power Administration (BPA) got a hand from Mother Nature.

Wind production had virtually ceased by mid-morning May 6, with BPA figures reporting 0 MW produced at 9:00 a.m. Since then, wind has been a virtual no-show, contributing well under 100 MW at any one time, with the exception of a 1-1/2 hour period around the noon hour on May 7, when production ticked up to about 150 MW.

The agency had curtailed wind and thermal generators in the early morning hours of April 29 and 30, and May 1 and 2 because abundant hydro generation left too little room on the transmission system.

Over the last several days, however, wind has contributed dramatically less to the area’s energy mix, freeing up capacity on the agency’s transmission system.

Wind generation, which had contributed as much as 3,372 MW during the evening of May 1, dropped to just 88 MW during the evening of on May 2. The wind picked back up on May 3 and 4, contributing 3,649 MW and 3,627 MW at the same time of day, but dropped to 2,419 MW on May 5 and into the single digits on May 6, as the chart at right shows.

Those developments are typical given the lack of geographic diversity of Northwest wind production. “With all of our wind being centrally located in the east end of the [Columbia] Gorge, a lot of times it’s an all-or-nothing situation,” a BPA spokesperson told TransmissionHub on May 8.

The current spate of relief, however, may be short-lived. BPA forecasts, as depicted at left, predict the winds will steadily increase starting in the afternoon of May 8 due to an approaching cold front. As a result, generation is expected to peak at an estimated 3,200 MW over the next 24 to 48 hours.

With hydro production remaining at a fairly high level, the additional wind generation could result in more curtailments.

“It certainly increases the possibility, but we’re also doing a lot of other things [to manage supply] such as the way we manage the hydro system and trying to find places to sell the additional generation,” the BPA spokesperson said.

Those same forecasts predict that the winds will drop off again during the morning of May 10.

“The wind tends to blow during the fall and during the spring, and during [those times] we often experience rapid weather changes,” the spokesperson said.