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The Impact of the Solar Eclipse on City Light’s Energy Production

On Monday, Aug. 21, 2017, the Seattle area will experience its first solar eclipse since 1979. While the path of totality — where the moon’s shadow will completely block out the sun to viewers on Earth — runs through central Oregon, 92 percent of the sun will still be eclipsed above the greater Seattle region.

Since this phenomenon rarely occurs in our area, you may be curious whether a solar eclipse will severely impact the region’s solar energy production, or even if your service will be interrupted during its duration.

We have good news for you: It won’t be as much of an issue as you may think.

“Even if the sky is clear on Monday morning, the solar panels will most likely lose around 60 to 70 percent of what they would normally generate during that time of day as the peak generation of solar power actually happens in the afternoon around 1 p.m.,” explains City Light’s Director of Power Management Wayne Morter.  “Solar produces about 0.2 percent of the energy our customers use on an annual basis.”

If an issue related to solar energy production were to arise, City Light is prepared. We constantly follow energy load trends to ensure there will be enough energy to meet the needs of our customers.

Other energy resources, such as City Light’s Boundary Dam, help balance any dips in energy production. Most of City Light’s power comes from hydroelectric generation, a renewable resource that a boon to our region. In fact, Washington State is the nation’s leading source of hydroelectric power. Concerns about the potential impact of the eclipse upon electric grids are more pressing in California, where solar contributes more than 5 percent of the Golden State’s electricity.

Even though California is leading the charge on solar energy production in the United States, more and more people across Washington are becoming interested in the subject. Whether the sun is shining, covered by clouds or eclipsed by the moon, you can be involved with solar energy at City Light.

City Light customers are installing solar equipment on their homes and businesses in greater numbers every year. Click here for an FAQ and find out if installing a solar electric system in your home or business is a good fit for you.


For more information on City Light’s solar energy programs, visit