Powering up: UK hills could be used as energy 'batteries'

[Harry Bloomfield, Esq.]

Tim Streater has brought this to us :

9.1 GWh

[John Rumm]

RheEnergise is bringing innovation to pumped hydro storage. We call our new solution High-Density Hydro ?.

The slope is not really of much interest - it's the height difference and the total mass of liquid that matters when determining the storage capacity.

The pipe cross section has no effect on capacity, but does affect power output - since it dictates the rate at which you can move a mass of fluid.

As usual (its the guardian, so what do you expect!) they seem to confuse energy and power (i.e. talking about MWh and MW in the wrong contexts)

So for example in the UK our main pumped hydro stations have a total storage capacity close to 30GWh, but a maximum power output of about

3GW. So in theory could provide 3GW of power for about 10 hours. (in reality is not quite that good since not all of the stations have the same ratio of capacity to power output).

[Brian Gaff (Sofa]

I don't know but where is the actual point? It is presumably that it will take up less room. So what do we know that is heavier by volume than water? Obviously not mercury if its benign, and one supposes does not evaporate either. Brian

[Brian Gaff (Sofa]

Yes but they say hydro, so if its not water how can it be hydro, and who would want this stuff running around on our lovely country hillsides anyway? Does this also mean that things that sink in water will float in this stuff? As I say the only saving I see is in the space needed to store it. Brian

[Brian Gaff (Sofa]

I don't think they are disputing that, its the actual mas vs volume that they are talking about. Everything I know that is heavy is certainly not benign, so what exactly is it? Brian

[Brian Gaff (Sofa]

Is it moreviscous though? Does it have to be? I wonder if it freezes like water does? That could be embarrassing on a day like today, sorry guv our battery is now an ice rink. Brian

[Tim Streater]

Depends whether the stuff expands when it freezes (like water) or not.

[Brian Gaff (Sofa]

Yes you could though get a better rate of power generation from the same size plant using a heavier fluid, as long as it was no more viscous, if it was then the power would plummet due to friction and various other losses. Brian

[Clive Arthur]

Figures from BBC article...

'Bigger than Olympic swimming pool'. Say twice as big, so 5000 m^3

'2.5 x density of water' so 12500 T or 12.5E6 kg

'200m high' so 200 * 12.5E6 * 9.81 joules = 24.5E9 J

/3600 = 6.8 MW-h

'700 sites around the country' so 4.77 GW-h

Is that right?

They claim '7 GW' presumably meaning 7 GW-h, so you'd need to make them bigger, or higher, or denser, or increase g, and no account taken of losses. But like all good schemes for attracting investment, within the realms of credibility, just.

Wouldn't fancy being in the village at the bottom of the hill when the pool breaks.

[Robin]

" Chief executive Stephen Crosher told Professional Engineering that the liquid is a fine-milled suspended solid in water, with low viscosity and low abrasion characteristics. The base material is used in oral medication applications, in a similar way that chalk is used as a bulking agent for pills and tablets. He said the raw materials are common and available, including in the UK, and the fluid could either be manufactured on-site or at a depot. "

[williamwright]

I never had any energy at all in PE.

Bill

[Fredxx]

I assume it is an inorganic salt, perhaps a solution of an iron compound such as Iron(II) Bromide which is very soluble but can't find any details of SG for a soltuion.

[Clive Arthur]

<snip>

Mind you, swimming would be a doddle.

[The Natural Philosopher]

Golly a whole planet! That's ambitious!

[S]

I'm sure Elon will lend you a extra heavy lift rocket to you!!!!

[Steve Walker]

It was supposed to be the Fairey Rotodyne - which actually first flew in

1957.

A clever idea. A large gyrocopter, using tip jets to power the rotor for vertical take-off, hovering and vertical landing. However, incredibly noisy and totally unsuitable for populated areas.

[Andrew]

[Andrew]

They could mount the land-based windmills on giant concrete 'sleds' running on rails. When it is windy the sled moves itself up the incline and then has the capability to generate power as it runs back down again ? :-)

Andrew

[Tim Streater]

Didn't I see a report about a US scheme that involved storing energy by having a railway line going up a long slope (few miles IIRC) and allowing trucks with

20 ton blocks of concrete on to roll down the hill to generate volts as they went?

[The Natural Philosopher]

I think that was powered by pixie dust and unicorn farts.Do they really think that engineers haven't considered all this years ago?