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Siemens Gamesa Unveils World First Electrothermal Energy Storage System (cleantechnica.com) 127

Posted by BeauHD from the first-of-its-kind dept.
An anonymous reader quotes a report from CleanTechnica: Spanish renewable energy giant and offshore wind energy leader Siemens Gamesa Renewable Energy last week inaugurated operations of its electrothermal energy storage system which can store up to 130 megawatt-hours of electricity for a week in volcanic rock. The newly-opened electric thermal energy storage system is billed by Siemens Gamesa as "The Future Energy Solution" and as costing "significantly" less than classic energy storage solutions. Specifically, according to the company, even at the gigawatt-hour (GWh) pilot scale, ETES "would be highly competitive compared to other available storage technologies."

The heat storage facility consists of around 1,000 tonnes of volcanic rock which is used as the storage medium. The rock is fed with electrical energy which is then converted into hot air by means of a resistance heater and a blower that, in turn, heats the rock to 750C/1382F. When demand requires the stored energy, ETES uses a steam turbine to re-electrify the stored energy and feeds it back into the grid. The new ETES facility in Hamburg-Altenwerder can store up to 130 MWh of thermal energy for a week, and storage capacity remains constant throughout the charging cycles.
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Siemens Gamesa Unveils World First Electrothermal Energy Storage System More

Siemens Gamesa Unveils World First Electrothermal Energy Storage System

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  • Well, at least carnot efficiency should be good. (Score:4, Informative)

    by Rei ( 128717 ) on Tuesday June 18, 2019 @08:11AM (#58781336) Homepage

    750C is fiercely hot for an energy storage system (max Carnot eff = ~70%). Molten salt storage is generally less than 300C (max Carnot eff. ~50%). And of course in the real world you can't get that close to the Carnot max, and as a general rule, the lower the temperature differential, the further your realized efficiency is from the theoretical limit.

    • Solar Reserve is building molten salt plants and they claim the temps are 1050âF (566âC).

      https://www.solarreserve.com/e... [solarreserve.com]

      Cresent Dunes already exists (110mw):
      https://www.solarreserve.com/e... [solarreserve.com]

      Here it is on the map (I would love to drive past it, probably as cool as the Very Large Array telescopes that I have driven past in New Mexico):
      https://www.google.com/maps/pl... [google.com]

      Their Sandstone project (2,000mw) is rather ambitious (but can be done in phases as it's 10 towers).

    • They are talking about 45% efficiency for generating electricity, 98% for using the heat itself and 98% for creating steam for chemical processes.

      • Actually 90% efficiency for steam from thier literature.

        This gets me back to my thermodynamic pet peeve with cycle efficiency - it calculates this with respect to an absolute zero cold side resovoir which is technically correct but also creates the impression that the process itself is the culprit. I often find it helpful to think in terms of relative efficiency which relates to comparing it to a process with a cold side resovoir at ambient giving a design the possibility of achieving near 100% - this i
        • Comment removed based on user account deletion
          • I wasn't speaking of steam but the thermodynamic efficiency in general. People see things like the low efficiency of internal combustion engines and get the wrong impression. It would be a better representation if it was -450F outside, not 75F.

            • Internal combustion engines are not inefficient because of the Carnot principle, but because of engineering constrains.
              According to Carnot they would be around 42% ... in practice they are around or below 20%.

              • Do you know why the Carnot efficiency is so low for an idealized process? It's because it's compared to the maximum possible efficiency which is achieved with an absolute zero cold side resovoir. see this example [gsu.edu] it dosent go to 100% unless your cold side is zero. This is technically correct but puts a spin on the efficiency that confuses people without engineering degrees. Also note how it dosent take into account that you are getting free heat from the ambient resovoir of the atmosphere. It would mak

                • Why are you posting this nonsense all the time?

                  You posted it minimum 2 times in this threat.

                  BTW: you are wrong. But I guess you know that and only want to provoke.

                  • Why are you posting this nonsense all the time?

                    You posted it minimum 2 times in this threat.

                    The only thing I threatened in this thread is the status quo of ignorance. Sorry if it stung. Usually I assume people just didn't understand so I reiterate the points while laying a larger foundation from which to see the truth. Curious though, if the minimum is 2, what's the maximum?

                    BTW: you are wrong. But I guess you know that and only want to provoke.

                    I'm not even close to wrong. My mechanical engineering graduate advisor didn't much like the idea either during my masters defense, but he couldn't refute a single point and conceded relative efficiency has its place. I'm c

    • Re: (Score:2)

      by necro81 ( 917438 )
      For point of reference: 750C is around the operating temperature for the second stage of a combined cycle gas plant, and higher than the temperature of superheated steam in a coal plant.

    • That might be "fiercely hot" for an energy storage system but just about right for a molten salt nuclear reactor.
      https://en.wikipedia.org/wiki/... [wikipedia.org]

      Also about right for a Brayton cycle turbine.
      https://en.wikipedia.org/wiki/... [wikipedia.org]

      This electrothermal energy storage is focused on storing electricity as heat, but that does not make much sense since in most every case the energy is in some usable form before it is converted to electricity in the first place. If you have that energy in some usable form already then s

      • Re: (Score:2)

        by dryeo ( 100693 )

        Using this to store hydro power is plain nonsense, as a hydro dam already has a storage system in the water behind the dam.

        Thing with (some?) hydro is that it has to keep running whether the power is needed or not. Reservoir can only store so much water and a steady flow of water is needed downstream for things like fish habitat.
        If it's like the dam down the road here, which is mostly used for peak loads, this would raise the amount that can be generated during peak usage.

        • Thing with (some?) hydro is that it has to keep running whether the power is needed or not.

          I'm not sure that is true but I'll assume it is. Do you know what also must be kept spinning? Steam turbines. Shutting down a steam turbine is a lengthy process to avoid expensive damage. Getting them spinning to where they can produce power takes anywhere from minutes to hours, depending on how long it's been since it last saw steam. Repeated cooling and heating cycles would be avoided as much as possible.

          With an electrothermal energy storage system the inherent inefficiency means half the energy that

          • Re: (Score:2)

            by dryeo ( 100693 )

            I misstated that a hydro plant has to keep running, as I meant keep the water flowing, usually through the turbine but not necessary. As the water is flowing, might as well generate electricity with it.
            Interesting what you say about steam turbines, something I know nothing about as steam isn't used around here for power and the potential damage from it cooling off is something I hadn't considered.
            I was thinking of cases where peak demand is predictable and the power (hydro) plant can meet needs 22 hours or

    • 750C is fiercely hot for an energy storage system (max Carnot eff = ~70%).

      Which is good, because they threw away a carnot penalty when they stored the heat:

      The rock is fed with electrical energy which is then converted into hot air by means of a resistance heater and a blower that, in turn, heats the rock to 750C/1382F.

      If they'd pumped in the heat from elsewhere using that power, they'd have kept closer to 100% of the energy, rather than throwing 30% away.

      • Re: (Score:2)

        by Rei ( 128717 )

        My assumption is that this approach would be used with e.g. wind. So you're not throwing away initial heat - you never had initial heat.

        • ... you're not throwing away initial heat - you never had initial heat.

          The history of the electricity's generation is immaterial.

          You "contract for the penalty" when you burn the electricity to heat in a ("100% efficient") resistive heater, rather than pumping heat from your heatsink into storage (at a coefficient of performance greater than 1, i.e. "more than 100% efficient"). Doing it with resisitive heaters ends up with less energy in the hot rocks.

          The carnot penalty comes due when you do your withdrawal

    • The reason higher temperatures are worse for storage is because the rate of heat transfer is proportional to the temperature differential. So if the environmental temperature is 20 C, then a 750 C heat storage unit (730 C differential) will lose energy at 2.6x the rate of a 300 C heat storage unit (280 C differential, 730 / 280 = 2.6). This is why your CPU gets hotter under load. The temperature increases until the increased rate of heat transfer to the air equalizes the increased rate of heat generation

  • 130MWh is approximately the same as 110 tons of TNT. Not in my backyard, thanks...

    • Re: (Score:1)

      by Anonymous Coward

      130MWh is approximately the same as 110 tons of TNT. Not in my backyard, thanks...

      Yes, but unlike .. say, liquefied natural gas or something ... that volcanic rock isn't going to catch fire or explode, it's just going to be hot rocks. It's far less volatile than 110 tons of TNT.

      It's interesting to store it as heat and then drive steam turbines later. It partly solves the problem of storage and managing supply for when you actually need it.

      I will be curious to see how this works out. If we can start solvi

    • Re: (Score:2)

      by atrex ( 4811433 )

      130MWh is approximately the same as 110 tons of TNT. Not in my backyard, thanks...

      Short of dumping 130 tons of cold water directly onto all that hot volcanic rock all at once, by what mechanism do you think it's going to explode?

      • 130MWh is approximately the same as 110 tons of TNT. Not in my backyard, thanks...

        Short of dumping 130 tons of cold water directly onto all that hot volcanic rock all at once, by what mechanism do you think it's going to explode?

        Well, since the recovery mechanism is... dumping cold water on the rocks... yes, that's pretty much what I had in mind.

      • Re: (Score:2)

        by gweihir ( 88907 )

        Some people do not even begin to grasp physics. This thing has no explosion risk.

    • Sure we can make sure it isn't in your backyard, we can just cut the power from your home too. I feel it is important for people to understand the trade-off we are facing for our luxuries.

      How many small town had their economy collapse, because their water supply got polluted, only for the wealthy company owners who live hundred miles away complain that they are being unfairly sued because of the value of their product.

    • Nobody tell him about E=mc^2

    • 130MWh is approximately the same as 110 tons of TNT. Not in my backyard, thanks...

      How about in your garage?

      If you have a large pickup truck with a 40-gallon fuel tank, you've got the equivalent of over one ton of TNT right inside your house.

  • I'll be looking at this closely.

    Even legacy generation plants often need storage. So we have various methods of doing it. Here's one https://en.wikipedia.org/wiki/... [wikipedia.org].

    The storage medium will depend upon the local conditions. In my area, we couldn't use volcanic rock because there isn't any, and I suspect there would be a lot of problems with trying to use shale and limestone. We are blessed to have a almost constant wind presence (Allegheny Escarpment)

    So some places - batteries, some places pumped s

    • I'll be looking at this closely.

      Even legacy generation plants often need storage.

      Legacy generation plants are often steam plants, and they already store their energy in the fuel. If they need any energy storage then it must be in a form that is somehow better than not burning the fuel in the first place.

      The advantage that pumped hydro and chemical batteries offer is the ability to react far more quickly to changing demand than any steal plant could. Since this storage system is a steam plant then it cannot react to changes in demand any faster than any other steam plant.

      Wind and solar

  • This is what counts as an 'new' energy storage system?

    Sorry, but this sounds like the total absence of an idea.

  • What problem does this solve? (Score:3, Insightful)

    by blindseer ( 891256 ) <blindseer@noSPAm.earthlink.net> on Tuesday June 18, 2019 @08:53AM (#58781518)

    The problem with wind and solar power is their intermittency. When the sun sets or clouds pass by the solar collector output drops, and it tends to drop fairly quickly. Same for wind, when the wind stops it can be fairly quickly. Same for load changes, the load on a grid will ramps up fairly quickly and quite suddenly in the case of some kind of failure in the system. The primary benefit of chemical battery storage is its ability to respond in fractions of a second.

    One large problem that is brought up time and time again against coal and nuclear power is their inability to change output quickly enough to match the changes in load. This is typically done with natural gas turbine generators, or less commonly this is done with diesel generators. The reason traditional coal and nuclear cannot follow the load is because it uses big steam turbines. Steam turbines are a very old technology, very efficient (by electrical generation standards) and therefore cheap to run. Like intermittent wind and sun this old steam technology could use chemical batteries to follow load if proven to be cheaper than the natural gas and diesel generators used currently.

    Now we see a proposal for energy storage that uses steam to convert the stored energy to electricity. This is a technology that cannot follow changes in load on the grid fast enough. What is even more boggling is the multiple, and not terribly efficient, energy conversion steps proposed. There is the conversion of solar radiation (in light or heat) or wind (a mechanical energy) into electricity, the electricity to heat, the heat to mechanical power, then back to electricity. Again, steam is used as part of this process and it cannot follow changes in load fast enough. There will still be a need for natural gas, fuel oil, chemical batteries, hydro (pumped storage or traditional), or some other power source capable of following load.

    With chemical batteries there is a rather simple, and efficient, shift of electricity to chemical energy, then back again, as storage. This is a system that can react very quickly to changes in load. With pumped hydro storage the water pumped up the hill is also a fairly simple and efficient conversion, and a hydro electric dam can follow load changes well enough on its own.

    This process does not solve the problem of the intermittent nature of wind and solar because it cannot match the load. That alone makes this a nonstarter. The inherent inefficiency of multiple conversions is also a problem. Had they used solar energy more directly in some way to heat the rock then it might make some sense. With the slow response of steam this process has there is already a far better energy storage system already in place. This is the piles of coal outside the many power plants already.

    This is a solution in search of a problem.

  • Conflating Storage Units (Score:3)

    by necro81 ( 917438 ) on Tuesday June 18, 2019 @09:25AM (#58781660) Journal
    The article is conflating thermal storage with electrical storage:

    which can store up to 130 megawatt-hours of electricity for a week in volcanic rock

    The new ETES facility in Hamburg-Altenwerder can store up to 130 MWh of thermal energy for a week

    So which is it? The Siemens press release [siemensgamesa.com] is clear that the number is thermal storage. But then the ignorant reporter saw "store 130 MWh of energy for up to one week" and immediately thought that meant electricity.

    To be clear: I am not griping about the technology. Large-scale energy storage is important now and only will become more so, and the more ways we have to do it, the better. I am just disappointed that, yet again, journalists can't keep their units straight.

    I guess it could have been worse, the reporter could have totally bolloxed the units and said some nonsense like "130 MW per week".

    • To be clear: I am not griping about the technology. Large-scale energy storage is important now and only will become more so, and the more ways we have to do it, the better. I am just disappointed that, yet again, journalists can't keep their units straight.

      I saw an article from a group of scientists that used to work on the Mars Climate Orbiter. They took a look at this process and declared that they can improve the energy conversion to within twelve parsecs.

  • Steam driven turbines seem to be de rigeur for converting heat into electricity. You'd think there would be a better way by now.

  • If this pans out it will solve the biggest problem with renewables outside of their inefficiency. It basically makes them viable.
  • Compared to the storage capacity of 130 MW, the turbine/generator are tiny, providing just 1.4 MW of electrical power. https://www.siemensgamesa.com/... [siemensgamesa.com]

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