The Pacific Northwest is likely to continue producing more electricity than it needs in the spring and early summer, a time when demand for power usually is low and the supply of hydropower and wind power can be high because of seasonal storms and the annual snowmelt runoff in the region’s rivers, says an analysis by Northwest Power and Conservation Council staff.
Surplus power from the Northwest typically is sold to utilities in the Southwest over high-voltage transmission lines known as the Pacific Northwest/Pacific Southwest Intertie.
The Council analysis indicates that in the future, excess electricity in the Northwest could exceed the Southwest market demand in the April-through-June period by 300,000 megawatt-hours.
That is enough power for approximately 100,000 Northwest homes for that three-month period. The analysis indicates this condition will occur about once every four years, and in some years could be as large as 1.2 million megawatt-hours.
“Oversupply is not a new issue in the Northwest, but it has become problematic as more wind power is added to the power supply,” Council Chair Joan Dukes said. “This analysis will help size the problem for those who are working on solutions.”
Hydropower, wind power, and power from plants that burn fossil fuels all contribute to the oversupply. The policy question for Northwest power producers, including the Bonneville Power Administration, which markets federal hydropower and owns about 75 percent of the high-voltage transmission in the region, is how to handle the surplus, which can flood the wholesale power market and drive prices to zero and even below for brief periods.
The Council analysis did not address that policy issue.
In December 2011, the Federal Energy Regulatory Commission responded to a complaint filed by wind-power generators that Bonneville’s “environmental redispatch” policy was discriminatory.
In that policy, Bonneville established protocols for replacing other types of power generation when there is an excess of hydropower. Reducing thermal and wind generation in order to accommodate increased hydropower generation allows more water to flow through turbines and less over dam spillways, thus protecting fish from excessive levels of dissolved gas in the river below the dams.
In 2011, the oversupply totaled about 98,500 megawatt-hours; Bonneville has estimated the amount could be significantly higher this year.
In response to the FERC ruling and after months of discussions with key stakeholders, Bonneville recently proposed compensating wind energy producers within its section of the regional high-voltage transmission grid in 2012 for periodically reducing their output when necessary to keep the electricity supply from exceeding demand during high river flows.
Discussions between Bonneville and the wind power generators are continuing. At the same time, the Northwest Wind Integration Forum, which includes utilities, the Council, and Bonneville, is working on potential long-term solutions to the oversupply problem.