Grid scale energy storage

[photoengineer]

Any thoughts on whether we will see widespread adoption of grid scale energy storage systems? These are most typically batteries, but can also be pumped water or liquid air or compressed air.

Any ideas as to which companies have the most promising engineering solutions?

Cedar Bluff Engineering

http://cedarbluffengineering.webs.com

 

[dgallup]

I guess it depends on what you mean by widespread. Duke Energy has been using pumped storage around here for over 40 years. You need mountains with rivers to dam up so it doesn't work everywhere.

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[cranky108]

We don't store energy, however we do schedule water through the hydro units to follow human activity. Sort of a storage.

We also have large storage piles of almost pure carbon.

 

[dpc]

There are no promising energy storage solutions that are anywhere close to practical widespread application at the grid scale at this point. I think most logical next step would be small-scale storage at the local level. But nothing that will have a significant impact on the grid.

Mostly just fertile ground for EE PhD students to get grant funding....

 

[cranky108]

The problem with most battery storage is the heavy metals used in the batteries. This can become an enviromental problem.

Pumped hydro, besides being site specific, also seems to irritate enviromentlistis because of the fish issue (We use run of the pipe hydro, from fish-less lakes).

There is also possible hydrogen storage, with fuel cells.

But all of them suffer the same problem in that the losses from input to output is about 50%. So the energy you use to store with must be about 50% cheeper than what you get for it on the output.
Good luck in finding that spread in energy prices.

 

[cswilson]

From the (limited) research I've done, pumped hydro is the only remotely economical storage today. Batteries, flywheels, hydrogen, etc. are far too expensive, with only modest improvements in sight. Even with pumped hydro, you need to pump up with cheap power (usually at night), because what you get out of it is much less than you put in. Plus, you need mountains, and to overcome objections of environmentalists.

 

[dpc]

Pumped storage implies dams - but the trend is to remove dams, not build new ones, at least around here. But the fusion reactor is just around the corner, so power will soon be too cheap to meter.

Actually, hydraulic fracturing seems to creating a lot of stored energy these days. So much that we have to flare off massive amounts in N. Dakota because we don't have any way to ship it.

 

[racookpe1978]

The problem with most battery storage is the heavy metals used in the batteries. This can become an enviromental problem.

True, but even the newest rechargeable batteries fail after only a few years, and each failed cell must be uniquely identified in its bank or sub-assembly, pulled out, replaced, and the unit re-inserted. A big job, because then each of the individual failed cells needs to be recycled and replaced as a new cell. At least the old, old wet cell lead batteries (and their phone company dry cells) had a longer useful life.

Like wind turbines - only possible because of the tax write-offs and bribes 9er, incentives to green manufacturing companies run by democrats, and extra rate hikes to green companies run by democrats - grid storage is not economical with anything known today except pumped storage. Besides, the funding incentives for wind turbines only cover fabrication and installation!

There is no money for routine maintenance, none for repairs, none for long-term maintenance; and NOBODY (in Washington, CA, OR, or elsewhere where they've been installed is interested in making sure that there ever will be. The will begin failing within 7 years of startup, and we will not see them continue even at their current 17-19% worldwide service factors.

Pumped storage is a good idea, but as pointed out, pumped storage has been opposed "environmentally" since the first construction outside of Niagara Falls back in the 1960's and 1970's. You need an extraordinary combination of geology, river conditions, lake sites, and service needs and power pricing to make it pay.

 

[waross]

http://en.wikipedia.org/wiki/List_of_pumped-storage_hydroelectric_power_stations

There is more pumped storage out there than I had imagined.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dgallup]

Interesting list but I can certify it is incomplete Bad Creek is just one part of Duke Energy's pumped storage chain. Lake Jocassee was built decades before and is between Bad Creek and Lake Keowee where they have a nuke plant. Before Bad Creek was built, Jocassee could go up and down 6 ft a day. This made it a little tough on inexperienced recreational boaters. Beach your boat in the morning and come back in the evening to find it a long way from the waterline. Beach it in the evening, camp overnight and find it floated away before morning if you didn't tie it up. You usually only made these mistakes once. Now with Jocassee a middle lake in the pumped storage chain it does not fluctuate nearly as much on a daily basis. Bad Creek, on the other hand, is a much smaller reservoir and can fluctuate 60 feet in a day! It is off limits to everybody.

I don't have the actual numbers on hand, but they claim better than 50% net efficiency. The main purpose is to keep the nuke plant humming along at constant output and meet the daily swings in demand. That is a lot easier than smoothing out the output of wind and solar which can go to near zero for days at a time.

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[cranky108]

Even at that, can pump storage keep up with the rise and decline of wind? What are the ramp rates for pumped hydro?
Granted battery storage is faster, but so is having a spinning mass with a motor/generator attached.

One issue with the storage is the waste energy is very difficult to capture and use like the cogeneration used with boilers, and OTTO cycle engines.

So what about the timing of hydro plants as a method of energy storage? It should be simple as many hydro sites have more capacity than they can normally use (future expansion that never happens).

Or what about using non-electrical energy storage, and only creating the electrical energy as a final output. Something like wind to direct compressed air storage. Maybe it won't be a grid size solution, but then neather is wind generation.

 

[GregLocock]

The loop efficiency even in an old scheme like the big old one in the UK, where they turned a large part of a useless conquered province into a pumped storage scheme back in Victorian times (wales, ca1960) was around 85%.

https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

is a handy summary


The problem with hydro storage is that most of the really attractive sites have been used (I suppose by definition that would be the case).

Using 'free-ish energy' to charge an inefficient but cheap energy storage system is a fascinating idea that I think hasn't been properly explored. By free-ish energy I mean energy sources where the 'efficiency' no longer matters, such as wind or solar, but the cost effectiveness does. For example, a solar power station in the desert doesn't need to use high efficiency cells, its effectiveness will be based on watts of electricity per dollar to generate it, not the %age of the incoming sunlight captured.

You can apply a similar argument to the storage system.

Spot wholesale electricity prices in Europe can easily exceed 4 times the average,

http://ec.europa.eu/energy/observatory/electricity/doc/qreem_2012_quarter1.pdf

and in Australia I have heard of 10x

If one were a gambler this might seem like an exploitable field. Coupled with politicians anxiety to be associated with greeny causes, no doubt crooks and wiseguys will get involved.





Cheers

Greg Locock


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[MartinLe]

In Germany, there's biogas plants that only have their motors running during the peak hours, usually 16h/d, when electricity is most expensive. This is not storage per se, but:
An additional idea is to use cheap electritiy at night (or when a windmill can't feed everything into the grid), produce hydrogen and feed that into a biogas plant when there's peak demand, biogas production from H2 and CO2 is apparantly pretty quick - but I'm not sure about the last thing, if this really gets of the ground.

 

[cranky108]

It's far easer to store natural gas in salt domes, and use it when there is demand for electricty, then to attempt to store energy in other methods. And natural gas dosen't have to be from a drilled source, it can also be produced from biogas facilities.

Just because we produce so much wind and solar electricty dosen't mean we should. After all it isen't cheep. We should be producing alternitives to other sources that can be converted into electricity so we can use existing facilities.

There was an article, which I doubt I can find now, where they were converting wood into a form of charcoal which could be burned in a tridential coal fired plant. I remember it because I was joking about kingsford coal for power plants.

 

[moltenmetal]

The reasons that mass grid-scale energy storage are not used more extensively are 1) scale and 2) cost/price. If electricity were more expensive, we'd see more of it.

The amounts of energy stored and hence the size of the storage reservoir need to be very large indeed, since the efficient means are either huge (low energy density) or very, very capital intensive (i.e. batteries and inverters). Storage means like pumped hydro are really energy generation deferral methods as well: in order to function as storage, you can't generate revenue from them for the storage part of the cycle, and you have to pay the capital for big generation capacity for brief periods during the generation part of the cycle. Both factors drive up capital cost a lot, and unless electricity is expensive and its price is highly time variable in a relatively reliable way, that's big investment with big associated risk.

Any storage scheme has to be able here to compete economically with a "peaker" gas turbine, which is what is typically used for load levelling. Those devices are not free but also not infinitely expensive.

 

[davidbeach]

The other place the pumped hydro shines is when paired with a nuke plant (not that we're building any of them any more...) so that the nuke can run flat out all the time it's up and the pumps can absorb unneeded power in the middle of the night and add that power to the nuke plant output during the daily peaks. PG&E's Diablo Canyon/Helms projects as an example.