Doubling Down on Clean Energy in California

Last week, Pacific Gas and Electric Co. announced that it wants to retire California's Diablo Canyon nuclear power plant by 2025. If the California Public Utilities Commission accepts the utility's proposal, it will mean the end of the nuclear era in California. Beyond that milestone, though, it marks what is now an undeniable trend. Clean, renewable energy like wind and solar -- combined with energy efficiency and storage -- can compete with any dirty fuel, be it coal, gas, or nuclear power.

The Sierra Club has unequivocally opposed nuclear energy for more than three decades, and Diablo Canyon is a good illustration of why we do. From the beginning it was a reckless enterprise. Nuclear power plants are not just accidents waiting to happen -- they are mega-disasters waiting to happen. Diablo Canyon was especially risky owing to the discovery of nearby earthquake faults, but no nuclear plant can be guaranteed to be safe. The potential consequences of a nuclear disaster are so horrific by themselves that they overwhelm any risk analysis.

In spite of all that, PG&E would likely have attempted to keep Diablo Canyon open if it could have done so profitably. What's driving the closure of this and other nuclear plants is not the obvious risks they pose, but their inability to compete economically. In Nebraska, the Omaha Public Power District decided to decommission its Fort Calhoun nuclear plant this year not because it had to be shut down owing to flooding of the Missouri River in 2011 but because clean, renewable energy and energy efficiency have helped drive the cost of electricity to levels that the plant couldn't match.

In fact, renewable energy has gotten so cheap so quickly that PG&E says it intends to replace all of the power from Diablo Canyon with carbon-free clean energy. That's a big deal, because Diablo currently generates around 18,000 gigawatt hours per year or 8.5 percent of the state's power mix. It's important to hold PG&E to that commitment. Diablo needs to be replaced with additional clean energy -- above and beyond what it would otherwise have developed -- by the time the plant shuts down less than 10 years from now. How PG&E actually does that (solar, wind, energy efficiency, and storage could all play a role) is less important -- as long as greenhouse gas emissions do not increase as a result of Diablo Canyon's retirement.

The good news is that last year, clean and renewable sources accounted for almost two-thirds of new electrical generation in the U.S. Even so, replacing Diablo Canyon with 100 percent clean, renewable energy is an ambitious goal for both PG&E and the state of California. But the fact that PG&E believes it's possible to do that in less than a decade speaks volumes about how far renewables have come and how quickly it is expected to dominate the energy industry.

It also sets a new, higher bar nationally. If indeed it is possible to do this for the largest power plant in California, then there's no excuse not to attempt to do the same thing on a rapid and responsible timeline for every polluting plant in the United States. From now on, the burden of proof is on polluters to show that clean, renewable energy can't do the job. In our work on retiring coal plants, we've seen utilities repeatedly fail at making that case, and it's only going to get harder to do so going forward.

The Diablo Canyon announcement is more than just another setback for polluting power plants. It reaffirms in a big way that renewable energy will be first and foremost in our future.