The Case for Expanding Pumped Hydroelectric Storage

The Case for Expanding Pumped Hydroelectric Storage.

The title of this diary is the title of an article from a March 21, 2008 essay by Harry Valentine on Energy Central's "Generation Technologies" Industry Article page. I'm not a big fan of Energy Central. I think they engage in far too much speculative energy writing that is often more fantasy than physical. Valentine, in my not-so-humble opinion is probably the worst of these. His articles border on the sci-fi under titles like:

Transmitting Natural Lighting around the world

Downstream Thermal Energy from Natural Gas Pipelines

Tidal Mega-Power and Hydrogen Production in Northeastern Canada

Micro-hydroelectric Power from Fog Fences

The articles try to be as well researched from an engineering perspective as they are wishful thinking in demeanor. A bundle of contradictions, lets say.

But one theme that Valentine has harped on in a number of articles is pumped storage. In his latest article on this top he focuses in on Niagara Falls and the recent proposals to expand existing hydro-electrical production. He argues, strongly and, convincingly, to make such expansions of this valuable resource into a combined engineering project by installing not just hydro turbine-generator sets but to hydro turbine-generator-pumped storage sets.

Pumped storage is not an energy source. It simply is a way of husbanding overproduction in an energy sector or region by storing it in the form of water to be used when ever the demand is there.

Diablo Canyon, PG&E's nuclear power plant in California, was built along with a 1200 MWs pumped storage facility across the state at Helms Pump Storage Facility. Built in tandem it allows Diablo Canyon to run flat out 24/7 and storing the unused power at night. During peak times, say, 1500 hours through 1900 hours on a hot, windless and hazy summer day, we get the power back 'for free'.

Helms, however, is a dedicated pump storage facility. It can run flat out for 14 days at 1200 MWs and drain it's upper reservoir if need be in an emergency. Valentine's proposal is more ambitious. He has been arguing to covert most of our big hydro projects in the US to pumped storage. Usually this means rewinding the generators to allow for them to have their polarity reversed to turn them into motors, rebuild the turbines so they can pump out water as well as receive water and a host of other engineering details that would have to be met.

The great thing about Valentine's proposals on pumped storage is that they can be done incrementally, during overhauls, or whenever funding becomes available.

But so what? What's the big deal. The big deal is efficiency. Now, Valentine suggests that using new Ultra-High Voltage DC lines we could transport large volumes of "surplus" South-West based solar  energy to the Northeast in Niagara Falls and "store it". Well, we 'could', but we 'can't' because there in NO "surplus" nor is their likely to be surplus, ever, of solar energy. Even the largest scale projects would have on site hot-salt storage (assuming it could ever be economical) and most solar energy, I predict, would be used up as it was produced. You'd have to have a HUGE solar project to produce a 'surplus'. A project that itself would become environmentally questionable in it's own right if it were big enough to produce enough power to wheel across country.

But Valentine tries to be objective. He speaks out for nuclear energy as a source of this surplus power. Indeed, what to do with "excess" nuclear energy after peak and before 0700 hours in the morning is a problem in some places. Indeed, pumped storage could this problem with nuclear's inherent efficiency in producing cheap power around the clock.

Recently, many un-educated solar and wind advocates see pump storage as their solution to the thorny issue of reliability. They fall to understand even what pumped storage is. They think you can simply build it anywhere, as if vast quantities of water at the proper elevations are easy to design. Valentine's proposals seem more appropriate for the high-power centralized energy production of a single nuclear power plant than the diffuse, spread-all-over-the-country-side wind and solar proposals. Financing, for example, a new light water reactor of 1200 MWs could be done in conjunction with a re-powering scheme for, say, the Grand Coulee Damn set on the Columbia River. With UHVDC also financed as part of the revenue stream from the nuclear power plant.

We could, for example, build a string of low-cost Liquid Fluoride Thorium Reactors, say, 6 GWs, in Wisconsin on Lake Michigan, and wheel the power to any number of hydro-converted-to-pump-storage facilities in the Eastern Rockies and upper Midwest or even to Quebec. The possibilities are endless.

David Walters

•  Tips, why don't ya'?

  Tips, free food, advice, and cheap entertainment.

  by davidwalters on Sat Mar 22, 2008 at 01:14:30 PM PDT

•  Thank you for this...

  This is a fascinating subject, and it's great that I now have some links to go get lost in.

  Perhaps if this diary doesn't get much attention, you will get rescued tonight. Come back and check it out after that if you don't get the attention this deserves now.

  Have you found anything on the man made circular island (in the great lakes perhaps?), with water pumped out for storage, and then letting it flow back in when needed in your reading travels?

  I know that here in Wisconsin, our gov is asking for off shore wind mills.

  We need to get moving, electricity generated locally, and sustainably, without prehistoric carbon sources, is the future.

  by red 83 on Sat Mar 22, 2008 at 01:34:50 PM PDT

  •  Thanks.

    No..nothing about the circular island. Some about trying to generate hydro from Huron to Superior but that's it.

    Please look up the link to the liquid fluoride thorium reactor: totally sustainable. Really.

    David

    by davidwalters on Sat Mar 22, 2008 at 02:13:12 PM PDT

•  Worked on a pumped storage facility

  in Warren, PA in my post-college what to do next with my life days.  Interesting to see how far the concept has come over the intervening 35 years.

  by Pinecone on Sat Mar 22, 2008 at 01:44:28 PM PDT

•  Yes!

  Pump-back hydro is like a giant battery.  You fill it up during off peak times, then let it out to cover peaks.

  Pump-back hydro is the perfect complement to wind power.  Wind is almost the perfect energy source.  Green and clean and for all practical purposes inexhaustible.  But it's intermittent.  It blows when it wants to.  It creates major headaches for the utilities that have to regulate around variations in the output of wind farms.  The only major obstacle to making wind the perfect power source is the availability of feasible, economic utility scale storage.  Pumped storage is the only really feasible utility-scale energy storage mechanism at present.  It's not perfect for an number of reasons, but it's pretty good.  

  I would like to see enough wind power dedicated to our pump back hydro facilities to keep them fully stocked, then use the energy to shave our peaks.  It's a win-win for everyone concerned.  It would guarantee a ready load for wind farms, and it would keep that hydro power readily available when we need it regardless of upstream water availability.

  by ignorant bystander on Sat Mar 22, 2008 at 02:00:38 PM PDT

  •  Generally I'm not a wind advocate like you, but

    what you say is true. Except...wind is expensive and payback based on capacity is very lousy. This is why nuclear is a much better "synergy" with both (U)HVDC and pumb-back storage. In my opinion.

    David

    by davidwalters on Sat Mar 22, 2008 at 02:04:03 PM PDT

    •  comments crossing in the ether

      I'm not really qualified to argue the economics.  Other things being equal I'd rather see us invest more in wind for all the obvious reasons.  I'd love to hear Jerome a Paris' take on this.  He makes a powerful case for wind, and he knows the economics of wind and nuclear power perhaps as well as anyone on the planet.

      by ignorant bystander on Sat Mar 22, 2008 at 02:20:51 PM PDT

      •  I would too. He's an interesting writer.

        He's pro wind AND pro nuclear.

        David

        by davidwalters on Sat Mar 22, 2008 at 02:23:20 PM PDT

        •  true

          by ignorant bystander on Sat Mar 22, 2008 at 02:46:14 PM PDT

•  ahem

  OK, I went off before I finished your diary.  My bad.

  For the record, I work for an electric utility.  I know exactly what pumped hydro storage is.  I know quite well what the limitations are.  There are only so many really good sites for pumped hydro, and the best ones are already taken.

  That said, I stand by my earlier comment.  At present utilities by and large use existing, mostly fossil fired generation to pump back during off peak hours, then use the stored energy to shave their peaks.  It's certainly better than building more peak generation.  But a much, much better solution in my opinion would be to use clean and green power -- wind primarily, but also solar as the economics justify it -- to pump back, rather than building either more fossil powered or nuclear generation.  Not that I'm totally against nukes mind you, I think nuclear power will inevitably come to be a significant portion of our base load capacity.  I just think wind is a better choice for power pumped hydro.  The two are an almost perfect complement.  

  by ignorant bystander on Sat Mar 22, 2008 at 02:14:00 PM PDT

  •  OK, cool.

    I also work in the power industry. I work as a power plant control operator in fact, natural gas thermal and, combustion gas turbines.

    If you go to energyfromthorium.com you will see a major discussion link for tons of stuff on nuclear and why Molten Salt Reactors (the generic term for LFTRs) is the way to go AS a green source of energy since there is only about 1/1000's the amount of waste you get from a regular, uranium fueled nuke.

    At any rate, Pumped Storage does indeed make wind far more attractive. But we would need so much wind to make it worth while...that is, a more or less 80% capacity of surplus wind energy so the payback for the investement in PS makes sense.

    You are correct about PS sites and it was my biggest "duh" about PS for a long time. But Valenine has noted that we don't need NEW sites, we can use OLD, already constructed megadams. In fact, technically, we can use all 70 GWs of existing hydro power as PS. This is what I meant by 'converting' existing dams to PS over the long haul, incrementally.

    david

    by davidwalters on Sat Mar 22, 2008 at 02:22:39 PM PDT

    •  thanks for the link

      I see I have some reading to do.

      by ignorant bystander on Sat Mar 22, 2008 at 02:57:35 PM PDT

•  I'm just going to throw this out...

  ...nuclear power is cheap, if you ignore the capital cost of establishing it in the first place, or demolition of decommissioned reactors. Subsidized nuclear power is cheap.

  That's not to say I don't think nuclear power has its place in our future energy policy, but I find it hard to believe that it is cheap, in its life cycle, any more than we believe coal (with its spewing heavy metals and sulfur compounds into the air) is cheap over the operating life of a coal-fired steam turbine station.

  by Shaviv on Sat Mar 22, 2008 at 02:37:43 PM PDT

  •  One should look at "costs" from what it means.

    There is 'cost' and there is 'price'. The price is what you and I pay retail for power and/or what a utility pays wholesale on the day ahead or other markets.

    Price is the amount of money and/or resources to produce 1 KWhour of power.

    The cost to produce coal, "clean coal", solar and, of course, natural gas, is higher than nuclear. Existing nuclear power plants according to the NEI on average produce power at 1.68 cents a KWhr. That is VERY low. Coal is 2.2 cents (and rising). Natural gas and solar (both CT and PV) approach double-digits. Wind is 'about the same' depending on where wind farms are located. Hydro is the cheapest.

    This is without subsidies, period. This is without paying off capital expenses which for new nuclear is very high, but most of the US plants are paid off or close to being paid off, recieve no subsidies, and make money for their owners.

    So...we have to compare new nuclear (expensive to build, even cheaper to run), new solar and wind, 'clean coal' and not-so-clean coal without subsidies and with carbon taxes and with CO2 sequestration and without.

    You will find coal, nuclear and wind near the bottom again, solar and gas near the top, even with carbon taxes and with subsidies.

    I'm for nuclear because it offers the most concentrated, cleanest and safest and relabile of any...read that "any" power source. It's actual capacity factor is higher than 90%, better than coal and hydro, better than natural gas and much better than solar and wind, which have very low capacity factors because of their intermintent or limited nature of their base source of power (sun shine and wind).

    If we switched to Molten Salt Reactors/Liquid Fluoride Thorium Reactors we'd probably have the cheapest and safest power source in human history.

    David

    by davidwalters on Sat Mar 22, 2008 at 03:21:44 PM PDT

    •  Ah, okay

      thank you. :3

      by Shaviv on Sat Mar 22, 2008 at 03:51:23 PM PDT

•  This may be a bit of chicken and egg

  I don't see how we will decide to allocate the tremendous resources to replace fossil fuel power generation without a plan for how we can store power (from wind or solar) to be used throughout the day or when the wind isn't blowing. There was an article in Scientific American about going all solar which discussed storage of compressed air in underground caves, I don't know if that is anymore realistic. I am heartened to see that serious attention is being paid to these issues.

  by Sacramento Dem on Sat Mar 22, 2008 at 03:04:31 PM PDT

  •  My own POV on the SciAm "Solar Grand Plan"

    is that it's pie in the sky and totally underestmates the cost, not to mention the issue or resources, objections to covering the entire S.West of the US, etc etc.

    I agree with Scramento Dem: compressed air is nonsense and can only be used, HAS only been used on small demonstration projects. No one knows what happens if you overpressurize a cavern under the ground with air. We can find out but it is not a good use of energy, surplus or otherwise.

    David

    by davidwalters on Sat Mar 22, 2008 at 03:12:22 PM PDT

    •  Compressed air energy storage

      Compressed air energy storage is totally feasible and adds very little to the overall cost of energy. Huge quantities of natural gas are routinely compressed and stored in underground caverns using very similar technology. Furthermore, the availability of such underground storage caverns is far greater than the availability of pumped storage locations. See  www.sciam.com/article.cfm?id=a-solar-grand-plan for details.

      by oldprof on Sun Mar 23, 2008 at 04:17:31 PM PDT

      •  CAES is not really energy storage

        Because of simple thermodynamics considerations. It is in reality a way to get more efficiency from natural gas turbines. The stored air pressure is just used to bypass the energy used in the compressor stage of the turbines.
        But this does NOT take into consideration the effects of large scale natural gas use. NG is mostly methane. Leakage rates of NG production and transport are estimated to be between 1.5 and 3% of the total volume used in the US. Much higher (up to 20% estimated) in other places. But methane is a greenhouse gas up to 70 times more potent than CO2. So, with a leakage rate of 3%, the actual greenhouse gas contribution of NG is MUCH higher than what the burning of it suggests. This means from that alone the solar grand plan is NOT a feasible way to reduce greenhouse gas emissions.
        With enough LFTRs to cover our baseload AND peak loads, there is enough capacity to divert part of the thermal energy of the reactors for desalination or thermal H2 or higher HC production using air extraction of CO2 for Hydrocarbon fuel production during off-peak operation.
        See: http://www.lanl.gov/...
        as example how the energy represented in the air movement of cooling towers can be used to air-capture CO2 as raw feedstock.
        We have to get away from the notion that thermal power plants ONLY produce electricity. They are energy resources that, correctly used and integrated, can supply ALL our energy needs. Especially if the different levels of thermal energy flow are used efficiently.

        by kla on Mon Mar 24, 2008 at 10:55:13 AM PDT

•  Environmental considerations are not trivial

  when proposing a pumped storage project, even at an existing hydro site.  The existing dam is allowed (and sometimes desired) because of its affect on the river's flow.  Adding a pumped storage capability can change that relationship drastically.  

  Just like a pumped storage project can't be built anywhere you like, not all existing dams can accomodate pumped storage.  You need a source of water available to pump up hill.  And by that I mean you need a base pond (the opposite of a head pond).  While the base pond doesn't have to be anyway near as large as the reservior, there needs to be room to build it.

  The only rational use for a pumped storage project is to store energy from non-hydro sources.  In order for pumped storage to make sense at an existing hydro dam, the generators have to be already shut down and the dam not spilling water.  On larger hydro systems, like Hydro-Quebec's, that never happens because hydro is the baseload generation.  The best one can do is to reduce generation and allow more storage to build up in the reservior.  If the reservior has spare capacity.

  There are times of the year (the rainy season - typically the Spring where I live) when there is no spare reservior capacity to speak of, and the dams spill water if the generators are not running at or near peak capacity.  This spilled water is lost for energy production.  There are other times when generators are required to run (or water must be spilled) in order to maintain flow in the river below the dam.  I presume that environmental permits have all sorts of these types of restrictions for hydro dams.

  While I'm not an expert in this field, my sense is that after taking into account all of the restrictions, there are not a lot of dams where pumped storage could be added cost-effectively.

  What is more cost-effective is to turn baseload hydro into peaking hydro, where environmental restrictions allow.  This is almost the same as what the diarist proposes, but without the pumping.  With an inexpensive non-hydro baseload source available (LFTRs), hydro production can be shifted to peak hours only.  But environmental restrictions still apply; the river must be capable of handling large daily flow changes downstream of the dam.  Additional generators might be required to increase the peak capacity of the dam, and additional transmission capacity might be required to move this additional peak capacity to the load.  Still, it is simpler than adding a pumped storage scheme.

  by Brad F on Mon Mar 24, 2008 at 10:04:53 AM PDT