Can Nuclear Power and Renewable Energy Learn to Get Along?

Here’s my contention then: If you want an ultra-low carbon renewable energy system, you need storage and flexibility. And if you have storage and flexibility, then renewables play just fine with nuclear.

That’s Jesse Jenkins’ wrapping up a provocative essay at Energy Collective. I disagree with the implication that ultra-low carbon energy systems must have huge amounts of classical storage and flexibility. Yes, if the system design followed the German Energiewende concept. No, if the system is designed to achieve the optimal nuclear-VRE contributions by exploiting productive variable demand or load-shedding to substitute for most of the storage and flexibility. The variable demand would be products with high value in the region of generation – e.g., syn-fuels, desalinated water, ammonia fertilizers, etc. Nathan Wilson explains the concept of using syn-fuels as the variable demand in the comments:

Should we over-build electrical generation and add fuel synthesis? It depends a lot on whether we need the liquid fuel for other purposes. There will always be some nations that can’t grow enough bio-fuel for their transportation system (maybe most nations). For these nations to get off fossil fuel, their syn-fuel industries will be roughly 1-2 times the size of their electricity industry.

Such a nation would need very little energy storage, since the syn-fuel plants would constitute enough dispatchable load. To put down some ball-park numbers, say the baseload power plant costs $6/Watt (plus fuel for nuclear at around 2¢/kWh) and the hydrogen plant costs an extra $1/Watt, including several days of storage. Then baseload electricity is around 8¢/kWh, and dispatch load at the syn-fuel plants adds 1¢/kWh to the cost of baseload for the idled equipment; this is really cheap peaking power (it does assume that as with today’s costs, per-Watt the chem plant is much cheaper than the nuke, and of course a cheap chem plant is crucial for applicability to low capacity factor off-peak wind and solar).

Thermal energy storage at nuclear plants or advanced batteries (for a few hours) might also fall to the $1/Watt point, but we would still have to pay depreciation for the storage, even on days we didn’t need it. When we don’t need the syn-fuel plant to load-shed, it makes product for its fuel customer, so it does not burden the electricity economics (in reality there would likely be a small payment).

I mentioned several days of hydrogen storage, but note that if liquid fuels (e.g. ammonia or DME) are produced, or if the local geology is suited to underground hydrogen storage, then seasonal energy storage is feasible.

Providing syn-fuel for the entire transportation market using plants configured for dispatchable load is such a powerful tool, that nuclear and renewables can almost be mixed freely on such a grid.

Note that the energy prices given (8¢/kWh for baseload electricity, $1/Watt for hydrogen plant) and 70% conversion efficiency suggest a hydrogen cost of $4.60 per gallon of gasoline equivalent. Conversion to ammonia fuel would add another 5-25%, depending on the technology (this improves storability/transportability and allows simpler ICE cars rather than expensive fuel cell vehicles).

This cost would not be attractive in the US unless the hydrogen/ammonia car got much better mileage than gasoline cars (20-50% better is likely). However, it is possible that the very high temperature nuclear plants in development coupled with thermo-chemical hydrogen production could reduce the cost substantially. Also in China and India nuclear power is only one third of what it costs in the US, so the retail price of ammonia syn-fuel would easily beat imported fuel.

I recommend going directly to the Jesse Jenkins essay Can Nuclear Power and Renewable Energy Learn to Get Along? which is generating a lot of well-informed discussion.

Update: later in the comments Nathan Wilson summarizes the specific case for ammonia instead of synthetic hydrocarbons.

Yes, fuel synthesis is a great way to utilize otherwise-curtailed sustainable energy.  But instead of making methane or other hydrocarbons we should make carbon-free ammonia (NH3), to get several benefits:

  • Capturing the needed nitrogen (which is 80% of air) is much cheaper than trying to capture CO2 from the air, sea, or biomass.
  • Like diesel fuel, ammonia can be burned in high compression internal combustion engines (ICEs), which deliver higher energy efficiency than is possible with gasoline engines; ammonia burns cleaner than diesel, with zero-particulate emissions guaranteed.
  • When leaked, ammonia is not a green-house gas (unlike methane), but it is a buoyant gas (unlike methanol and MTBE which can find their way into waterways).
  • Ammonia use would not create another dependence on continued fossil fuel use to assure CO2 availability.
  • Unlike hydrocarbons, ammonia does not release CO2 when burned, so ammonia (which is made today from fossil fuels for a price competitive with gasoline) can be used to allow fossil fuel with CC&S to join sustainable energy in providing non-CO2-emitting energy for transportation, construction, combined heat & power, or electrical peaking applications (so even countries and regions with deeply entrenched fossil fuel industries can achieve deep reductions in CO2 emissions).
  • Ammonia can be economically stored in large above ground (refrigerated) tanks for seasonal energy storage (applicable to all locations, unlike underground methane storage which requires special geology). 

see also: 

Update: Jesse Jenkins inserted a comment that nicely illustrates the arithmetic of the curtailment impact on VRE of more or less nuclear contribution:

Hi Alan,

I grant that without lots of economic storage/sinks, you’d hit the cieling on renewables faster if you have a share of nuclear in the system as well. So if your goal is to increase renewables to their highest penetration before hitting their cieling before needing storage, then you’d want to back off of nuclear. But if your goal is to get to the lowest carbon power system as possible before needing storage, then I doubt that’s the best way to go.

Simple math here but I think this gets at the gist of it: if your system is say 20% nuclear, then you’d hit the renewables cieling roughly when their energy share = their capacity factor x (100% – nuclear’s share). So for solar at 10% CF, you’d hit the cieling at 10% x (100% – 20%) = about 8% of the energy mix from solar instead of 10% if you had no nuclear in the system. For wind at 33% CF, you’d hit the cieling at 33% x (100% – 20%) = about 26% of the energy mix from wind instead of about 33% if you had no nuclear in the system.

So yes, you lose a few percentage points of renewables share if you have 20% nuclear in your system versus if you don’t. But if carbon is your priority, it makes no sense to give up that 20% from zero-carbon nuclear in order to get 2% more solar or 7% more wind!

So again: if you want an ultra low-carbon energy system with high penetrations of solar or wind, you need massive amounts of economic storage and sinks and DR. And if you have those, nuclear and renewables seem to work just fine together. And if nuclear and renewables aren’t mutally exclusive, the lowest CO2 for the least money may very well be a hybrid system.



9 thoughts on “Can Nuclear Power and Renewable Energy Learn to Get Along?

  1. I don’t think there’s a problem with nuclear advocates and renewable energy. Carbon needs to be forced out and the market to determine a sensible mix of nuclear, wind and solar.
    I think that any reasonable person would conclude that it is foolish to close the door on an of the above. I foresee much greater problems with biomass, with CCS, and with geo-engineering, but whilst I would steer away from them, I would not closer the door completely.
    But the problem isn’t reasonable people. It is the totally monolithic, closed-mind, anti-nuclear crowd. They are fanatically anti-nuclear and everything is seen thru this jaundiced window. So when Germany opens 10 new coal-fired power stations, they somehow think it’s a good thing. I think that any reasonable person who examined the evidence would conclude that renewable energy, by itself, is unlikely to fix the problem.
    But the anti-nuclear activists need to believe, and when they look at the evidence, they need to delude themselves that renewables are the 100% answer, because the alternative is admitting that nuclear power is necessary to combat climate change.
    I defy anyone to find one 100% renewable believer, who wasn’t an anti-nuclear believer first, and the only way to accommodate fierce anti-nuclearism, is to fool yourself into believing that 100% renewable is possible.
    And a 100% renewable believer with an even slightly open-mind, would say, as I have said above about biomass, CCS, and geo-engineering, that I don’t want the door closed completely.
    But the fanatic anti-nukes are demanding that the door to nuclear energy be closed completely. I will do everything I can to fight these people because they are a serious threat to the planet Earth.

    • I would not shut the door on fossil fuels either. Stop burning it and try a different chemistry approach, maybe some like direct coal fuel cells. This would also apply to oil and natural gas as well.

    • What are the by-products of nuclear and fossil? What are the by-products of wind and solar? That is the reasoning I use to justify or not justify renewables. What are the replacement materials and processes for all the by-products of nuclear and fossil?

  2. the problem with nuclear and solar/wind is that if you already have a system that can provide 100% of your eletricity CO2 free reliably (nuclear), why making another one that interferes with that?(solar/wind).
    Its either nuclear or wind/solar with very, very, very much storage/ fossil fuel backup. in any other system, turning off your nuclear so you can sell your solar/wind power has disadvantages without any advantages at all.
    that being said making nuclear ammonia is of course a wonderfull idea. as long as you have a plant that runs 24/7, making use of your power (and/or workers, raw materials) most efficiently. a plant that only works in the summer, and/or calls its workers to the workplace in the middle of the night when the wind suddenly started blowing, simply will not work. With full nuclear you can also use nuclear heat directly, skipping conversion loses from turning heat into electricity.

  3. Kroll nailed it. If one does a real-world analysis, there is no reason for wind and solar to be used at all. They add nothing of value to the energy mix and come with many disadvantages.

    The idea that you can fit them into a modern, reliable grid, using demand management ignores the facts of capital costs. Once you’ve paid for an installation which creates synthetic fuels, or desalinates water, it makes sense to run that facility full time and take full advantage of the large capital investment in equipment. It makes no sense at all to leave that expensive equipment idle much of the time, just to give wind and solar the privilege of being on the grid.

    Even if large scale storage was practical and affordable, it would still make zero sense to use wind and solar. The amount of storage required to provide a reliable grid, if powered by wind and solar would be at least one week’s worth of the grid’s full demand of electricity. Or one could dispense with the expensive, ecologically catastrophic wind and solar installations scattered across square miles of landscape, power the entire grid with nuclear, and just build enough storage to provide about 6 hours worth of the difference between peak demand and base load demand; in other words less than 1/50 as much storage to smooth out the demand and let nuclear run full tilt 100% of the time.

    If demand management is economical for wind and solar, then it is economical for nuclear. Again, just as for storage, if it made any sense to build facilities like desalination or syth-fuel plants and run them part time, then it is a much better idea to use such schemes to smooth demand and supply it all with nuclear than it is to put unreliable, horribly expensive, ecologically catastrophic wind and solar on the grid.

    The very worst thing about wind and solar is that they fool people into thinking that they are doing something to reduce CO2 emissions, when in the real world they are not. They are nothing but a waste of time, energy and resources that could have been used to actually reduce CO2 emissions by building nuclear plants.

    For the money that Germany has already spent on wind and solar, which supplies less than 15% of their annual electricity demand, they could have converted their entire electrical supply to nuclear (taking into account existing nuclear and hydro) and reduced their CO2 emissions to zero for electricity production. Instead they still emit more than 450 grams per KWHr of CO2 after 20 years of all-out effort and hudrends of billions of Euros squandered.

    That there are people who cannot see this for the abject failure that it is is just mind boggling.

    • 14.2%, and energy consumtion in germany is going down (not suprising with super expensive electricity)… konventional power plants are goin down faster than solar, wind and even biogas can replace them, even with massive subsidies.
      only a few power plants can economically adjust to producing part time, mainly gas power stations. even water power plants are strugling, not only in germany. I read reports that hydro power plants in swiss are strugling to not go bancrupt, becouse when wind blows and the sun shines electricity prices are being pushed down… even into the negative. Yes, when demand is low, and wind/solar produce electricity Germany needs to pay people to use the excess eletricity. nobody can compete with negative prices… so the power plants switch to expensive standby. turning the generators on and off is responsible for increasing wear and tear, limiting the lifespan of the instalations and/or causing expensive repairs.
      Even gas power strugles. The lucrative peak load market is occupied by solar in the summer (of course if it cloudy the gas plants are still needed, so its impossible to close the plant and simply send workers on summer vaccation). pump water storage has the same problem… it used to buy in the night, sell during peak load in the day. now they need to stay idle for weeks in a row… and for storing energy in the summer, selling in the winter… their capacity is waaay to low, and what price difference betwen summer and winter would be necessary to make something like this economical? buying and selling only once a year + losses from longtime storage… how to pay for operating costs with such a bisness plan? not to mention construction cost to increase capacity.
      Basically wind and solar is currently killing off the very storage and bacup plants it would need to become succesfull.
      The situation in entire europe is so grim, tha even in countries tha commit to conventional powerplants guarenteed feed in tarifs are the requirement for investments (like currently nuclear powerplant in Great Brittain). New build projects for baseload eletricity are practically non existant.

  4. Basically wind and solar is currently killing off the very storage and backup plants it would need to become successful.

    Thank you for briefing us on the destruction of the German power system. We are twelve time zones apart, literally the opposite side of earth. So we do not see much factual analysis of what Energiewende is doing to the power generation and distribution industry. Similar but less extreme damage is being done in USA for the same basic reasons:

    • Priority dispatch rules mean that VRE, if generating, take many of the higher priced hours
    • Dispatchable generation receives no compensation for dispatchable capacity
    • Similarly storage is not compensated for the actual value

    What do you see as the way out of this mess? And can you recommend any studies of the European energy market that show the rate that the grid is loosing firm capacity?

  5. I hope we build a nice nuclear plant as the result of this, and provide a nice baseload source of electricity. We ought to then build another reactor with a dual purpose, to produce hydrogen, and when additional electricity is required, the button simply be switched, and a variable amount of the output be diverted to electricity generation. Overnight, and when it’s sunny & windy, all the heat goes to making hydrogen.
    Maybe a decade after we’ve got this in place, the wind turbines and solar wear out. Do they get replaced by the same or do we build another nuclear reactor? The market can decide. In the 10-20% range, they may work ok.

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