The Pacific Northwest just finished four days of triple digit temperatures, which put the heat on renewable energy sources to keep up with demand. Just as records were being set for power consumption, wind power generation slowed due to the calm air from the locked-in high pressure system.

The extreme weather highlights the reality that wind — and to a lesser extent hydropower — may not be a panacea for power production.

Southern Washington and the Portland metro area had a record breaking streak of warmth that pushed energy demand to record highs, but the high pressure system also featured calm breezes. The local utility Bonneville Power Administration (BPA) had to quickly balance the reduction in wind power with increases in hydropower.

To make matters worse, during long hot and dry spells the water levels in the rivers that produce power can also drop, further reducing the ability for renewables to meet peak demand.

Granted, this is an extreme example of both weather and a utility that has a strong (and growing stronger) portfolio of renewable power. Despite the Northwest’s infamous frequent cloud cover, BPA might consider installing concentrated solar farms on the sunnier (east) side of the Cascades if it wants to avoid adding more fossil fuel production.

BPA has been dealing with wild fluctuations in wind for some time, as reported by the Seattle Post Intelligencer. The utility has been making wind power producers pay for its cost in balancing wind with other resources, and recently spiked fees by “only” 90 percent after considering quadrupling the cost.

Per the paper: “By 2011, the agency estimates the system will run out of the capacity to adjust enough to accommodate for the variations of wind power. As a result, the BPA, a nonprofit federal power-marketing agency, is accelerating plans for change, including: building more capacity, flexibility and quicker response times; implementing better forecasting tools; and sharing the responsibility for moving power within and outside the region.”

While wind is approaching grid parity for cost, it can’t be equally dispatchable without energy storage or being augmenting by other more manageable resource. This reality check shouldn’t detract from wind investments; it merely suggests a more balanced approach for utilities.

This article originally appeared on Matter Network.

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