Vogtle Unit 3 initial criticality

Unit 3 at the Vogtle plant has achieved a self-sustaining nuclear chain reaction for the first time.

The operators will now perform several low-power physics tests to ensure the reactor performs as designed. After that, they will increase power, spin up the main turbine and connect the generator to the grid. This is forecast for sometime this spring or early summer.

  • Pete


     I am curious how you view the economic viability of new nuclear relative to solar plus storage?
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The large scale battery storage systems I am familiar with will provide their design power output for about 4 hours.

1600 MWh / 400 MW = 4 hours

Vogtle Unit 3 will provide a constant 1100 MW of power 24 hours a day, 7 days a week, for months at a time. Therefore, it is difficult to compare solar plus batteries against nuclear. I am not aware of any solar plant with enough capacity and enough battery storage capacity that can provide the same kind of 24/7 baseload power.

A few other questions regarding the solar plant. What happens if it is cloudy for a week or two? How does the output of the plant vary depending on the time of year? June/July have more daylight hours per day, compared with December/January.

I guess I am going to give a disappointing answer and ask to be shown where does that sort of solar/battery system exist that can provide continuous electricity?

  • Pete

I don’t believe it does yet. It appears as though battery tech and solar adoption are trending towards removing nuclear power as a viable source from an economic standpoint within ten years, at least the demand for new build nuclear. I am not in any way against nuclear for a power option, it just seems that cost is against the industry if I look ten years out. More storage capacity, be it battery, pumped storage, or other seem to be emerging and solar cells are improving as well.
Doesn’t seem to be much room for multi billion dollar projects especially with interest rates

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A few other things to consider. Vogtle 3 and 4 are designed to operate 60 years each. With proper maintenance, they could go at least 80 years. How long do solar PV panels last? I understand their output tends to degrade over time. Same question regarding Lithium batteries. How many times will the solar panels and batteries need to be changed out during the 60 years that the Vogtle plants operate? These things need to be considered in the Levelized Cost of Electricity (and Storage) calculations.

The LCOE calculations often assume all power sources will operate 40 years, or whatever their standard is. Real world experience is often different.

  • Pete

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Solar, even with storage, is a different class of energy generation than nuclear. Nuclear is what they call “base load” because it operates 24/7 and stays running for very long periods of time. The best of all worlds, at least with regards to CO2 emissions would be “all” nuclear for base load, and “all” solar+some storage for the rest. That’s not possible in reality for various reasons (for example, neither can be turned on/off quickly), so there will also be some natural gas powered generators as well in the ultimate system.

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The important concept is dispatchability. During the course of a day, supply must always exactly match demand. If there is a mismatch, then the grid frequency and possibly the voltage go out of spec and equipment can start failing.

Here is a link for the demand curve for the California grid operator.

For today’s curve, everything below about 18,000 MW is baseload. From 18,000 to about 28,000 MW needs to be supplied by adjustable, dispatchable, load-following power plants. This can be done with hydro, natural gas, or batteries for the peak demand in the early evening. Of course, the curve will change slightly tomorrow, depending on conditions. Summer peak demand is going to be higher than today in the late winter, early spring.

As stated earlier, batteries cannot load-follow 24 hours a day. They generally deliver for a few hours, then they need to be charged up again. It should also be remembered there is a 20% energy loss in today’s storage systems. If you charge up batteries with 100 MWh of energy, you can only get 80 MWh out. The rest is lost in heat and other inefficiencies.

Nuclear plants can and do load-follow, if needed. It is just that in the US, it is more economical to run them as baseload plants. The Columbia nuclear station in Washington state is often run with adjustable load, as one example. France, with around 70% of its power coming from nuclear, must load-follow with its nukes. There are limitations regarding core life, but the French operators do it daily, along with dispatchable hydro and natural gas to supplement the supply.

  • Pete

Building on what others have said, it is apples to oranges. The issue is that peak demand is usually about four hours or so in the late afternoon/early evening in most places. To meet that demand, you must have generating capacity that is idle 20 hours a day. For that reason, electricity in those peak hours will always be the most expensive.

In recent years, solar PV plus storage has become cheap enough that in sunny locations like the southwest it is the cheapest form of peak power. But batteries are still too expensive to use for storage longer for periods much longer than peak demand, in most cases. In the flip side, nuclear plants are so capital intensive that it is not economically feasible to run them at less than the maximum practical capacity all the time. So nuclear can’t fill the peak power role. For that reason, solar PV plus storage and nuclear power are complementary, not competing technologies. Neither can fill the other’s role. They are in different lanes.

On the topic of solar PV plus storage, the EIA estimates that 29.1 GW of solar and 9.4 GW of battery storage will come online in 2023.



A Utah-based energy developer has filed a final license application for construction of a major pumped-hydro storage project in Nevada. rPlus Hydro on March 8 said it made the filing with the Federal Energy Regulatory Commission (FERC) for the company’s 1,000-MW White Pine Pumped Storage installation in White Pine County.

White Pine, the first pumped-hydro storage project in Nevada, is expected to provide about eight hours of energy storage at peak output of 1 GW. Officials said the installation could supply power to support more than 12% of the state’s peak electricity demand on a hot summer day.

The project is the second developed by rPlus Hydro to reach the final license application milestone this year, joining the Seminoe Pumped Storage Project in Wyoming.

$2.5 Billion Investment

“White Pine is located at an important crossroads of existing, planned, and proposed electric transmission in Nevada,” said Matthew Shapiro, rPlus Hydro CEO. “From this location, the project would help the state meet peak power needs in its northern and southern load areas, and help stabilize the grid, while making the most effective use of renewable energy sources. With planned third-party transmission build-outs, the White Pine project will sit at the intersection of regional energy markets. It’s hard to imagine a more strategic location for this project.”

Local officials in White Pine County, located in east-central Nevada about 240 miles north of Las Vegas, said the project represents about a $2.5 billion investment in Nevada’s energy infrastructure.


If US nuclear plants were to load-follw, then their economics would be even worse than they are now.

France is having lots of trouble keeping their old nuclear reactors online because of safety related rework required for many of their old reactors. 2022 was the worst year yet for French nuclear power generation in last 5 years.


Vogtle Unit 3 turbine/generator was synchronized to the grid early Saturday, and started producing electric power. Twenty five days between initial criticality and producing electric power isn’t too bad, in my experience. It will probably be several weeks before the reactor is brought up to full power and the plant generates its full 1100 megawatts.

Meanwhile, Unit 4 is currently undergoing hot functional testing of its reactor coolant system. These tests bring the reactor system up to normal operating temperature and pressure, to ensure everything works correctly prior to loading in the uranium fuel.

News release from Georgia Power here.

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A bit of trivia…
The Vogtle nuclear power station was named after Alvin Vogtle, a former president of Southern Company. Earlier in life, Vogtle was a fighter pilot in World War II, was shot down, captured by the Germans, and eventually escaped to Switzerland. Vogtle was the inspiration for the Steve McQueen character in the 1963 movie The Great Escape.

  • Pete

One of the two long-delayed nuclear units at Plant Vogtle near Augusta successfully generated electricity and connected to the grid for the first time, Georgia Power announced Saturday morning.

Georgia Power said in a news release that operators will continue to increase power levels and conduct more tests to ensure the reactor functions as designed in the coming weeks, before placing it into commercial service. The company said it still expects Unit 3 to begin sending power out to hundreds of thousands of Georgia homes by May or June. Its twin, Unit 4, is expected to be complete by the end of this year or the first quarter of 2024.

Both Unit 3 and Unit 4 have been plagued by delays and are more than six years behind schedule. Meanwhile, their total price tag has ballooned to above $35 billion, more than double what was initially forecast.

The average Georgia Power customer will have paid a total of about $913 in their monthly bills for Vogtle construction by the end of this year, according to witness testimony delivered to the PSC.

As soon as Unit 3 enters commercial service, another $3.78 rate increase approved by the PSC will begin hitting customers’ monthly bills. Additional hikes could follow, with the exact amount to be determined by the commission in hearings expected to start later this year.

Are the ratepayers happy?