Coupling nuclear energy facilities with underground storage/hydrogen generation: turning nuclear’s perceived weaknesses into opportunities

As someone who has written a lot about renewable energy and working towards a post-fossil fuel future I have been disheartened by the strong anti-nuclear stance of much of the environmental community. As has been noted more times than I can discuss (but was best summarized by Brad Plumer at Vox.com) nuclear power and renewables don’t have to be enemies. Moreover as Jesse Jenkins and Samuel Thernstrom have recently written the most cost-efficient deep decarbonization systems require some dispatchable low-carbon baseload. In their paper on the topic they point to nuclear energy as being a prime example of a low-carbon technology that can be used to fill the need for baseload power. The nuclear industry does have its critics in the renewable energy community with Dr. Marc Z Jacobson being a notable example. The arguments made by Dr. Jacobson against nuclear include issues like nuclear proliferation, thermal pollution from cooling tower return water and the potential for disruptions to power supply by terrorists? I have addressed two of these (terrorism and nuclear proliferation) in a previous post and today I want to address the final one “thermal pollution” and its associated issue water use.  More specifically in this blog post I want to see if we can turn some of the biggest criticisms about nuclear energy into opportunities in a post-fossil fuel energy system.

Coupling Nuclear power facilities to underground thermal storage systems

One of the most commonly discussed complaints about nuclear power is water use. There is a stat I have read in blogs and articles by anti-nuclear activists, that about 40 percent of the nation’s fresh water use goes toward energy generation. To be clear, this water is not consumed, rather enters the system at one end and leaves the plant at the other to siphon off heat (via once-through cooling systems). The water is not chemically changed it is just used to dump thermal energy. It enters at a lower temperature and leaves at a slightly higher temperature. Technically the water is used but not in the manner most associated with industrial process where the water is consumed and doesn’t re-emerge on the other end. In some places this warmer water is good for the environment (manatees love the heat) but in others it can be a serious problem. Thermal waste is a serious concern for the nuclear industry but it is a problem that provides a wonderful opportunity in a post-fossil fuel economy. If that heat was treated as a valuable commodity rather than a waste product nuclear could turn a recognized weakness into a strength. This could be done by coupling nuclear facilities with thermal storage facilities.

Coupling nuclear with thermal storage is not a new idea as scientists have previously suggested linking nuclear to thermal storage blocks and even underground storage. Unfortunately, in my research to date most of the cases  I have found involve storage of the primary heat from the system. In my searching, I have not found a lot of examples of a much simpler idea: coupling nuclear power station process water to underground thermal energy storage (UTES) systems.  I’m sure someone has written a lot about this and assume that shortly after I post this blog I will get a stream of links sent to me but as I write this I cannot easily find plans for these apparently straightforward adaptions to existing technologies.

To explain for the lay reader, underground thermal energy storage (UTES) is a form of energy storage that provides large-scale seasonal storage of cold and heat in natural underground sites. Three common types of UTES are aquifer thermal energy storage (ATES), borehole thermal energy storage (BTES) and rock cavern thermal energy storage (CTES). Essentially what you do is you take waste energy in the form of heat from your system and store it underground until you need it at some later date. Readers of this blog will surely remember the Drake’s Landing solar community in Alberta as I have written about it regularly. At Drake’s Landing the community is connected to a solar energy system which provides electricity during the day but the system also stores excess energy via BTES. The BTES energy is then used in winter to help heat the houses within the community. According to the Drake’s Landing website over the 2015-2016 heating season 100% of the heat required for space heating was supplied by the combination of solar and BTES. Sure setting up a system like Drake’s Landing can be expensive but in the end it provides a useful model for how we can eliminate dependence on fossil fuels for household uses.

So I asks, why haven’t we done this at any nuclear plants? Why are they just dumping their excess heat into the environment when they could instead store it for the winter? By storing that heat the nuclear plants could eliminate their thermal pollution issue and increase the amount of energy generated by their facilities. As for the critics in the 100% Wind, Water and Sunlight (100% WWS) community I can’t see them raising a fuss. After all, in his 100% WWS plans Dr. Jacobson suggests building all sorts of energy generating systems with thermal storage so thermal storage associated with a nuclear plant would not appear to be a major concern for the renewable energy community.

Coupling Nuclear power facilities to hydrogen generating facilities.

My second suggestion is one that has been better studied and discussed but once-again not to the extent I believe it should: the use of off-peak nuclear energy to produce hydrogen. One of the big complaints from the environmental community about nuclear energy plants is that they are not very flexible. They take a while to get running and so need to be kept running most the time. They argue that this is a bad thing as it makes it harder for renewable energy to find a foothold. Moreover, in an electrical system that is heavy with renewables there are peaks during the day when there is virtually no demand for the energy produced by the nuclear plants (see the duck curve). This challenge for the nuclear power industry could potentially provide another useful opportunity in a post-fossil fuel future: hydrogen generation.

As anyone who has followed the energy discussions around climate change knows one of the biggest challenges to moving off fossil fuels is the transportation industry. I have written numerous blog posts discussing the issue (most recent here) and while electric vehicles seem a reasonable alternative for most commuting needs the one place where electric engines are struggling is in the air. Put simply electric storage devices are too heavy and simply don’t carry enough juice to power a modern airliner. One alternative to fossil fuels in the air could be hydrogen but even minimal attempts to use the gas have stumbled on the issue of a limited supply of hydrogen. The problem with hydrogen is that it is not an energy source but rather an energy storage medium. Like a battery, hydrogen acts a carrier of energy from other processes like nuclear, solar or wind power via fuel cells or combustion into electricity.

The Alternative Fuels Data Center of the US Department of Energy has lots of info on hydrogen but notes that a challenge for the hydrogen economy is production near where it will be used. This seems like another opportunity where nuclear can be useful. By coupling nuclear plants with hydrogen generating facilities we could kill two birds with one stone. During the low demand times the nuclear plants could provide energy to the coupled hydrogen facility to generate hydrogen. When demand for electricity ramped up in the evenings the nuclear energy could be used to supplement the renewable supply. In this manner, the nuclear facilities could continue to run at a steady output sometimes producing hydrogen, sometimes producing electricity for the grid, always with little energy being wasted and without the need to ramp up or down, thus reducing wear and tear and increasing capacity.

Once again, the renewable energy community has repeatedly suggested that hydrogen is a necessary fuel of the future and Dr. Jacobson and his team have suggested building numerous facilities to generate hydrogen. But who needs to build new facilities when we have all these nuclear plants waiting to provide the electricity necessary to produce hydrogen.

To conclude, I am by no means a nuclear engineer and I am sure that there are some pretty significant hurdles to my suggestions but decarbonizing the North American energy system is going to be full of technical hurdles. As I pointed out earlier, I’m betting that nothing I have written above will come as a surprise to the informed (like the people at the Breakthrough Institute) but I continue to wonder why I’m not reading about these ideas as part of the battle to preserve the existing nuclear infrastructure and as a selling point for the next generation of facilities. It is clearly time we started talking more about these topics since opponents of nuclear power are making themselves heard and it is time that we turn some of their biggest complaints about the nuclear industry into some of the biggest selling points for keeping the nuclear industry.

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8 Responses to Coupling nuclear energy facilities with underground storage/hydrogen generation: turning nuclear’s perceived weaknesses into opportunities

  1. Todd D. says:

    Speaking of Breakthrough Institute, perhaps ammonia could also be used as a transportation fuel “It’s even possible to bypass hydrogen and Haber-Bosch altogether, and make ammonia directly from water, air and electricity, using a modified fuel cell technology.” http://thebreakthrough.org/issues/decarbonization/ammonia-is-everest-base-camp-for-clean-energy

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  2. Any concept of using surplus nuclear power as an energy source when demand for nuclear generated electricity is low needs to examine the capital cost for the industrial process per kWhr used versus the capital cost for the nuclear power plant. So far, the conclusion I come to is that the industrial application capital costs per kWhr used is higher than for a nuclear power plant. So it make more sense to overbuild nuclear and idle it than to overbuild the industrial process and idle it.

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    • chrism56 says:

      Lars – There are two problems with your suggestion. The first is that nukes are expensive to build, but cheap to run, so they need to be base load. The second is allied to the above in that most nuke designs don’t load follow very easily – easy to do significant damage to the reactor.
      The hydrogen storage is just an alternative for pumped storage which is standard industry practice (think Dinorwic) – the economics would determine the best option.

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  3. Jeff Norman says:

    Good luck. You are trying to convince a class of people who believe the electricity coming from nuclear generation is radioactive.

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  4. Some info from my website re hydrogen and transportation.

    “May 1999 – Transportation and Hydrogen

    Our transportation system presents some particularly thorny problems with respect to greenhouse gas emissions. Combustion gases, mainly carbon dioxide and water vapor, from fossil fuels burned in our cars are discharged to the four winds through their exhaust pipes. From there they are dispersed and quickly mixed throughout the atmosphere. Carbon dioxide is continuously removed from the atmosphere by earth’s growing plants. Nevertheless, it seems plant life has not, so far, been able to keep up with the growing release of carbon dioxide from human use of fossil fuels.

    The use of hydrogen is often discussed as a possible source of energy for transportation. It can be chemically combined, like fossil fuel, with oxygen in the atmosphere to release energy. Hydrogen can be stored and is portable under high pressure and/or low temperature. It produces only water as it’s main combustion product. Sometimes particularly keen proponents forget to tell us that hydrogen is not freely available to us in nature. Producing it requires an energy source which may produce emissions and greenhouse gases.

    Hydrogen does open up opportunities to use stationary low emission sources of energy such as renewable and nuclear power in our planes, trains and automobiles. Exhaust emissions from stationary fossil fuel plants which produce hydrogen could also be captured and isolated.

    I prepared a paper in 1999 which compares greenhouse gas emissions from hydrogen fuelled cars and light trucks using several alternatives for producing hydrogen from electricity. Nuclear power plants were found the the most effective of the alternatives considered. The David Suzuki Foundation and Pembina Institute produced a related report in 2000 focusing on greenhouse gas emission reductions using hydrogen fuel cells – which summarily dismissed the use of nuclear energy for this purpose. Another interesting paper presents a case for the use of hydrogen fuel cells to power Canada’s trains. (DRP 03/11/05)”

    Check out David Sanborn Scott. He was linking hydrogen and nuclear in the 1970’s

    http://www.computare.org

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  5. Canman says:

    Rud Istvan has a small section about hydrogen in this post at Climate Etc.:

    https://judithcurry.com/2015/07/01/intermittent-grid-storage/

    I suppose I might as well quote it:

    Hydrogen

    Hydrogen can certainly be hydrolyzed from water. And the necessary electricity can certainly come from intermittent renewables. The most efficient way to convert hydrogen back to electricity at grid scale would be a PEM fuel cell or an SOFC. The math can be done using Ballard’s 1MW PEM, since a few have actually been sold as demos. Ignore the technical difficulties of bulk hydrogen storage, which the following methane alternative ‘solves’.

    The theoretical efficiency of hydrolysis is ~88%. About 4% of commercial hydrogen is made this way today, with real efficiencies of ~75%. EERE says PEM fuel cells can be 60% efficient. But that is also theoretical. Ballard’s real 1 MW ClearGen® is 40±2% efficient, with a lifetime of ~15 years (similar to NaS). The round trip efficiency of a hydrogen electricity storage system would be about (0.75 * 0.4) 30%. For a utility, that is awful.

    The electricity to be stored comes mainly from otherwise flexed base load generation, with chemical storage buffering renewable intermittency no different than PHS buffers peaks. The energy cost alone would be about ($57/MWh baseload / 0.3 efficiency) $190/MWh. Ballard’s ClearGen® costs about $10 million/MW (including inverter, transformer, and installation).That calculates a capital LCOE of about $114/MWh. Adding hydrolysis and H2 storage, the system LCOE is >>$304/MWh. It is simply not commercially viable–by nearly an order of magnitude. Before solving the hydrogen storage problem.

    Joe Romm wrote a book titled, The Hype About Hydrogen: Fact and Fiction in the Race to Save the Climate. If Joe Romm thinks hydrogen is hyped …

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  6. Chester Draws says:

    Instead of using the reliable nuclear power to generate hydrogen, would it not be much more efficient to use the intermittent power of solar and wind to do that? Particularly as this would also remove the transmission problem.

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  7. Bryan White says:

    The proponents for hydrogen as an energy storage medium seldom discuss the flexibility of large industrial processes. There are few that tolerate ramping up and down in capacity over a large range to meet an external constraint. The processes are tuned up to work well in a steady-state condition — and often take many hours or days to get there.

    Heat storage is the only one I can think of that works well provided no phase change is required (such as a molten salt). Stored heat is not so easy to use efficiently as there are transfer losses and if converting to high pressure steam there are rate of temperature change limitations for piping and thick wall vessels.

    Some propose large batteries. Achieving a utility scale storage system with desirable dynamic response characteristics, adequate safety, and acceptable cost might take a while.

    The other interesting aspect of hydrogen is its propensity to leak out when under pressure. Closed garages and underground parking would likely need modifications to make the risk of explosion and fire acceptable to insurers if not the owner / operators.

    Liquid hydrogen has been proposed as a fuel for airplanes, trains and other heavy vehicles. I once read a report from NASA that their experience of the risk of detonation for hydrogen leaking from a cryogenic system in a confined space is 100% (not 99% — 100% — engineers hate things like this). A train accident in a tunnel might be unacceptable. Fueling aircraft would not likely be done near a passenger terminal — more probably it would be behind a blast shield distant from everything.

    As fuel costs for nuclear energy are small, diverting excess capacity to heating cold water where it is environmentally acceptable to do so looks economic. Obtaining approval to do so would not be simple for most locales.

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