Energy storage (dull but important)

Recent science-via-press-release: http://www.seas.harvard.edu/news/2014/01/organic-mega-flow-battery-promises-breakthrough-for-renewable-energy

Congrats Joshua.

More about that here. Everybody knows about the Corning Museum of Glass, right? Best long day you’ll ever spend indoors in upstate New York, or two days if you care about both the art/archeology and the science. Less than an hour from Ithaca, if you’re ever visiting Cornell.

Something I read just the other day:

ABB and Samsung have announced they will design and construct a hybrid Grid Energy Storage and Diesel Generation System (GESS) for Victoria’s SP AusNet.

Where do you locate the storage? How much load will it support and for what duration?

In what circumstances is it designed to be used? Who pays to build and maintain it?
Is there a business in just doing storage (I buy it off a solar farm and sell it at night) or do we require that intermittent producers “smooth” their output by adding storage?

Does an increase in “off-grid” houses result in “white-anting” of the distribution system?

How to reconcile the desire for uninterruptable power with safety (eg: islanding) ?
What control systems do we use? (There’s a whole career in that one alone).

So, not dull. Definitely technical, wonkish. Also the corner stone of any real solution…

Quinone flow batteries vs. metals: it isn’t even a question of expense (and lifecycle toxicity). If you run the numbers, there just isn’t that much vanadium in the world, by a couple of orders of magnitude. But there are no fundamental obstacles to making AQDS and hydrogen bromide in million-tonne lots.

Joshua, I find the interesting properties of flow batteries intriguing… the idea of moving about the electrolyte or using asymmetric arrangements of recharge and discharge cells for DC-DC power conversion.

I’m not across the chemistry enough to answer this: do I want a few hundred litres of this stuff in my back yard? Or is it best handled at a local utility level – eg: local water utilities regularly handle chlorine etc without incident.

Ah, I found a free full PDF of the quinone battery article that I couldn’t find when it first came out. It looks like it still doesn’t match vanadium flow batteries on one really attractive property: leakage across compartments only wastes energy for vanadium, it doesn’t damage the chemistry of the system. According to the article AQDS is stable in the presence of bromine and HBr, but it sounds like you would still see capacity degradation from mixing until an external process re-purifies the materials for their respective compartments. If the side that is supposed to contain the quinone is only rated for corrosion resistance to dilute sulfuric acid, not hydrobromic, that could be another crossover concern since HBr is much more aggressive toward most metals. But, OK, these are wonky details; it sounds great and I really hope they can build a production-scale prototype.

I don’t think storage is yet cheap enough to make going off-grid cheaper than traditional distribution networks in any urban area. The medium term threat is people staying connected to the grid but drawing from it less, making the proportion of fixed costs higher for people who use the traditional system more heavily. To avoid underfunding distribution as rooftop solar becomes more popular, it’s probably better to make the fixed distribution infrastructure expense a separate billing item instead of folding it into the per-unit price of grid electrical consumption. Of course that fix may bring its own problems, like placing a proportionately higher burden on low-income, low-usage households.

@Will:

Solar is considerably more predictable than wind. I scraped data from CAISO and ran some calculations for the month of January. Left column on each date is megawatt-hours of PV production, right is wind:

2014-01-01 18326 1012
2014-01-02 20441 698
2014-01-03 16721 4411
2014-01-04 15228 20086
2014-01-05 18207 4885
2014-01-06 17318 1389
2014-01-07 11109 18326
2014-01-08 17370 37052
2014-01-09 15611 53929
2014-01-10 18015 29893
2014-01-11 16878 27430
2014-01-12 13112 41398
2014-01-13 19644 9316
2014-01-14 19773 7601
2014-01-15 18286 4430
2014-01-16 21006 7091
2014-01-17 20806 1936
2014-01-18 20573 982
2014-01-19 13389 545
2014-01-20 20620 1628
2014-01-21 13296 1992
2014-01-22 18838 6176
2014-01-23 18601 17438
2014-01-24 9054 14577
2014-01-25 16816 2625
2014-01-26 14575 17289
2014-01-27 18938 36225
2014-01-28 18779 30685
2014-01-29 19964 36173
2014-01-30 11704 40001
2014-01-31 12918 44257

Standard deviation for PV in January is 3143, for wind it’s 15926. But there’s also more wind capacity installed; normalizing by peak value in each population, it’s 0.30 for wind and for solar it’s 0.15.

I’m working on similar scripts for German and Australian output, though so far I only know data sources for solar production, not wind.

As a practical matter, for planning purposes you’re ok with just a few minutes’ worth of buffering storage and a reasonably accurate 15-minute-interval forecast produced 12-24 hours in advance. I unfortunately don’t have any data handy on how much forecast error there is in PV and wind day-ahead modelling. If you look at e.g. the UK, http://www.gridwatch.templar.co.uk/ , you can see that coal plants are already load following night vs. day and weekday vs. weekend. Recent research also concludes that cycling fossil plants up and down in response to renewable output loses only a small portion of the expected fuel savings from startup inefficiency. The main thing for integrating renewables, then, is producing good near-future forecasts and building enough fast-reacting storage (and/or demand response) to cover residual forecast error. You may still have the fossil plants around but you can reduce how much fuel they’re burning and CO2 they’re emitting.

To avoid underfunding distribution as rooftop solar becomes more popular, it’s probably better to make the fixed distribution infrastructure expense a separate billing item instead of folding it into the per-unit price of grid electrical consumption. Of course that fix may bring its own problems, like placing a proportionately higher burden on low-income, low-usage households.

Or you could fund it out of consolidated revenue / general taxes like some other bits of infrastructure, just bill for the power consumed.

Some storage slutions will scale down well, and some won’t. LiIon scales down well enough that some will end up in the home. Flow batteries, probably will be larger nodes on the grid, maybe at the substation level or larger.
Predictability of PV should be pretty high. Geographic distribution helps a lot here, clouds don’t instantly appear at the same time miles apart, so if some of your PV plants are surprised, others won’t be -or at least the timing of the surprise will be different. The same thing applies to wind.

The solar that you read on the CAISO site, is only about 2/3rds of the state’s PV, the rest is distributed on hundreds of thousands of roofs. In California rooftop solar does not count as renewable, but as demand reduction. The state’s grid is actually a lot greener than it appears. Much of the utility scale solar is concentrated in the sunny desert parts in the south of the state, much of the rooftop PV is in the greater bay area, which is usually a day ahead of the deserts cloudwise. So geographic PV distribution in California is actually better than what you see on the CAISO site.

Charlie,

I think there is a fruitful possible parallel between solar PV generation and battery storage. PV technology has not changed a lot on the surface. 15 years ago you could buy modules with the same basic technology (crystalline silicon), conversion efficiency, and form factor as you might install on a rooftop today. But the module cost several times as much 15 years ago. What has changed in the mean time is an enormous increase in production scale, with corresponding cost reductions, and a thousand little improvements at every level of the production chain, most of which would not make news on their own.

I think something similar may be possible with lithium iron phosphate batteries. Lithium, iron, and phosphates are fairly abundant and inexpensive, even after they’ve been purified to battery-grade. Turning those cheap raw materials into batteries is currently expensive; the finished battery costs something like 80 times as much as the purified but bulk-form mineral inputs. Silicon based PV modules were once in a similar position, but due to the improvements mentioned above the manufacturing cost is now in the neighborhood of 8 times as much as the purified mineral inputs (solar grade silicon, silver or copper, glass, aluminum, and plastic). I know relatively little about battery manufacturing, so I don’t know if a drastic cost reduction is possible following the same incentives-and-buildout model shown by PV. But the possible parallel seems provocative to me.

For a long time (and it still happens now) people were trying to make PV cheaper by pursuing big technological leaps: thin-film devices based on exotic metals, printable organic cells, proton beam wafering, ribbon silicon. But thin film cells are a smaller part of the market now than 10 years ago, and those other technologies are dead for the foreseeable future. Slow and steady (and big) won the race for crystalline silicon.

“If you run the numbers, there just isn’t that much vanadium in the world, by a couple of orders of magnitude.”

Not entirely convinced. There’s around 20 million billion tonnes of V in the Earth’s lithosphere. Sure, reserves are only 14 million tonnes and resources 63 million, but they’re not anything like, in fact entirely unconnected to, how much is actually available to us.

As to the point of the post, energy storage, I tend to think that it’s going to be fuel cells. Admittedly, this belief is likely because this is where I’ve bet my own money in business. One type of fuel cell (like the Bloom Box) uses the metal that I happen to deal in, the one I’ve spent some years working out how to extract and process. So clearly and obviously I’m highly biased here.

Solar to electrolise water and we then store the H2 until we want to run it back through the fuel cell again and use the resultant electricity. This would have to be a local system, given the difficulty of storing or moving H2 around. But conversion to other things isn’t all that hard: methane for example, which can be piped through the normal gas networks.

This is obviously an inefficient system: there are inevitable losses at each conversion. But that’s not quite a killer for such a system. It depends only on how cheap solar cells get. And given that they’re governed by something akin to Moore’s Law I would bet that there’s another order of magnitude reduction in cost possible (we’re currently seeing a 20% pa reduction in costs). And we’ve most certainly no shortage of sunlight to collect.

Worth noting also that fuel cells themselves, at least the type that I’m thinking of (SOFCs) are also governed by something akin to Moore’s Law. They are about tracing a circuit on a substrate. The current cost of those boxes could also come down by an order of magnitude (I’ll leave out the boring bits about how but one manufacturer was, at least they were two years ago, hand painting the substrates when something like thin film vapour deposition would clearly reduce materials costs radically).

I wouldn’t say that this will happen, only that it could. If solar PV comes in at a capital cost of 10 cents per W as opposed to the around $1 now then conversion losses would be a near irrelevance. And my best guess (and it is a guess) is that the solar and fuel cell prices will be low enough to make this a very cheap system indeed in 15 or so years.

“What are the advantages of distributed electrolysis-plus-fuel-cells vs. distributed batteries?”

Essentially, I think that fuel cells are going to be cheaper. There’s just nothing in them that is inherently expensive. They’re basically a zirconia plate with a thin layer of rare earths.

There are patent costs currently and the manufacturing of them is incredibly inefficient in both process and use of raw materials. But these are exactly the sorts of problems that tend to get solved over time. I just think they’re going to end up cheaper than using a whole bunch of lead/vanadium/whatever.

I’ll agree that I’ve not thought it through in detail but I can’t see much in there that would make it impossible to have a household running solar cell/fuel cell system for under $10k in a decade or so’s time.

Electricity is a weird “market”. Fluctuating demand levels must be met instantaneously by a system that has no warehousing on a 24-7 basis. It’s quite a lot different from just cranking out widgets.

Demand response and load shifting can do a lot of the same things that energy storage does, but there’s a very significant difference between the two. The more you do energy storage then the cheaper it gets as you slide down the cost curve. Changing the way people use electricity is the opposite. There’s a bunch of low hanging fruit applications that are cheap to do (like doing your laundry and dishwashering off-peak), but once you’ve harvested those opportunities, each additional amount of demand becomes harder. It’s quite similar to conservation and energy efficiency in this way.

Regarding price incentives for storage – it’s actually worse than zero incentives. A standalone energy storage facility would actually be penalized. Most jurisdictions have uplift and transmission costs which are levied per unit energy delivered. Energy that goes into storage for use at a later point in time would have these uplifts charged to it twice when it got to the end user.

(While the gnomes of the Crooked Timber pile go through my previous linky post, here’s a general remark.)

I think it’s too early to pick winners and losers in these technologies, by the way. As usual in such cases it’s likely that the technically best technologies will not be the winners; these things depend on unpredictable social and economic contingencies.

Another thing to consider about energy storage is that it shifts energy in both time and space. Being able to use off-peak generation to meet on-peak demand is amazing and all, but we shouldn’t forget about the locational effects it can provide.

When load centres are geographically situated at a distance from generators, energy storage technology can move power from the big generator closer to the load during off peak, alleviating the need for major transmission upgrades. This effect is scalable downwards as well. A growing load centre can defer transmission line and distribution network upgrades by strategically placing energy storage units throughout the system. Being required to meet peak demand everywhere and all the time means under utilized infrastructure, so shaving the peak with some well placed batteries should be very useful.

One other thing to consider – when we talk about “Energy Storage” we are referring to a pretty wide range of products and technologies. Normally electrochemical batteries is what we think of, with maybe some fancy new high tech alternatives. And yet, the overwhelming majority of MW and MWh operating energy storage is pumped hydro.

What technology you might want for diurnal or even weekly power shifting is not necessarily going to be the same thing you would want for seasonal storage or renewables integration and voltage support. Focusing on technologies is fun and all, but I think what would really get the ball rolling is better definitions of the problems the electricity systems of the world face and then quantifying how much a solution to those problems would be worth.

As a chronic pessimist, I will also point out that local storage and generation imply complex nonlinear interactions between large numbers of all sorts of megawatt-rated things, run by all sorts of people. It’s bound to be interesting and, er, flashy.

Interesting times ahead.

@Mario I would have said “interesting and… dark.” There’s a lot of gear already deployed whose sole purpose is to disconnect things when it gets too interesting, with a history of working quite well, eg the Northeast in 2003 and the Southwest in 2011. Not much flashy, but plenty of dark.

Regarding the useful comments others have made on pumped hydro, the problem at least in the US is that too much of the population is too far from where pumped hydro has room to expand. The Western Interconnect has a reasonable opportunity: deep narrow canyons not too far from either the demand centers or the best of the more-intermittent renewables. The hunt for flow batteries or hydrogen or compressed air storage is largely to find solutions for the Eastern Interconnect.

@36:

Speaking from VT, for New England, there’s Quebec and Labrador.

The issue is EITHER energy storage or energy transmission. High efficiency transmission serves the same purpose

“I’ve heard Tim’s argument about batteries, “been around a century, didn’t work then, won’t work now” before. Sure there was effort soent back then, especially by the likes of Edison. But the scientific/engineering equiment and knowledge back then can properly be considered to be possitively stone-aged compared to whats available now. Many technologies are inveted too-soon, and were found unworkable simply because the technical support structure didn’t exist.”

That’s not an argument I’m making at all. Indeed, entirely the opposite. Solid oxide fuel cells have been around for 150 years after all.

Sort of semi-related, but… what effect will a rise in the fraction of people living in multiple-dwelling buildings have on distributed PV construction, gien you don’t have the rather nice owner/occupier/electricity-consumer synergies that have been driving PV construction locally?

Thoughts, anyone? I mean, if you rip down a house and put up some strata-title flats, the land still supports the construction of the same PV capacity, it’s just I don’t think the interests align quite as strongly to favour putting it there.

Why wouldn’t the condo corporation own the PV system? I guess it depends on the specifics of your market, but in Ontario I have seen both third party ownership of the PV system with the condo corporation receiving revenue from a roof lease agreement and condo corporation ownership of the facility. We have a Feed In Tariff program though.

There’s also a premium for condos that can advertise themselves as “green” even if a third party owns and operates the PV and the PPA counterparty contractually claims all the monetizable environmental benefits (i.e. RECs, etc.).

One advantage of condos over single family homes is having maintenance staff on site. While they may not be trained electricians, they can keep soiling losses under control as well as monitor the system to report any significant malfunctions.

On the conventional liion battery technology cost side, they seem to have followed a similar price path as solar on the long term, arround 7% cheaper each year so far. Long distance grid technology had no such price path. Thus odds are good, its going to be a lot cheaper to stay more local. Either way, i dont think running a grid with 100% renewables will be an important topic anytime soon. The climate will survive 20% natural gas.

hix is right – the issues around demand matching will always be far more difficult for a fully renewable system than for a partly renewable one. But getting the climate under control does not require fully renewable systems, just systems that spew out less CO2 than the current ones.

Good old fashioned supplementary natural gas turbines can do a lot of the work here, as they increasingly do in coal-based systems anyway. One day in the distant future, of course, we will run out of affordable natural gas but sufficient unto the day be the evils thereof …

I think we should distinguish our motives a bit better here too. Lets not mix the “small is beautiful” or the “smash capitalism” agendas with the climate control one. If getting the climate under control means more, not less. centralisation that might be unfortunate – but we shouldn’t hesitate to do it anyway. Let’s see where the technology takes us.

derrida derider writes: But getting the climate under control does not require fully renewable systems, just systems that spew out less CO2 than the current ones.

I was under the impression that most climate scientists think we are already screwed, and that a reduction in the rate we add CO2 to the atmosphere will not save us, wikipedia summary at Avoiding dangerous climate change

I’m not suggesting that spewing out less CO2 is a bad idea, just that it won’t stop catastrophic climate change at this stage.

@50 is just completely delusional.

derida,
No. Slowing emission rate will only slow the descent towards a hellish climate, not stop it. While reducing is probably the best we will do during my lifetime, the goal has to be to ramp those net emissions to zero (or preferably negative something). Zero or negative doesn’t mean we can’t have some emissions somewhere, but that they must be more than offset by some sort of long term sequestration. The later would probably be a combination of biochar and enhanced silicate weathering, but I doubt it will pull down CO2 at even ten percent of the current emissions rate.

But, you are right about priorities with regard to centralisation. Opposing say utility scale PV and wind, because we don’t like the ownership model is harmful to the future climate. We need all scales and ownership models to be part of the solution.

Insulated houses are a good and important energy storage technology, and in some places, insulating a house is subsidised.

Pete, Martin, there’ve been some interesting (imo) developments in the fundamentals of thin film PV in the past year or two:

http://www.nature.com/news/365-days-nature-s-10-1.14367
http://www.sciencemag.org/content/338/6107/643.abstract
http://www.nature.com/nature/journal/v495/n7440/full/nature11936.html
http://www.nature.com/nature/journal/v501/n7467/full/nature12509.html

Caveats: efficiency still low compared to c-Si (so far up to 15%), contains lead. However, if you’re willing to extrapolate it looks like there could be a competitor, especially in specialty applications (e.g. windows, flexible substrates).

There’s a big difference between being screwed and being really screwed.

Getting emissions reduced makes the difference between (say) a 3 degree increase and a 6 degree one. A 3 degree one is something you’d certainly avoid if you could (and, yes, we no longer realistically can – that’s actually part of my point) but a 6 degree one is civilisation-ending stuff.

It is certainly not “delusional” to seek the achievable rather than the utopian; this is an issue where daydreams and nightmares alike can cost us big. Bend your wish to your judgement, not the other way around. I say make a cool estimate on what is politically achievable (that is, achievable at relatively small economic cost) and go hard as you can for that. Forget the “now wouldn’t it be nice if we could just force everyone in the whole world to radically reconfigure their lifestyle so they use only a tenth as much energy” dream because however pleasant it is but a dream.

Only getting emissions down, but not stopping them completely means we will sonn enough blow past 6C, it will just take longer to get there. Unless you only care about 2050 or 2100 -but but 2200 or 2300.

China’s CO2 emissions are now greater than the EU, USA, Canada, and Australia combined. India has plans that would take it beyond the USA on emissions by decade’s end; the only reason it may emit less is because endemic dysfunction has impaired the expansion of coal extraction and power generation just like every other governmental plan. In short, it looks like the planet is screwed on climate even if everyone in the OECD gets serious about emissions.

Since a global dynamic of cooperative emissions reduction does not appear to be on the table in the next decade, I have some hope that an an alternative oppositional approach might work. If you’re in a nation that has committed to curb emissions, why should trade still flow freely with nations where emissions are going up 7% every year? It’s just shifting coal use to other parts of the world if manufacturing can relocate to dodge the costs of cleaner power. An oppositional approach based on tariffs penalizing use of dirty energy could also find support among domestic workers since dirty energy is strongly correlated with low wages. If you’re really lucky, the penalized nations will retaliate with trade barriers of their own out of spite, thus further slowing emissions. For example, Australia puts tariffs on Chinese manufactures, and China puts tariffs on Australian coal and iron ore in return — win/win for the climate!

@derrida derider

It is certainly not “delusional” to seek the achievable rather than the utopian; this is an issue where daydreams and nightmares alike can cost us big.

True, a few people have not “done the math” to realise that there is no low hanging fruit in low-emissions energy production.
Those people pretty much balance out the “other side” who haven’t looked at the math that says we’re screwed in the BAU scenarios (which, IMHO, includes holding off until all the possible problems are neatly tied up in a bow).

There is much inertia in billion dollar infrastructure projects… I want to see them happen too. Until then we have to rely on “holding actions” to shave off as much GHG production as we can, as early as we can.

If you can get a million people to spend $10k for some storage on top of their existing solar installation, you can start shutting down gigawatt sized slabs of coal fired power. $10k is not a huge impost (~3% of your house) and many people will do that just because it will help. Even more will if there’s money in it not too far down the track.
(see previous discussion as to how to provoke the housing/construction to get higher efficiency, solar equipped housing as a starting point)

If you can guarantee that your 10MW solar or wind plant could deliver today’s production tomorrow because you have storage, then you’re in a better position to sell at a higher price or get better terms on your contracts, and reduce the payback time for your investment.
Again, this is a ~$50m level of investment; we can do thousands of those a year with much less red tape and, co-incidentally, mothball another gigawatt slab of coal fired generation.