>…See the total cost of the energy produced (integrating capacity/load factors): https://www.lazard.com/perspective/lcoe2020

From your lazard source on levelized costs, take a look at the Unsubsidized Levelized Cost of Storage Comparison-Capacity table. The storage extra costs to get around the variability of wind and solar are substantial. They will hopefully come down in the future, but when and exactly how much, no one could really say right now. If you want to actually rely 100% on renewable, you need to take into account the capacity factor - to pretend the intermittency of these power sources doesn't matter is silly.

>…As for land use the main renewable reserve in nearly all nations are offshore wind…

Well there are dozens of landlocked countries, so I am not sure I would say 'nearly all'

>…which doesn't use land, or hydraulics. Moreover in most nations there are unused/unusable zones, even on buildings/parking lots/arable zones (photovoltaics)/...

You have mentioned several times how cheap renewable power has become. As your source shows, rooftop solar has not been, is not and likely will never be cheap. Consumer rooftop is particularly expensive and the cost is is usually hidden by implementing a big subsidy to wealthy consumers that is paid for by less wealthy consumers - sort of a reverse robin hood scheme. We are well past the point where anyone can argue we should subsidize rooftop solar because we need to help build a fledgling industry - yet I see solar advocates continue to advocate for this wealth transfer from the poor to the well off.

>> If you need to spend billions of dollars to add new transmission lines or some hypothetical new grid storage, that also increases the costs

>Indeed, and that's the reason why the very fact that the total cost of the energy produced by renewable energy sources is low (and declining) is of paramount importance because it offers financial provisions to compensate this.

That is a bit of a handwave answer that ignores the actual costs (and difficulties) of doing that. One study estimated that to support renewables, the US would have to double the number of power lines at a cost of around 700 billion. Such a project could end up being much more expensive than that since in places like CA, climate change is causing dryer summers, which has lead to many more fires from power lines. There is now a move to spend billions to move current power lines underground. Besides that huge buildout expense of the power grid, one estimate is that maintaining even the current grid already costs $750 per year per customer. A substantially larger grid will cost more to maintain. Besides direct cost, getting agreement from all the stakeholders seems to sometimes be an issue - even the relatively small proposed Tres Amigas SuperStation has dragged on for many years.

https://blogs.scientificamerican.com/plugged-in/the-u-s-elec...

>> Everyone making any power source will try to get as high as possible capacity factor.

>Absolutely, my thesis is not that such a strategy isn't always sound, it is that a low capacity/load factor isn't, by itself, a show-stopper.

I never said it was a 'show stopper'. I said it was a big deal and right now it is neither cheap or simple to work around.

>> In the 100 years since pumped hydro was developed, we haven't really deployed much of any other kind of grid storage.

>Because fossil fuels are so convenient for storage...

A coal plant isn't cheap to build. A nuclear power plant isn't cheap to build. Building extra plants to cover for planned/unplanned maintenance, daily variations in demand, seasonal variations, etc. is very expensive and wouldn't have been done if anyone thought building grid storage was going to be cheap or simple. The very fact that the first pumped hydro was built a hundred years ago means people have been thinking about it for a very long time. The difference is that coal/nuclear/hydro don't absolutely need grid storage. Solar and wind do, so even if the cost is high, it would need to be paid.

>…Same for storage: as the need for it raises, gorillas appear in the room (see batteries https://ourworldindata.org/battery-price-decline , green hydrogen https://en.wikipedia.org/wiki/Green_hydrogen , V2G https://en.wikipedia.org/wiki/Vehicle-to-grid ...)

Yes there are lots of people researching grid storage since it would be impossible to build a reliable grid using intermittent sources without it. And hopefully, we will find some technologies that are economical and scalable. In order to meet climate goals, there will have to be much more dependence on the grid as fossil fuels are removed from transportation, heating, etc. The goal has to be to make a carbon free grid that is at least as reliable as the current grid. As the small power failure in Texas showed blackouts kill people. Not only does our economy rely on reliable electrical power, so do human lives.

>> You didn't actually answer

>IMHO I did, bar any other option than nuclear or renewable sources. Can you name one?

My original question was simple:

>…It is possible there will be some major advances in grid storage that will allow us to stop using fossil fuels to cover for the intermittent nature of wind and solar. In that case - great, problem solved! But... what if that doesn't pan out? The dangers we are facing in the coming decades are immense. If you were forced to choose, would you prefer the world to suffer through catastrophic climate change rather than use nuclear power?

>> If countries actually decide they need them and commit to building them, they obviously can build them.

>In which wonderland 'wanting to' is equivalent to 'being able to'?

If we could build nuclear plants 50 years ago, we can build them now. This isn't like nuclear fusion where we've never built a commercial plant. France went from about 0% to >70% electrical power from nuclear energy in 15 years using the technology available in the 1970s. We haven't entered some primitive dark age where he knowledge to build a nuclear power plant has been lost to time.

>> France was able to build enough plants in a 15 year period to make it the majority of their power

>This is not exactly comparable. France built a nuclear fleet in 25 years (1974-1999) See https://web.archive.org/web/20211225120958/https://upload.wi...

France built the bulk of them (56 reactors) in about 15 years.

https://en.wikipedia.org/wiki/Nuclear_power_in_France

>As for present times France tries, since 2005, to build a reactor in Finland and it is a major failure https://en.wikipedia.org/wiki/Olkiluoto_Nuclear_Power_Plant?... another one in France and this is another major failure https://en.wikipedia.org/wiki/Flamanville_Nuclear_Power_Plan...

The EPR is a next generation design that was supposed to be a French/German collaboration, but since Germany decided to phase out nuclear power, Siemens sold their shares in the joint venture. (If Siemens had been involved, maybe things might have gone smoother.) It does make one realize that the approach France took in the 70s of using a proven design and committing to building a number of them was a good approach. France has recently committed to to implementing small modular reactors, which is what a lot of people are recommending. We will see how they do.

>…Those last years China built between 1 and 5 reactors per year and nuclear produces about 6% of their electricity.

To add some context, in 2009, China's National Development and Reform Commission indicated the intention to raise the percentage of China's electricity produced by nuclear power to 6% by 2020. In 2018 the China NDRC said that China's nuclear generating capacity must increase to 554 GWe by 2050 if the country is to play its part in limiting the global temperature rise to below 1.5 °C. They estimate nuclear power would grow to 28% of power transmitted on the grid.

https://world-nuclear.org/information-library/country-profil...

In terms of the present, China has released its 14th Five-Year Plan covering the 2021-2025 period and announced its aim to increase its nuclear power capacity by 40% from 50 GW in 2020 to 70 GW in 2025.

https://www.enerdata.net/publications/daily-energy-news/nucl...

Much as China now dominates solar cell production, it appears that they intend to dominate nuclear power plant construction. China plans to build as many as thirty nuclear power reactors in countries involved in the Belt and Road Initiative by 2030.[17][18][19] On COP26 in 2021 China has announced plans to build 150 new civilian reactors until 2035.

https://en.wikipedia.org/wiki/Nuclear_power_in_China

If China can decarbonize its grid with solar/wind and some new grid storage they develop in the future that would be amazing. If China ends up decarbonizing its grid by building hundreds of nuclear power plants along with solar/wind, that would also be amazing.