From liquid air to supercapacitors, energy storage is poised for a breakthrough

http://www.theguardian.com/environment/2016/feb/04/from-liquid-air-to-supercapacitators-energy-storage-is-finally-poised-for-a-breakthrough

by jsingleton • 10 years ago

50 68 10 years ago

theguardian.com

dragontamer8• 10 years ago

A good overview, although missing Vanadium Redox Flow batteries (liquid battery), which is one of my favorites.

Redox Flow batteries can be pumped into storage tanks and distributed (theoretically anyway). In contrast, the entire set off Lithium Ion battery needs to be connected to the grid to take advantage of its storage, you can "pump" Redox Flow batteries into storage tanks to increase capacity without increasing power.

For day/night cycle storage (or longer), I'd expect Redox Flow to be more cost efficient than Lithium Ion, despite LiIon having numerous advantages (density / power / etc. etc.). Mainly because you can save on "Power Output" and instead build larger and larger tanks to store the charged electrolyte.

LiIons get more and more expensive ($$$ per KW-hr storage) the "bigger" they get. Redox Flow batteries achieve scalability (cheaper $$$ per KW-hr the bigger they get). I do realize I'm imprecisely using the word "bigger", but I hope yall will forgive me on that :-)

My personal favorites:

1. Pumped Hydro -- Old technology, but a favorite of mine. Very simple design, just take advantage of lakes that already exist in your vicinity and use the water in the lake as a gravity storage device.

2. Flywheels -- Store energy by spinning a heavy object. Spin-spin-spin... spinning and gyroscopes are cool.

3. Vanadium Redox Flow Battery -- Liquid batteries, how cool is that?

AnkhMorporkian• 10 years ago

(...) you can "pump" Redox Flow batteries into storage tanks to increase capacity without increasing power.

Why wouldn't you keep them at maximum capacity all the time?

dragontamer8• 10 years ago

Cost efficiency.

If your neighborhood only needs 50MW of power, but you want 1000 MWhr of storage (~20 hours at full power), a Redox flow battery would be able to do that. Or if you were building a Hospital (Lets say 5MW of power) and need to spec out 3-days of power (ie: 360 MWhrs of storage on 5MW Power), you just build a tank that can store a lot of the electrolyte.

I guess... the best way of putting it is that Lithium Ion batteries are like AAA batteries, while a Redox Flow battery could be configured as a larger D battery. D Batteries don't give any more power or voltage than AAA batteries, but are more efficient for energy storage.

It is very easy to imagine how to build a 3000MW-hr 50MW Redox Flow battery (just build a huge storage tank). It is almost impossible to imagine the same with Lithium Ion (I guess you can build massive Li-Ion cells, but note that the Tesla is powered by tiny 3.7V 18650 cells wired up together. So it really hasn't been done before)

Day/Night cycle storage is a low power (Megawatts) high-storage (Megawatt-hours) use case. Lithium Ion batteries are more useful for high-power / medium-storage situations (like frequency balancing, or maybe a couple hours-long storage).

Flywheels are exactly the opposite. They are high-power low-storage devices. Flywheels would be very useful for smoothing out power when birds / clouds come up in front of solar panels (for example). Its easy to build a 300MW flywheel with almost no capacity (only a few minutes of storage). Flywheels could be used when a power-source goes offline suddenly, while a few minutes need to be spent spinning up a new power-source. (ex: Main grid goes down, you need 30 seconds before your diesel generator fully turns on. The flywheel will keep very high-power for the next 2 minutes while things switch over). Although supercapacitors are also a promising technology for this problem.

Different storage technologies for different purposes.

zardo• 10 years ago

They would be charged. You're confusing energy and power, by increasing the reservoir sizes you increase energy storage capacity but not the speed at which the total stored energy can change (power).

jsingleton3• 10 years ago

Pumped storage is great if you have the geography for it. In a lot of places (such as the UK) it's all already in use.

RobertoG• 10 years ago

Yes. Some places, like the island of 'el hierro', even are disconnected of the main grid:

http://www.npr.org/sections/parallels/2014/09/17/349223674/t...

jsingleton3• 10 years ago

I posted this yesterday but today there's a story about "Welsh home installs UK's first Tesla Powerwall storage battery". Good news.

http://www.theguardian.com/environment/2016/feb/05/welsh-hom...

This project to store energy in trains also looks interesting.

http://www.aresnorthamerica.com

jonawesomegreen3• 10 years ago

I've spent the last couple years working on a very interesting project using ultra-capacitors for energy storage. We are storing 33kWh of energy in ultra capacitors, charging and discharging with a very short period (seconds) for peak-demand shaving. It really is an exciting time for energy storage technology. I think we are going to see a lot of cool innovation in the next few years, even just finding new uses for existing technologies.

saosebastiao• 10 years ago

What sort of volume/weight dimensions are required for 33kWh of ultra capacitors?

jonawesomegreen3• 10 years ago

They are quite large, but in the particular application weight and volume are not a huge concern. All sitting side by side they are about 20 meters long, 3 meters high, and a meter deep. Probably weighs on the order of 15 tonnes.

oh_sigh• 10 years ago

I don't know much about this field, but how does charging/discharging on the order of seconds help shave peak demand?

jonawesomegreen3• 10 years ago

Think of a sinusoidal demand for energy, with a period of a few tens of seconds. By charging when demand is low and discharging when demand is high, peak load is lowered.

beat8• 10 years ago

Energy storage is such a no-brainer. It makes solar/wind viable for both base load and peak load generation. The numbers required are very measurable and predictable. It doesn't require magical, exotic technology (as the elevated reservoir and compressed air mechanisms show). There's always going to be some thermal losses in transformation, but they're going to be pretty similar across technologies.

Another nice thing about solar + storage is that it can scale very small, very inexpensively. Imagine putting a set of solar panels or a wind turbine plus some storage in a village in Africa. It may not be worth wiring it to an expensive grid, but just getting electricity there can make so many other differences.

Beyond that, the ability to small-scale and decouple reduces the power and influence of large corporations and the government-industrial complexes that wreak so much havoc. You don't need the drama and abuse of the petroleum or nuclear industries anymore.

SilasX3• 10 years ago

Scalable? Compressed air and reservoirs are about the opposite of energy-dense and require a lot of space per unit energy.

I'm optimistic about the role that energy storage can play in converting green tech to base-load capability, but it seems like it requires some technological advances unless you want to devote huge territories to becoming low-density batteries.

beat8• 10 years ago

I'm not talking about physical size. I'm talking about cost and complexity. An air tank with a compressor pump at one end and a turbine at the other is simple, reliable, well-understood, off-the-shelf technology. How much energy can you store in an air tank that would fit on the back of a truck? Hook it up to another truck full of solar panels, and you have a local electric grid, capable of powering at least a few buildings, at very reasonable cost and minimal sophistication required for operation and maintenance.

oconnore2• 10 years ago

These buzz articles always focus on the sexy energy storage methods: lithium ion, liquid batteries, electrolysis, supercapacitors, etc. I've seen very little evidence that these can compete on either $/kWh, or efficiency, with pumped hydro (where available), thermal (Isentropic Energy Ltd [1]), or kinetic.

[1] https://www.greentechmedia.com/articles/read/Isentropics-Pum...

ohitsdom• 10 years ago

Correct me if I'm wrong, but none of the options you listed are portable.

mikeash5• 10 years ago

The article is all about storage for the electrical grid, to shave peak demand and allow more wind/solar use, so portability isn't a requirement.

oconnore2• 10 years ago

Right. In the context of grid storage of renewable energy, that doesn't matter.

You need a li-ion or similar in your phone and your laptop (and maybe your car), but that doesn't make it the best tech for flattening out a peaky solar/wind grid.

nordify16• 10 years ago

Could somebody enlighten me on the economics of energy storage?

The local retail energy prices are approximately 10c/kWh year round, rain or shine. The price is fixed, unless you buy a contract based on the spot market.

All the energy storage products I've heard about cost more or about the same per kWh just to store the energy. So even if the energy to charge the energy storage was free, it still would not make economic sense to store energy if you have grid power.

Am I missing something or is consumer energy storage only for off-grid applications?

beat8• 10 years ago

Solar/wind are inconsistent, and their output doesn't map to consumption patterns. So a totally solar/wind grid would require massive overbuilding in order to provide sufficient power for peaks. By caching the surplus generated when supply exceeds demand, we can significantly reduce the overall supply footprint, by using the generated supply much more efficiently.

nordify16• 10 years ago

But why bother storing the solar/wind excess, if storage costs exceed traditional generation costs?

For a purely economical perspective, it does not make sense.

fweespeech• 10 years ago

All the energy storage products I've heard about cost more or about the same per kWh just to store the energy. So even if the energy to charge the energy storage was free, it still would not make economic sense to store energy if you have grid power.

1) They are re-usable. Power generation [e.g. Solar Panels] to refill them is frequently inconsistent enough that you will need to go 12+ hours without power. Cycle through enough time and paying a multiple of grid power for energy storage that lasts years is worth it.

2) If I lose grid power [happens a couple times a year] I need backup power.

EDIT:

Iirc, I'm pretty sure Powerwall and such is ~$.30/kwh with generation included and I know I eat ~$.30/kwh for a certain level of usage.

https://www.sce.com/wps/portal/home/residential/rates/Standa...

http://www.forbes.com/sites/christopherhelman/2015/05/01/why...

$.15/kwh during the day and $.30/kwh at night is actually comparable depending on usage.

If you don't want to do generation, you can arbitage rates at $.15/kwh storage + $.14/kwh charge from grid:

https://www.sce.com/wps/portal/home/residential/rates/Time-O...

nordify16• 10 years ago

No energy storage solution is infinitely re-usable. Thus there is a price per kWh per cycle.

Consumer energy storage solutions have a higher kWh price than traditional energy generation.

So why store energy as a consumer?

EDIT:

So energy storage only makes sense in a market where power is very expensive (~0.30c/kWh) and even then you might never recoup the investment required to store the energy.

mikeash5• 10 years ago

Not all places are like this. Some places have variable time-of-use rates with high premiums at peak times and large discounts at times of extreme low demand. For example, rates with Southern California Edison can be as high as 45 cents/kWh and as low as 11 cents/kWh. If you can charge up a storage system at times of low demand and then use it at times of high demand, you could save a lot of money.

The bigger use is probably industrial applications, though. Commercial users can get hit with huge surcharges if they draw a lot of power, for example, so users which only draw huge amounts of power briefly could save a lot of money by using storage to smooth that out. The utilities themselves can end up paying extremely high rates for extra capacity at peak time, so if they can use storage to eliminate that need it can save them a lot of money.

amelius• 10 years ago

If you can charge up a storage system at times of low demand and then use it at times of high demand, you could save a lot of money.

In a sufficiently advanced energy market, you could actually make money.

nordify16• 10 years ago

Not all places are like this.

Is there a reason why all places couldn't be like this? Wouldn't a well run and properly regulated power grid solve these problems?

dragontamer8• 10 years ago

The local retail energy prices are approximately 10c/kWh year round, rain or shine. The price is fixed, unless you buy a contract based on the spot market.

Chances are, you live close to the Bath County Pumped Storage Station.

https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta...

Its because of these big infrastructure projects that your region has cheap energy all year (and all day) round. In areas like California, big infrastructure projects have been shuttered, and they have 41c / kWhr prices in the day, and 10c at night.

Other locations in the US have their own energy storage public-infrastructure projects that stabilize the grid. But some states (Hawaii or California) have... issues.

nordify16• 10 years ago

So energy storage is a technical solution to market failure?

Sonthun• 10 years ago

In addition to the comments above about solar/wind inconsistency, it is also a lot cheaper to run baseload power plants constantly rather than to ramp peaker plants up and down. So, if they can store the baseload power and then tap it later the total cost of electricity will come down. Plus, storage makes it easier to level the grid to make output match demand.

nordify16• 10 years ago

Is storing power cheaper than using peaker plants? That is, is storing power at scales required to replace peaker plants economically viable?

stcredzero• 10 years ago

Contextually relevant question: How much would it cost to do a major revamp of the North American electrical grid? (For various values of "major revamp" of course.) I found this article that mentions a $2 Trillion figure from Rocky Mountain Institute, but I take that with a big grain of salt. [1]

Since the patents around Tesla's Supercharger are open, what about the idea of giving the US highway commission a few hundreds of millions to double the number of Supercharger stations? (This would create more demand while not improving the infrastructure, but I would benefit personally.)

    [1] - http://www.renewableenergyworld.com/news/2015/04/us-power-grids-2-trillion-upgrade-needs-european-efficiency.html

mikeash5• 10 years ago

Superchargers only work with Teslas, and Tesla is doing fine when it comes to doubling the number of installations on their own (there are currently 270, and they installed 113 of those last year), so having the government come in and install them doesn't seem like a good use of money.

Further, what's the relevance of Supercharger stations to electrical storage? Maybe I'm missing something but that seems like an irrelevant tangent here.

1024core• 10 years ago

This stuff is always "poised for breakthrough". But we are still stuck on LiOn batteries, which have been around for what, 20 years? Wake me up when we have something that doubles the capacity of LiOn batteries in a similar form-factor and safety rating, propelling Teslas to 600km+ ranges. That would be a real "breakthrough".

gravypod• 10 years ago

"It doesn’t always rain when you need water, so we have reservoirs - but we don’t have the same system for electricity,” says Jill Cainey, director of the UK’s"

Actually... we do. It is called pumped hydroelectric storage [1], and it is essentially just a reservoir, a pump, and a turbine.

[1] http://energystorage.org/energy-storage/technologies/pumped-...

From liquid air to supercapacitors, energy storage is poised for a breakthrough

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