Energy storage technologies

With the rise of renewable energy generation in much of the world there has been a need to compensate for their intermittency.

The leading energy storage technologies of today are batteries and pumped hydro storage. Pumped hydro storage is the dominant energy storage system in the world currently.

An alternative being developed in the USA is Advanced Rail Energy Storage (ARES).

http://s3.amazonaws....ES_-_070616.pdf

Instead of pumping water up and down a hill, ARES drives trains up and down a hill.

They claim the system is cheaper to develop and deploy than pumped hydro, doesn't require water and has an efficiency of up to 78%.

My thought is that there would be more maintenance cost to ARES than pumped hydro, through wear and tear of the rails and carriages, etc.

Compressed air is also used as energy storage at the moment.

With the increase in use of electric cars and home battery packs , these can be used to stabilise the grid. Allow home owners to set a price they will sell for and when the spikes rise above this limit the grid can draw upon these reserves. Cars are already being sold with this capability.

Eventually you may find that your electric car can earn more money than you do at work.

With hybrid cars there is no problem for the owner as they can use the depleted car on petrol if necessary. A full electric car would need to be recharged when the price dropped. The more intelligence in the grid the better it should work. Allowing the owner to set times when the car can be accessed for power would be another wise option. Allowing them to state what capacity is needed at a certain time (i.e. to drive to work) would be helpful.

A home owner with enough solar generation capabilities and an electric car, should be able to be self sufficient, and also able to sell his surplus to the grid when it is needed.

Geothermal is an under used resource in most of the world and can provide the base load power when there is no sun, rain or wind for other green power sources. 

Edited by scolbourne, 25 September 2017 - 06:28.

I kinda like the idea of using big spheres at the bottom of lakes or the sea and pump the water out of them with surplus energy. Then when power is needed again, let water flow in the sphere to drive a turbine. But this is probably way to expensive to do, the maintenace only possible when the sphere is brought up or with remote robots at the ground. How long will the mechanics survive in salt water?

https://arstechnica....storage-sphere/

Compressed air is also used as energy storage at the moment.

Or KE via spinning discs.

We may not need batteries if we can create super capacitors.

Using excess electrical power capacity for something like local manufacturing of materials/goods is probably more cost effective than building large scale battery or compressed air systems for storing the excess electrical power. Consider Iceland. The country has a tiny population, and a massive amount of hydro power generating capacity. Rather than storing the excess power in battery or compressed air systems, they use it to produce aluminum from bauxite shipped from overseas.

This energy storage discussion is in itself very interesting (- I favour the hydro option) - but ultimately it is based on the Global Warming Myth. There is no need for energy storage - just build a few proper power stations - fossil-fuel burning or nuclear - but nor windmills or solar.

Pumped hydro is used for balancing supply and demand in systems with coal fired power stations already, as they can quickly respond to increases in demand whereas the coal fired power stations can't.

Using excess electrical power capacity for something like local manufacturing of materials/goods is probably more cost effective than building large scale battery or compressed air systems for storing the excess electrical power. Consider Iceland. The country has a tiny population, and a massive amount of hydro power generating capacity. Rather than storing the excess power in battery or compressed air systems, they use it to produce aluminum from bauxite shipped from overseas.

Thats ok for countries where there is a surplus at all times, but in places where they are trying to make renewables such as wind and solar give a reliable supply, some kind of storage or additional generating capacity is required.

Although frequently touted I think that using your expensive limited lifetime EV battery to earn a few dollars a day, coupled with not being able to use your car in the afternoon and early evening when electricity demand typically peaks, means that it is more of a theoretical idea than a realistic one.

If the power is needed to cover for the extra power requirements of air-conditioners, I would say that at least in the day time extra solar generation would be the best  route. In the evening after people have driven the EV's home any left over battery capacity could be made available until the batteries can be charged at cheap rate over night. 
Often it is better for batteries to be discharged (to the correct voltage) before recharging , but I do agree it would be a bad policy to over use the battery if you are not receiving an acceptable payment.

Pumped hydro is used for balancing supply and demand in systems with coal fired power stations already, as they can quickly respond to increases in demand whereas the coal fired power stations can't.

For the German market, you can see the hourly production of the different sources here: https://www.energy-c...ek=38&year=2017

If you select Hard Coal at the top, you can see that these power plants do some big ramps during the day, similar to Gas. Brown coal on the other hand doesn't react much, as it is cheaper than Hard Coal and Gas here.

For the German market, you can see the hourly production of the different sources here: https://www.energy-c...ek=38&year=2017

 

If you select Hard Coal at the top, you can see that these power plants do some big ramps during the day, similar to Gas. Brown coal on the other hand doesn't react much, as it is cheaper than Hard Coal and Gas here.

The ramp ups are over 3-4 hours, whereas hydro can do it in minutes.

Compressed air is also used as energy storage at the moment.

It may work but compressing air has to be the most inefficient system, surely. Everything i have ever learned about air and work involves lots of energy loss.

Personally i like the idea of a giant gyro or whatever they call it, with oil bearings or magnets for instance. Water turbines uses oil. I am unsure about how viable magnets are for multi ton spinners tho.

Edited by MatsNorway, 27 September 2017 - 18:49.

flywheel storage my father used to develop used electromagnetic suspension for the flywheel, in vacuum of course..

This energy storage discussion is in itself very interesting (- I favour the hydro option) - but ultimately it is based on the Global Warming Myth. There is no need for energy storage - just build a few proper power stations - fossil-fuel burning or nuclear - but nor windmills or solar.

Nothing wrong with solar especially and windmills either [provided you do not have to look at or listen to the monsters] as a second tier generation system.

Living here in the blackout state is proof of what happens if you do not have adequate base load.

We will soon  have a bit more with Green Jays diesel generators!!! And Mr Musks big battery. And reputedly only half a billion as well!  Though like many I believe it is considerably more. Plus the very intensive add campaign telling us how clever they are. With their 'green' diesel generators!

What difference would it make if every house had a solar array and a Musk home battery?

WAG - say 5 kW of installed solar per 20 people (not all houses are suitable). 5kW system gives about 7000 kWh per year, or just about 1 kW 24/7, if the battery works. So in Oz that's about 1/20*1kW*25 million, or 1 GW. So that's about the size of the Vic to SA interconnector, ie significant but not a complete solution nationally. Oz generates about 15 GW (roughly) on average.

A powerwall is what 8k, and the true cost of a 5 kW installation is say 11k, so this would cost 19k*1/20*25 million, or 15 billion dollars . For a measly half a billion ole windy brain is going to install his 250 MW fossil fuel powered generators and a 100 MW 130 MWh Tesla (which is a nice start but not big enough by a long chalk). As you can see the difference in price is enormous, mainly because of the enormous costs associated with installing a million individual systems instead of a few dozen. 

So I think the correct politically correct solution is to change the way the market operates, and insist that at some level the large renewable generators (which are currently subsidised to hell and back) team up with sufficient storage that they become despatchable (ie reliable) power. this could be done at each generating facility or else have remote storage for each generator. Also nukes. Less politically correct, I would guess that within 2 years the Feds will subsidise the construction and operation of a  fossil fuel plant of the order of 1-4GW, to compete with the subsidised renewables.

15 billion buys something like 2x1100 MW nuclear powerplants?

Oz generates about 15 GW (roughly) on average.

The NEM generates roughly 25GW.

 

So I think the correct politically correct solution is to change the way the market operates, and insist that at some level the large renewable generators (which are currently subsidised to hell and back) team up with sufficient storage that they become despatchable (ie reliable) power. this could be done at each generating facility or else have remote storage for each generator. Also nukes. Less politically correct, I would guess that within 2 years the Feds will subsidise the construction and operation of a  fossil fuel plant of the order of 1-4GW, to compete with the subsidised renewables.

The Finkel report has a recommendation that new renewable facilities have dispatchable power. ie they have their own storage.

Personally I think that is a mistake, designed just to increase the cost of renewable energy generators. Storage in the system is required, but not, necessarily, at the source. 

Always the focus is on the subsidies of renewables. Never mentioned is that the majority of them were built by state governments years ago and flogged off at bargain basement prices. And that they are subsidised themselves.

A gas plant would work if the government can unlink local supply prices from international prices. At the moment Australian gas is sold overseas cheaper than it is sold here. And if the gas is cheaper, then maybe the existing gas plants would fire up more often.

Hard to find the numbers online but I think residential accounts for about 30% of total electricity consumption. If half that was generated by rooftop solar/battery storage, you are looking at a big chunk of the NEM.

Maybe commercial premises should be looking more to solar. Most businesses operate and consume their energy during daylight (sunshine) hours.

The Finkel report has a recommendation that new renewable facilities have dispatchable power. ie they have their own storage.

 

Personally I think that is a mistake, designed just to increase the cost of renewable energy generators. Storage in the system is required, but not, necessarily, at the source. 

Probably wouldn't need to be at the source eg the requirement could be met by building a pumped hydro system some distance from the renewable generating facility. The hydro could even be large and shared by a number of renewable providers.

 I realise SA lives in the 1950s but decoupling the price of a fungible resource from world markets is a pipe dream, and a speculators delight.

 I realise SA lives in the 1950s but decoupling the price of a fungible resource from world markets is a pipe dream, and a speculators delight.

Well, at least they could buy gas at the same price as it is sold overseas.

That would be a start.

15 billion buys something like 2x1100 MW nuclear powerplants?

Probably 1 in AUD.

Maybe commercial premises should be looking more to solar. Most businesses operate and consume their energy during daylight (sunshine) hours.

Driving around, I see a lot of commercial premises with large solar arrays, 20kw plus.  Not enough, but I suspect more are starting to see the light ...

But as I think i have demonstrated, small arrays are not cost effective to society as a whole. Sure, they are cost effective to the owner, but if the same capital was spent on a large scale system society,overall, would benefit more from that capital. Yes, I'm being  a bit hypocritical, I installed subsidised domestic solar and sell electricity to the grid at a politically motivated price, whereas in theory i should have bought into a large solar farm somewhere where the sun actually shines. But the whole market is so stuffed up by grants and discounts and bribes and special rates and feel-good politics that any overall strategy is impossible to work out rationally.

I think we'll start seeing more large scale solar PV farms in the next few years, as the price of panels comes down. Some will, possibly, have battery storage also.

We may even see solar thermal installations with storage in the next 5-10 years in Australia.

This energy storage discussion is in itself very interesting (- I favour the hydro option) - but ultimately it is based on the Global Warming Myth. There is no need for energy storage - just build a few proper power stations - fossil-fuel burning or nuclear - but nor windmills or solar.

Presumably you don't like to eat fish. Either that or you also don't believe that we've tripled the amount of mercury naturally occurring in the upper ocean.

http://file:///C:/Us...rt-chapter3.pdf

so Australia has 38% of the worlds uranium and no power plants. something is wrong . we also have very stable geological sites suitable to locate them with abundant supply of preheated artesian

water to increase the efficiency .and very suitable geological stable storage sites   we should look to the French example not the Japanese one . trouble is it would Be political suicide for whatever party tried to do it .if we are serious about reducing co2 then it is very obvious.   

Edited by malbear, 29 September 2017 - 21:11.

But as I think i have demonstrated, small arrays are not cost effective to society as a whole. Sure, they are cost effective to the owner, but if the same capital was spent on a large scale system society,overall, would benefit more from that capital. Yes, I'm being  a bit hypocritical, I installed subsidised domestic solar and sell electricity to the grid at a politically motivated price, whereas in theory i should have bought into a large solar farm somewhere where the sun actually shines. But the whole market is so stuffed up by grants and discounts and bribes and special rates and feel-good politics that any overall strategy is impossible to work out rationally.

So you know how the big players in the energy market feel and why they are reluctant to push their chips onto the table.

with abundant supply of preheated artesian water to increase the efficiency   

If you take heat from another source you are not increasing the efficiency. I doubt that heat from artesian water would be useful in a nuclear-thermal power station anyway - they don't seem to be using it in coal-thermal plants.

http://www.abc.net.a...-viable/7798962

"If you take heat from another source you are not increasing the efficiency."

have you ever noticed how a kettle takes shorter time to boil if press the button  for a second time because forgot to make your cuppa 5 minutes ago.

Edited by malbear, 30 September 2017 - 03:12.

That doesn't make the second boil cycle "more efficient" - it just means you paid for extra energy from somewhere else.

Efficiency = (electricity out)/(heat in). If you increase "heat in" by adding some geothermal, you will reduce overall efficiency since "electricity out" will not increase in proportion. (Geothermal heat is lower quality (temperature) than nuclear reactor heat).

Presumably you don't like to eat fish. Either that or you also don't believe that we've tripled the amount of mercury naturally occurring in the upper ocean.

Whether this Hg problem is real or just another load of crap from the lefties/greenies - I don't know. But the fact remains that the amount of coal we would burn to make a bit of electricity is a drop in the bucket on a world scale. Do we really want to ruin the economy etc. for no real reason?

Does natural gas have Hg?

Much less Mercury in gas than in coal.

Of course it has to be "lefty crap" if it doesn't agree with your 19th century world view.

Ruin the economy? The line that right wingers come out with, makes it sound like we serve the economy, not the other way around. In any case, there are doubtless benefits to the economy if new technologies are embraced.

And yes, we are but a small amount of greenhouse gas emitters - but so are the majority of countries. Only a dozen countries, or so, emit more greenhouse gas emissions than we do. 

And yes, we are but a small amount of greenhouse gas emitters - but so are the majority of countries. Only a dozen countries, or so, emit more greenhouse gas emissions than we do. 

That weak argument is used over in the States as well. "Well, China and India are going to keep building coal plants, why should *we* do anything???" As if nobody has responsibility for their own pollution ...

Armchair dwelling theorists seem to think it is ok to export jobs to India and China (which is the outcome of transitioning to a low carbon economy) but have yet to identify real effective  mechanisms to deal with the consequences.

Armchair dwelling theorists seem to think it is ok to export jobs to India and China (which is the outcome of transitioning to a low carbon economy) but have yet to identify real effective  mechanisms to deal with the consequences.

Hasn't that happened already? Before transitioning to a low carbon economy?

To some extent, but now any energy intensive industry will face a huge competitive disadvantage if it wants to operate in a sanctimonious economy. Alcoa didn't leave Oz because of the high wages.

This is why carbon trading is a good idea. Australia produces a large amount of CO2 in refining ores which are then exported to other countries. In a similar way China  produces a large amount of CO2 manufacturing goods that are then exported to other countries.

It should be the final customer who has to pay for the CO2 produced over the whole manufacturing/shipping process. Countries like Iceland can produce electricity using geothermal power stations with little CO2 output and need to be given credits for this , to encourage more use.

I expect in the future we will have an electric grid using super-conducting cables, circling the world (could be close to the arctic to reduce length and help with cooling) so that solar can be used 24hr and electricity is available where needed.

Armchair dwelling theorists seem to think it is ok to export jobs to India and China (which is the outcome of transitioning to a low carbon economy) but have yet to identify real effective  mechanisms to deal with the consequences.

This argument applies to any "sanctimonious" law. I rather appreciate the rules against child labor, for example.

It is acknowledged that governing is hard.

In the industry I'm involved in, transportation pipelines (such as for oil and gas), there is talk of converting excess electrical energy to hydrogen gas for storage (e.g. in depleted gas fields) and distribution - via pipelines of course.

I wonder, what would be the efficiency of such a system: conversion loss, transit loss, etc. Anybody any idea?

Jan.

Depends what process you use for the hydrogen bit. You will be amused to learn that most  commercial hydrogen is made from methane. Electrolysis seems the obvious approach, at first sight, that's about 4% of the market. Efficiency is an eye watering 70% or so (better in lab experiments, worse in industrial). 

 . . . and I think that might be just the production efficiency. Converting the hydrogen back to electricity is also fairly inefficient. It all makes pumped hydro look pretty amazing.

The "win" for hydrogen storage is the small scale portability and energy density (for automotive applications)

On board fuel cells working from gaseous hydrogen are about 80% so far as I can tell. This situation is rather like wind energy and solar power, if the input energy is widely available and nowhere near saturation, then traditional engineering measures of efficiency become less important., You really want to be talking about costs not efficiency. A cynic might argue that's why we have brown coal generators.

On board fuel cells working from gaseous hydrogen are about 80% so far as I can tell. This situation is rather like wind energy and solar power, if the input energy is widely available and nowhere near saturation, then traditional engineering measures of efficiency become less important., You really want to be talking about costs not efficiency. A cynic might argue that's why we have brown coal generators.

I guess that's the point. With excess power from the wind/solar the wholesale price of electricity goes very low. And electrolysis becomes a more cost effective way of producing hydrogen.

Yes, hydrogen gas is a storage medium not an energy source, a concept that some politicians seem to be deaf to.

Trouble is that it isn't a very nice storage medium. Not awful, just fussy. Your pipeline, valves etc need a lot of care.All solvable, just hassle.

If we take the path solar->hydrogen->distribution->service station->fueltank->fuelcell->EV (don't let them fool you, you still need a few kWh battery bank on an FCV)

compare the costs and efficiencies with

solar (+backup batteries)->HVelecticity->distribution->transformer->mains charger->EV

WAG you'll need roughly twice as many solar cells for a hydrogen distribution system. It will however not need batteries for the grid (a big saving), and you could run fuel cells or generators off the hydrogen to provide backup power (that would be fairly daft given the effective cost of the hydrogen). So, when we coat the deserts in PVs this actually might be a sensible scheme.