Fast, long-life energy storage

As the world generates more and more electricity from intermittent renewable energy sources, there is a growing need for technologies which can capture and store energy during periods of low demand and release it rapidly when required.

At Gravitricity we are developing a novel storage technology which offers some of the best characteristics of lithium batteries and pumped storage. 

Ideally suited to network-constrained users and operators, distribution networks and major power users, the technology operates in the 1MW to 20 MW power range and enables existing grid infrastructure to go further in a renewable energy world. 

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Our patented technology is based on a simple principle: raising and lowering a heavy weight to store and release energy. The Gravitricity system suspends weights of 500 - 5000 tonnes in a deep shaft by a number of cables, each of which is engaged with a winch capable of lifting its share of the weight. Electrical power is then absorbed or generated by raising or lowering the weight. The weight is guided by a system of tensioned guide wires (patents applied for) to prevent it from swinging and damaging the shaft. The winch system can be accurately controlled through the electrical drives to keep the weight stable in the hole.

Gravitricity™ technology has a unique combination of characteristics:

  • 50-year design life – with no cycle limit or degradation
  • Response time – zero to full power in less than one second
  • Efficiency – between 80 and 90 percent
  • Versatile – can run slowly at low power or fast at high power
  • Simple – easy to construct near networks
  • Cost effective – levelised costs well below lithium batteries

Each unit can be configured to produce between 1 and 20MW peak power, with output duration from 15 minutes to 8 hours. 

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The key requirement is a deep hole in the ground; it can be a disused mineshaft brought back into use, or a purpose-sunk shaft. Shaft depths can be from 150m for new shafts down to 1500m for existing mines.

The grid connection is through modern power electronics to permit rapid switching between generation and absorption of power and the system can deliver active as well as reactive power to help with grid stability.

While the weight system can be used on its own, the energy storage capacity of the overall system can be much increased when the shaft is used as a pressure vessel, allowing a compressed air energy storage (patent applied for.) to operate alongside the weight system.  This involves adding a pressure-tight “lid” to the top of the shaft and lining the shaft to prevent leakage. The ground provides the bursting resistance other than at the very top of the shaft. The winches and generators will be contained in the pressurized space so that only electrical cables need to penetrate the pressure vessel walls. 

Initially we will prove the technology using existing mine shafts. Future deployments will be able to utilise existing mines or purpose-built shafts, allowing development wherever storage is required.

During 2019/20 we are undertaking sub-system design and will be building a 250kW concept demonstrator in 2020.  We aim to deploy our first full-scale prototype in 2022 or 2023 at a disused mine in the UK.

Gravitricity Ltd has patents dating 2011, 2013, 2017 and 2019.



We are working with Dutch winch and offshore manufacturer Huisman Equipment BV and are developing an Industrial Consortium to take the technology to market.


Huisman is a privately owned company operating globally with extensive experience in the design and manufacturing of heavy construction equipment for world’s leading on and offshore companies. 

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Huisman was originally founded in 1929 as a steel construction company and now has the capacity to develop products from concept to delivery. Their product range can be subdivided into four main categories: Heavy Lifting Equipment, Drilling Equipment, Pipelay Equipment and Mooring Systems and varies from stand-alone components to highly engineered integrated systems. 

Their operations are divided between offices in The Netherlands, Brazil, China, Czech Republic and USA and production facilities in The Netherlands, Czech Republic and China.

$620 Billion Market Opportunity

The International Energy Agency estimates that in order to limit global warming to below 2°C, the capacity of storage connected to the grid worldwide should increase from 140 GW in 2014 to 450 GW by 2050.

Bloomberg New Energy Finance [Global Energy Outlook 2018] has forecast over $620 billion of global spend on energy storage to 2040. Today, new energy storage technology investment is around $5 billion per year, this will grow to £50 billion by 2040. 

Our technology will provide balancing services on transmission grids as well as appealing to network-constrained users and generators, distribution networks and major power users seeking a reliable, fast response, and long-term means of storing power.

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The Gravitricity technology is inherently durable and flexible. Where ever it is deployed it will provide balancing services such as Frequency Response and Reserve to the  high voltage transmission grid in the region.  It can also be sited at locations where energy storage is particularly required: on constrained distribution grids, behind customer meters, and on micro-grids where the technology can provide long-term system balancing.

On existing grids Gravitricity installations can be considered as long term infrastructure assets that maximise the utility of existing grid hardware.  In many situations they can be deployed to minimise or remove altogether the requirement for expensive distribution grid upgrades as demand and supply patterns change.

On emerging grids, Gravitricity systems will significantly reduce the requirement for redundancy in grid hardware. There is very significant opportunity to reduce the cost of rural electrification across the developing world by deploying long-life storage technologies.


Martin Wright, Chairman, has a background in entrepreneurial company development (eg. MCT) Venture Capital, oil and gas and, earlier, as a Seaman Officer in the Royal Navy. Today he is Chairman of both the UK Renewable Energy Association (the main UK trade association for renewable energy) and of Mojo Maritime Ltd, a leading marine installation and operations company focused on marine Renewable Energy.

Peter Fraenkel, Technical Director and inventor, is a chartered mechanical engineer with a background in international energy consultancy and technology development R&D, and he is also a visiting professor at the University of Edinburgh.  He was the inventor and Technical Director of Marine Current Turbines, which deployed the world's most successful tidal turbine in Northern Ireland. In 2013 Peter received an MBE for services to Marine Energy. 

Charlie Blair, Managing Director, joined Gravitricity in 2015 having been Head of Marine Energy in the Carbon Trust's Innovation Team. He is an experienced commercial leader, delivering millions of pounds of innovation funding, and has 15 years’ experience in clean energy technology innovation. He has supported numerous early-stage technology start-ups ranging from electric vehicles through to biomass heating. Charlie is a fellow of the Energy Institute and member of the Institution of Engineering and Technology. 

Niall Moffat, Director of Finance, is a Chartered Accountant and joined the Gravitricity team in April 2020. Having spent 10 years in practise, including 4 years with Ernst & Young in Bermuda, Niall has spent the last 15 years in both commercial and strategic roles within industry. 

Ruth Apps, Business Development Manager, joined Gravitricity in 2020. Ruth has 6 years of commercial experience, having worked as a consultant, business development for an innovation centre and business analyst. Ruth is responsible for the strategic management of business development activities for Gravitricity. She has a degree in Geology and an MSc in Environmental Technology (Energy Policy), both from Imperial College London. 

Miles Franklin, Lead Engineer, is a chartered mechanical engineer with 7 years experience in new technology innovation from a number of fields, including novel borehole drilling machines in West Africa and new product development at Dyson.  Miles leads the engineering team in Edinburgh, which also works with partner engineers at Huisman, the Edinburgh University Institute for Energy Systems, and various external contractors.

Richard Montague, Chief Technical Advisor, is a Chartered Mechanical Engineer and joined Gravitricity part time in December 2018. He has worked for most of his career in the marine renewables industry, developing devices for both wave and tidal power companies. He has played a leading role in taking some of that sector’s highest-profile projects from early concepts through to product delivery.

Chris Yendell, Project Development Manager, is a mechanical engineer with 9 years of experience in renewable energy project development. Having worked both on the consultant and the developer side, he has successfully delivered numerous consented onshore wind, solar and hydro power projects to the point of financial close.  Chris is currently responsible for the strategic management of project development activities for Gravitricity’s demonstration and full scale sites.

Steven Kirk, Senior Mechanical Engineer, is a Chartered Mechanical Engineer with over 9 years of experience designing and commissioning mechanical systems and structures. Steven has delivered to market a variety of leading edge mechanical systems in the offshore, space and construction industries and is currently responsible for design work on Gravitricity's 250kW concept demonstrator.

Julie Le Négaret, Mechanical engineer, joined Gravitricity in 2020. She is a graduate in Mechanical Engineering (MEng) and specialised in integrated design at the University of Technology of Compiègne (France). Julie worked previously within design & manufacturing teams mainly in the aerospace industry. She is currently working on the design of the Gravitricity's 250kW concept demonstrator.

Gavin Edwards, Senior Mechanical Engineer, has over eight years of experience specialising in the design, analysis and management of large-scale bespoke offshore handling/lifting projects, from concept through to commissioning. Gavin is currently responsible for design work on Gravitricity’s 250kW concept demonstrator. Gavin joined Gravitricity in Spring 2020. 

Frances Tierney, Engineering Project Manager. Frances is responsible for the build out of the concept demonstrator project.   She previously worked in the wave energy industry, managing complex generation technology deployments in Orkney. She is working on all aspects of the concept demo, from site-work in Leith through to liaison with fabrication works in Czechia and the UK.

Douglas Hitchcock, Project Engineer, joined Gravitricity in Summer 2020. He is a Mechanical Engineer with two years’ experience in innovative technology development in the oil and gas industry. Previously part of a small team taking a disruptive new technology to market Douglas was heavily involved with the design and testing through to managing and running commercial deployments internationally. He is currently working on the delivery of Gravitricity's 250kW concept demonstrator.


Open Roles

We are growing our engineering and commercial teams as we prepare to build our 250kW Concept Demonstrator and progress towards full-scale systems. 

We are actively working to build a dynamic, diverse team so we would like to hear from anyone who is passionate about what we are doing.  If you are interested in any of the following roles please email, with a covering letter, explaining why you are keen to join us.  All jobs are in Edinburgh and full-time roles, though any employees who want to work a 4-day week are encouraged to do so. 

Future Roles

We are always happy to hear from passionate individuals with skills that would be valuable to our projects. If you are excited about what we are doing and see ways you could contribute, you can get in touch with us at the email below, to explain how. 

Whilst we will do our best to respond to all expressions of interest, we may not manage this at busy times.

To be the first to hear about new job roles as they become available, please subscribe to our Job Alert. You will be notified by email when we advertise new roles.

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Gravitricity Ltd

Phone: +44 131 554 6966


Company Reg. No: 7827384 England 
Registered office: Regent House, 316A Beulah Hill, London, SE19 3HF

If you would like to stay up to date with Gravitricity technology developments, please subscribe to our newsletter. We expect to send updates when there is news, and roughly every 2-3 months.  Our privacy policy is available here should you wish to view it.


31 Aug 2020

Press Release - Work starts on Gravitricity's £1million Edinburgh energy storage demonstrator

This morning we released a press release that our demonstrator project is officially underway. Early pick-ups include, ReNews and The Times. 

Links and orginal press release, below.

ReNews - Work underway on Gravitricity storage demo

The Times - Gravitricity test set to add weight to energy prospect

200820 Work Starts On Gravitricity Demonstrator Final


10 July 2020

Gravitricity closes additional Seed Equity round

Gravitricity is very pleased to have raised an additional tranche of Equity in a ‘Seed Plus’ round which completed at the end of June.  Thank you to all our new shareholders, whether you have invested £10.20 or £75,000.

8 May 2020

Signing of lease with Forth Ports

Gravitricity has signed a land rental agreement with Forth Ports to build their first demonstrator project on land within the Port of Leith.

Work will begin on the £1 million project in October, on an industrial site at the Port of Leith with plans to be up and running by late December.

The 16-metre high rig will utilise the port’s extensive electrical network and grid connections and will be used to demonstrate the speed of response of their innovative energy storage system.

Gravitricity’s energy battery works by raising multiple heavy weights – totalling up to 12,000 tonnes – in a deep shaft and releasing them when energy is required. We plan to roll out our technology in disused mine shafts worldwide.

The demonstrator at the Port of Leith will allow the technology to be trialled on a much smaller scale, utilising an above ground structure. 

Commenting on the project, Gravitricity Lead Engineer Miles Franklin said:

“This grid-connected demonstrator will use two 25-tonnes weights suspended by steel cables. In our first test we’ll drop the weights together to generate full power and verify our speed of response. We calculate we can go from zero to full power in less than a second – which can be extremely valuable in the frequency response and back-up power markets

“We will then run tests with the two single weights, dropping one after the other to verify smooth energy output over a longer period. Together, this two-month test programme will confirm our modelling and give us valuable data for our first full-scale 4MW project which will commence in 2021.”

The Times May 11 2020 Gravity-powered batteries generate electricity when the wind dies down

Socially distanced Miles and Chris, Forth Ports, Spring 2020.
Socially distanced Miles and Chris, Forth Ports, Spring 2020.

30 Mar 2020

Gravitricity wins Energy Catalyst grant

Gravitricity has won a grant under InnovateUK's Energy Catalyst programme, which is supporting UK businesses when developing new technologies for energy access in Sub-Saharan Africa and Asia. 

The £300,000 grant, means Gravitricity will undertake site and project feasibility work in Southern Africa, with project partners, RESA Energy.

4th Nov 2019

Gravitricity completes successful crowdfunding campaign with Crowdcube

We ran a crowdfunding campaign in October 2019 and received a very positive response. The campaign reached its initial target of £246,000 on the first day of an intended 30 day campaign. The raise ultimately attracted investment of over £750,000 before hitting its upper limit and closing to further interest, all in the first week. Gravitricity are truly grateful for the support and are now all set to commence fabrication of our proof of concept demonstrator.

We proudly share below our crowdfunding video, filmed with some of our team at our offices in Edinburgh and the National Mining Museum Scotland by local filmmakers Melt the Fly. Please note the investment round is now closed. 

7th Oct 2019

Gravitricity selected as Finalists in  New Energy Challenge

Charlie and Miles spent a week in the Netherlands at the beginning of October after Gravitricity were selected as one of 7 start ups out of 300 entrants in the New Energy Challenge. The competition, which is jointly organised by Shell, Rockstart, YES!Delft and Get In The Ring, offered finalists the chance to exchange ideas with coaches and experts as well as validate business plans. 


03 June 2019

Gravitricity's MD Charlie Blair is speaking at the Global Entrepreneurship Summit

Charlie is speaking on energy access and green finance at the event in the Hague. 

Here is Charlie giving an elevator pitch on Gravitricity at the event. Click the image to see the video. 

Charlie Elevator Pitch


01 May 2019

Gravitricity is the Cover story in Professional Engineering magazine, the magazine of the IMechE. 

Renewables Underground - why the solution to energy storage could be right beneath our feet


01 September 2018

Gravitricity explainer animation released.

24 April 2018

Imperial College Analsysis suggests early Gravitricity projects will be cheaper than lithium for frequency response applications.

A report by independent analysts at Imperial College London predicts that Gravitricity’s gravity-fed energy storage system may offer a better long-term cost of energy storage than batteries or other alternatives – particularly in grid balancing and rapid frequency response services. 

Gravitricity's first-of-a-kind 4MW prototype system will be cheaper than batteries on a levelised cost of storage basis.  The modelling emphasizes the importance of long life and lack of degradation for revenue stacking.


News links at Business Green and Engineer News Network.  Please contact Gravitricity by email if you would like a copy of the report.

09 April 2018:  

Gravitricity shortlisted for UK's Renewable Energy Association  Innovation award and Lead Engineer Miles Franklin nominated for Scottish Renwables young Professionals award


REA shortlist here

Scottish Renewables Shortlist here

21 March 2018: 

Gravitricity teams up with worldwide lifting, drilling and subsea specialists Huisman to build prototype energy store


Gravitricity has teamed up with worldwide lifting, drilling and subsea specialists Huisman to develop the 250kW  Concept Demonstrator. Dutch-based Huisman Equipment BV are a perfect winch partner for Gravitricity and form the centre-piece of the Industrail Consortium being built to take the technology to market.  They will supply winch-drive modules for the 4MW full-scale prototype planned for 2019-20, and future systems. 

07 February 2018: 

Gravitricity awarded £650,000 funding from Innovate UK's Infrastructure Systems Innovation competition.

This innovation funding will be used to design and build our 250kW concept demonstrator, ready for testing in late 2018.  The project will be completed in collaboration with our international winch partner and with controls engineers Industrial Systems & Controls in Glasgow.  It will confirm Gravitricity's commercial characteristics, validate our simulations, and provide a physical proof-of-concept demonstration.     During 2018 the company will also develop the site and engineering designs for the full-scale prototype, planned for a UK mineshaft in 2019-20. 

Gravitricity is now raising seed funding to match the grant and would like to speak to potential investors, particularly those with power systems or mining experience.  

Plenty of press pick up: 

Times Headline Thursday 8 Feb 18

19 December 2017:

Gravitricity selected to present at CleanTech Innovate Showcase

Gravitricity ltd has been selected for the prestigious Cleantech Innovate Investor Showcase in March 2018.  Charlie Blair will be presenting details of the 250kW Concept Demonstrator and the associated investment proposition. This adds to a list of showcasing and pitching events that Gravitricity has attended in 2017, including the Greentech Challenge, Clean & Cool, and Rushlight.

See https://www.cleantechinnovate.... for a list of 2018 finalists.

10 December 2017: 

Levelised cost of Storage in the spotlight

Lazards have published Version 3 of their Levelised Cost of Storage benchmarking analysis.  This time the financial advisory firm have included capex and operating data from numerous new Lithium Ion batteries deployed since Version 1 in 2015.

The report can be accessed directly at . Lazards report various use-cases where Energy Storage projects are now cost effective, primarily behind-the-meter industrial applications and grid-support applications such as Dynamic or ‘Enhanced’ Frequency Response. Both of these require high-power and rapid response and are of interest to Gravitricity.

Gravitricity has worked with experts from Imperial College London to understand how our storage costs compare.  Our fast-response, multi-cycle technology is exceptionally well suited for any application requiring a high c-rate and several daily cycles.  As expected, our levelized cost of energy is lower than lithium ion and any other technology in the Lazard’s report for the applications we are targeting. 

Commentators have taken the opportunity to read between the lines of Lazard’s report.  Greentech Media’s observations on lithium-ion round trip efficiency are well worth a read.

Gravitricity is working with Imperial College Storage Labs to understand how our costs compare to other technologies. Results are very encouraging.

27 November 2017: 

Charlie Blair will be speaking at Energy Storage & Connected Systems in London, February 2018

Gravitricity will be presenting at the REA supported conference at London's Oplympia on 6th February 2018. He'll be speaking in the late morning session fittingly titled 'Scaling to GW; It's not just Lithium' along with speakers from flow-battery, CAES and electrolyser technology developers. 

Conference programme is available here

25 May 2017: 

Charlie Blair has been selected as one of Britain's leading cleantech entrepreneurs and will be traveling to Silicon Valley as part of the Clean&Cool mission

Clean & Cool is a UK Government supported mission for British CleanTech innovators to San Fransisco.  Gravitricity has been selected as one of the most exciting clean technology innovations coming out of the UK and will be showcased to investors and potential partners in America's capital of innovation from 10th - 17th June 2017.

See and and for updates