When there is zero wind and zero sun then it doesn't matter how much over provisioning there is: your output will be zero.
I live in Ontario, Canada, where we do have wind and (some) solar in our energy mixture. Wind can go from 100 to 2900 MW, and solar from 0 to 350 MW.
Looking at the Supply tab (18-24 Oct), on Tues, Oct 20, at 05:00 we had 173MW of wind and zero solar (sunrise@07:48):
* http://www.ieso.ca/power-data
The amount that we would have had to to "overprovision" to get useful renewables would have been ridiculous. Luckily our 9,500MW of nuclear just chugs along filling our base load with >4,000MW total available hydro helping, as well as some gas peakers.
If we built another 3000MW of nuclear then we could handle our base load with that, and hydro would be used for the variable portion of demand.
As someone who lives <50km from a nuclear power plant [0] bring in more.
[0] https://en.wikipedia.org/wiki/Pickering_Nuclear_Generating_S...
What he suggested is that we use the overprovisioning to generate methane or hydrogen so it propells us through a few weeks of no wind or sun.
So, instead of 1GW of Nuclear you have 2GW of solar/wind + 1GW electrolysis and 1GW of hydrogen capacity.
This gives you better network stability than nuclear and the cost are or will soon be lower than the nuclear
I have no issue with using renewables per se; I'm just skeptical about basing the entire system on them:
That does not really happen over large geographic regions, within which one can distribute energy via the electrical grid. In Germany, there has been a lot of research put into that before the non-nuclear strategy was decided. It was a political decision, but it has been prepared by many, many engineers and researchers.
In fact, there are times where Germany exports needed energy to France, in spite of that France has much more nuclear power. Sometimes that happens in hot sommers, when rivers have to little water and they become hot. Then, nuclear plants need to be shut down because otherwise they would cause environmental damage.
Other times, it happens in winter, because a lot of heating in France is electrical to accomodate for nuclear energy. But sometimes there is a shortfall, and it turns out that on windy winter days there is an excess of wind energy in western and northern Europe.
Another thing, storing energy is not necessarily expensive. A lot of energy use is things like room heating, room cooling, or hot water. Now, heat can be stored efficiently for many hours. (In larger tanks or earth installations, it can even be stored efficiently for months).
In general, Germany has not planned for and refuses to build any significant kind of energy storage. Existing pumped hydro plants are even shut down. Transmission lines to even out the regional differences due to weather and consumption are planned, but do not exist yet for the usual reasons and will not exist for the next decade or so. This means that Germany relies on the rest of the European grid to balance out its excess production or consumption phases, of course at a significant cost in stability and money. Cherry-picking times where the balancing-out causes energy exports to France is just propaganda imho.
How connected are grids in Canada?
* https://en.wikipedia.org/wiki/North_American_power_transmiss...
Ontario specifically is part of the NPCC:
* https://en.wikipedia.org/wiki/Northeast_Power_Coordinating_C...
It connects to Michigan, NY in two places, and Quebec in a few.
I think there are a lot of complications that are encountered when doing this sort of calculation. You might get a max output of "$15/MWh" or "$112/MWh" but that's only a portion of the picture.
Firstly Nuclear is X amount of power essentially on tap 24/7 where X is between some Min and Max value. From what I understand this makes grid management much simpler and reduces storage, transmission, and conversion losses. Even in the best case situation of "renewable" energy you'll see, in the absolute best case claimed by pumped hydro storage, you're seeing about an 87% efficiency.
Suppose you had a nuclear power plant that could output 100W consistently. Suppose you wanted to build a similarly efficient "renewable" energy source. How much more peak power would it need to output to be competitive? If we assume the power source is 0% efficient at night and 100% efficient during the day, off the bat, you'd need to generate 200W continuously during the day. Then you'd need to generate an extra 13% on those extra 100Ws to make up for storage losses (1.13*100 ~= 113). That means 100W from Nuclear is ~= 213W "renewable". Obviously this is a terrible calculation and not at all accurate but it's just a sample of some of the math that needs to be done.
Another factor that I've been skirting around is that "renewable" sources of energy are often not so renewable. Specifically things like like solar require a huge amount of rare metals & complex fabrication. Right now none of those externalizations are represented in the price of solar because there are no carbon taxes in countries that manufacture them.
Money in this case is a proxy of what needs to be measured and should not be the only factor we optimize for.
Also, nuclear combines well with thermal storage because you don't incur double conversion losses. If you store heat from the reactor during the day when solar is generating, use it during the peak demand in the evening when it isn't, and then run directly from the reactor overnight, you don't really need any other storage.
The bottom half of the demand is the easy half, why would you use your most expensive power for the easy stuff?
> Also, nuclear combines well with thermal storage because you don't incur double conversion losses. If you store heat from the reactor during the day when solar is generating, use it during the peak demand in the evening when it isn't, and then run directly from the reactor overnight, you don't really need any other storage.
In other words, you're running your nuclear at a 50% duty cycle, doubling it's price. I don't think there is much appetite for power that costs over $200 per MWh.
> The bottom half of the demand is the easy half, why would you use your most expensive power for the easy stuff?
Factoring in carbon footprints nuclear would likely beat our battery based storage options if carbon output was taxed. Nickel–metal hydride battery and LiPo are not carbon neutral and are consumable components.
> In other words, you're running your nuclear at a 50% duty cycle, doubling it's price. I don't think there is much appetite for power that costs over $200 per MWh.
50% duty cycle means 50% fuel usage (not really but not not) meaning you're not really "wasting" energy here.
Another question to ask ourselves: we make the Total Cost of Ownership of a plant far better than it even currently is? We can do this by extending the lifespan of a plant to amortize construction. If you could design a power plant to last 100 to 200 years, that could be amortized further factoring into lower costs. We can also do this by reducing construction costs or improving efficiency.
I think those are accomplish-able goals (at least judging by China's adoption of Nuclear). Current plants in the USA operate for ~40 years. That means current plants were built with ~$today-50 (or more) years of physics and material science knowledge.
For context, that's the 70s. In the 70s:
- C was invented
- TTL logic was just starting to be used
- Stainless steel did not exist <- this statement was wrong
Edit: philipkglass pointed out that stainless steel is quite a bit older. Disregard that last item.
Stainless steel was about 60 years old in the 1970s.
That’s one type of building material among many that are needed in huge quantities.
Concrete sold today can be bought with an advertised lifespan of 100 years. If you replace a coal plant with a nuclear plant how many years would it need to be net carbon negative? What is the grams of CO2 / kWh of nuclear vs coal vs solar?
https://en.wikipedia.org/wiki/Concrete_degradation#Carbonati...
Also there is the all energy used for processing concrete which a lot times is not from CO2 neutral source.
It's not so easy when you have to meet it even when there is no wind or sunlight for twelve hours straight.
> In other words, you're running your nuclear at a 50% duty cycle, doubling it's price.
You're still running it at a 100% duty cycle, you're just shifting the generation times. You have a reactor that can produce heat enough to generate 1GW continuous power, so it stores that heat for six hours a day during peak solar generation, then generates 2GW for six hours to cover peak demand in the evening, then generates 1GW directly for twelve hours overnight. It's generating 1GW worth of heat at all times, you're just converting the heat to electricity at different times of the day.
The problem are week long wind droughts with heavy cloud cover. That's where there's a clear argument for geothermal, hydro, and hydrogen. Maybe natural gas with carbon sequestration. If nuclear wants to join these options, it needs to prove itself as something that can be built. And as somebody who doesn't believe that we are close at all to natural gas with carbon sequestration, I think we are a lot closer to making that work than we are to having the managerial and technical skill capacity to build new nuclear.
Nuclear is not the only option, we have so many more.
We have that with current generation systems too; we don't run natural gas at full bore all the time, usually. Most generators run at a capacity factor far below 100%.
The difference is that renewables generate power at zero marginal cost, while a natural gas turbine has fuel costs and wear and tear.
So we are going to have massive amounts of super cheap energy, for those applications that are not time sensitive.
Hydrogen production through electrolysis would be a great way to store this extra, nearly free energy. However this is unfortunately not a perfect match the intermittent surplus of renewables, since the capital costs of electrolyzers makes it so that constant production would be best. But at least some surplus energy will go this route.
Storage has several options, for example we could store hydrogen only for short periods before converting to methane or ammonia or other more stable chemical forms. We could convert pipelines perhaps.
Hydrogen has a lot of difficulties, but it is also, even now, an essential part of our economy and we work with it at scale. It will be a while before "green" hydrogen from electrolysis is cost competitive with fossil fuel derived hydrogen, but it will almost certainly happen.
There's a great, but long, two part series on hydrogen in Europe from what most would call a very skeptical stance, yet as a fellow hydrogen skeptic it convinced me that hydrogen will play a much larger role in the future:
https://about.bnef.com/blog/liebreich-separating-hype-from-h...
https://about.bnef.com/blog/liebreich-separating-hype-from-h...
And also industrial feedstock, immediately, and after a while, aircraft fuel.
While you can do an emergency shut-down quickly, normally adapting the power output of a nuclear plant takes many hours:
https://www.quora.com/How-long-does-it-take-to-shut-down-a-n...
The usual figures given for PWRs are something like "These reactors have the capability to regularly vary their output between 30–100% of rated power, to maneuver power up or down by 2–5%/minute" (https://en.wikipedia.org/wiki/Load_following_power_plant#Nuc...). This means that you can regulate your PWR over its power range within slightly more than half an hour at worst.
There is a lower limit to how much you can regulate your reactor down due to various limitations like Xenon poisoning. Because of that, a controlled complete shutdown is slower, because you need to get through the "icky" region between e.g. 30% and 0%. Also, you usually prepare for the longer phase the reactor will stay shut down. But all in all, shutdown is different from load following, and a conclusion that nuclear plants can't load-follow from a question about shutdown is just asking the wrong questions and drawing questionable conclusions from it.
A lot of energy use is room heating. But nobody wants their bedroom and living room in the night warmer than during the day.
Besides cost, the other issue with nuclear, or any large single generator, is that they can go down unexpectedly and their output drops from whatever to 0. This is less common when generation is from many individual generators. If a wine turbine goes out, it only drops the output of the wind farm by some small fraction.
However, it does require lead, cadmium, and other dangerous materials. Solar power can produce up to 300x the toxic waste as nuclear power does.
[0] https://www.cfact.org/2019/09/15/the-solar-panel-toxic-waste...
A quick search shows that the company referenced in that article, Solyndra, made CIGS panels, which, like I said, are relatively rare, in large part because they were a failed startup that went out of business.
https://en.m.wikipedia.org/wiki/Solyndra
The vast majority of panels use crystalline Silicon.
The article also conflates warrantied lifespan with average lifespan. Solar PV cells can last much longer than 20 years.
https://www.presse.uni-oldenburg.de/einblicke/54/files/asset...
https://www.popularmechanics.com/science/a34372005/solar-che...
That's not so simple. Demand for energy is fluctuating hugely, and nuclear power cannot be freely switched on and off. This is also the case for large coal plants. So, with using renewable energy, grids need to become more agile, and a somewhat larger amount of freely controllable power sources is needed. Another strategy is to average out fluctuations over large areas.
Even today, 6% of all natural gas consumed in the world goes to making hydrogen (about 700 cubic kilometers of H2 per year at STP). The major use is in making ammonia.
Which makes a lot of sense: It's a way to utilize the overproduction from renewables and existing gas infrastructure can be retooled for hydrogen without too much investment [1].
There are even considerations for a European hydrogen backbone by gas infrastructure companies from nine EU member states [2]
[0] https://www.fraunhofer.de/content/dam/zv/de/ueber-fraunhofer...
[1] https://www.rechargenews.com/transition/german-pipeline-oper...
[2] https://www.euractiv.com/section/energy/news/gas-grid-operat...
The hydrogen industry exciting right now, and honestly I can't imagine saying that even a year ago. Europe's investing tens of billions of dollars in it, which will result in massive changes and improvements for the technology. A similar investment in nuclear would not move the needle at all.
Renewables are about an order of magnitude cheaper than nuclear. $15/MWh vs $112/MWh. So what you do is overprovision your renewables. In other words, build more than you need. The major reason to do this is so that when the wind is barely blowing and/or it's a cloudy day you still get enough power to supply your needs without peakers. Then on the days when you're producing excess power (ie, most of them), you use that excess energy to produce methane from CO2. Use that methane to run your natural gas peakers, making them carbon neutral. This is likely much cheaper than batteries, certainly if you already have the gas peakers.
You'll have to overprovision to cover the very unlikely time that both the wind and sun disappear for a long stretch, so you'll be overprovisioned all other times. Methane production takes Hydrogen as an input, so you can use some of that excess energy to create extra Hydrogen. Or you can turn methane into plastic for use or storage. Or just sell the extra electricity, there are several industries that can soak up cheap electricity (please not to bitcoin miners though).
> Nuclear energy is more cost effective than alternatives. The main issue is that antinuclear activists, funded by the fossil fuel industry, have lobbied to make it cost prohibitive to build nuclear power plants by way of onerous regulation and prolonged legal battles.
Even in China, nuclear is incredibly expensive and takes a long time. So I don't think regulation is the main problem.
> Why? Producing hydrogen is inefficient and unnecessary
Clean steel & cement.