[sf-lug] ARES, too (was: Battery Storage to expand rapidly.)

[Rick Moen]

Quoting Bobbie Sellers (bliss-sf4ever at dslextreme.com):

> Hi Team,
>     This is for Don Cox who tells us about energy storage all
> the time.   But this was pushed not by new power sources but
> by the loss of a lot of natural gas which will result in shortages
> by mid-2017 in the Los Angeles area.
> 
> <https://www.scientificamerican.com/article/battery-storage-poised-to-expand-rapidly/

There's a pilot project -- well, a small post-pilot real-world
implementation -- in western Nevada to store electic power in a different way
that I think is brilliantly elegant.  Current capacity of this
deployment, now being constructed, will be 50 megawatts -- and it can
scale cheaply and easily to 2 to 3 gigawatts using nothing but cheap off
the shelf components.

And this, or something equivlant such as the big banks of lithium ion
cells discussed at the link, will be needed soon because of, e.g.,
California's legal mandate for 50% renewable energy by 2030.)


Ready for the description?  I hope you are dazzled by the simplicity and
elegance the way I am.

It's called ARES (Advanced Rail Energy Storage) -- from a group called
ARES North America.  What they have a lot of in western Nevada is empty
dry land, and slopes.  And they have mountains, and thus a lot of empty,
dry land with sloping contour so you can make systems that go up and
down half a kilometer in elevation inside of ten kilometers of
horizontal distance.

And there are two technologies humanity has that are ultra-efficient 
as to energy loss, and we have them down cold.  One is rail transport,
and the other is electric motors.  And pretty much any electric motor,
if you impel its rotors, can do double-duty as an electric generator
instead of a motor.  _And_, western Nevada is a short power-grid
hop away from power-hungry Southern California.

So:

In places with not just moutains but also big reservoirs, you could 
store electricity (during hours when you have excess electricity that
you want to store, like during the day when big photovoltaic farms 
in the desert are pumping out juice) by using an electric motor to pump
lots of water from a low-altitude reservoir to a higher-altitude one.
During the night or at other times you need electricity again, you open
valves to let the water fall back through the electric motor, making it
function as a generator, feeding the grid.  This is cheap if you have
the right topography for two big reservoirs at different altitudes --
and a lot of water to shift up and down.

But you don't _have_ lots of water in western Nevada (nor in the west
generally).  You have dry, you have space, you have mountains.

So, you have a 10km railroad track with an electric third rail.  It has
a 7% grade, and one end is 640 meters lower than the other.  On the
track, you put an engine railroad car with a big electric motor, and on
that car you put a huge 300 tonne block of concrete.

During the day (spare electricity to store), you draw from the grid to
feed the motor, which chugs the concrete block higher up the track.
During the night (need to feed electricity to the grid), you send a
signal to the car to start coasting back downhill, which drives the
motor shaft and makes it function as a generator (aka regenerative
braking), feeding the grid.

Need more capacity?  Either couple additional cars and blocks to the
existing one, turning it into a multicar train, or add more tracks
parallel to the existing one.  Or both.

2 to 3 gigawatts, cheaply, easily, nothing exotic, no pollution, hardly
any noise, no significant environmental impact.  The train goes up; the
train goes down.

For perspective, this is from the cited _Scientific American_ article:

   As much as 1,800 megawatts of new energy storage -- mostly
   from lithium-ion batteries -- is expected to come online by 2021,
   according to GTM Research, which tracks the sector for the Energy
   Storage Association.

   That's eight times larger than total U.S. installed energy storage
   capacity in 2016.

And ARES North America figures it can provide over 50% more new storage
than _that-, just using some concrete blocks and some railroad track.
(But the current phase won't come online until 2019.)  

One advantage batteries have over ARES is instant response to shifting
power demand, but if 5-10 second response time is good enough -- and it
generally is -- then ARES is competitive.  And, unlike lithium ion
batteries, big blocks of concrete, big electric motors, and rail setups
really don't wear out much.

The unknown is whether, at scale, the cost would be low enough --
because the motors cost a bunch of money, as does making 10 km of
railbed able to reliably support a very heavy train.  This we'll have to
wait to see.

http://www.aresnorthamerica.com/article/8878-the-train-goes-up-the-train-goes-down-a-simple-new-way-to-store-energy
http://www.aresnorthamerica.com/grid-scale-energy-storage
https://www.wired.com/2016/05/forget-elons-batteries-fix-grid-rock-filled-train-hill/
http://www.amusingplanet.com/2015/03/gravity-train-as-energy-storage.html
http://oilprice.com/Latest-Energy-News/World-News/Is-This-The-Best-Answer-Yet-To-The-Energy-Storage-Question.html
https://hardware.slashdot.org/story/16/05/23/0334232/nevada-startup-stores-energy-with-trains
http://now.howstuffworks.com/2016/06/09/ares-train-renewable-energy-storage-nevada-blm