Which Electricity Source Will Best Weather the Drought in California?

April 8, 2014 | 1:47 pm
Laura Wisland
Former contributor

The late-March storms in California gave the Sierra snowpack a belated boost, but the state is still bracing for dry times ahead. This was confirmed by the Department of Water Resource’s April 1 snow survey, one of the closest watched of the year because it marks the expected end of the wet season.

I hope that California residents are reading the bill inserts from their water suppliers, which are asking people to take shorter showers, water lawns less often, and fix leaky toilets. My house is old, and it takes a while for my water to heat up. I’ll be keeping a bucket handy to capture all the cold water that comes out while I wait — not ideal for my morning shower, but my plants will love it.

Photo: California Department of Water Resources

Snow surveyors measure the snowpack on April 1. Photo: California Department of Water Resources

But what does a snowpack only 32 percent of its normal size mean for electricity generation? Using water to generate electricity — hydropower — is an important component of California’s electricity mix. Between 2001 and 2012, hydropower from large dams averaged 14 percent of in-state generation, but annual generation varied greatly. This is not surprising: in a wet year, you get lots of hydro; in a dry year, you get little.

Since 2013 went down as the driest year on record for California, utilities have no choice but to look elsewhere for power sources this summer. There is no doubt that spending money on energy efficiency investments is cheaper than investing in new generation, but for the electricity we do need, utilities should consider drought-proof sources like solar, wind, and geothermal that won’t run out once harnessed, rather than lock us deeper into another finite and unpredictable source of fuel: natural gas.

Of course I have been listening to those excited by the natural gas fracking boom, who think that our days of fuel shortages are over. But I can’t help but think this attitude is short-sighted. This February, the California grid operator called a FlexAlert asking people to reduce gas consumption because extreme weather events were constraining supplies to California.

The supply of natural gas in this country is not infinite, and we are still trying to understand the degree to which production and transportation will cause methane, a powerful greenhouse gas, to leak into the atmosphere. Moreover, if our country is to avoid the worse consequences of climate change, we must move beyond natural gas to very low- or zero-carbon fuel sources.

Even though renewables (not counting small hydro) averaged 12 percent of the in-state power mix between 2001 and 2012, compared to hydropower that generation did not vary unpredictably from year to year. That predictability is very valuable to your electric utility, which needs to plan ahead and unfortunately can’t forecast the water year.

Source: California Energy Commission

Source: California Energy Commission

Yes, renewables pose their own challenges to the electricity grid. Wind and solar have daily and seasonal variable generation profiles and part of our country’s effort to modernize a very old electricity grid should be to make it more flexible and resilient to changing conditions. But in all this talk about renewable energy intermittency, we should not lose sight of the fact that once a renewable facility is built, we have a very reliable estimate of how much power to expect on a yearly basis.

Since we expect climate change to increase the frequency and severity of droughts in California, hedging our electricity supplies with predictable, renewable resources becomes not only an important step to combat climate change, but a smart insurance policy to keep the lights on.