Advanced Rail – New Concept in Energy Storage
Jim Kelly, CEO of ARES (Advanced Rail Energy Storage) has generously consented to do a webinar with me in the near future, which I think readers will find valuable. Insofar as solar and wind are intermittent resources, energy storage at the utility scale is a requirement if we are going to integrate large volumes of renewable energy. Currently, there is 129 gigawatts of energy storage on the grid, almost all (over 99%) of which is pumped hydro, i.e., water that is pumped uphill in time of excess power capacity, then released downhill to generate electricity in order to address peak loads.
ARES replaces water with extremely heavy rail cars, and the company claims that its solution is faster and less expensive to build, while providing better efficiency. Are they on the right track (pun intended)? More on this soon.
Just as well they didn’t call themselves Advanced Rail Storage of Energy! They might have had to back out in embarrassment. Let’s hope they don’t get steamrollered by the opposition.
This looks quite interesting, Craig – I’m curious about the capacity and engineering. I look forward to learning more about it. We can always use more, and better, storage solutions!
It’s too soon to know whether this will be practical, but surely it would make sense to do the necessary R & D and, if it seems promising, try it first on a small scale.
Craig,
This concept cannot compete with pumped-hydrostorage. That’s likely not their intent (if it is their intent it won’t work). Their competition would be for high-power / short-duration / multiple cycles/day storage needs… which means they’ll be competing with some battery technology and things like flywheels.
The cost/power handling would be less than a comparable water pump/turbine system, but there would be an extraordinary cost for energy capacity. So this could only be viable in high power/low energy installations.
Note I’m not discounting it at large… I’m just saying that it wouldn’t compete with pumped hydro in applications that are suited for pumped hydro.
I agree with Glenn, there is no way this system could compete with pumped hydro on “continuous power for days” basis, however for lots of power for an hour or two for peak shaving, and ramp rate buffering – giving extra time for conventional power stations to adjust their output, the system looks interesting.
Suppose you have a large solar farm – on a day with intermittent cloud,you might have output rise and fall by tens of megawatts hundreds of times a day. This system could part cycle hundreds of times a day to give a smooth net output removing the need for peaking plant to make these adjustments.
Gary,
I suspect this will not be competitive in any application where power is required for more than a couple of minutes – at best.
Pumped hydrostorage is usually used for a few hours at a time at most.
Why do you think this? It would seem to me that the operator could throttle these cars for a wide variety of power settings, including lower power over a longer period of time.
I have just looked at the ARES website
http://www.aresnorthamerica.com/grid-scale-energy-storage
ARES are claiming the capability to scale all the way to gigawatt plus with around 8 hours worth of power at this level.
Given that energy = force x distance (approximately 10 newtons needs to be applied to lift 1 kg by 1 meter) you would need to lift 36 kg by 1000 meters to store 1 kWh. 36 tons by 1000 metres for 1 MWh, and 36,000 tons by 1000 meters to store 1 GWh. (This at near 100% efficiency). In practice, 80% would be an exceptional achievement)
In other words, we are looking at a lot of very heavy carriages moving a long way up and down a mountain.
Possible? Probably, practical and cost effective – still to be confirmed, however there are inevitably going to be geographical limitations on where this opportunity exists.
I think that this technology will bias towards high power rather than high energy and be best suited to balancing frequent large variations of relatively short duration – possibly competing with batteries or even ultra-capacitors in stabilising the grid.
Using or deferring hydro generation scores strongly for longer term storage – weeks or months, and pumped hydro possibly comes somewhere in the middle mostly in the range a few hours up to a day or two.
Craig,
I’m answering here because it’s getting a little crowded up there.
Gary responded well with regard to the physics. I’m going to respond with the economics.
For any fluid (H2O, oil, mass of fine grains, etc), the motor that is used to accelerate the fluid to a higher elevation can accelerate a small portion of the mass, while leaving the rest of the mass untouched – but that mass can still be immediately available for gravity acceleration so as to recover the energy stored.
The pump doesn’t have to lift a billion tons of water up the mountain, it just has to pump a few hundred gallons per second.
With large solid mass – like rail cars – that is not the case. Whatever mass you are lifting has to be lifted all at once, which means the motor driving the mass uphill has to be quite large with respect to the total potential storage. Furthermore, steel fashioned into rail cars is extremely expensive compared to water…
All told, the potential energy stored should be small and expensive compared to the power handling of the system – which is the opposite of pumped hydro, where the water handling systems, the pumps, and the turbines are expensive… but the capacity is very cheap per MWh (just set up a few dams in a good bowl-shaped geological formation).
This is total BULL PLOP!
They propose to build a 4 track rail line with a 10% gradient to achieve a 1 km rise.
A 2% gradient is a VERY STEEP hill for a freight train.
Never mind, I am sure they plan to sprinkle FAIRY DUST on the wheels to improve the grip.
Tell me dudes…is that a constant 10% grade?
Or are you planning a freaking ROLLER COASTER?
Sad thing is, they will probably find plenty of dumb bureaucrats or fund managers to stump up plenty of OTHER PEOPLES MONEY!
(sigh)