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Why energy storage sucks

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Re: Why energy storage sucks

#51

Post by zackmorris »

The comment I was writing turned into a blog post, so I'll just post the links. IMHO these are trending towards solving many of the problems faced by alternative energy generation and storage:

http://www.npr.org/sections/thetwo-way/2016/02/04/465568055/...

http://www.wsj.com/articles/energy-storage-startup-lightsail...

https://en.wikipedia.org/wiki/Nickel–iron_battery

https://en.wikipedia.org/wiki/Sodium–sulfur_battery

https://www.littleboxchallenge.com

https://www.littleboxchallenge.com/pdf/finalists/56568-Tech.... <- PDF

Re: Why energy storage sucks

#53

Post by jsingleton »

mangecoeur wrote: post #28

Very limited view of energy storage tech frankly. Quick list of things I am aware of (some deployed and some in labs) - Pumped hydro, by far the most widespread - Flywheel storage, used at grid scales for frequency regulation - Thermal storage used in conjunction with solar power using various materials - molten salt, HTF, hot dry rock - Many different battery chemistries: - High temperature batteries (e.g. ZEBRA bat…

The title of the article is just a bit inaccurate. Perhaps 'Why domestic energy storage sucks' would be better. The full title is in fact 'Why energy storage sucks. (but there is hope)' but the last bit is left out above.

Pumped storage is great, but not in your house or for an off-grid hut in Africa. One interesting application of pumped storage is applying it to tidal power. You could build a tidal lagoon and not only get the super reliable free tidal energy but also use it as a store. Pump extra water out or in when renewable sources are producing. Then use the power when demand is high.

This is covered a bit in this excellent free book: http://WithoutHotAir.com

Re: Why energy storage sucks

#54

Post by specialist »

dangravell wrote: post #40
mangecoeur wrote: post #28

Very limited view of energy storage tech frankly. Quick list of things I am aware of (some deployed and some in labs) - Pumped hydro, by far the most widespread - Flywheel storage, used at grid scales for frequency regulation - Thermal storage used in conjunction with solar power using various materials - molten salt, HTF, hot dry rock - Many different battery chemistries: - High temperature batteries (e.g. ZEBRA bat…

Some interesting products utilising PCMs in the domestic hot water markets... Replacing traditional hot water cylinders which suffer from very high heat loss even when insulated.

Had to look up PCM, which stands for phase-change materials.

https://en.wikipedia.org/wiki/Phase-change_material

Found a few vendors of various interesting products, here's just one:

http://www.pcmproducts.net

Found a few articles advocating water heaters using PCM. Sounds cool.

Aside: I've tried HotSnapZ brand hand warmers. They're reusable. Neat. I should have guessed this strategy could be scaled up for bigger applications.

http://hotsnapz.com/FAQ.html

Re: Why energy storage sucks

#55

Post by aidenn0 »

pjc50 wrote: post #8
brownbat wrote: post #2

Surprised there's no mention of Vanadium Redox as an alternative that solves several of these problems even better than Lithium Ion. They can be fully cycled over 100,000 times (compare to Li-ion's 400-1200, lead's 500-800) and are expected to last 20 to 30 years. They can stay in a single state for long periods of time without degradation and can be rapidly and efficiently charged or discharged. There's also no fire…

Personal VRBs make about as much sense as having your own gas turbine, but utility-scale ones for peak demand response make a lot of sense.

Speaking of having your own gas turbine, that was my existence proof a while back for how to handle events where lots of people want to charge there cars all at the same time: 30MW in a trailer http://www.pwps.com/gas-turbines/30-mw-mobile.html

Granted there are almost certainly better solutions, but anywhere we can deliver NG to, we can deliver stupendous amounts of electricity to, for a price.

Re: Why energy storage sucks

#57

Post by gene-h »

mangecoeur wrote: post #28

Very limited view of energy storage tech frankly. Quick list of things I am aware of (some deployed and some in labs) - Pumped hydro, by far the most widespread - Flywheel storage, used at grid scales for frequency regulation - Thermal storage used in conjunction with solar power using various materials - molten salt, HTF, hot dry rock - Many different battery chemistries: - High temperature batteries (e.g. ZEBRA bat…

There is also Superconducting Magnetic Energy Storage(SMES), train energy storage, molecular spring energy storage.

Train energy storage is driving a trainload of concrete blocks uphill when power is cheap and doing regenerative braking on the way down[1]. It's just like pumped hydro, but without the need for water.

Molecular spring energy storage is essentially making a windup mechanism, except with advanced materials like carbon nanotubes. Unfortunately it is not very practical today.[2]

[0] https://en.wikipedia.org/wiki/Superconducting_magnetic_energ... [1] http://www.gizmag.com/ares-rail-energy-storage/28395/ [2] https://en.wikipedia.org/wiki/Carbon_nanotube_springs

Re: Why energy storage sucks

#58

Post by Dylan16807 »

stcredzero wrote: post #21
davedx wrote: post #3

I really want to read this article, but there are too many spelling and grammar mistakes or lack of punctuation. Please consider spellchecking it?

Spellchecking? What about innumeracy? As you can see if you only drain your battery to 75% (meaning you only use 20% of your capacity) you get tremendously more cycle’s (more than double!) then say using 50%. So when systems are designed for energy storage you generally want your batteries to last a long time (since they’re expensive) so you want the maximum amount of cycles for them, which means that you should only…

Plus, getting 2100 cycles at 75% vs. 1000 cycles at 50% is barely an improvement at all. With this particular example battery there is absolutely no reason not to discharge it completely. You get roughly the same number of watt hours before it dies, no matter what you do.

Re: Why energy storage sucks

#59

Post by Dylan16807 »

mhandley wrote: post #34
bloat wrote: post #29

Earlier quoted context omitted.

How big of a tank on your roof do you need to replace a box of lead acid batteries?

A 12V deep-discharge lead-acid battery is typically 120amp-hours. That's 1.4kWh. Suppose you only 50% discharge it for longevity, that's 700Wh. I'll assume your box of batteries has ten of them, so a usable capacity of 7kWh. 1kWh = 3.6MJ, so 7kWh = 25MJ How high is your roof? Lets say 10 metres. Potential energy U = mgh. (m=mass in kg). h=10, g~=10, so U=100*m. So, to equal those batteries, assuming 100% efficiency,…

So 'roof' is clearly out of the question. Now let's look at basement. I install a 4x4x2 meter tank, then drill down 100 meters to create another such tank. 32 tonnes lifted 100 meters gives me 32MJ, perfect.

Now how expensive is it to build a water storage area underground? Is this a 50 thousand dollar project or a 50 million dollar project?

If the ground water is at the right depth, you would only need to drill a well. So this should be practical somewhere, at least.

Re: Why energy storage sucks

#60

Post by debacle »

wglb wrote: post #26
masklinn wrote: post #12

Earlier quoted context omitted.

> They are only able to store energy for very short periods. Your own link quotes self-discharge rates of 5%/day (for high-vacuum wheels I assume), that's more than sufficient for daily solar storage.

I would consider that to be short-term storage. Long Dark periods could be weeks.

Even a long dark period would see very little discharge. The flywheel would take a trickle of power (enough that a human being could generate, if necessary) to maintain their energy.
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