[KaiserJeep]

Arpa-E's $85 Million Plan to Build a Battery the Size of the Grid

By Mark Anderson

As the electric grid is increasingly powered by renewables, it will need energy storage for when the wind isn’t blowing and the sun isn’t shining. But the three top grid-scale energy storage technologies today—pumped hydropower, lithium-ion batteries and “flow” batteries—arguably, aren’t up to the challenge.

The U.S. Department of Energy’s technology incubator ARPA-E (Advanced Research Projects Agency-Energy) wants to change that. It’s going long on a number of high-risk, high-reward R&D projects that might change the entire grid storage equation. U.S. Energy Secretary Ernest Moniz has said he thinks grid-scale battery storage will be the key innovation that enables the grid to completely decarbonize by midcentury.

“There’s a lot of discussion about what the grid of the future will look like,” says Eric Rohlfing, ARPA-E Deputy Director for Technology. “Of course what we want to do is enable much higher penetration of renewables. So storage is an obvious way to do that… The two key points of grid storage are: it has to be cheap, and it has to be durable—to go through a lot of cycles.”

Full article is at: http://spectrum.ieee.org/energywise/green-tech/fuel-cells/arpaes-85million-plan-to-build-a-battery-the-size-of-the-grid

[SeaGypsy]

Rocks in railcars is good, can be done using junk. Lithium for the grid is fantasy land. The flow battery work around iron chloride sounds good, time will tell if it's scalable, cheapness & common available inputs will help.

For efficiency an extremely perfectly balanced flywheel riding on a magnetic field in a vacuum was invented decades ago & it's a mystery to me why they are not 'around'.

[Simon_R]

Hi Seagypsy

The rocks in trains is an interesting idea, but you would need the right geography, ie a nice long slope. there is no point generating 1Twh when what is called to balance the grid is 100mwh.

Pumped storage is the way to go, we have loads of mountains and we need gravel, its a win all around.

Flywheel, probably because no one has done this as a POC, sounds expensive and with leccy at about 35-45 Eur/Mwh it doesn't sound financialy viable.

thanks

Simon

[dolanbaker]

Building tidal lagoons along the coast would be one of the best long-term strategies as tidal energy is the most reliable form of natural energy. While some lagoons are producing electricity from the difference between internal and external water levels other lagoons can be "charged" by pumping water in (or out) to produce an extra large height differential to allow for a windless night or other energy sapping reason.

[ROCKMAN]

And for the benefit of those who don't bother to read more then the thread titles:

First, there is no new plan: the program started 7 years ago in 2009.

Second, if one thought the title meant they were going to try to build an "$85 Million Battery the Size of the Grid" you're wrong: the $85 million is the research budget they've already distributed: "ARPA-E has invested $85 million in energy storage research projects since 2009. The website for ARPA-E chronicles some 73 projects at companies, labs, and universities—among them, MIT, Harvard, Stanford, UCLA, Penn State, Oak Ridge National Laboratory, Lawrence Livermore National Laboratory, Ford, Boeing and General Electric."

Third, there was never a plan to invest $85 million to research the development potential of a grid scale storage. Most of those funds targeted other storage systems such as ones folks have been discussing here: "Of the 73 energy storage projects listed on ARPA-E’s website, the agency recognizes eight grid-storage technologies that it says are very promising and/or well along the path to wide-scale deployment."

So time will tell what shakes out. Who knows: maybe they can create a grid size battery system that might only cost several $billion.

[sparky]

.
Just to get things in perspective a battery holding 50 MW would be equivalent to 43 ton of TNT
if it goes pop , the neighbors would be somewhat inconvenienced

I love the concept of the rolling storage , it's great fun and seems doable ,
no need of having a slope , a flat loop would be better ,
what matter is the inertial force of 1000 tons of rolling metal ,one could even make some or all the load a set of flywheels

there is plenty of options with electric trains ,
some regenerative braking is even already used
they could be used as DC /AC convertors for interfacing with those pesky renewables

it would be really neat

it would not be to supply the grid for days on end
just to dampen the peak and trough as any decent storage should
A massive problem is the interface between the wire and the train ,
overhead line with existing pantographs don't have a lot of instant capacity

playing with trains is great fun even if it's a money wasting effort ,
after all plenty of stupid energy schemes have been subventioned costing a great deal for zero practical use

[KaiserJeep]

No, sparky, the inertia of a level rolling train is not where (very much) energy could be stored. The energy storage is in the vertical displacement of all that weight, as the electricity is consumed in the electric locomotive drivers that move the train uphill. Then as the train rolls downhill, energy is generated when those large electric motors are reversed as generators. It is a larger example of the "regenerative braking" used on smaller EVs.

The key to an efficient energy store would be a constant slope on the tracks, which would be optimal for power recovery as the train would be at a constant speed when both ascending and descending the mountain.

As for flywheel storage, I have seen it it the older buildings in Chicago and New York, back when I visited my former employer's customer sites - flywheel UPS storage is cheaper than batteries for very large computer rooms - so that as time passes and computers and their power requirements shrink, it is going away.

A flywheel UPS uses a motor generator with a large motor at one end of the shaft, a generator at the other. In between, on the same shaft, are a number of modular wheel-shaped flywheels, the more storage needed, the longer the shaft and the more flywheels and the more energy stored. In between each motor and flywheel is a large bearing which has a pressurized oil supply, the finely machined sleeve bearings "float" on a film of pressurized lubricating oil, there is no metal-to-metal contact until you shut the UPS off and it spins down, and you shut off the lubricant feed.

In operation, you turn on the electric motor and spin up the flywheels, while monitoring the AC line frequency from the generator. When the AC gets to about 48Hz, you start up your computers and other UPS protected equipment. (Most large computers are designed to work on either 50Hz or 60Hz power.) Then as you approach 60Hz, the motor is throttled down by reducing the power input. Note that you have been accelerating the flywheels for approximately 30 minutes and that all the electricity consumed to spin up the flywheels is stored as mechanical energy.

When power goes away, the critical UPS-protected loads such as the computer CPU and memories (disks or solid state) and emergency lighting and one operator console per each computer and your fire protection system are kept online by the flywheel energy storage. Non-critical loads such as room lighting and HVAC are shut down when the main power goes away. You then have 20 minutes or so to start up the diesel generators to replace the main power. Your critical loads stay online as the mechanical energy is bled off, and the power frequency bleeds down from 60Hz to 48Hz at which point you either have to shut the computers off or begin spinning up the flywheels again.

All the equipment I am describing is rather large - found in brownstone buildings when computers were IBM type mainframes, and still in use with newer computers. In the most recent machines, the UPS is a battery tray with an inverter circuit, in the same rack as the computer hardware itself.

[ROCKMAN]

Sparky - An even better idea: put wind turbines on top of the rail cars. Imagine how much electricity the would produce with just a constant 20 mph wind. And then think of the solar panels mounted on the tops ofvtyhe cars under the turbines. Damn, it might be close to a perpetual motion system!

KJ - Have fun but be gentle. LOL.

[Simon_R]

Rockman

I have heard of a power island concept. Whereby you have windmills surrounding a pumped storage facility, then there is no energy flowing in, only out. So surrounding your leccy train with windmills is not such a crazy idea !!

Simon

[sparky]

.
@ Rockman ..." flywheel UPS storage is cheaper than batteries for very large computer rooms "
probably more reliable too , those UPS are expensive and a headache to maintain .
I know ! that was one of my jobs
the best system I saw was a DC motor linked to the batteries banks powering an AC generator ,
the motor rotating inertia avoided the milliseconds drop which would crash the system
as for computer rooms needing less power !!
the power requirement is increasing a bit less than the computing power but it is following the same curve

....the UPS "in the same rack as the computer hardware itself."
ours were in the same building ,with their own floor , row upon row of cupboards filled with stacks of batteries .
it didn't just power computers , it gave back up to 200 kw motors and the whole factory instruments and control
about 5000 loops items and this just to maintain power until the diesel generators got up to speed
..if and when they started

-"The inertia of a level rolling train is not where (very much) energy could be stored"
....to have an idea of the inertia power of a 1000T train going at 40 miles per hour , just stand in front of one !

admittedly the friction losses would be very great .
I'm not saying this would be a word saving system but it would be sooo fun to tinker with !

[Simon_R]

Given 1 Watt is 1 Joule for 1 Second

A 500 Tonne Train
A 1km useable slope (not gaining speed, that is generating range)
50% efficiency
60Kmh Generating speed (speed needed to get it all moving)

You will be generating for only 16.67 Seconds
but will generate a huge amount of energy, enough to blow most carrying capacity, and almost entirely useless.

you would need the train to be running for 30 mins minimum to be useful, and given 60Kmh that's a 30 Km slope (plus 1 or 2 to get up to speed)

That's the only downside I can see

Simon

[vtsnowedin]

Loaded railroad cars are 100 ton each and trains can be 100 cars long.
But not that practical beyond regenerative braking for commuter trains that make frequent stops wherein the energy generated doesn't need to be transferred to the grid just returned to the drive motors on restart.
A more practical Grid battery may one day be all the plug in electric vehicles we may one day drive. If there were say fifty million of them plugged in sixteen hours a day while the owner was working or sleeping. A central control computer could drain power off units as needed to balance wind and solar fluctuations and just top off each unit just prior to the next planned trip.