
Solar and Wind Energy May Be Nice, but How Can We Store It? - evo_9
http://www.npr.org/sections/alltechconsidered/2016/04/05/470810118/solar-and-wind-energy-may-be-nice-but-how-can-we-store-it
======
infiniteparamtr
I haven't researched the overhead costs, but there are alternative kinetic
"batteries" that have been proposed, some of which are already being used:

\- Use excess energy generation to drive a gravel-filled train up a few miles
of 2% grade, back down the track to drive turbine(s) for energy to be tapped

\- Run water up an incline into a reservoir. This can simultaneously serve
irrigation purposes. Water level is indicative of available energy to be sent
through turbines

\- Multi-ton flywheels. I've seen that some fusion experiments use this for
massive, quick energy bursts. Magnetism prevents excessive wear/tear on
bearings

~~~
basicplus2
composite thin cylindrical flywheels have the best energy storage
characteristics

"greater than 400 Wh/kg can be achieved by certain composite materials"

[https://en.m.wikipedia.org/wiki/Flywheel_energy_storage](https://en.m.wikipedia.org/wiki/Flywheel_energy_storage)

~~~
karterk
Flywheels sound exciting but their energy density is about the same as Li Ion
batteries (even when carbon composites are used). There are very few large
scale deployments of flywheel energy storage systems in the world despite lots
of active interest in them. Safety is also a huge concern since if there is a
mechanical failure, a huge amount of kinetic energy will have to be safely
disposed or you are going to have shrapnels flying everywhere.

~~~
jakeogh
You can recharge the flywheel over 10M times. Containment is designed in.

------
crdoconnor
By and large, don't. Let the market for electricity react to fluctuations in
output via variable pricing.

This is already being done to a certain extent in Germany (aluminum smelters
will scale production up or down based upon the supply of electricity).

Over time as fluctuations in electricity supply from renewables become more
common, the demand side will react. Those periods when the wholesale price of
electricity drop to zero won't recur forever as somebody enterprising will
make use of it. It won't happen overnight but it will happen.

It's ironic that the same industry (utilities) that told us the market was a
solution to all of our energy problems when it wasn't (see Paul Krugman's
defence of Enron's bullshit in the early 00s) is now conveniently forgetting
that canard when it's actually true for once because renewables threaten its
bottom line.

------
taneq
Molten salt batteries are actually really good for this kind of usage. High
power output and cycle life are key requirements, constant usage means energy
usage for thermal maintenance is less of a factor, and the fact that it's
stationary means energy density and impact resistance are less important.

------
bluthru
Worst case scenario, how many batteries alone would be required:
[https://youtu.be/NvCIhn7_FXI?t=4m47s](https://youtu.be/NvCIhn7_FXI?t=4m47s)

Surprisingly low.

------
AtlasLion
Molten salts. The world's biggest solar installation being built in Morocco
generates energy at night.

[http://money.cnn.com/2016/03/11/technology/solar-power-
elect...](http://money.cnn.com/2016/03/11/technology/solar-power-electricity-
morocco-ouarzazate-night/index.html)

------
WalterBright
Not exactly storing energy, but a functional equivalent is load shifting. This
means shifting demand from when the electricity supply is low to when it is
high. An awful lot can be done with this.

This can be implemented by adjusting electricity rates in real time, and
having loads that can be shifted monitoring the rates and turn on when they
are low.

~~~
mikekchar
I live in Shizuoka, Japan where a lot of cars and motorcycles are built. When
the nuclear reactors were shut down one of the ways they managed the reduction
in power usage was to have the factories cooperate on their work schedules. So
Suzuki would open from 9-5 and then Yamaha would open, etc. It only lasted for
a few months, but I've heard it made a huge difference in helping the grid
meet demands.

~~~
WalterBright
That makes a lot of sense. Our current system of a flat rate for power
regardless of demand is ridiculously wasteful.

For example, consider an electric hot water heater. The water will stay hot
for a day in a well insulated one. Having it set to run only when rates are
lower would to a lot to match supply with demand, reduce pollution, costs,
etc.

------
jakozaur
Maybe store it in electric car batteries? The ppl already buying Tesla Model 3
at scale.

Why utilities should pay for storage, when they could just offer cheaper
electricity when there is excess of it. E.g. charge your car when we told you
to and save %30 on your bill!

~~~
greglindahl
Yes, this is one of the classic suggestions for overnight or at-work charging:
cars which choose to charge depending on the owner's goals and energy prices.

------
marze
"Nice"? The whole world will be running on solar and wind electricity in 20
years. "Nice" is a bit of an understatement.

~~~
pjc50
Hardly. There are fossil and nuclear plants being built today with design
lifetimes of 20 years. Adoption is certainly shooting upwards in some
countries, but it's going to be a while before renewables go over 50%
worldwide.

------
ccvannorman
LightSail energy [0] has been working on this problem for the past five years.
They store the energy in (surprise!) highly efficient, long-term storage air
compressors.

[0] crunchbase.com/organization/lightsail-energy -- $42M funded

------
dschiptsov
Why shall we?

~~~
reacweb
As usual, the best storage solution is first to avoid storage. It applies also
to network communication, database access, etc. Often used as a first slide of
a presentation, but you still need a follow up.

~~~
dschiptsov
One way of thinking about energy storage is traditional fossil fuels, with a
whole speculator's oil market attached to it.

There is another way of thinking. When one barely have a shortage of
something, like spring water, which flows from mountains (and fluctuates
heavily depending on season, monsoon, etc) one probable doesn't store much and
let it flow.

For wind and solar, it seems, this is much better paradigm. Send it to the
grid when its available, get it from the grid when it is still and cloudy.

------
robomc
Water pumps.

~~~
taneq
You need very particular geography for pumped hydro, plus in hot dry climates
your stored energy literally evaporates.

~~~
cnlevy
A more general solution: just use weights
[https://www.gravitricity.com](https://www.gravitricity.com)

~~~
ps4fanboy
Be interesting to see how you could build this on a smaller scale for home
use, using something very heavy but cheap like lead.

~~~
tsomctl
Lead is actually not that cheap. Lead ingots are $6/pound (at McMaster), while
steel is $.50/pound (from Alibaba, but that's a minimum purchase of 1 ton).
Scrap lead is around $.40/pound, versus steel at $.02/pound. The cheapest
thing would probably be rock/concrete, or water.

~~~
cellularmitosis
A clip and pulley system which could hook onto a barbell or kettle bell would
be great.

Hrmm, perhaps this isn't so feasible. Performing a clean & jerk of 95 pounds
to a height of 7 feet would yield about 900 watt seconds of potential energy.
So even if you had a very efficient laptop (15 watts) and perfect energy
conversion, you'd have to perform a clean & jerk every 60 seconds to keep
computing. Even if you were in good shape, you probably couldn't keep that up
for more than a hour.

[http://hyperphysics.phy-
astr.gsu.edu/hbase/gpot.html](http://hyperphysics.phy-
astr.gsu.edu/hbase/gpot.html)

