Green Electricity Storage Concept

[exchemist]

We all know one of the limitations of renewable electricity generation is the intermittent character of much of it: the sun doesn't shine at night, the wind doesn't always blow, and so on. So a lot of work is going into storage systems: batteries, flywheels and pumped storage.

This last one works by using surplus electricity to pump water up from a low reservoir to a high one. When there is a deficit of electricity supply, the water can run back down, converting the pump into a turbine and providing extra electrical supply. Essentially, electrical energy has been converted to gravitational potential energy, and can be turned back to electrical energy again later.

The limitation is often lack of locations with sufficient height difference to provide the head of water needed to run a turbine efficiently. Now, however, there is a new idea, in which minerals are suspended in the water to increase greatly its density, up to 2.5 times that of water itself. This greatly concentrates the energy storage, since for every cubic meter of fluid lifted through a given height, 2.5 times as much work is done and so 2.5 times as much energy is stored.

This enables either smaller reservoirs, for a given storage capacity, or smaller height differences to become viable. This last possibility could make it feasible to make use of relatively small changes in level in a local topography, vastly increasing the scope of pumped storage.

There is an article about it here: Powering up: UK hills could be used as energy 'batteries'

Inevitably, the journalists get it a bit wrong (the steepness of the slope is irrelevant), but the basic idea is very interesting, I think.

(However I'd like to know more about this fluid, how stable the suspension is, what pollution risks it might entail, etc, etc.)

Anyway I thought it was worth sharing. We need all the ideas we can get........

 

[Revoltingest]

That's an amazing density increase.
I wonder how the mineral content
would affect component life.

 

[ChristineM]

That's an amazing density increase.
I wonder how the mineral content
would affect component life.

Trust you to ask that, i was going to say the same thing... Oh my oh my, I'm turning into an engineer...

I think the more dense water/minerals the more wear and tear on bearings etc. But maybe be more efficient than using standard water and bigger hills with more equipment /pipes

 

[Revoltingest]

Trust you to ask that, i was going to say the same thing... Oh my oh my, I'm turning into an engineer...

I think the more dense water/minerals the more wear and tear on bearings etc.

It's like we share one....

 

[Nakosis]

 

[Polymath257]

I wonder about that increase in density. if heavy metal ions are used in some way, that could be very bad for the environment, let alone potentially costly. Details would need to be investigated.

 

[JoshuaTree]

Couldn't this be done better with red mercury?

 

[Valjean]

Besides a gravitational potential, there's also heat -- energy's lowest common denominator. Focus sunlight during the day on a reusable container of liquid with a high coefficient of heat, and use the stored energy at night to run electrical turbines.

Of course, with geothermal, wave or tidal energy generation, all these day/night problems would be eliminated.

 

[Subduction Zone]

That's an amazing density increase.
I wonder how the mineral content
would affect component life.

And the clean up problems if it leaked.

 

[Brickjectivity]

We all know one of the limitations of renewable electricity generation is the intermittent character of much of it: the sun doesn't shine at night, the wind doesn't always blow, and so on. So a lot of work is going into storage systems: batteries, flywheels and pumped storage.

This last one works by using surplus electricity to pump water up from a low reservoir to a high one. When there is a deficit of electricity supply, the water can run back down, converting the pump into a turbine and providing extra electrical supply. Essentially, electrical energy has been converted to gravitational potential energy, and can be turned back to electrical energy again later.

The limitation is often lack of locations with sufficient height difference to provide the head of water needed to run a turbine efficiently. Now, however, there is a new idea, in which minerals are suspended in the water to increase greatly its density, up to 2.5 times that of water itself. This greatly concentrates the energy storage, since for every cubic meter of fluid lifted through a given height, 2.5 times as much work is done and so 2.5 times as much energy is stored.

This enables either smaller reservoirs, for a given storage capacity, or smaller height differences to become viable. This last possibility could make it feasible to make use of relatively small changes in level in a local topography, vastly increasing the scope of pumped storage.

There is an article about it here: Powering up: UK hills could be used as energy 'batteries'

Inevitably, the journalists get it a bit wrong (the steepness of the slope is irrelevant), but the basic idea is very interesting, I think.

(However I'd like to know more about this fluid, how stable the suspension is, what pollution risks it might entail, etc, etc.)

Anyway I thought it was worth sharing. We need all the ideas we can get........

I was sad to hear that in-ocean turbines have turned out to be somewhat expensive. I always did wonder how those could be kept in good repair. Apparently the answer is with money.

Have you heard of the energy systems that can store energy as momentum in revolving cylinders? Its not very cheap but is more energy dense than some of the systems currently in use. You pump a vacuum into a chamber and spin a heavy cylinder, and you can store energy that way.

The limitation is often lack of locations with sufficient height difference to provide the head of water needed to run a turbine efficiently.

Any chance the locations could be increased using lined wells or human fashioned underground reservoirs? Too expensive? It seems that the important thing is the relative height, so if you don't have a reservoir perhaps you can create one underground or perhaps a connected system of deep chambers to store the water. Or I just like hearing myself type.

 

[sayak83]

We all know one of the limitations of renewable electricity generation is the intermittent character of much of it: the sun doesn't shine at night, the wind doesn't always blow, and so on. So a lot of work is going into storage systems: batteries, flywheels and pumped storage.

This last one works by using surplus electricity to pump water up from a low reservoir to a high one. When there is a deficit of electricity supply, the water can run back down, converting the pump into a turbine and providing extra electrical supply. Essentially, electrical energy has been converted to gravitational potential energy, and can be turned back to electrical energy again later.

The limitation is often lack of locations with sufficient height difference to provide the head of water needed to run a turbine efficiently. Now, however, there is a new idea, in which minerals are suspended in the water to increase greatly its density, up to 2.5 times that of water itself. This greatly concentrates the energy storage, since for every cubic meter of fluid lifted through a given height, 2.5 times as much work is done and so 2.5 times as much energy is stored.

This enables either smaller reservoirs, for a given storage capacity, or smaller height differences to become viable. This last possibility could make it feasible to make use of relatively small changes in level in a local topography, vastly increasing the scope of pumped storage.

There is an article about it here: Powering up: UK hills could be used as energy 'batteries'

Inevitably, the journalists get it a bit wrong (the steepness of the slope is irrelevant), but the basic idea is very interesting, I think.

(However I'd like to know more about this fluid, how stable the suspension is, what pollution risks it might entail, etc, etc.)

Anyway I thought it was worth sharing. We need all the ideas we can get........

If the costs work out, then go for it. Leakage concerns need to be handled though. Also sedimentation may be a concern.

 

[exchemist]

Besides a gravitational potential, there's also heat -- energy's lowest common denominator. Focus sunlight during the day on a reusable container of liquid with a high coefficient of heat, and use the stored energy at night to run electrical turbines.

Of course, with geothermal, wave or tidal energy generation, all these day/night problems would be eliminated.

I'd have thought the problem there would be getting a sufficiently high temperature for Carnot efficiency not to make it very inefficient.

 

[Heyo]

There is much fluff in this new industry. Some projects are just fraud:

 

[exchemist]

If the costs work out, then go for it. Leakage concerns need to be handled though. Also sedimentation may be a concern.

Indeed. It seems to be a proprietary material from this outfit:https://www.rheenergise.com
They give zero details of the composition or stability and, to be honest, having looked at this website, it all seems a bit scammy.

But I do know that drilling muds used in oil well operations can have densities of this order of magnitude. I think they use mainly bentonite clay, sometimes with added BaSO4 (which is famously inert enough to ingest) to increase density. What I don't know is whether these materials would tend to settle out if left in a storage reservoir for some days or weeks. I suppose one might be able to overcome that by some sort of circulating pump in both reservoirs, to stop this happening.

 

[exchemist]

There is much fluff in this new industry. Some projects are just fraud:

True.

This one sounds good in principle. The issues, as ever, will all be in the practical details: what the fluid is, how stable and inert it is, what it costs, how one would deal with any spills, and so on. Frustratingly, there are no details on any of that.

 

[Secret Chief]

The glaring need.

'Invisible killer': fossil fuels caused 8.7m deaths globally in 2018, research finds

 

[WalterTrull]

Interesting post, interesting ideas. I don't think anyone has come up with a super practical solution to storing energy, but I'm sure someone will. Chemical or bio solutions seem interesting. I'm thinking a more practical solution might have to do with distribution networks. Seems to me the sun is always shining somewhere. Current technology probably not there yet. Monster satellites really impractical. Be interesting to see what eventually works out.

 

[exchemist]

The glaring need.

'Invisible killer': fossil fuels caused 8.7m deaths globally in 2018, research finds

Haha, yes I saw this too and thought there must be something wrong. Sure enough, in spite of the make-your-flesh-creep headline, the effect on life expectancy is to shorten it by one (1) year.

The other thing about this is it singles out fossil fuels, but actually burning any fuel of any sort produces pollution with adverse health effects. I remember reading years ago about the terrible effect on people's health from wood fires and cow dung fires. And even burning hydrogen will produce NOx unless countermeasures are taken.

So what's going on here? People are not immortal, so they will die of something in the end. It looks to me as though this study has attributed a combustion pollution component to whatever medical condition finally carries off a lot of people. But if we all stopped using all fossil fuel tomorrow, life expectancy would only go up by 1 year.

So, yeah, it would help - so long as we did not burn anything else in its place, but it is not going to be transformative.

 

[Secret Chief]

Haha, yes I saw this too and thought there must be something wrong. Sure enough, in spite of the make-your-flesh-creep headline, the effect on life expectancy is to shorten it by one (1) year.

The other thing about this is it singles out fossil fuels, but actually burning any fuel of any sort produces pollution with adverse health effects. I remember reading years ago about the terrible effect on people's health from wood fires and cow dung fires. And even burning hydrogen will produce NOx unless countermeasures are taken.

So what's going on here? People are not immortal, so they will die of something in the end. It looks to me as though this study has attributed a combustion pollution component to whatever medical condition finally carries off a lot of people. But if we all stopped using all fossil fuel tomorrow, life expectancy would only go up by 1 year.

So, yeah, it would help - so long as we did not burn anything else in its place, but it is not going to be transformative.

I hope we're travelling in the right direction. I come from an area where, until the clean air act, you couldn't actually see the city on week days. And there was an in-situ dedicated government agency (as we'd call it now) that was concerned solely with lung diseases (my mother worked there; I remember once seeing some lungs in a formaldehyde jar). If anyone didn't die from a lung disease (dirty industries) they probably died from an RTA - because they couldn't see the bus that hit them.

 

[exchemist]

I hope we're travelling in the right direction. I come from an area where, until the clean air act, you couldn't actually see the city on week days. And there was an in-situ dedicated government agency (as we'd call it now) that was concerned solely with lung diseases (my mother worked there; I remember once seeing some lungs in a formaldehyde jar). If anyone didn't die from a lung disease (dirty industries) they probably died from an RTA - because they couldn't see the bus that hit them.

Yes, that was in the era of domestic coal fires. Now almost everyone has natural gas (methane) heating, which produces hardly any pollution, apart from the inevitable CO2. So we have made huge strides since the 1950s. Those pea-souper fogs could take decades off people's lives, rather than a year. But then almost everyone smoked cigarettes in those days too - and a lot died early of lung cancer or chronic respiratory diseases brought on by it. Basically smoke and exhaust from burning, of any kind, is not great.

It gets better each year. Modern vehicles have for some time been fitted with particulate traps as well as exhaust catalytic converters. But I still find the glass-topped table in my garden in S London gets filthy. Leave it a couple of days in summer and, when you wipe it, the cloth picks up streaks of black. I'm breathing that every day. But in the family house in rural Brittany, the outside table stays completely clean - apart from bird s***.

Once we have converted road transport to electricity, the next thing will be tyre and brake pad dust: Pollution warning over car tyre and brake dust

So it's a never ending process.