Essay by Eric Worrall
h/t mleskovarsocalrrcom – Some Californians question why they need a nuclear plant, given all their renewable and battery investments.
California’s last nuclear plant clears major hurdle to power on
By Hayley Smith and Noah Haggerty
Dec. 11, 2025 6:35 PM PT
- California’s last nuclear power plant received permission to operate for at least 5 more years in exchange for conserving thousands of acres of land in San Luis Obispo County.
- The agreement between The California Coastal Commission and Pacific Gas & Electric seeks to balance damage to the marine environment going forward.
- Some stakeholders in the region celebrated the deal while others, including a Native tribe, were disappointed.
California environmental regulators on Thursday struck a landmark deal with Pacific Gas & Electric to extend the life of the state’s last remaining nuclear power plant in exchange for thousands of acres of new land conservation in San Luis Obispo County.
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The Coastal Commission voted 9 to 3 to approve the plan, settling the fate of some 12,000 acres that surround the power plant as a means of compensation for environmental harm caused by its continued operation.
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“This plan supports the continued operation of a major source of reliable electricity for California, and is in alignment with our state’s clean energy goals and focus on coastal protection,” Paula Gerfen, Diablo Canyon’s senior vice president and chief nuclear officer, said in a statement.
…A key development for continuing Diablo Canyon’s operation came in 2022 with Senate Bill 846, which delayed closure by up to five additional years. At the time, California was plagued by rolling blackouts driven extreme heat waves, and state officials were growing wary about taking such a major source of power offline.
But California has made great gains in the last several years — including massive investments in solar energy and battery storage — and some questioned whether the facility is still needed at all.
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Read more: https://www.latimes.com/environment/story/2025-12-11/diablo-canyon-coastal-commission-vote
I’m shocked California has wavered in their commitment to renewables like this.
Keeping this plant open will be seen as some as an admission that California’s enormous renewable investments are not delivering stable electricity supplies.
If hundreds of billions of dollars investment in renewables and batteries is not enough to prevent blackouts during periods of energy stress, surely the solution is more hundreds of billions of dollars of green energy investment.
Do I need a /sarc tag?
Some Californians question…etc…They’re not joking, are they..!
Only idiots would question. Right now, nuke (Diablo) is supplying 8%. NG is 18%, imports are 25%, large hydro 4%.The renewable basket is 45%.
Kind of hard to cut 8% without covering it with NG or imports.
It also supplies PG&E 20 % of the baseload capacity….no way to replace that with W&S or batteries, that continue to catch fire.!!
No sadly they aren’t. Too many Californians have not experienced what it is like to run out of electricity. 2/3rds of the state live in cities where all they have to do is plug something in and it works. Worse, they just open a tap and the water appears. It’s all Magic to them.
Con Edison had Indian Point on 240 TO 320 acres. Why the hell wool this facility need 12000 acres. What a crock of shit. Is it because the land is entirely useless for anything?
Diablo Canyon does EVERYTHING it needs to (generation and fuel storage) on 12 acres while the plant maintains around 750 acres as a security zone and an additional 11,000+/- acres as a buffer zone. Its those adjacent buffer zone acres that PG&E agrees to “Set Aside” for “Conservation”.
At least California recognizes (if not directly admits) that Renewables are “Infirm energy sources” that require “Firm” energy sources to make them kinda work.
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Diablo canyon has a Nameplate Rating of 2256MW so replacing just the nameplate capacity with Solar would require 4 Topaz Solar Farms or some 36M panels covering 38M sq mi or 24,320 acres. More than twice the PG&E agreed conservancy acreage. However Solar only produces DC energy near nameplate for 4 hours a day while Nuclear produces AC power for 24 hours a day so replacing Diablo would take (24 hrs/4hrs=6) 6 times the overbuild of Solar plus sufficient GWh of battery storage to make that energy available when needed.
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Diablo Canyon does a much better job of creating usable energy…no batteries required.
During the Summer months when Diablo is producing 100% of nameplate, the solar panels on this part of the Central Coast are producing way below nameplate because of the morning fog.
Morning Fog
Passing clouds
Dust build-up
Shadow from trees on adjacent property
Too Cold
Too Warm
Before 10am
After 2pm
Many factors limit/reduce the effectiveness of Solar and it’s overall capacity
It’s a fallback position that politicos use. The equivalent in the northeast is/was power imports from Canada.
The last paragraph fingers a fundamental truth: the medieval mindset of green activists.
“The Coastal Commission voted 9 to 3 to approve the plan, settling the fate of some 12,000 acres that surround the power plant as a means of compensation for environmental harm caused by its continued operation.”
What environmental harm would that be exactly?
Good question. Nuclear power plants require large quantities of fresh water for the cooling towers. However, I don’t see any of these at the site.
It appears that seawater is being used for condensing the spent steam after it exits the turbine. Notice the water being discharged into the sea from the long brown building which has the condenser and heat exchangers. This warm water might harm local sea plants and animals.
Which is why Diablo Canyon has always had temperature limits on its water discharges.
Surfers love this warm water.
“for the cooling towers”
Nuclear facilities are designed site-specific. Cooling towers are not always the solution. The web can provide information.
Yes, that’s correct. Diablo has a small bay with it’s own ecosystem which has sea life similar to that found in San Diego.
In Florida in the vicinity of power plants are more not less fauna. When Indian Point was in operation a lot of fish congregated near the outlets. One problem was if they shut down for maintenance especially in the winter. Not happy campers.
Exactly, indeed! I’m guessing Paula Gerfen, Diablo Canyon’s senior vice president and chief nuclear officer had to choke down that crap sandwich she was forced to say as part of the settlement.
Harold The Organic Chemist Asks:
What type of chemist are you?
We need to inform the people that CO2 does not cause any warming of air because there very little of it in the air. Here is a comment I post here often for the benefit of new comers:
At the MLO in Hawaii, the concentration of CO2 in dry air is currently 426 ppmv. One cubic meter of this air has a mass of 1,290 g and contains a mere 0.84 g of CO2 at STP.
In air at 21° C and 70% RH, the concentration of H2O is 17,780 ppmv. One cubic meter of this air has a mass of 1,200 g and contains 14.3 g of H2O and 0.78 g of CO2. To the first approximation and all things being equal, the proportion of the greenhouse effect (GHE) due to H2O is given by:
GHE=moles H2O/(moles H2O+moles CO2)= 0.79/(0.79+0.019) =0.98 or 98%.
The above calculation assumes that a molecule of H2O and a molecule of CO2 each absorb about the same amount of out-going long wavelength IR emanating from the earth’s surface. Actually, H2O absorbs more IR light than CO2. Keep in mind that H2O covers 71% of the earth’s surface.
The above empirical data and calculation falsifies the claims by the IPCC that CO2 causes warming of air and is the control knob of climate change. The purpose of these claims is to provide the UN the justification for the distribution of doner funds, via the UNFCCC and the UN COP, from the rich countries to the poor countries to help them cope with the alleged harmful effects of global warming and climate change.
After Administrator Lee Zeldin of thr EPA the rescinds the Endangerment Finding of 2009 for CO2, he will put an end to the greatest scientific fraud since the Piltdown Man.
Thank you, Harold, for showing how simple analysis cuts through all the bull manure
The other comment I post uses some of the late John L. Daly’s temperature charts to show that CO2 does not cause warming air such as the chart for the port city Adelaide which shows a cooling after 1940 and up to 1999.
NB: If you click on the chart, it will expand andc become clear. Click on the “X” in the circle to return to comment text.
The IR absorption of H2O is very broad and blocks most of the CO2 absorption bands. There is a single narrow CO2 absorption band which lies in a narrow trough of wave lengths in which CO2 does absorb IR. The assumption of equal absorption is way off. Water is the predominant GHG in the atmosphere.
Harold, your equation is way too simplistic. It’s not just quantity of gases but also their absorption spectrum. At some wavelengths CO2 is a thousand times more IR absorbing….but yes the endangerment finding is contextually nonsense…was just a power grab…
Not a five year extension, now 25 years.
Cost Comparison for Diablo Canyon vs Solar + Storage vs CCGT
Extending Diablo Canyon’s license for 25 years costs about $1.4 billion, producing roughly 18,000 GWh/year. Spread over 25 years, that’s 450,000 GWh, making the capital cost only 0.31¢/kWh. Add nuclear fuel and O&M (~3.2¢/kWh), and the total is about 3.5¢/kWh.
To match that output with solar at 25% capacity factor and 40 hours of battery storage at $500/kWh, you’d need 4 GW of solar plus 160 GWh of storage, costing about $84 billion. Over 25 years, that’s 18.6¢/kWh for capital plus ~1¢ for O&M, totaling ~19.6¢/kWh.
A new combined-cycle gas plant running at 67% CF would cost about $3.06 billion in capital (0.68¢/kWh) plus fuel and O&M (~3.4¢/kWh assuming gas at $5/mcf — currently under $3/mcf), for a total of ~4.1¢/kWh
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Bottom line: Diablo Canyon extension ≈ 3.5¢/kWh, CCGT ≈ 4.1¢/kWh, Solar + 40h storage ≈ 19.6¢/kWh. Nuclear wins on cost and reliability by a huge margin.
(Solar & gas parameters from writer, calculations by Copilot AI)
Storage costs seem to have fallen:
How cheap is battery storage?
https://ember-energy.org/latest-insights/how-cheap-is-battery-storage/
Ember’s stated mission –
We create targeted data and policy insights that accelerate the transition to a clean, electrified energy future.
They “create” data?
As in – make shit up?
I wouldn’t trust any cost estimate for battery storage that isn’t based on real life experience with battery lifetime. The original poster underestimated the amount of solar panels needed to replace Diablo Canyon. At 25% capacity factor for solar, one would need 8GW of solar.
how cheap is it when it catches fire…again ?
From your link:
Two recent auctions in Saudi Arabia were priced at around $120/kWh. The Tabuk and Hail projects awarded equipment supply contracts in August 2025 of $179–183 million for 2.45 GWh each, or just $73-75/kWh. The EPC contracts added another $116–118 million, or $47–48/kWh
$125/kWh (down from $139/kWh used in my estimate) cost at the gate of the battery manufacturer plus the cost for shipping, site prep, interconnecting the enclosures, providing switch gear, overcurrent protection, transformers, fire suppression, and the labor for doing all that plus testing and commissioning and much more adds at least $200/kWh. Costs get moved around on major projects.(I worked for Saudi Aramco for five years. ]The up and running battery storage array is going to cost at least $500/kWh).
Why did my comment on utility battery cost per kWh get deleted?
I am an energy systems analyst with over 40 years of experience.
Sorry, I made that comment on another article.
The battery storage cost is much higher, because:
1) the batteries must not be charged above 80% and not be discharged below 20%, meaning only 60% of capacity is available on a daily basis.
2) the battery system ages at about 1.5% per year, meaning any available capacity decreases
3) the turnkey capital cost is closer to $600/installed kWh delivered as AC at outlet of backend electronics.
4) the battery system plus auxiliaries has an A to Z throughput loss of at least 20%
5) the battery system life is about 15 years, meaning all costs must be amortized over that period
6) a solar system lasts at most 30 years, meaning you need two battery system to cover its life
Now you know why Europe, with a lot of expensive, short-live, wind, solar and battery systems, is no longer viable, because its energy costs/kWh are about 2.5 times higher than the US, plus it is spending more on defense, plus it has to deal with tens of millions of Islamic destroyers of European traditional cultures
BATTERY SYSTEM CAPITAL COSTS, OPERATING COSTS, ENERGY LOSSES, AND AGING
https://www.windtaskforce.org/profiles/blogs/battery-system-capital-costs-losses-and-aging
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Utility-scale, battery system pricing usually not made public, but for this system it was.
Neoen, in western Australia, turned on its 219 MW/ 877 MWh Tesla Megapack battery, the largest in western Australia.
Ultimately, a 560 MW/2,240 MWh battery system, $1,100,000,000/2,240,000 kWh = $491/kWh, delivered as AC, late 2024 pricing. Smaller capacity systems cost much more than $500/kWh
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Annual Cost of Megapack Battery Systems; 2023 pricing
Assume 45.3 MW/181.9 MWh; turnkey cost $104.5 million; 104,500,000/181,900 = $574/kWh, per Example 2
Amortize bank loan, 50% of $104.5 million, at 6.5%/y for 15 years, $5.484 million/y
Pay Owner return, 50% of $104.5 million, at 10%/y for 15 years, $6.765 million/y (10% due to high inflation)
Lifetime (Bank + Owner) payments 15 x (5.484 + 6.765) = $183.7 million
Assume battery daily usage, 15 years at 10%; loss factor = 1 / (0.9 *0.9)
Battery lifetime output = 15 y x 365 d/y x 181.9 MWh x 0.1, usage x 1000 kWh/MWh = 99,590,250 kWh to HV grid; 122,950,926 kWh from HV grid; 233,606,676 kWh loss
(Bank + Owner) payments, $183.7 million / 99,590,250 kWh = 184.5 c/kWh
Less 50% subsidies (tax credits, 5-y depreciation, loan interest deduction, etc.) is 92.3c/kWh
Subsidies shift costs from project Owners to ratepayers, taxpayers, government debt.
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Excluded costs/kWh: 1) O&M; 2) system aging, 1.5%/y, 3) loss factor 1 / (0.9*0.9), HV grid-to-HV grid, 4) grid extension/reinforcement to connect battery systems, 5) downtime of parts of the system, 6) decommissioning in year 15, i.e., disassembly, reprocessing, storing at hazardous waste sites. Excluded costs would add at least 15 c/kWh
COMMENTS ON CALCULATION
Almost all existing battery systems operate at less than 10%, see top URL, i.e., new systems would operate at about 92.4 + 15 = 107.4 c/kWh. They are used to stabilize the grid, i.e., frequency control and counteracting up/down W/S outputs. If 40% throughput, 23.1 + 15 = 38.1 c/kWh.
That is on top of the cost/kWh of the electricity taken from the HV grid to charge the batteries
Up to 40% could occur by absorbing midday solar peaks and discharging during late-afternoon/early-evening, in sunny California and other such states. The more solar systems, the greater the midday peaks.
See top URL for Megapacks required for a one-day wind lull in New England
40% throughput is close to Tesla’s recommendation of 60% maximum throughput, i.e., not charge above 80% and not discharge below 20%, to perform 24/7/365 service for 15 y, with normal aging.
Owners of battery systems with fires, likely charged above 80% and discharged below 20% to maximize profits.
Tesla’s recommendation was not heeded by the Owners of the Hornsdale Power Reserve in Australia. They excessively charged/discharged the system. After a few years, they added Megapacks to offset rapid aging of the original system, and added more Megapacks to increase the rating of the expanded system.
http://www.windtaskforce.org/profiles/blogs/the-hornsdale-power-reserve-largest-battery-system-in-australia
Regarding any project, Banks and Owners have to be paid, no matter what. I amortized the Bank loan and Owner’s investment
Divide total payments over 15 years by the throughput during 15 years, to get c/kWh, as shown.
Loss factor = 1 / (0.9 *0.9), from HV grid to 1) step-down transformer, 2) front-end power electronics, 3) into battery, 4) out of battery, 5) back-end power electronics, 6) step-up transformer, to HV grid, i.e., draw about 50 units from HV grid to deliver about 40 units to HV grid. That gets worse with aging.
A lot of people do not like these c/kWh numbers, because they have been misled by self-serving folks, that “battery Nirvana is just around the corner”.
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NOTE: EV battery packs cost about $135/kWh, before it is installed in the car. Such packs are good for 6 to 8 years, used about 2 h/d, at an average speed of 30 mph. Utility battery systems are used 24/7/365 for 15 years
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NOTE: Aerial photos of large-scale battery systems with many Megapacks, show many items of equipment, other than the Tesla supply, such as step-down/step-up transformers, switchgear, connections to the grid, land, access roads, fencing, security, site lighting, i.e., the cost of the Tesla supply is only one part of the battery system cost at a site.
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Europe is much further north of most of the US, thus the solar power output per panel is much lower.
Are numbers all in ‘same-year’ dollars? 25 years is a long time.
What are these $1.4Billion in capital costs? The plant and it’s associated costs are already accounted for. Does it really need 1.4billion in capital repairs/improvements?
I may be dumb, but I am not stupid?
That comment reveals a lot.
Does the 800 pound AI energy consuming gorilla in the room have any effect on this decision?
Probably not yet. For now they’re outsourcing all their AI to cheap power states like Virginia. They’re not seeing that by doing so they’re choking off their startup pipeline, and giving Virginia a leg up.
Startups tinkering in a garage can’t afford to rent AI, they scrounge enough pennies to buy someone’s discarded AI box, then power it with cheap energy – cheap energy which isn’t available in California.
Keeping this plant open will be seen as some as an admission that California’s enormous renewable investments are not delivering stable electricity supplies
You have to look at the bigger picture and blot out everything they got wrong
Scientists Think We’ve Officially Entered the ‘Lunar Anthropocene’
Dubbed the “Lunar Anthropocene,” the epoch has now seen over 100 spacecraft visit the Moon, and humans are becoming a dominant force in shaping the surface.
It is yet to be seen how exactly growing human influence will shape our natural satellite.
https://www.popularmechanics.com/space/moon-mars/a69720247/new-moon-epoch-lunar-anthropocene-science/
Weyland Yutani – building better worlds.
Wow. Just sad. In a few hundred years maybe…
Wow, 100 whole ships! Talk about a nothingburger.
6 were the sizes of garages but had the interior cubic footage of a cargo van. The remainder were about the size of small cars and some smaller than Golf Carts. None of which can be resolved from the surface of Earth. And none which, even combined, could have any measurable effect on the lunar surface.
Looney Anthropopocene
Lunar Anthropocene???
More like
Loony Anthropocalypse
The Democrat/Socialist/Marxist Loonies are in charge or pushing for more power and constantly threatening the Anthropocalypse if power isn’t ceded to them.
I would like to think that these knuckledraggers are finally seeing the light but I know better than that.
They’ve seen what happens when the lights go out. Gray Davis got recalled.
People forget that Diablo Canyon runs the Helms Creek pumped storage and the Tehachapi California water project pumps at night, the single biggest electrical use in the state.
No Diablo means democrats get recalled. It’s not a mystery.
Diablo Canyon Nuclear Plant should be closed immediately, along with all Californian fossil fuel plants, refineries, airports & fuel stations;
Californians need to show the world how to survive (or not) on renewables alone in a green utopia !! Battery fires should keep them warm in winter (:-))
Many fuel stations will be closing this month because they could not receive California loans to replace their old tanks with new double walled tanks. The state took more than 2 years to look at these loan requests. Not process the loans, just look at the requests. We don’t know the total number of gas stations that will permanently close this month, but it will be significant.
And 2 refineries are closing for good thanks to CARB’s stupid rule about adding more CARBOB storage. Down from 40 refineries in 1980 to 11 after April 2026. We will be importing refined products from South Korea and India.
Just when you think that California has reached peak lunacy, this happens. Sacramento has a high percentage of morons.
Having concerns or questions is a typical debating tactic. When I have a concern or question, I do a little research.
I used to work at the first nuclear power plant to close before the end of its design life. I built my dream house where I planned to live out my life. Had to sell it and move. When I retired I did not move back to California. A beautiful state ruined by ugly politics.
If you drive by Rancho Seco you will see some token slave labor solar panels and gas fired power plant.
That makes me old school power generation where supply = demand. I am concerned that stored energy escaping. It does not take much research to validate my concern.
Just up the road from Diablo Canyon there were two massive fires in Moss Landing storage facility requiring evacuations.
Furthermore the huge amounts of spent batteries are hazardous waste. There have been numerous serious fires during transportation and storage. Again requiring evacuations.
Before retiring I did some reviews of extending nuke plant life. So much the cost has no environmental impact unlike slave labor solar panels from China.
Many of us in Australia are demanding the resignation of the Prime Minister Anthony Albanese and members of his “Platitude Party” fundamentally because they have placed their pet ideologies ahead of what is demanded from detailed credible analysis. Sticking to net zero was sin enough, but yesterday the 16 dead and 40 injured from Bondi terrorism is evidence of the national irresponsibility of chasing votes from western Sydney antisemitic groups who have been permitted to protest weekly for 2 years now in many Aussie cities.
In the US, this California example from Diablo Canon is yet another of the same pattern. The anti-nuclear ideologues are few in number, deny neutral economic analysis that harms their pet views, yet are given massive overweight in debate. Some of your top CA politicians are inviting a disaster because they refuse to accept the neutral best plan for future energy.
Time for them to retire as well before deaths mount on the score card from net zero and anti nuclear protesters and their keepers? Geoff S
The bystander that wrestled the gun out of one of the terrorist’s hands deserves high praise.
No doubt his heroic actions saved many innocent lives.
When leftwing politicians condone violence, in Australia or the United States, then they get violence. Leftists are agitating the psychos in our society with their violent rhetoric, and the psychos are taking the violent rhetoric against the Right and Jews as validation for committing real violence, and they go out and kill someone, thinking they are doing something that needs doing.
Radical Leftists should stop agitating the psychos. Unless, the Radical Leftists really want violence. And I can’t say that they don’t from the way they act.
“,,,about taking such a major source of power offline.”
Major source? It’s putting out 2,255 +/- 5 MW – which on a sunny day, is less than 10% of total production. It falls to half of that when maintenance is being performed.
My take? Someone finally noticed what happened in Spain. We need something still spinning on which to base the restart.
Here are two articles from Dan Yurman at Neutron Bytes concerning Diablo Canyon:
Opinion – Relicensing Diablo Canyon Puts It in Good Company
“In a world in which nuclear energy is experiencing a resurgence of interest and action, the determined efforts of groups opposed to the relicensing of the twin 1,100 MW PWRs at the Diablo Canyon nuclear plant flies in the face of global wisdom. “
Diablo Canyon Agrees to Coastal Commission Land Use Plan
“Environmental Groups and others opposed to the reopening of the Diablo Canyon nuclear plant thought they’d latched on to a sure thing when the California Coastal Commission told Pacific Gas & Electric (PGE) that the Diablo Canyon Plant needed to set aside 4.000 acres of its site to prevent future development for residential or commercial use.”
The anti-nuclear environmental groups are now gearing up in a serious way for opposing Nuclear Renaissance 2.0.
Fifty years ago, the anti-nuclear groups started out by focusing on issues of basic nuclear safety. They got nowhere in the courts with those arguments.
But then they switched their efforts towards highlighting the severe problems many nuclear projects were then having with their quality assurance programs and were quite successful in challenging projects which hadn’t met the QA requirements outlined in their NRC construction licenses.
What tack will the anti-nuclear groups take this time around? For example, will they choose to move back towards pushing basic issues of nuclear safety in the belief that 21st Century progressive liberal courts will be more receptive to those kinds of arguments?
Hooray I can import another Citroen diesel! A Ned what were their plans for road haulage? None . So stupid it hurts
“and some questioned whether the facility is still needed at all.”
I met some the other day at the supermarket. Some told me lots of detailed and important stuff that would make whoever said it sound smart, but wanted me to say it because I’m so good, Some didn’t want credit at all. I said “Some, you’r eone heck of a source!” Some said, “Yes and I’m a very specific source too.”
“Do I need a /sarc tag?”
No. Only the 3 on the Coastal Commission who voted “NO” could say something like that without sarcasm.
Since Diablo produces 9% of CA’s power and we already import 25 – 30% of our power from out of state, losing Diablo would mean frequent and long blackouts. Newsom would have seen his dream of running for president go up in smoke.
Aren’t you looking forward to paying $8-$10 per gallon for gasoline thanks to the idiots in Sacramento?