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Fluctuations and Storage David MacKay; Sustainable Energy Without The Hot Air

Energy Storage Association

UK Energy Storage Network

Energy Storage News

News, analysis and opinion on energy storage technologies

Distributed Energy Storage Revenue To Exceed $16.5 Billion By 2024 Joshua S Hill; CleanTechnica; 13 Jan 2015

Is large-scale energy storage dead? Roger Andrews; Energy Matters; 8 Apr 2016

Many countries have committed to filling large percentages of their future electricity demand with intermittent renewable energy, and to do so they will need long-term energy storage in the terawatt-hours range. But the modules they are now installing store only megawatt-hours of energy. Why are they doing this? This post concludes that they are either conveniently ignoring the long-term energy storage problem or are unaware of its magnitude and the near-impossibility of solving it.

Green Energy Doesn’t Work Without Energy Storage That Doesn’t Exist Yet Andrew Follett; Daily Caller; 29 May 2016

from Investment in energy storage vital UEA press release about paper:
The value of arbitrage for energy storage: Evidence from European electricity markets Dimitrios Zafirakis, Konstantinos J. Chalvatzis, Giovanni Baiocchi, Georgios Daskalakis; Applied Energy; 27 May 2016

From liquid air to supercapacitors, energy storage is finally poised for a breakthrough Damian Carrington; The Guardian; 4 Feb 2016

Smarter Network Storage UK Power Networks

We are undertaking trials to improve understanding of the economics of electrical energy storage. The learning gained will help improve cost effectiveness and provide a more sustainable, efficient and flexible way to reinforce networks.


Power to Gas Wikipedia

Science for Energy Scenarios

3rd Science and Energy Seminar at Ecole de Physique des Houches, March 6th-11th 2016
presentations on EROI, power-gas-power, intermmittency, grids, etc


DOE Global Energy Storage Database

The DOE Global Energy Storage Database provides free, up-to-date information on grid-connected energy storage projects and relevant state and federal policies.
All information is vetted through a third-party verification process. All data can be exported to Excel or PDF. Our hope is that this site will contribute to the rapid development and deployment of energy storage technologies.

Energy Storage in the UK - An Overview Renewable Energy Association; Winter 2015-16

Energy Storage Procurement in California - APR2014 24 Jul 2014


Battery Storage Needed to Expand Renewable Energy Umair Irfan; Scientific American; 13 Feb 2015

The U.S. Department of Energy is exploring energy storage strategies to accelerate the use of wind and solar power

UC Irvine invents nanowire battery material with off-the-charts charging capacity Next Big Future; 20 Apr 2016

University of California, Irvine researchers have invented nanowire-based battery material that can be recharged hundreds of thousands of times, moving us closer to a battery that would never require replacement. The breakthrough work could lead to commercial batteries with greatly lengthened lifespans for computers, smartphones, appliances, cars and spacecraft. Scientists have long sought to use nanowires in batteries. Thousands of times thinner than a human hair, they’re highly conductive and feature a large surface area for the storage and transfer of electrons. However, these filaments are extremely fragile and don’t hold up well to repeated discharging and recharging, or cycling. In a typical lithium-ion battery, they expand and grow brittle, which leads to cracking. UCI researchers have solved this problem by coating a gold nanowire in a manganese dioxide shell and encasing the assembly in an electrolyte made of a Plexiglas-like gel. The combination is reliable and resistant to failure. The testing electrode was cycled up to 200,000 times over three months without detecting any loss of capacity or power and without fracturing any nanowires.

Lithium-Ion Will Be Tough To Beat, Says Argonne Battery Whiz Jeff McMahon; Forbes; 26 May 2016

People who are working on next-generation batteries often put lithium-ion down, saying the current technology is too costly, too flammable, or too limited to meet the clean energy and clean transportation demands of the future. But four years into a five-year effort to develop a better battery at Argonne National Laboratory, one Argonne engineer concedes Li-ion will be tough to beat in the marketplace.

UCI Student Accidently Creates A Rechargeable Battery That Lasts 400 Years Tod Perry; Good; 13 Sep 2016

.... recent discovery at the University of California, Irvine by doctoral student Mya Le Thai. After playing around in the lab she made a discovery that could lead to a rechargeable battery that lasts up to 400 years. ... Thai coated a set of gold nanowires in manganese dioxide and a Plexiglas-like electrolyte gel. ... nanobattery developed at UCI made it though 200,000 cycles in three months



AES Constructing Largest Battery-Based Energy Storage Array in United Kingdom AES Energy Storage

Carrickfergus, Northern Ireland, 20 July 2015 – AES announced today that it has begun construction of its first advanced, battery-based energy storage facility in the United Kingdom. The Kilroot AdvancionTM Energy Storage Array will provide 10 MW of interconnected energy storage, equivalent to 20 MW of flexible resource. The array is expected to begin operations by the end of 2015.

Gigha - redT - redox

Utility Scale Storage for Gigha redT energy

Thanks to a £3.6m funding award from the UK Department for Energy and Climate Change (DECC), redT are currently working on the demonstration and pre-commercialisation of a 1.68MWh version of its grid scale flow battery. The energy storage system is being designed for the remote Scottish Isle of Gigha and will be integrated with the island’s wind farm and deployed with the help of project partners; Scottish and Southern Energy (SSE), EA Technology Ltd., Community Energy Scotland (CES) and Gigha Green Power Ltd. (GGPL). The MWh scale vanadium battery will provide much needed energy storage for a location which has limited grid connection via an ageing subsea cable.
The wind farm on Gigha was one of the first community owned grid connected wind farms in Scotland and currently consists of three wind turbines with a combined capacity of 775kW. A fourth turbine of 330kW is being installed, however it will need to operate at an extreme 0.85 power factor to overcome voltage rises and is also constrained to 225kW. Over the 25 year life span of the turbine, this constraint will amount to a loss of 3GWh at a value of around £300,000 and approximately 1.5kt CO2. Furthermore, under the current passive network operating arrangements, the constraint also prevents additional renewable generation capacity from being added to the island, including wind turbines, photo-voltaic panels and tidal stream generators.
The MW Scale Energy Storage system to be implemented on Gigha will address the constraint, allowing for a 20% minimum increase in wind energy generation, which will provide additional income for the island.
In addition to creating revenue from removing constraints from the wind turbine, the implementation of the redT Energy Storage system could potentially enable:
  • The sale of wind energy to the market during peak times and price spikes
  • Local backup power supply in the event of network faults
  • Further generation connections downstream of the Energy Storage System (ESS)
  • Replacement of the fish-farm diesel generators with an Uninterruptible Power Supply (UPS) derived from the ESS - creating environmental benefits and reducing fuel costs.
  • Electricity Trading (arbitrage)
  • The Dispatch of network services (voltage control, load-shifting for assets)
  • The Dispatch of balancing and capacity services such as Frequency Response and Short-Term Operating Reserve (STOR) through an aggregator
redT Vanadium Redox Flow Batteries were chosen for the project because of their ability to balance variable generation from renewable sources and its cost effective time shifting. The new VRFB utility scale technology will meet the need for efficient distributed storage, combined with the ability to respond instantly to demand, dispatching energy over a 12-hour duration when required. The all-Vanadium batteries contain no heavy metals, use non-flammable materials and the electrolyte is completely recyclable. This 2.5-year project aims to demonstrate the utility scale system in a demanding UK application and to develop the technology further towards the goal of full scale commercial manufacture.

Frequency stabilisation

UK’s fastest energy storage system launches The Engineer; 17 Mar 2016

A £4m battery-based energy storage facility has launched today at Willenhall substation near Wolverhampton as part of research led by Sheffield University. The system, which the university said is the UK’s fastest as well as one of its largest, is capable of responding to National Grid demands in 4/10ths of a second. It is also the first in the country to use a lithium titanate battery. Toshiba’s 2MW battery is made up of 21,120 cells and can supply energy to 3,000 homes for 20 minutes. It was chosen for its rapid charge and discharge times, its long lifetime and its safety.
UK National Grid Enhanced Frequency Response

How Britain will keep the lights on Emily Gosden, energy editor ; Daily Telegraph; 26 Aug 2016

Eight new battery storage projects are to be built around the UK after winning contracts worth £66m to help National Grid keep power supplies stable as more wind and solar farm are built. EDF Energy, E.On and Vattenfall were among the successful companies chosen to build new lithium ion batteries with a combined capacity of 200 megawatts (MW), under a new scheme to help Grid balance supply and demand within seconds.

Britain Is About to Take a Great (Battery) Leap Forward Jessica Shankleman; Bloomberg Technology; 25 Aug 2016

Grid-scale electricity storage will move closer to commercial reality on Friday when the U.K.’s grid operator offers contracts to companies to help balance the network, a key measure needed to help balance increasing supply from renewables. National Grid Plc will announce the winners of a bidding round for as much as 200 megawatts of storage capacity, which is about the size of a small power plant. It’s likely to be the storage industry’s biggest award this year in global market expected to install $5.1 billion of equipment in 2020, according to Bloomberg New Energy Finance. Storage plays a key role in the greening of utilities’ networks by allowing grid managers to handle higher volumes of intermittent power from the wind and sun.
Any winning bidder of National Grid’s tender must be able to supply power within 1 second and deliver 100 percent of the capacity it offered for at least 15 minutes.
200MW * 15m = 50MWh



UK 2 and 3kWh batteries in wall-hung box



Powervault tech specs

Why Tesla's Powerwall Is Just Another Toy For Rich Green People Forbes

Tesla Discontinues 10-Kilowatt-Hour Powerwall Home Battery Julia Pyper; Green Tech Media; 18 Mar 2016

Tesla has quietly removed all references to its 10-kilowatt-hour residential battery from the Powerwall website, as well as the company’s press kit. The company's smaller battery designed for daily cycling is all that remains.

Tesla Wins Massive Contract to Help Power the California Grid Tim Randall; Bloomberg; 15 Sep 2016

Tesla Motors Inc. will supply 20 megawatts (80 megawatt-hours) of energy storage to Southern California Edison as part of a wider effort to prevent blackouts by replacing fossil-fuel electricity generation with lithium-ion batteries.

Vaca system / CAISO / Sodium-Sulphur batteries

CAISO Battery Storage Trial Todd "Ike" Kiefer; Transmission and Distribution World / The Grid Optimization Blog; 21 Nov 2016

Despite all the hype and giga-promises, there has yet been no breakthrough in electricity storage technology that delivers all the requisite features of high energy density, high power, long life, high roundtrip efficiency, safe handling, and competitive cost. Batteries are still a long way from being a substitute for fossil fuel power plants or any other actual power generators because of physical and economic limits of current technology.


Energy Storage Technologies Energy Storage Association

Lithium Ion batteries wikipedia

Batteries Not Excluded Simon Parkin; How We Get To Next; 11 Feb 2016

The supercomputer in your pocket and your next car rely on them — so what will we do if we run out of lithium?
battery history, chemistry, sustainability

US agency reaches 'holy grail' of battery storage sought by Elon Musk and Gates ARPA-E

Uncle Sam's boffins stumble upon battery storage holy grail ARPA-E

Spanish company Graphenano claims Graphene Polymer batteries with triple the energy density of lithium ion and commercialization by end of 2016


Redox Flow Batteries Energy Storage Association

Redox flow batteries (RFB) represent one class of electrochemical energy storage devices. The name “redox” refers to chemical reduction and oxidation reactions employed in the RFB to store energy in liquid electrolyte solutions which flow through a battery of electrochemical cells during charge and discharge.

Flow battery Wikipedia

Vanadium-Flow Batteries: The Energy Storage Breakthrough We've Needed James Conca; Forbes; 13 Dec 2016

the new V-flow batteries reduce the cost of storage to about 5¢/kWh.
UniEnergy Technologies (UET) of Seattle produces the largest MW-scale vanadium flow batteries yet, using a molecule developed at the Pacific Northwest National Laboratory. PNNL’s breakthrough was to introduce hydrochloric acid into the electrolyte solution, almost doubling the storage capacity and making the system work over a far greater range of temperatures, from -40°C to 50°C (-40°F to 122°F), removing a large previous cost of maintaining temperature control.
Presently, the largest installed V-flow battery in the U.S. is a UET 2MW/8MWh (power/total dischargeable energy in a single full charge) system in Washington State at the Snohomish County Public Utility District’s Everett Substation. This vanadium battery can keep the lights on in 1,000 homes for eight hours.
A V-flow battery system planned for Dalian China by UET's sister company Rongke will soon be the largest battery in the world at 200MW/800MWh.

New type of ‘flow battery’ can store 10 times the energy of the next best device Robert F. Service; AAAS Science; 27 Nov 2015

Lithium instead of Vanadium

See Gigha above.

zinc-bromide / Redflow


My home Redflow ZBM2 energy system installation by Simon Hackett Redflow; 28 Nov 2016


SunVault Energy

claims 80 / 175-200 / 375 WH/kg
> 500 cycles
"significantly lower - under market" cost
90-95% charge depth
carbon + non-toxic electrolyte

Fast-charging everlasting battery power from graphene Han Lin;; 19 Jul 2016

Swinburne University researchers have invented a new, flexible energy-storage technology that could soon replace the batteries in our cars, phones and more. Han Lin's new super battery (actually, a supercapacitor) can store as much energy per kilogram as a lithium battery, but charges in minutes, or even seconds, and uses carbon instead of expensive lithium.
Previously, a major problem with supercapacitors has been their low capacity to store energy. But Han has overcome this problem by using sheets of a form of carbon known as graphene, which has a very large surface area available to store energy. Large scale production of the graphene that would be needed to produce these supercapacitors was once unachievable, but using a 3-D printer, Han is able to produce graphene at a low cost.

economics & feasibility

A Nation-Sized Battery pdf Tom Murphy - associate professor of physics at the University of California, San Diego.

what it would take to build battery-based storage for the US for 100% renewables

The Holy Grail of Battery Storage Roger Andrews; Energy Matters; 18 Aug 2016

A recent Telegraph article claims that storage battery technology is now advancing so fast that “we may never again need to build 20th Century power plants in this country, let alone a nuclear white elephant such as Hinkley Point” and that the “Holy Grail of energy policy” that will make this solution economically feasible – a storage battery cost of $100/kWh – will be reached in “relatively short order”. This brief post shines the cold light of reality on these claims by calculating battery storage costs based on the storage requirements for specific cases estimated in previous Energy Matters posts. It is found that installing enough battery storage to convert intermittent wind/solar generation into long-term baseload generation increases total capital costs generally by factors of three or more for wind and by factors of ten or more for solar, even at $100/kWh.

Hydro / pumped hydro

Pumped Storage SEWTHA

Pumped Storage Energy Education

Assessment of the European potential for pumped hydropower energy storage - A GIS-based assessment of pumped hydropower storage potential Marcos Gimeno-Gutiérrez, Roberto Lacal-Arántegui; European Commission JRC Scientific and Policy Reports; 2013

'Store more energy in water', says Scottish Power dodgy figures

Dinorwig Power Station

c. 340MW (?)
Synchronised and spinning-in-air emergency load pick-up rate from standby: 0 to 1,320 MW in 12 seconds


Norway Could Provide 20,000MW of Energy Storage to Europe Mike Stone; Green Tech Media; 10 Aug 2015

Norway has a lot of hydroelectric plants: a total of 937 of them, which provide a population of 5 million with around 98 percent of its electricity. In fact, the Scandinavian country is home to roughly half of all the hydroelectric water storage reservoirs in Europe.
This vast system could also offer a Europe a substantial amount of energy storage -- up to 20 gigawatts of it -- if an ambitious scheme currently being proposed can overcome political and social hurdles and get the necessary funding. That’s according to Kaspar Vereide, an engineer at the Norwegian University of Science and Technology in Trondheim. And his models suggest it could all be achieved in seven years.

Why Norway Can’t Become Europe’s Battery Pack Jason Deign; Green Tech Media; 13 Mar 2017

New research casts doubt on the view that pumped hydro power could allow Norway to act as battery pack for other parts of Europe.
Dr. Björn Peters, a German energy investor turned researcher, says that even though Norway’s hydro capacity is “huge,” most of it is in fact needed to power Norway. “Theoretically, Norwegian electricity storage would be sufficient to compensate for the fluctuations in solar and wind energy in Germany, even if Germany was supplied solely by sun and wind energy,” he said. “However, since 2002 an average of about 44 terawatt-hours had to be stored between the summer and winter in Norway. The lowest and highest filling levels of the reservoir lakes were [between] about 15 terawatt-hours and slightly over 77 terawatt-hours.” This means nearly all the country’s 82 terawatt-hours of storage was used by Norwegians, Peters said.


UK hydro storage is ‘undervalued’ RE News; 4 Oct 2016

There needs to be a radical overhaul of the way pumped storage hydro’s benefits are quantified to reflect the value it can bring to the electricity system, according to a new report by DNV GL. The report – ‘The Benefits of Pumped Storage Hydro to the UK’ – was funded by the Scottish Government, SSE and ScottishPower and makes several recommendations to encourage the expansion of the technology. There needs to be a radical overhaul of the way pumped storage hydro’s benefits are quantified to reflect the value it can bring to the electricity system, according to a new report by DNV GL. The report – ‘The Benefits of Pumped Storage Hydro to the UK’ – was funded by the Scottish Government, SSE and ScottishPower and makes several recommendations to encourage the expansion of the technology.

Strath Dearn

World’s biggest-ever pumped-storage hydro-scheme, for Scotland? Scottish Scientist; 15 Apr 2015

The Loch Ness Monster of Energy Storage Euan Mearns; Energy Matters; 22 May 2015

further comments on Strath Dearn


Glenmuckloch Pumped Storage Hydro Scheme Glenmuckloch Pumped Storage Hydro Ltd; Dec 2015

Non-Technical Summary

The Glenmuckloch Pumped Storage Hydro Scheme Euan Mearns; Energy Matters; 12 Dec 2016

Scotland is to get a new pumped storage hydro scheme, not in the Highlands but in the Scottish Borders. With a capacity of 400 MW and an estimated 1.7 GWh of storage this plant can make a meaningful 4 hour contribution to peak generation every day. But wooly[sic] arguments made about smoothing intermittent renewables makes it unclear if this commendable strategy is the intended use.


Dubai to build Persian Gulf’s first hydroelectric plant, 880 million gallon ‘battery’ Michael Kowalczuk; electrek; 23 Dec 2016

The plant will make use of the 1,716 million gallons water stored in the Hatta Dam to generate electricity. It will also see the construction of an upper reservoir that will be built in the mountain 300 meters above dam level, which will be able to store up to 880 million gallons. The 250 MW power station will make use of falling water passing through turbines to generate electricity during peak hours. During off-peak hours, the station will utilize solar energy to pump water back up to the upper reservoir.

compressed air

Compressed Air Energy Storage (CAES) Energy Storage Association

The Intermountain Energy Storage Project Power Engineering; 19 Apr 2016

Compressed Air store in underground salt cavern in Urah for wind power supply for Los Angeles

underwater balloons

Storing Energy in Underwater Balloons R. Kress; EnergyBiz Magazine; Spring 2016

Hydrostor, a Canadian startup that has launched the world's first underwater compressed-air energy-storage solution ... recently brought online a grid-connected, 1-MW system using inflatable balloons positioned 180 feet below the surface of Toronto's Lake Ontario. The system -- capable of holding enough energy to power 330 homes -- will be operated by Toronto Hydro. The utility intends to use the Hydrostor system to store electricity during offpeak hours and then tap into it as demand grows.

ARES rail

The train goes up, the train goes down: a simple new way to store energy David Roberts; Vox; 28 Apr 2016

It's from a company called ARES. Here's how it works:
  • The train carries big rocks uphill, consuming electricity.
  • Then the train carries big rocks downhill, generating electricity.
That's it. The energy stored by going uphill is released by going downhill.

ARES Performance

An ARES facility will provide the full range of energy storage capabilities generally associated with pumped-storage hydro at approximately 60% of the capital cost and at a significantly higher efficiency. Additionally, ARES has system features which are not traditional to competing forms of energy storage, including but not limited to the following attributes:
  • Reactive Power Production – The shuttle-trains onboard Dual 3-Level Active Rectifier/Invertors are capable of supplying 25% of generated system power as reactive power for grid VAR support in full discharge mode and in excess of 100% of system power as reactive power while synchronized to the grid in standby.
  • Heavy Inertia – When in direct grid synchronization the ARES shuttle-trains provide beneficial heavy inertia -- augmenting grid stability against the loss of heavy generating facilities and increasing reliance on solar energy.
  • High Efficiency Regulation – While providing Regulation-Up and Regulation-Down support to the ISO a separate dedicated pool of loaded ARES shuttle-trains are available to dispatch from mid-system elevation complying with ISO regulation commands without having to overcome the efficiency loss of operating on pre-stored energy. As such an ARES facility is able perform a round-trip regulation Reg-Up/Reg-Down command at over an 86% operating efficiency.
  • Variable Output at Constant Efficiency – Unlike CAES and pumped-storage hydro there is no loss of system pressure during discharge. ARES system efficiency is constant over the full range of discharge and power output.


  • efficiency > 80%
  • capacity 50MW 12.5 MWh

Is ARES the solution to the energy storage problem? Roger Andrews; Energy Matters; 6 Apr 2016

many sources and calculations, extensive discussion of storage technologies in the comments


Articles in category: Flywheel Energy Storage Association

Making the Case for Spinning Reserve on the Grid Chris Campbell; Renewable Energy World; 31 May 2011

an[] application for which advanced energy storage is showing significant benefits is spinning reserve. In this application, storage assets can efficiently increase the reliability and improve the responsiveness of the electric power grid. Advanced energy storage can also release traditional generation—otherwise encumbered by an obligation to provide some amount of spinning reserve— to sell more valuable energy output.
To help ensure consistent availability and reliability of electricity, utilities keep generation capacity on reserve that can be accessed quickly if there is a disruption to the power supply. For example, if a base load generator or a major transmission line delivering imported power goes down, the utility and/or grid operator will access its reserve capacity to compensate.
Typically, this reserve capacity is created by generators that are already synchronized with the power grid but are not operating at full capacity. If backup power is needed, utilities will increase the output of these generators, usually by increasing the rotation of the turbine (hence “spinning reserve”). Typically, a 10-minute response time is a minimum requirement to qualify as spinning, or “operating” reserves.
However, leveraging traditional generation assets for creating reserved capacity creates a number of inefficiencies. For example, because these generators are operated below their rated value, the utility is not maximizing their power output that could be used for base load supply. Also, it requires the use of additional fuel to ramp these generators up in the event that their reserved generation potential is needed, which increases emissions while reducing the net efficiency of the power system.
Alternatively, energy storage can be implemented onto the power grid as spinning reserve assets. These systems provide a cleaner, more efficient mechanism for utilities to compensate for disruptions to the power supply while enabling them to leverage the full capabilities of their generation assets to deliver base-load power. The most advanced storage solutions are also equipped with sophisticated monitoring and control systems, enabling them to detect disruptions in the power supply and communicate quickly with the grid to near-instantaneously discharge and provide the reserve capacity when it is needed.

Amber Kinetics

Amber Kinetics: Turning Flywheels Into Multi-Hour Energy Storage Assets Jeff St. John; Greentechmedia; 10 Dec 2015

Flywheels are a well-known energy storage technology, at least on the power side of the equation. They work by spinning up a heavy disk or rotor to high speeds, and then tapping that rotational energy to discharge high-power bursts of electricity. Companies like Vycon, Active Power and Beacon Power provide emergency ride-through power for buildings, or fast-responding frequency regulation services for grid operators, to name two typical use cases.
But it’s a lot harder to use flywheels to store energy for hours at a time. Mainly, that’s due to “coasting losses” -- the inevitable mechanical and electromagnetic forces that slow down a heavy spinning object. These challenges have pretty much relegated long-duration flywheels to research labs -- at least, until now.
Last week, Amber Kinetics unveiled a four-hour duration flywheel system, one it says combines the efficiency and flexibility of an electrochemical battery with the durability and lifespan of a simple mechanical device.
The core system is a 25-kilowatt-hour flywheel, capable of charging and discharging for more than one duty cycle per day,
Ten flywheels in a storage container make up what the company is calling an “energy block,”


Europe’s first flywheel storage plant set to debut Power Engineering International; Apr 2015

The first grid-connected hybrid flywheel project in Europe has been announced and is to be sited in the Irish midlands.
SchwungradEnergie Limited is behind the project and will collaborate with the Dept. of Physics and Energy at the University of Limerick and US company, Beacon Power.

Irish flywheel storage project could prove crucial tech for EU green ambitions Diarmaid Williams; Power Engineering International; Apr 2015

The first grid-connected hybrid flywheel project in Europe could potentially be rolled out across the rest of the European Community once it initially gets off the ground in Ireland.
Frank Burke, Technical Director at Schwungrad, the company behind the flywheel project told Power Engineering International that the Irish experience in using the technology to maintain a stable grid as more and more renewable power is loaded on will serve to inform other member states.
“With the Irish context there is the pretty high target of going 40 per cent renewable by 2020 which is only a few years away now. One of the problems at the moment is that the system can’t allow more than 50 per cent of non-synchronous renewable generation at any one time; it’s not just renewable, that also applies to the interconnectors because those interconnectors are DC and are not synchronised. The problem is growing every year where a renewable plant is having to be curtailed because they can’t allow more than 50 per cent on.”

gravity battery

Gravity Battery: An illustrated concept detailing the long-term, low-maintenance storage of energy through the use of the force gravity


Thermal Energy Storage - Technology Brief IRENA: International Renewable Energy Agency

Thermal stores Energy Saving Trust

Borehole Field In The Drake Landing Solar Community, Okotoks, Alberta American Association of Physics Teachers; 21 Jul 2008

The Future Role of Thermal Energy Storage in the UK Energy System: An Assessment of the Technical Feasibility and Factors Influencing Adoption Eames, P., Loveday, D., Haines, V., Romanos, P.; UKERC; 2014

ThermalBanks™ store heat between seasons ICAX Interseasonal Heat Transfer]

Ice store

Viessmann Installs First UK 'Energy from Ice' Heating System Heat Pumps Today; 10 Oct 2015

Heating and refrigeration solutions manufacturer, Viessmann, has installed 'ice store system, in a UK property domestic property, the company announced this week. The innovative system recovers energy from renewable sources to heat or cool buildings, and supplies hot water. Viessmann installed the first system in a new, sustainable housing development at HUF HAUS' UK show room near Weybridge, Surrey. The system takes energy from ice to heat or cool the house. It supplies the energy to heat pumps for heating and hot water in the winter, and for cooling in the summer. The Viessmann system takes energy from water in its ice store. The water temperature drops and, as the energy is withdrawn, the water freezes . The system keeps on taking heat from the ice.

Fighting Air Conditioning's Peak Demand With Thermal Energy Storage James Conca; Forbes; 7 Jul 2016

As we head into the hottest part of summer in the Northern Hemisphere, in what could be the hottest year on record, we barely give a thought to what using air conditioning does to our electricity grid. And what it will do to a hotter world in the future.

Pumped Heat Energy Storage (PHES)

Pumped Heat Electrical Storage (PHES) Energy Storage Association

In Pumped Heat Electrical Storage (PHES), electricity is used to drive a storage engine connected to two large thermal stores. To store electricity, the electrical energy drives a heat pump, which pumps heat from the “cold store” to the “hot store” (similar to the operation of a refrigerator). To recover the energy, the heat pump is reversed to become a heat engine. The engine takes heat from the hot store, delivers waste heat to the cold store, and produces mechanical work. When recovering electricity the heat engine drives a generator.
PHES requires the following elements: two low cost (usually steel) tanks filled with mineral particulate (gravel-sized particles of crushed rock) and a means of efficiently compressing and expanding gas. A closed circuit filled with the working gas connects the two stores, the compressor and the expander. A monatomic gas such as argon is ideal as the working gas as it heat/cools much more than air for the same pressure increase/drop - this in turn significantly reduces the storage cost.



Isentropic Ltd was established to develop Pumped Heat Electricity Storage (PHES), a standalone energy storage system based on a novel, high efficiency reciprocating engine and large scale thermal stores. The long-term market opportunity for energy storage is a low-cost stand-alone system which will allow the grid to respond to variation in load and generation as more power comes from intermittent renewable sources.
Isentropic Pumped Heat Electricity Storage (PHES) is in development at our UK facility.
The development of the thermal stores has also led to an energy storage technology integrated into gas power plant: Gas Turbine Integrated (GTI) Storage.
GTI-Storage offers either Rapid Response or Enhanced Turndown systems, one a fast reacting technology to support frequency response on the grid and the other to provide longer term storage. Both of these technologies are at the development stage.

Isentropic PHES Technology Explained Isentropic Ltd; Youtube; 19 Mar 2014

Molten Silicon

Silicon will blow lithium batteries out of water, says Adelaide firm Ben Potter; Financial Review; 10 Feb 2017

An Adelaide company has developed a silicon storage device that it claims costs a tenth as much as a lithium ion battery to store the same energy and is eyeing a $10 million public float. 1414 Degrees had its origins in patented CSIRO research and has built a prototype molten silicon storage device which it is testing at its Tonsley Innovation Precinct site south of Adelaide. Chairman Kevin Moriarty says 1414 Degrees' process can store 500 kilowatt hours of energy in a 70-centimetre cube of molten silicon – about 36 times as much energy as Tesla's 14KWh Powerwall 2 lithium ion home storage battery in about the same space. Put another way, he says the company can build a 10MWh storage device for about $700,000. The 714 Tesla Powerwall 2s that would be needed to store the same amount of energy would cost $7 million before volume discounts.
The device stores electrical energy by using it to heat a block of pure silicon to melting point – 1414 degrees Celsius. It discharges through a heat-exchange device such as a Stirling engine or a turbine, which converts heat back to electrical energy, and recycles waste heat to lift efficiency.