Puget Sound Energy claims to be the first utility to own both wind and solar power plants in a single location. The company is testing the natural synergy between the two renewable resources to see how consistently the intermittent power generators can provide power in tandem. This is an option that more utilities with conducive environments will likely try, according to the Oregonian.

Wind tends to blow more vigorously at night as the Earth cools, and when solar fizzles to darkness. And breezes often cease on intensely hot days, leaving only the sun to provide power.

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Wind energy in Washington state is already competitive with fossil fuel-generated electricity, but ratepayers will bear the burden of the extra cost of the solar experiment, which is 4 times (20 cents per kWh) as expensive as wind.

Utilities across the country will watch PSE's trial closely because if they are to forego building new coal or natural gas plants, they'll need to be able to balance both resources as a combined round-the-clock power source. Photovoltaic power will have to get much cheaper for mass utility deployment, but for now the ability to add PV arrays as needed (instead of spending tens of millions for a new large capacity coal plant all at once) can make it attractive.