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There's no good ecological, economical or safety-related reason to reduce nuclear to 50%, especially if it is intended to be replaced by Solar and Wind

There is a very simple and fundamental reason to "reduce nuclear": France has a fleet (roughly 60) of aging nuclear power plants. Many of them already reached their planned life time and are kept working by extending their life time. But nuclear reactors definitely age, so this extension can keep them operating only so long before it becomes a real safety hazard. But France isn't building enough new reactors to keep the numbers up. Currently they have one or two in construction, with construction times over 10 years, the numbers game is obvious. They don't "want" to reduce the nuclear production, they have to.

At the same time, France has ideal conditions for renewables. A very sunny south, lots of wind on the west and north coasts. Add to that a big supply of water power, this should cover most storage needs. The European electrical grid already plays a large role in the energy balance - France is usually selling surplus nuclear energy across Europe - and could do so even more with renewables.

> Many of them already reached their planned life time

That's a misunderstanding of how nuclear plants are built. They don't have a "planned life time"; they have a "safe window" of 10 years, and it is reexamined every 10 years. The age of a reactor doesn't have an incidence on whether it should be stopped or not, only this decennial visit can say if it is safe to continue or not, and if it isn't, what needs to be done to make it safe again. The organ in charge of that (ASN, Agence de Sûreté Nationale) is an independent entity and has the know-how to do their work diligently. If they say it's safe, it's safe.

> At the same time, France has ideal conditions for renewables. A very sunny south, lots of wind on the west and north coasts. Add to that a big supply of water power, this should cover most storage needs

For every kW of installed intermittent energy you need a kW of gas to still have electricity when the intermittent doesn't run. Propping up intermittent is propping up gas and that's the sadness of it.

Also, pretty much all developed countries in the world are at capacity in terms of hydro. We can't build more dams at large scales, unless there's a magic way of creating mountains.

The rate of nuclear reactor production being low isn't a force we of nature, its a choice. They choose to produce reactors slowly, and hence they choose to transition away from nuclear and to renewable and imported coal in whatever ratios.

But the choice how many new reactors are getting built happens for a reason: in France it is clearly the price, not political resistance. If a nation like France, which runs to 75% on nuclear, doesn't build new reactors, who else would be doing it? And of course, their currently sole attempt to build a new reactor confirms this: late and way over budget. The new reactor in Flammaville already costs 12 billion, but it isn't operating yet. And that is only the building costs. Do the math what this means for the renewal of the whole fleet of French reactors.

The administration of this new reactor's construction was a farce from the beginning: they expected to be able to build this reactor in half the time and half the price it took when France was building 10 reactors in parallel, ie when it still had experience. There is no doubt that the estimation was not just optimistic, but unrealistic (not my word, the word of the rapport on the overblown budget of this reactor)

That said, it's still going to be a good amount. The danger that too many people do is that they don't understand the amount of power a nuclear plant produces, especially when they compare it to wind turbines or photovoltaic panels.

The construction of the entire French fleet of reactors was done for 100 billion current euros, and you can clearly see the effects in terms of CO2 (https://www.macrotrends.net/countries/FRA/france/carbon-co2-..., starting in 1980). If you consider the changes in safety thresholds, rebuilding it anew is in the order of 300 billion euros. 300 billion euros is the amount Germany spent between 1996 and 2014 to build renewable capacity, and yet their emissions of CO2 barely dropped (https://www.statista.com/statistics/449701/co2-emissions-ger...).

A wind turbine or a solar panel is cute if you're talking about powering your own home (even though you'll need more than one) but if we're talking about an entire country with its industry, it's far from being a viable solution. It's always been a problem of scale.

It's sort of a self-fulfilling prophecy though. As we build fewer reactors we lose economies of scales, we lose sub-contractors, we lose the knowledge to build these reactors efficiently and without incurring huge financial penalties due to delays and sub-standard deliveries by contractors. This in turn is used to justify building fewer reactors which creates this feedback loop.

You can always expect the first type of a new reactor (like this EPR design we've been working on) is going to face challenges, missed deadlines and cost inflation. If in the long run you plan to build a hundred of those it doesn't matter as much as if you only have 4-ish reactors in the pipeline.

You will never get economies of scale with nuclear. There is just not enough of them being build and wouldn't be even if we'd go full nuclear. You need to build to local conditions etc..

Also for those of you who say it's a problem of too much regulation. That's a hilarious proposition: yes sure let's remove regulatory control over technology which could yield large areas of densely inhabited aras no go zones for 100s of years (even if it's 10s it would be unacceptable). It's not like it has been shown over and over again that if you remove regulatory control companies will start taking shortcuts to maximize profits

There might not be huge economies of scale but there seems to be a baseline under which we basically lose our capacity to build more power plants. At this point we have additional delays and costs (and loss of trust) because of manufacturing errors. That seems to be a real problem for Areva nowadays.

Right. But what are the realistic prospects of the next EPR designs getting considerably cheaper?

I am very excited about any new design which has a good chance to be cheaper, but so far the track record hasn't been very good.

And of course, we haven't talked about the nuclear waste.

The prospects are poor. Cost improvement comes from iteration and learning, and demand for new reactors is low. Even when they are built, the time span is so long that learning is balanced by forgetting.

No, intermittent sources need an affordably dispatchable source to produce when they can't. A steady, fixed cost source like nuclear, that must be producing most of the time to minimize the cost of its output, is unsuitable for acting as a backup to intermittent sources.

That's assuming you're using the steady source to cover for the intermittent source when it isn't generating. If you're using the steady source to replace the intermittent source entirely (as France had been doing) then it is producing most of the time and you don't have that problem.

This is probably the largest impediment to a 100% renewable grid. You might be able to get over the solar day-night thing with batteries if you had to because you can justify a lot of batteries if they're getting used every night, but the thing where sometimes it's cloudy for a straight month is a serious issue.

Right, it's an either-or situation. And now, with renewables crashed in cost and continuing to fall, it look's like renewables are winning.

You bring up batteries, but they would not be used for long term load leveling. The optimal solution is some combination of overcapacity w. curtailment, batteries for short term leveling, and hydrogen for long term leveling. Simple cycle turbine power plants can have a construction cost maybe ~5% of the cost/kW of a nuclear power plant (CC, around 10%), so building them and letting them sit idle most of the time is not a big deal.

> Right, it's an either-or situation.

Not exactly, they're still complementary, just not in that specific way.

Suppose you have 100% solar generation with enough batteries to survive the night, and then it's cloudy for a month and they generate half as much power. You can suppress demand some by raising prices, but suppressing it by 50% is unreasonable. Suppose you can suppress demand by 20%. Well then you still need enough long-term storage to cover 30% of your total demand for a month, which is really expensive for something you only use once every two years.

Now suppose you have 50% nuclear and 50% solar. Immediately this gets you out of needing the day/night batteries because nuclear generates at night. Then it's cloudy for a month and you lose half the solar generating capacity, but now you're only down 25% instead of 50%. Suppress demand by 20% through pricing and you only need enough long-term storage to cover 5% of the load.

This also makes the leveling a lot less precarious. If two weeks into the cloudy month it turns out you've already burned up all your long-term storage fuel and it's still cloudy, you can lean a little harder on pricing and get to a 25% reduction even if people gripe about it some. If that happens with pure solar, pricing high enough to cut demand by the full 50% would have people rioting in the streets.

Long term storage of the kind I'm talking about has two parts: a capacity part, and a consumable part. The capacity part is the same whether you need it for an hour or a month, and would be MUCH cheaper than nuclear plants of the same capacity. The consumable part (in my example, hydrogen) would be expensive, if needed for a month. But that doesn't happen very often, so on average the cost is quite reasonable.

Do you have some numbers ?

That affordable dispatchable source is gas, and will continue to be for the foreseeable future. It's never been nuclear.

Propping up intermittent is inevitably propping up gas, that's the danger of it

It's gas because CO2 is not taxed. Don't tax gas and renewables will prop it up, but also nuclear doesn't stand a chance of competing. Tax CO2, and renewables will displace gas. The CO2 tax for renewables to take over will be lower than the CO2 tax needed for nuclear to take over. So the point you make there doesn't help new nuclear.

What CO2 taxes would do is keep existing nuclear plants operating a bit longer.

You _can't_ replace gas with intermittent. All sources aren't freely interchangeable. Intermittent doesn't work when the sun doesn't shine or when the wind doesn't blow, so you _need_ something to compensate it, and that's always gas.

Don't look at the system as "this source emits X kW when it's running". Look at the system as "the total demand _right now_ is Y xW, how can it be met ?". Because that's what drives the viability of sources of electricity, and whether they can be replaced with another one. Intermittent, by its very nature, isn't enough for producing electricity, it always needs an additional source.

It's always gas right now, because gas is the cheapest.

But if CO2 is taxed, hydrogen (from water electrolysis with surplus renewable electricity) becomes cheaper. And with cheap renewables, renewables + batteries + hydrogen would be cheaper than a system including nuclear.

> And with cheap renewables, renewables + batteries + hydrogen would be cheaper than a system including nuclear

* Definitely not. Looking at France, Solar and Wind are "cheap" because producers can sell on the grid, and the national operator _must_ buy it, at a higher cost than its own electricity, in a move to prop it up.

* Water electrolysis + electricity generation from hydrogen hasn't been proven to work cheaply at scale, what's the biggest project in existence ?

* Batteries are already not cost-effective at high scales

* All of those imply that storage will be on the same site as production; if not, the grid needs to be overhauled (it is built for few stable sources, not for numerous variable sources) and that cost is never taken into account by those who root for this kind of solutions

When I say renewables are cheap, I mean in comparison to NEW nuclear plants. Of course nuclear plants that already exist, where the sunk costs of construction can be ignored, will be more competitive. But France would spend less money building solar and wind instead of building new nuclear plants.

There is little electrolytic hydrogen today because hydrogen is mostly produced from chemical reforming of natural gas and other fossil fuels. Of course, this ignores the cost of CO2 emission from that process.

Batteries are already being installed in the real world, at very large scale. What exactly prevents them from being installed at even larger scale? And their costs are dropping rapidly, just as the cost of wind turbines and PV modules did.

Why hydro is not as flexible? A cable from Germany to Norway is being built to use hydro plants in Norway as energy batteries. This is despite Germany having natural gas plants.

A hydro power plant can't be used as a battery, it must be purposely built as a pumped storage plant. The cable in question allows Norway to sell hydro power to Germany (and if Germany has a surplus, they can sell electricity back). There's no storage solution in it, though.

It's sort of a battery, you just can't charge it with electricity. If you oversize the generators, you then can discharge the battery when renewable generation is low, and let it charge when renewable generation is high.

Yes, but by using that definition all baseload power generation (coal, gas, hydro, nuclear, etc.) are "energy batteries", which makes the term meaningless. By "energy batteries" when talking about the electric grid, people normally mean different kinds of large scale rechargeable energy storage solutions, such as pumped storage, molten salt, etc.

With oversized generators hydro provides an extra storage that can last weeks and even months at the pick usage depending on reservoir capacity. This is the battery effect that cannot be matched with molten salt.

As I just stated, yes, that's called baseload power. It applies equally to hydro power, nuclear, coal, gas and all other baseload types. If you make them larger they can produce more. "Energy batteries" when talking about the electric grid are generally rechargeable, because as I stated otherwise the term is meaningless and just means "baseload power" in general.

Increasing capacity at hydro power stations or other baseload stations isn't as easy as just "putting a larger generator in". Everything needs to be considered and sized up: turbines, piping, outlets, new environmental assessments, etc., just as in any other type of power plant.

A natural gas plant cannot be used as a battery either. So again, why hydro is not as flexible as such natural gas?

If I were to hazard a guess, I'd say it's because production in a gas power plant is simply regulated by burning more or less gas. If you need more gas, you can likely buy more. While production in a hydro power plant can be brought up and down by draining the reservoir faster or slower, a hydro plant has a lot of external factors that a gas power plant hasn't.

The current water level in the reservoir, expected drainage and rainfall over the year, environmental regulations concerning water discharge and intake levels, fish, etc. all play into it. Note that a hydroelectric power plant doesn't just generate electricity, it also regulates water levels pretty far up- and downstream from the plant.

Large battery storage I feel in the future can offset the sudden demand giving enough time for nuclear or less carbon producing power to ramp up. We are not there yet but I feel as batteries keep getting cheaper and hopefully smaller we will reach a point where homes and business have enough battery power for few hours of their peak use. This could flatten the demand spikes on the networks as well as maybe allow to use solar power when the sun is not out.

"Storage" is a big word. Methods of storage are not interchangeable with one another.

Think about food storage: your shelf doesn't have the same properties as your fridge, which is not the same as your freezer, which is not the same as jars in your basement. It's the same for batteries: they're good for very short periodicity, but fail at anything beyond the week. So you can't store your energy from the summer to use it during the winter, for instance.

Your point of view is one of a cornucopian (https://en.wikipedia.org/wiki/Cornucopian), hoping that it is fine to wait for better days because "surely" progress will arrive. The situation is that we don't have some time to think and wait for innovation, we're already a number of decades late. Why wait for something that might or might not happen, in 5, 10, or 50 years, instead of doing what already works today ?