California is on the verge of closing its last nuclear plant. Is that really a good idea?

Aerial view of the Diablo Canyon Nuclear Power Plant which sits on the edge of the Pacific Ocean at Avila Beach in San Luis Obispo County, California, on March 17, 2011.

California’s half-century dalliance with atomic energy could soon be over. on Tuesday, Pacific Gas & Electric Co. announced its proposal to close Diablo Canyon, the state’s last remaining nuclear power plant, by 2025.

This is just the latest in the utter decimation of America's nuclear fleet. Back in 2013, the United States had 104 reactors supplying one-fifth of its electricity. Since then, five reactors have been retired early and at least seven more are scheduled to close — all victims of cheap natural gas, unfavorable economics, and local opposition.

These closures are almost always terrible news for climate change. When two reactors at the San onofre nuclear power plant in southern California closed in 2013, they were largely replaced by natural gas generation, leading to higher carbon-dioxide emissions. And Diablo Canyon is even bigger, supplying 9 percent of California’s electricity.

PG&E claims it can avoid a similar carbon disaster this time around. In a deal struck with environmental groups, the utility plans to ramp up investment in efficiency, solar, wind, and storage between now and 2030 to replace Diablo Canyon with clean energy rather than fossil fuels. The question, however, is whether it can actually pull off this tricky balancing act — and whether spending all this effort simply to displace existing zero-carbon energy is really the best way for California to slash emissions.

The plan isn’t final yet; PG&E still needs approval from California’s Public Utilities Commission. It has the backing from various green groups, including the Natural Resources Defense Council andFriends of the Earth. But other environmentalists, like the recently formed Friends of Diablo Canyon, have argued that it doesn’t make any sense to shut down such a huge source of carbon-free power so long as climate change is a major priority. Let’s take a closer look.

Why Diablo Canyon is facing heavy pressure to shut down

(MARK RALSTON/AFP/Getty Images)

The intake and outflow chutes for Diablo's cooling system have attracted lots of attention.

Diablo Canyon was first proposed in 1958 and attracted controversy from the very start. The Sierra Club initially supported this new source of pollution-free electricity, provoking some members to leave and start Friends of the Earth, an anti-nuclear green group. After the plant finally came online in 1985, perched on a sea cliff near San Luis Obispo, many environmentalists continued to lobby for a shutdown.

Opponents have raised two big concerns: First, they’ve argued that the plant is surrounded by earthquake faults and faces the risk of seismic disaster. (PG&E disputes this, saying the plant is built to withstand any expected quake.) Second, they’ve argued that Diablo Canyon’s intake of ocean water to cool the reactors kills local marine life in the tidelands. Both claims are debatable, and Will Boisvert does a nice job of sifting through them here.

In recent years, however, California’s politicians have been increasingly siding with the plant’s foes. Diablo Canyon sits on land owned by the state, and its leases are up in 2018. The State Lands Commission is mulling a new (and costly) environmental impact report for the plant as part of the renewal process. And the California State Water Resources Control Board is debating a mitigation plan for its cooling system, which could add further costs.

In principle, Diablo Canyon might have been able to weather these extra costs. The plant’s two reactors are licensed by the federal government to operate until 2024 and 2025, and PG&E had applied for a 20-year extension. The bigger problem is that the energy landscape in California was shifting in such a way as to make the reactors unprofitable.

California’s shifting energy policies are crowding out nuclear

Over the past 10 years, three big trends have unfolded. First, thanks to the fracking boom, the United States has been flooded with cheap natural gas, which has put downward pressure on electricity prices everywhere. In California, this was compounded by a second factor: Electricity demand has stagnated.

That meant that Diablo Canyon is now receiving less and less money for the electricity it sells. The utility has fewer funds to pay for upgrades, cooling towers, and other fixed costs associated with operating large reactors.

On top of that, California has been massively ramping up policy support for wind and solar power, which benefit from both federal subsidies and state renewable policies. The state now gets about 10 percent of its electricity from utility-scale and rooftop solar panels. And due to the quirks of electricity markets, those sources are threatening to squeeze out nuclear.

The chart below from PG&E tells the tale. Nuclear reactors operate 24/7 providing baseload electricity — they can’t ramp their output up or down very easily. But solar only ramps up during the day. This creates a traffic jam of excess electricity during the afternoon — an issue known as the "duck curve":

(PG&E)

Right now California is curtailing (i.e., not using) some of that excess wind and solar during the day. But if the state wants to keep ramping up solar power, that’s untenable. As the chart on the right shows, solar curtailments would get increasingly frequent by the early 2020s without major changes.

There are a few options to mitigate the "duck curve": California could link up with nearby grids to share the load. Utilities could deploy more storage (pumped hydro, air storage, batteries) to shift around some of this excess solar power for morning and nighttime uses. They could try to juggle energy demand so that it lines up better with solar peaks. In theory, renewables, storage, and nuclear could work well together.

But there’s also another option: PG&E could simply shut down its large, inflexible nuclear reactors in order to make more room for solar and wind, as well as more flexible natural gas plants that can ramp up and down more easily to follow that duck curve.

Given all the other challenges Diablo Canyon was facing — low electricity prices, environmental opposition, regulators forcing costly upgrades — PG&E decided to take that last route. The utility is now proposing retiring the reactors when their federal licenses are up for renewal in 2024 and 2025. In exchange, the state would agree to renew the plant's leases in the short term and drop the requirement for costly new cooling towers.

"I am sorry to see it go, because from a national energy policy standpoint, we need greenhouse gas-free electricity," Tony Earley, PG&E’s chief executive, told SFGate. "But we are regulated by the state of California, and California’s policies are driving this. I’m not criticizing those policies, but it’s a fact.

The big challenge: How will PG&E replace Diablo Canyon’s zero-carbon electricity?

(Photo by Marcus Yam/Los Angeles Times via Getty Images)

Utilities in other states have gone through similar calculations and shut down their reactors early. The problem is that when these nuclear plants have been closed, they typically get replaced (in part) by natural gas or even coal generation — which increases CO2 emissions.

PG&E is hoping to avoid this fate. The utility has outlined a plan to try to replace the 17,000 gigawatt-hours of electricity per year from Diablo Canyon — without resorting to fossil fuels. The details are still fuzzy, but it broadly includes three steps:

1) Between 2018 and 2024, PG&E says it will invest in various efficiency improvements in homes and businesses — such as better insulation or newer air conditioning units — to cut electricity demand by about 2,000 gigawatt-hours total.

2) Between 2025 and 2030, PG&E will add 2,000 gigawatt-hours per year of wind, solar, efficiency to replace Diablo Canyon's lost output. It will also make use of other "GHG-free resources," such as storage, as needed to fill in any gaps remaining.

3) By 2031, PG&E says it will get 55 percent of its electricity from renewable sources.

(PG&E)

Here’s another slide showing how PG&E envisions its electricity mix to change between 2017 and 2031. The column on the left shows how it expects renewables to replace nuclear:

(PG&E)

This may well work out. But there are also some hard questions worth asking here. What happens if PG&E can’t replace all the electricity that Diablo Canyon produced with renewables and efficiency alone? Will it rely on natural gas generators to fill in the gaps? If so, CO2 emissions and air pollution will go up. Period.

Also: What happens if natural gas prices unexpectedly spike, as they have in the past? Or what if demand rises faster than expected (say, because global warming causes air conditioning use to soar)? Will California regret having shuttered a cheap source of reliable electricity because of short-term economic concerns? Energy markets can be tough to predict. But any decisions around large nuclear plants have to be made many years in advance — and they’re tough to reverse. once PG&E begins laying off workers and decommissioning the plant, it can’t backtrack if it runs into unexpected difficulties.

Here's one final question: How would PG&E's proposal stack up against an alternative plan in which Diablo Canyon stayed open and renewables and efficiency ramped up to displace fossil generation elsewhere? It's entirely plausible that emissions would fall even faster if PG&E kept the plant open and also made all those planned wind and solar investments. Why isn't that under consideration?

California's regulators still have to approve the closure

Diablo Canyon’s fate isn’t set in stone just yet. The California Public Utilities Commission still has to review and approve PG&E’s plan. So there's still opportunity for more battling and maneuvering around the plant.

On the one side, a number of green groups and labor unions have signed on to PG&E’s plan, including Friends of the Earth, NRDC, the International Brotherhood of Electrical Workers, the Coalition of California Utility Employees, Environment California.

On the other side, a smaller group of greens and climate scientists, including NASA’s James Hansen, have been lobbying strongly to keep the plant open for climate considerations. Their argument is simple: Even if PG&E can replace all of Diablo Canyon's zero-carbon energy, we'll have made zero progress on climate change. At best, we're spinning our wheels. At worst, we're increasing emissions.

Back in January, David R. Baker wrote a good overview of this debate in SFGate. Note that this fight occasionally gets framed as nuclear versus renewables. But it doesn't have to be so: in theory, the two sources could complement each other.

If Diablo Canyon does close, America will have lost 14 reactors since 2013

Photo by David McNew/Getty Images

The San onofre nuclear power plant in Southern California closed in 2013.

Here’s a complete list of nuclear reactors that have already closed since 2013 — as well those scheduled to retire early:

2013: Crystal River 3 in Florida, San onofre 2 and 3 in California, Kewaunee in Wisconsin

2014: Vermont Yankee in Vermont

2016: Fort Calhoun in Nebraska

2017: Fitzpatrick in New York, Clinton in Illinois

2018: Quad Cities 1 & 2 in Illinois

2019: Pilgrim in Massachusetts, Oyster Creek in New Jersey

2024: Diablo Canyon 1 in California (??)

2025: Diablo Canyon 2 in California (??)

That’s a lot of zero-carbon electricity coming offline. Writing in the Los Angeles Times, Robert Bryce offers this comparison: The six nuclear reactors scheduled to retire between 2016 and 2019 produce roughly as much electricity as all of America’s solar panels combined did last year. And much of that capacity is getting replaced by fossil fuels.

There are also a number of additional reactors that could face early retirement in the years ahead, due to competition from cheap natural gas, needed upgrades, local opposition, or some combination of those factors. That list includes: Indian Point and Nine Mile in New York State; Three Mile Island in Pennsylvania; Davis-Besse in Ohio; and Millstone in Connecticut.

At this point, avoiding further closures would likely require proactive policy changes that provide additional support for existing nuclear facilities to keep running. Nuclear, for instance, could be included in state clean-energy standards, which typically only favor renewables. The pro-nuclear group Environmental Progress fought for a policy like this in Illinois to save the Quad Cities and Clinton reactors, but the legislature never took it up.

One obstacle here: it's hard to persuade people that the government should step in and subsidize unprofitable reactors being roiled by market forces. You'd basically have to make the case that this is a coherent part of a larger strategy — along with support for renewables and efficiency — to stave off climate change.

As for new nuclear reactors that could replace the old ones, there are only five on the horizon. The Tennessee Valley Authority just brought the Watts Bar 2 reactor online in May, America's first new reactor in decades. Another two reactors are under construction in Georgia, as well as two more in South Carolina. But that's it.

The biggest problem facing new nuclear construction is that the plants require billions in upfront investments, and most utilities are far more interested in smaller renewable and natural gas plants. I’ve written before about why nuclear power became so expensive in the United States (along with some ideas for bringing those costs down). Perhaps smaller modular reactors of the future will turn out to revive nuclear’s fortunes, if they ever pan out. But for now, the outlook for what is still America’s biggest source of clean electricity looks bleak.

http://www.vox.com/2016/6/21/11989030/diablo-canyon-nuclear-close