Energy

Waterless high-density hydro makes more energy from less elevation

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More hydro energy storage using less fluid, less infrastructure and lower elevations
RheEnergise
More hydro energy storage using less fluid, less infrastructure and lower elevations
RheEnergise
The dense, heavy fluid shrinks the size of hydro installations, or generates 2.5 times more power using existing facilities
RheEnergise

UK company RheEnergise is quietly rolling out an interesting new approach to pumped hydro energy storage, aiming for a capacity of at least 100 MW by 2030. It works with small hills instead of mountains, making it relevant in many more areas.

It's one of the simplest and lowest-tech ways to store energy and then recover it on demand: use cheap energy during the day to pump a bunch of water up a big hill into a tank, then release it slowly at night, letting gravity do its work and running a turbine to generate energy as and when you need it.

But RheEnergise has added a simple tweak: it doesn't use water. Well, not by itself. It uses a proprietary "high-tech fluid" it calls R-19, which it says is both environmentally neutral and 2.5 times as dense as water.

The result: you can generate the same power from just 40% of the elevation change, using tanks just 40% of the size. That "dramatically" cuts down on materials and installation costs – and thus energy storage costs – and since the tanks are so much smaller, they're often able to be buried underground.

So what is this R-19 fluid? Well, it's a secret sauce, so RheEnergise isn't saying. But we do know it ships as a powder that's added to water to form a pasty-looking high-density goop. And the company says it's "ultra-cheap."

The dense, heavy fluid shrinks the size of hydro installations, or generates 2.5 times more power using existing facilities
RheEnergise

Individual projects are designed to feed between 10 and 50 MW of energy back into the grid on demand, and since you don't need such a big hill to make it work, it could play a significant role in the renewable energy transition, storing bulk power that can be released to cover daily, weekly or even seasonal renewable energy shortfalls.

RheEnergise has just signed an agreement with fellow UK company Mercia Power Response, aiming to deploy 100 MW of R-19-driven energy storage by 2030 at Mercia's existing grid connections and planned installations.

RheEnergise says it's identified more than 6,500 potential sites in the UK alone, and that its solution costs less than lithium-ion "big battery" projects – although in lithium's defense, batteries will certainly have a higher instant output power, making them much better for load peak smoothing. Slower technologies like this one will shine in longer-duration storage, when it's time to deliver reliable base load power in bulk.

Check out a short video below.

Source: Mercia Power Response via the consistently excellent Recharge News

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14 comments
Buk
Let's see. Medium sized (hills not mountains) pump efficiency ~75%. Medium-sized hydrogenerator (say:Pelton wheel) efficiency: ~75%. Round trip using water ~56%.

But...heavy fluids are also viscous fluids and (https://www.pumpsandsystems.com/what-drag-effects-fluid-viscosity-centrifugal-pumps) viscous fluids "dramatically reduce a pump’s efficiency".; maybe cutting it by half.

So, medium size tank at top of hill; ditto at bottom; large bore pipes (to reduce drag effects of viscous fluid); large volume of (proprietary) fluids and maybe 35% round-trip conversion efficiency.

For the same price of infrastruture dig a shaft; put a big wheel at the top; hang a big iron weight on a hawser wrapped around the wheel; add a motor/generator. No pipes, pumps or turbines to get gooped up. Minimal land area requirements. And 95%+ round trip energy conversion efficiency.

And hey. There may even be a local redundant coalmine shaft already dug.
The Doubter
@Buk, you have a point. Viscous fluids will be lossy. And you cannot have 40% less of both - elevation and volume. But a weight hung on a wheel is quite impractical. You can store approximately 0.1 MWh energy if you hang a 100 ton mass in a shaft 400 m deep, and that too considering no losses.
DaveWesely
Oi, and how much will a million gallons of this stuff cost? A million gallons of water is practically free. How much is the container compared to the cost of a man made pond? (No doubt a lot more.) It only takes 250 gallons of water to provide a ton of mass. A ton of rock costs $50. ($200,000 for the weight equivalent of a million gallons of water.) More than double that for iron, Buk.
We have plenty of places for conventional pumped hydro. It's cheap and easy. It just needs to be developed.
windykites
Buk, check out Gravitricity. They are doing what you suggest!
How about using mercury? Very dense! 13.5 times denser than water! I know, not practical, because it is poisonous. Think how small you could make a unit.
David F
Mercury is around 14x as dense as water. If there's enough Hg available, perhaps it'd make for a storage system to fit inside a tall building.
Twisted Hydro Concepts
I have something much better. Currently using three quarter inch PVC tubing for a small scale prototype.
To turn the little micro hydro generators I bought on Amazon for that size I need 20 ft of 3/4 in tubing using just gravity.
Doing it my way I can scale those down to 6 inches for the exact same power output.
quasi
PFAS were once thought to be "environmentally neutral" until they became not. Let's be constructively skeptical of such "secret sauce" claims until we know what they entail, lest we embrace another disappointing panacea.
byrneheart
Secret recipe liquid.
What's the bet this means highly toxic
zort
Good lord! Put a volume control on these videos--or at least a mute button!!
Trylon
I would be more inclined toward a hybrid pneumatic-hydraulic approach. Seal the upper reservoir and inject compressed air above the water. Open the valve to release the water through the turbine, getting energy from both gravity and compressed air. Basically the principle behind the bottle rocket.