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Thread: New electrothermal energy storage system consisting of volcanic rocks

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    Default New electrothermal energy storage system consisting of volcanic rocks

    Siemens-Gamesa has developed an electrothermal energy storage system consisting of volcanic rocks.

    The heat storage facility, which was ceremonially opened today in Hamburg-Altenwerder, contains around 1,000 tonnes of volcanic rock as an energy storage medium. It is fed with electrical energy converted into hot air by means of a resistance heater and a blower that heats the rock to 750C. When demand peaks, ETES uses a steam turbine for the re-electrification of the stored energy. The ETES pilot plant can thus store up to 130 MWh of thermal energy for a week. In addition, the storage capacity of the system remains constant throughout the charging cycles.

    The aim of the pilot plant is to deliver system evidence of the storage on the grid and to test the heat storage extensively. In a next step, Siemens Gamesa plans to use its storage technology in commercial projects and scale up the storage capacity and power. The goal is to store energy in the range of several gigawatt hours (GWh) in the near future. One gigawatt hour is the equivalent to the daily electricity consumption of around 50,000 households.

    https://www.siemensgamesa.com/en-int...system-thermal

    It has a energy efficiency of 45 % in comparison to H or fuel cell.


    Spoiler Alert, click show to read: 
    In Hamburg-Altenwerder, the Siemens subsidiary Siemens Gamesa has put into operation a new energy storage system that uses simple technology to store electricity as heat and later regain electricity via a steam turbine. The facility, which was built on the site of an aluminum smelter, uses hot air to heat a storage facility with 1,000 tons of volcanic rock to around 750 degrees Celsius. This is an unspecified volcanic rock.
    The system has a heat capacity of 130 megawatt hours, comparable to about 10 tons of heating oil. To recuperate the energy as electricity, hot air is used to heat up cold air and produce water vapor at 600 degrees Celsius, which then generates electricity via conventional power plant turbines. This amount of heat should be stored for about a week.

    The pilot plant in Hamburg has a 1.5 MW steam turbine that can be operated with a full tank for around 24 hours. After that, the capacity of 120 megawatt hours is by no means exhausted, but the temperature of the extracted hot air drops below 600 degrees Celsius. Thus, the turbine can not be operated with its full efficiency of about 45 percent.

    The store can also use combined heat and power

    The operators assume that 30 megawatt hours of electricity can be generated with steam at 600 degrees Celsius. This retrieves 67 of 120 megawatt hours. Subsequently, however, the storage could be brought back to full temperature with 67 megawatt hours of electricity. The rest of the energy is not lost. For heating, hot exhaust air from the aluminum smelter could also be used.
    The remaining 53 megawatt hours could also be accessed at lower temperatures and used differently. In addition, the plant could be operated in combined heat and power. The otherwise unused waste heat of power generation would be provided as hot water. Depending on the temperature of the water but that would be associated with certain losses in the production of electricity.

    Much larger facilities are planned

    The concept was first tested in 2014 with a first prototype and 40 tons of rock. It had a capacity of 5 megawatt hours and powered a 700 kW turbine. The Hamburg plant with 1,000 tons is the demonstration plant. According to the company's plans, a pilot plant with 10,000 tons of rock and a capacity of more than one gigawatt hour is to follow in 2020, before the technology is to be commercially sold from 2022 onwards. The turbine of the pilot plant should be able to generate 30 megawatts of electricity.

    The construction of the largest possible systems has great physical advantages in the technology. The most important advantage is the minimization of heat loss. The storage rock is stored in a concrete building and surrounded by thermal insulation. The heat is lost but only on the outer surface. A building that is twice as big in all directions has four times the outer surface but eight times the volume. Compared to the content, the losses would be halved.

    Hydrogen has much greater losses

    How large the bearing losses are exactly, Siemens did not announce. Energy Nest, which builds similar concrete storage tanks, claims the losses of larger plants at less than 2 percent per day. At exactly 2 percent loss per day, half of the initially stored energy would be lost after 35 days. At Energy Nest, the losses will decrease according to the size of the plants. Energy Nest's largest planned plants are similar to Siemens' demonstration plant in Hamburg.

    In practice, the technology is currently intended primarily to compensate for short-term peaks in power generation and consumption. But Siemens wants to build storage facilities that even go far beyond the planned 2020 pilot plant with 30 MW and 10,000 tons of rock. The storage technology could also operate the turbines of coal power plants, where powers of several 100 MW are common.

    Even in such large plants, even storage times of weeks or a few months with low losses could be realistic. However, other factors could make the enlargement more difficult. Thus, the air resistance while blowing the memory should not be too large. In addition, the repeated thermal expansion of the rock could cause it to collapse over the long term, reducing the gaps in it. At the moment the effect has probably not been observed yet.

    Technology does not need scarce resources

    In terms of cost and resources, the simple storage medium and conventional power generation make even large plants seem at least realistic, unlike molten salt storage tanks or Energy Nest's embedded concrete pipes. In stationary storage of electricity, over days and weeks, this technology should already be clearly superior to hydrogen storage.

    In current hydrogen storage systems, around 40 percent of the energy is already lost in the electrolysis, as 2017 spokesman of ITM Power Golem.de said at the Hannover Messe. When stored in the accumulator, another 10 to 15 percent of the energy is lost. In methanation and similar processes for hydrogen storage in oil, these losses are about 25 percent. When generating electricity, the fuel cell then loses around 40 to 50 percent of the energy, which makes the overall system less than 30 percent efficient.

    A Cheops pyramid as memory is not enough

    Of course, the thermal storage is significantly less efficient than a pumped storage power plant with an efficiency of around 80 percent. However, there is needed for the storage of a kilowatt hour of electricity over a ton of water, with a difference in altitude of 360 m. In the thermal storage of the demonstration plant suffice for 30 kg of rock.

    For comparison, a store of the volume of the Pyramid of Cheops would consist of 3.1 million tons of rock and would thus have a storage capacity of about 105 gigawatt hours. Enough to run a 1 Gigawatt power plant over 4 days. Germany-wide, about 1,600 gigawatt hours of electricity are needed per day. In order to save this amount, 47 million tons of rock would be needed. Coal production in Germany in 2017 was around 175 million tonnes.


    https://www.golem.de/news/energiespe...-142012-2.html

  2. #2
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    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    You could get a lot better efficiency out of this using a Helium Brayton Cycle, but the Helium shortage is certainly a major issue right now.

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    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    How can we be short on the second most common element in the universe.
    Under the patronage of Pie the Inkster Click here to find a hidden gem on the forum!


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    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    It's rare on Earth.

  5. #5

    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    Quote Originally Posted by Settra View Post
    How can we be short on the second most common element in the universe.
    Helium is rare on Earth. Unlike hydrogen, it doesn't chemically bond with other elements, and remains a gas under earth conditions. Earth's gravity is not strong enough to retain the light helium molecule, and it escapes to outer space. .ost of the helium we now have was produced by radioactive decay, and can be obtained from the release of natural gas. US at one time required the recovery of the helium during the mining of natural gas, but stopped it years ago, probably because the oil companies complained it was too expensive.

    The Hindeberg zepplin was using hydrogen, because the US at the time refused.to sell helium to Nazi Germany, so the Germans had to use hydrogen instead of helium, which led to the tragic loss of the Hindeberg due to fire.

  6. #6

    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    I wonder how efficient water energy storage facilities are, where you pump the water up in a reservoir during electric.off peak hours, then let the water out when you needed electricity woupd be more efficient. Guangzhou Pumped Station has an energy efficiency of 76%< significantly higher than the storage using hot volvsnic rocks. Of course, you have to have the available geography and land available to talk to use water storage, while the hot volvsnic rocks method described would not have the same restrictions.
    Last edited by Common Soldier; July 15, 2019 at 02:56 PM.

  7. #7

    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    This looks like lowtech solution for lowtech areas. Great for places like rural Africa where electrification depends often on local sources, rather than major electric grid.

    But that also means limited profit from it, as places that need this the most are often electrified only through humanitarian efforts, rather than commercial...so I wonder who's going to fund further refinement and deployment of this technology.

  8. #8

    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    Quote Originally Posted by Sar1n View Post
    This looks like lowtech solution for lowtech areas. Great for places like rural Africa where electrification depends often on local sources, rather than major electric grid.

    But that also means limited profit from it, as places that need this the most are often electrified only through humanitarian efforts, rather than commercial...so I wonder who's going to fund further refinement and deployment of this technology.
    Actually, if you are going to rely mostly on solar or wind power for electricity, energy storage ability is going to be essential. This system sounds like it is less restrictive in geography than current water energy storage units are, where you need the ability to construct large water reservoir with sufficient height difference. Without the ability to store large amounts of energy, the variability in wind and solar effectively restricts how much of your electricity can be generated from it. You will need fossil fuel (gas) and nuclear plants to provide power during the night when the wind isn't blowing. Large energy storage unit reduces the need for fossil fuel backup.

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    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    Quote Originally Posted by Common Soldier View Post
    Actually, if you are going to rely mostly on solar or wind power for electricity, energy storage ability is going to be essential. This system sounds like it is less restrictive in geography than current water energy storage units are, where you need the ability to construct large water reservoir with sufficient height difference. Without the ability to store large amounts of energy, the variability in wind and solar effectively restricts how much of your electricity can be generated from it. You will need fossil fuel (gas) and nuclear plants to provide power during the night when the wind isn't blowing. Large energy storage unit reduces the need for fossil fuel backup.
    Exactly. And thats why this news is so interesting.

    And those vulcano rocks are not rare minerals.

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    Default Re: New electrothermal energy storage system consisting of volcanic rocks

    Yeah if you have cost-effective energy storage then the only major barrier is the issues with system stability, frequency instability, and declining value as penetration increases with Wind/Solar/Storage. It allows you to get to 50% to 60% in an economically feasible manner in most energy systems, and as far as 80% VRE (the last 20% has to be dispatchable energy such as Hydro, Geothermal, or Nuclear, as it's widely believed that 100% VRE even with storage technology is most likely impossible in large energy grids).

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