Levelized cost of energy dooms nuclear.

Even if some nuclear plants last 100 years just like some cars do, the average age of plants retired last year was 42 years and the oldest so far is about 50 years. Any CFO financing such an investment has to take this into account, regardless of future promise. To reach a 100 year life the plants have major refurbishments including new turbines and rewound generators as well as replacing almost all the steam system. Many of these refits have cost 1/4 to a third of the original cost of the plant. That does not mean they weren't a good idea because 1/3 the original price might be 1/8 of the replacement cost. However, that refit cost plus lost sales during the period must be added to the original cost to work out the total capital cost

In any case if you go to your spreadsheet and feed in a weighted cost of capital 5.5%, which Plant Vogtle used, and spread the cost over 40 years it works out at $7.10/h per thousand dollars. If you stretch it to 60 years the cost only goes down to $6.54. Now if you reduce the lifetime capacity factor from 90% to 85% and still neglect major refurbishment cost, the capital cost per MWh is only 6% lower. As the operating, fuel and other overheads, grid fees, local taxes, insurance and admin don't change extending the life by 20 year at best reduces lifetimes cost of power by 3~4% 

In summary extending life makes little difference to the initial investment decision and many people would argue it increases the investment risk because there is more chance of market, technology changes or environmental changes, impacting the out years and reducing the value of power. 

For example, 5 years ago average power prices across the Australian grid were almost US$90/h and even higher in Victoria state which relied on old lignite plants. All the experts suggested prices would only go higher as world prices for coal and gas jumped. lignite provided 38 TWh to Victoria. The Latrobe Valley Region, where the lignite plants are, or the nearby coast were touted as ideal locations for nuclear power plants

An optimistic nuclear developer might have said they could make money at that price. Let's say they lined up permits and finance within a year to build a couple of Korean AP 1400's on the coast, with an all-in guaranteed price from Kepco of US$85/MWh, lower than the Emirates cost with a target of supplying 22 TWh/y at 90% utilisation.

Now fast forward 4 years. For the last 18 months wholesale power prices have averaged less than US$33/MWh, the state which had a few wobbles in reliability in 18/19 has reduced lignite generation by 15% and yet over the last year has exported an average of 9% of generation. Meanwhile minimum demand has dropped to about 3,000 MW and falling by about 100 MW/y, so in the interests of power security both reactors would have to throttle back to less than 50% at times and over a year would be extremely lucky to average 70% CF regardless of price.  

Our plucky nuclear developer would have found themselves in a Plant Summer situation very quickly. Fortunately, he would probably have only blown $1~2 billion not $9bn     

Thanks for your reply, in a small country, things are different.  But US electricity consumption is only about 510 MWh/sq km vs say 1,400 MWh/sq km in Germany and the larger geographic spread means that variation in renewable output is smaller. The smaller the area the more variable wind and solar become, so the more backup you need. However, I would be very surprised if wind is anywhere near saturated. Many of the early wind farms operate at 18% CF.  They can be replaced with fewer taller turbines with larger rotors which in the same environment can get to 35~40% CF. For example the ninety turbines of the 30 MW El Cabrito wind farm were replace d with 12 turbines in 2018 with 27 MW capacity yet annual output will be increased about 30%. The important point is not peak output but output at low winds and therefore the amount of storage required. The new turbines will supply 4 times as much power at wind speed of say 6~7m/s so over the years a renewed wind turbine fleet could supply 30~50% more energy and require less than half the backup 

I am not advocating lithium batteries or in fact batteries at all for most of the storage, much of it can be ice or hot water, altering the peak capacity of hydro and a big one eventually will be smart charging of EVs. Solar thermal is also a possibility. That can be supplemented by resistance heating or heatpumps powered with excess wind and solar and using a low temperature organic Rankine cycle for generation as well as conventional steam generators. There are dozens of possibilities

Lithium batteries do have a role in replacing spinning reserves so for example a 50 MW/1/2 hour battery can be paired with a 100 MW hydro or gas plant to provide the instant response for fault current so the hydro or gas generator is still providing grid services without using fuel /water, but if there is a loss of supply the battery allows the rotary generator to spool up. 

Then for longer term stationary storage batteries, where they are necessary, and where weight and energy density is not an issue, sodium, aluminium, and even iron are suitable battery metals as well as all the redox flow battery chemistries.   

No nuclear plant gets free water, Peter, any more than you do when you go for a swim at the beach. And calling programs which have never paid out a dime "subsidies" (loan guarantees and Price-Anderson)? Please. You're grasping at straws. 

"Why do we still have the Price-Anderson Act + its permutations over the years still in place..."

Because it hasn't cost taxpayers a dime?

"France may get 70% of its electricity from nuclear, but they are contemplating dropping that down to 60%."

They have changed their minds. Prime Minister Emanuel Macron, in November:

"'To guarantee France's energy independence, to guarantee our country's electricity supply and achieve our objectives, in particular carbon neutrality in 2050, we are going, for the first time in decades, to relaunch the construction of nuclear reactors in our country and continue to develop renewable energies.

'These investments will allow us to live up to our commitments. As we close COP26 in Glasgow, this is a strong message from France,' he added.

He said the European Union must work together 'to build a credible strategy for reducing our CO2 emissions, compatible with our industrial and technological sovereignty.'

Macron added: 'This new model of investment and growth in which I believe for France and for the European Union is the one that I will defend on your behalf from next January when taking the presidency of the Union.'"