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  • Writer's pictureClare Nasir

Hydro Reinvented. Why Size Matters

The novel Energy Storage Solution that’s winning the hearts of investors

Subtitle of article - The Holy Grail of Energy Storage Photo - Green Hills
The Holy Grail of Energy Storage

There’s an undeniable buzz around energy storage solutions. As the world shifts towards renewables, the need for efficient and reliable ways to balance out the intermittent nature of these energy sources grows.

Battery storage in particular has seen a significant rise in the last few years with an inspiring wealth of new businesses producing smart solutions.

The benefits include,

  1. reducing the strain on the grid, during peak times, and so lowering energy costs for everyone,

  2. improving the reliability of the grid (important during blackouts),

  3. and with greater integration of renewables, greenhouse gas emissions are lowered as the need for fossil fuel-powered backup generators becomes secondary, or better still, supernumerary.

Against this blossoming landscape RheEnergerise was born.

They have produced a theoretically simple yet cleverly practical solution that is piquing the interest of numerous investors.

Their timeline, punctuated by astute decision making, is paving the way to pretty much guaranteed success.

Mission Driven Leadership

CEO and founder Stephen Crosher has decades of experience under his belt. Ten years in the renewable energy industry, 5 years developing innovation and policy, and 15 years in architecture and design.

He has an impressive track record in disruptive thinking and innovation, bridging the gap between policy, innovation, technology, the public and finance.

I interviewed him for the latest episode on the Cultivating Conversations podcast. Straightaway I was drawn to his engaging intelligence and obvious passion for the sector. He has a brilliant way of clearly relaying a lot of information; often tinged with an infectious charm.

A leader who understands the market and all its permutations; one of many reasons why the company’s crowdfunding exercise was so fruitful (more about that in a moment).

Cue their High Density Hydro®

Reinventing the (Water) Wheel

Like a text book 30 second back-of-an-envelope pitch, Stephen explained how he and CTO, co-founder Tamás Bertényi created their alternative energy storage solution. It’s based on the engineering of hydropower; a tried, tested and clean way of generating electricity that has stood the test of time.

Info slide - Global Hydropower
Global Hydropower, an established energy source

We knew that pumped hydro was 95% of the world’s energy storage by capacity. Stephen commented, and by duration, or total energy stored, it was well over 99% and still is.

And so the question we asked ourselves,

Why are all these commentators saying that this very mature technology is a solution for the past, but it’s not a solution for the future?

So they looked into why that was the case. The main reason was water abstraction and lack of available sites.

Hydropower fleets require significant elevations, so their location is limited to the largest hills or mountainous regions.

The time it takes to consent and construct such large projects are far longer timescales than the climate crisis demands.

High School Physics

By replacing water with a high density fluid, either the elevation can be lowered or the volumetric size of the project. This allows for many more siting opportunities. Both reductions are proportionate to the increase in density.

The density of their fluid is two and a half times that of water and so the vertical elevation can be reduced by up to 60%. A 200 metre installation with their high density hydro system produces the same performance as an equivalent 500 metre water project.

The concept is simple.

At times of low demand, when energy prices are low, the High-Density Fluid R-19™ is pumped to the top storage tanks.

Diagram of Storage Tanks
The high density fluid allows for significant reduction in project size or elevation

As demand goes up and energy prices rise, their HD Fluid R-19™ is released, passing through turbines and regenerating electricity to supply power to the grid.

No Need to Climb a Mountain

Bringing an engineering blueprint to life, that on paper works like a dream, takes a very high level of skill, experience, knowledge; call it what you will — in today’s world where the global climate is tipping out of balance, solutions need to be time-critical.

Challenges that are being overcome.

Deployment is faster due to the smaller size of the installation and the choice of location is far greater; all they need is a hill. So more opportunity to position pumped storage sites close to the grid, the road network or co-locate with renewables.

Stephen has suggested that whilst a traditional hydro system takes up to 15 to 20 years to be consented and constructed, for their high density hydro storage project it’s a matter of years; making an important difference to the energy transition.

Testing the Market

After early government funding they decided to crowdfund. A shrewd way to test interest in their business as well as to raise further cash. For such an funding initiative the timeframe is very predictable which has huge decision making advantages.

The great thing about crowdfunding you’re very much in control of the timing. It is quite a lot of effort, but once you start in that process, from the day you start it to roughly five months later, you’re have the money in the bank, or you would have failed to get it.
… it means that you can get on with running the business and and get on with the next stage of that development, rather than having to hunker down.

Their strategy paid off.

Building a Global Business

Stephen has hired an impressive set of highly qualified industry professionals. They have six PhD’s and two MBA’s in their team of twenty.

The business is located in Montreal, Canada and London, UK. Countries with forward thinking energy policies and on the doorstep of Europe as well as the US.

They are targeting beachhead markets with grid issues, such as in South Africa as well as mining companies. Ultimately their biggest aim is to co-locate with renewable energy projects, a natural place I sense for their High Density Hydro®.

Innovation in gravity energy storage may be happening across the world yet only RheEnergise are utilising a high density fluid model as a scalable and cost-effective energy storage solution.

Each step to success, including being armed with a good data room, have now propelled them into Series A funding rounds.

All the elements are there for excellent returns.

Timing is Everything

The interest has been phenomenal, Stephen remarks, clearly delighted.

If we had started ten years earlier, we probably wouldn’t be any further forward than we are now, because the market was just wrong.

The technology was just not needed. The need is here in some markets now and in many, many more markets in three to five years, and then across the world ten years time, so the need is very much upon us.

It’s a tidal wave of opportunity for us as a business, and it’s just beginning to take off.

It’s a super exciting time.

Timing is everything.

In October 2022, BloombergNEF predicted the global Energy Storage Market growing 15-Fold by 2030 and likely to be worth $620B by 2040.

Whilst last year Wood Mackenzie forecast the global energy storage market to reach 500GW by 2031.

Statistics for Global Energy Storage Market Outlook
Wood MacKenzie Projections of Global Energy Storage Market

I learned much more during my podcast conversation with Stephen, including plans to partner with companies that supply otherwise unwanted benign materials for the production of their high density fluid; a smart way of igniting circular economy strategies.

Adam Small, Head of CleanTech, Chaseman Global

The journey to success for RheEnergise was realised many years before, as Stephen and his talented team worked their way along many career pathways. The experience they accrued through the past decades has allowed them to make shrewd business decisions and develop their Pumped Energy Storage System. Bringing the brightest minds together on this project not only injects a higher level of future success, it allows them to confidently navigate the current unchartered waters as we all push towards net zero.

Congratulations to Stephen, Tamás and their team. We will watch with interest, wishing them every success.

Cultivating Conversations is a Life Sciences podcast produced and hosted by Clare Nasir.

More in the series can be found at

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