Building an adequate energy storage system is one of the central challenges of the renewable energy transition. Pumped hydro storage is a very important option. Most people associate this with a dam in a valley behind which water can be pumped upwards in times of excess renewable energy available, in order for it to be released later, when the electricity is required.
But there are more options. One of them is building a large reservoir on top of mountain. Another one, attractive for the flatlanders, is building a high dike in the sea.
Elevation: 510 m (highest in Europe),
Reservoirs: 2.7 million m3 (higher) and 3.4 million m3 (lower)
Pump-generators: 2 x 325 MW
More than 2 GW, generating 5,000 GWh/year.
[source] So-called Plan Lievense, dating from 1981. With the massive Dutch multi-GW wind power plans for the North Sea, to be realized before 2023, some form of energy storage is inevitable. One of the options is building dike structure that allow for fluctuating water levels of up to 40 meter.
Design consists of a closed ring-shaped dike of ca. 6 x 10 km. Water levels will very from 32 to 40 meter under the water level of the surrounding North Sea. Lake surface area: ca. 40 km2. Storage capacity is more than 20 GWh (value 5 million euro consumer end price of 25 cent/kWh), sufficient to produce 1,500 MW during at least 12 hours to the national grid. this plan could be profitable from 9 GW wind offshore wind power, expected after 2020..
[Google Maps] – Brouwersmeer
[deepresource] – Pumped Hydro Storage
An innovation from Perdue University, Laffayette, USA, could dramatically reduce the time needed to recharge a battery. E-vehicles could enter a charging station en route and recharge in a matter of minutes, like in the petrol car days and as such could significantly lower the acceptation threshold for e-vehicles. Gone would be the necessity of a nation-wide power plug infrastructure in front of every home to recharge the car at night.
Purdue scientist John Cushman presented his findings at the recent International Society for Porous Media 9th International Conference in Rotterdam, Netherlands.
Recharging consists of refilling a car with fluid electrolytes, not with electricity kWh’s:
The spent battery fluids or electrolyte could be collected and taken to a solar farm, wind turbine installation or hydroelectric plant for re-charging… Instead of refining petroleum, the refiners would reprocess spent electrolytes and instead of dispensing gas, the fueling stations would dispense a water and ethanol or methanol solution as fluid electrolytes to power vehicles… Other flow batteries exist, but [this is] the first to remove membranes which reduces costs and extends battery life… Membrane fouling can limit the number of recharge cycles and is a known contributor to many battery fires.
[purdue.edu] – ‘Instantly rechargeable’ battery could change the future of electric and hybrid automobiles
Europe is a front-runner in implementing renewable energy sources, but is lagging behind with producing essential electricity storage. This is about to change with Daimler’s planned new giant battery in Kamenz, Germany. Purpose: build batteries for 10 new Daimler EV-models, on the road by 2022. The plant will be carbon neutral, with a combined heat-and-power plant and solar power. The initiative is aimed at competing with Tesla.
[media.daimler.com] – Daimler lays foundation for one of the biggest and most modern battery factories in the world
[rt.com] – Europe joins race for cheaper batteries with new gigafactory
[energy-saxony.net] – Daimler baut weitere Batteriefabrik fuer Elektrofahrzeuge in Kamenz
[source] “MyReserve”, 93% efficiency. 4,4 kWh; 6,6 kWh; 8,8 kWh; 11 kWh units
Solar installation company Solarwatt from Dresden/Germany has announced that it will offer batteries for substantially lower prices in the Summer 2017.
Price 4.4 kWh unit: 5.499 Euro
German price context:
1 kWh from the grid: 30 cent
1 kWh grid feed-in compensation: 12 cent
1 kWh cost from panel: 10 cent
Under these (very German) price conditions does it pay to install this Solarwatt battery.
This btw is still a far cry from the promised $100-200/kWh.
Energy from wind, solar and water in; ammonia (NH3) as energy storage medium out, eliminating carbon from the cycle. The idea is to convert renewable energy into liquid ammonia when electricity prices are low and burn it as fuel in gas-fired power plants when there is a shortage of renewable energy.
Liquid ammonia at 1 Bar in a 60,000 m3 tank contains more than 200 GWh of energy (annual production of 30 wind turbines).
Demonstration facility planned in Holland to be completed in five years.
[vattenfall.com] – Dutch gas plants made fossil free?
[resilience.org] – Is ammonia the holy grail for renewable energy storage?
[wikipedia.org] – Ammonia (NH3)
[protonventures.com] – Proton Ventures, What We Do
[energyoutlook] – Ammonia As An Alternative Fuel? (negative assessment)
EU scientists are investigating if high pressure air, stored in empty mines and tunnels, could provide an alternative for pumped hydro storage in mountain basins. Currently pumped air storage efficiency merely reaches ca. 50%. The goal of the project is to substantially increase that efficiency to 70-80%. The trick is to not ignore the thermal losses accompanied with putting air under pressure, c.q. releasing it.
[ricas2020.eu] – RICAS Project (Research Infrastructure Compressed Air Storage)
[wikipedia.org] – Compressed air energy storage
[cleantechnica.com] – EU Proposes Air As World’s Next Big Energy Storage Option
[sintef.no] – Air could be the world’s next battery
[trouw.nl] – Energieopslag in Bergen: een heel luchtige zaak
[ethz.ch] – Pilot in Switzerland; expected efficiency 75%.
Cheap storage to counter the intermittent supply of renewable electricity is the missing link en route towards the desired renewable energy base of the future, but that problem could now have been solved. Technology has developed so rapidly in recent years that cost of electricity storage has been brought down from $1000 to $100 per kWh.
City College NY has improved an old concept of mangandioxide-zinc batteries. Result: 6000 charge-cycles for less than $100/kwh.
Price storage of a single kWh: 1.67 dollar cent or say 8 cent per day per 5 kWh/day household. Peanuts.
Can also be used for cars: 40 kWh battery for $4000. Bye-bye gasoline.
Mangan-Oxid is abundant and non-toxic.
This NYC startup is going to produce the batteries first:
[sciencedaily.com] – Sustainable, high energy density battery created
[nature.com] – Regenerable Cu-intercalated MnO2 layered cathode for highly cyclable energy dense batteries
[pnnl.gov] – Unexpected discovery leads to a better battery
[newatlas.com] – Power dense zinc-manganese power unit as cheap as a car battery
[wikipedia.org] – Manganese
[wikipedia.org] – Zinc
[trouw.nl] – Batterijdoorbraak: magische grens van 100 dollar is geslecht
Storage of intermittent renewable energy is one of the core challenges that needs to be addressed to make the energy transition away from fossil fuel work. Pumped hydro is a reliable method, but this requires the presence of mountains and valleys and these are in overpopulated Europe in short supply. Another approach is the conversion of renewable electricity into gas, like H2, CH4, CO, etc. “Power-to-gas”.
Tests have been completed in the German Bodensee with a 20 ton, 3 meter concrete hollow sphere, sunk to the bottom of the lake. When water flows into the sphere, electricity can be generated. Alternatively, wind power can be used to empty the sphere again and as such (virtually) load the battery again. Future dimensions are thought to be 20 meter or lager (4,200 m3 volume). Assuming 100 meter of water above the sphere, that’s an amount of storage energy 1167 kWh or 86 Tesla Powerwall 2.
[spiegel.de] – Riesige Betonkugel speichert Energie
The key challenge with setting up a 100% renewable energy base is providing storage facilities. This applies to intermittent supply of electricity via wind and PV-solar, that needs to be matched with equally intermittent demand. The same consideration applies to space heating, the demand of which currently is mostly covered via fossil fuel. If you want to phase out fossil fuel for space heating, you will need to get serious about seasonal storage of heat: trapping solar heat in the summer, use it to heat large bodies of soil and withdraw these Joules in the Winter.
The city of Hamburg is considering a large scale heat storage that should cover 25% of Hamburgs needs. For the moment the buffer would be charged with industrial waste heat from fossil sources. But once realized the storage bugger could be fed with thermal solar as well.
Estimated cost: 4 cent/kwh, half of the price customers currently pay for district heating.
[energypost.eu] – Hamburg considers innovative heat storage scheme
Everybody prefers to talk about wind and PV-solar when it comes to renewable energy. The reality is that electricity is only a relatively small part of the energy consumption of private households. Take the Netherlands:
[clo.nl] – Energieverbruik door huishoudens, 1990-2013
Natural gas: 3/4 (space heating, cooking, bath)
Electricity: 1/4 (lights, TV, fridge, freezer, router, etc)
In other words: the greater challenge is to replace fossil fuel for heating purposes with renewable sources. Two major renewable sources for heating are
1) thermal solar
The problem with thermal solar is the mismatch between supply and demand. You need heat in the Winter but the sun shines mostly in the Summer. Apparently a major breakthrough has been achieved in storing large amounts of solar heat in molten salts.
US researchers at the Massachusetts Institute of Technology have developed a liquid metal battery that could fulfil that role. Such a battery would lower the overall costs of energy storage, and have the advantages that they are mechanically simple and don’t take up much space… Indeed, the team’s experiments with this novel storage system carried out at 450°C displayed a current density of 275mA/cm2, with a cycling efficiency of 98% on charging and 73% ‘round-trip’ energy efficiency… The team’s experiments completely charging and discharging their battery over 450 cycles over 75 days suggests that the battery will still have 85% of its initial storage capacity after 10 years active service… The team adds that at today’s prices, the electrode materials costs are approximately $65/kWh.
Editor: is this is true and no serious (environmental) disadvantages come with this technology, this could mean the final breakthrough for wind and solar.
[rsc.org] – Molten metal batteries set to store grid power
The idea is not new: build a circular dike in the sea and pump water out of it with energy from wind turbines for storage purposes if there is no actual demand for energy, like during the night. Let water flow back in again, propelling turbines to generate energy on the moment that you need it.
In 1981 the Dutch engineer Lievense presented the plan for this type of storage, but that was 1981 (when we heard him present his plans at our university) and now is 2015, where the energy problem has become acute. Decision for a go ahead: this summer.
Discharge capacity: 500 MW for four hours
Max. difference water levels: 30 meter
[source] Original Plan Lievense
Residential energy storage systems of 8.0 kWh and 5.5 kWh were recently introduced by Samsung SDI at Intersolar Europe 2015 in Munich, Germany. The two new systems were designed to work well with electricity generated by solar PV power, and they use lithium-ion batteries. There is a product warranty for 5 years and a performance guarantee for 10.
Tesla’s selling price to installers is $3500 for 10kWh and $3000 for 7kWh. (Price excludes inverter and installation.) Deliveries begin in late Summer.
[mashable.com] – The killer feature of Tesla’s Powerwall is the price
[cleantechnica.com] – Tesla’s Home Battery Offering In Context
[teslamotors.com] – Energy Storage for a Sustainable Home
[spiegel.de] – Batterie für Selbstversorger
Energy equivalent is one liter gasoline
The US company JuiceBoxSolar brought a 8.6 kWh energy storage system to the market, specifically designed to support a domestic solar system. This kind of storage provides for the missing link between electricity production during the day and electricity consumption at night, when people return home from work. The system is advertised as maintenance free for a minimum of ten years and can be installed outdoors, against a wall.
Editor: the price is still a mystery and for that reason probably high.
In comparison, your average $135 fully charged car battery has a capacity of something like 0.6 kwh, that’s $225/kwh. Energy efficiency battery storage: better than 90%.
[cleantechnica.com] – Eos Energy Storage’s Aurora Battery System Commercially Available In 2016, At $160/kWh
EOS Aurora 1000 | 4000 [source]
Storing electricity safely, efficiently and in large amounts that is one of the greatest challenges for the power supply of the future. RWE Power, General Electric, Züblin and DLR are facing this task in the ADELE project.
Located in McIntosh, Ala., PowerSouth’s McIntosh Power Plant currently includes four natural-gas fired combustion turbines and the United States’ only Compressed Air Energy Storage (CAES) unit. The Plant’s first two natural-gas units went commercial in 1998, with a capacity of 240 megawatts. The second set of two natural-gas units went commercial in 2010, with a capacity of 360 megawatts. The CAES facility has a capacity of 110 megawatts. Total plant capacity is 710 megawatts — enough electricity to power approximately 710,000 homes. The natural-gas fired, simple-cycle units are classified as peaking units. They are designed to provide additional electricity to the PowerSouth system during “peak” usage periods — usually short periods of time during early morning or evening hours. The McIntosh Plant’s turbines and generators offer simple-cycle technology with short start-up time, making them suitable for continuous, peaking and emergency operation.
The principle: demonstration of a small compressed air battery. The bottle stores compressed air. The high speed air from the bottle moves a turbine connected to a DC motor who acts as a dynamo. This turbine-motor comes from a home hairdryer.