
Electric cars may hold solution for power storage - EEGuy
http://www.latimes.com/business/la-fi-electric-cars-20131229,0,7309111,full.story
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jawns
My first impression:

This idea sounds great ... until you need to hop in your car and drive
somewhere midday and learn that the battery is mostly drained because it's a
hot day and everyone's turned their A/C on full blast.

I'm sure the engineers have thought about that scenario and maybe only allow
20% of the battery to be used for the purpose of grid maintenance, but I
imagine it will be difficult to sell the average car owner on the idea,
because people are always thinking about worst cases.

I mean, think of it in terms of a conventional car. How would you like to
never know with certainty whether you have a full tank or not when you get in
your car?

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sliverstorm
The other problem: Constant activity (charging/discharging) is going to murder
battery longevity. Murder with a rusty spoon.

~~~
msandford
The car batteries are really only stop-gap measures to allow the utilities to
better match their plants with demands. It's for synchronization only.

A coal power plant might take several days to reach a "set point" and to
generate a certain amount of power.

A natural gas plant might take as little as 5 minutes or as long as an hour to
get operational.

A diesel generator might turn on and make power in as little as 30 seconds.

A hydro plant might be able to go from 0% to 100% in just a few seconds.

Given that the utility companies can't KNOW for sure EXACTLY how much power
people will demand in the future they've always got excess capacity ready and
waiting. But these idling plants aren't free and that drives the price of
electricity up.

The idea behind V2G is that the utility companies can get some of their demand
power from the cars whilst they fire up diesel generators or natural gas
plants or whatever, thus saving them from having to keep those plants idling
until they're definitely needed.

EDIT: The idea isn't that you constantly charge/discharge car batteries it's
that you charge them in the morning after the drive to work so they're full by
noon. Then as the day heats up you can pull small amounts of power from large
amounts of cars until the demand is high enough that you fire up a peaker
plant. Use that to charge the cars back up and provide the afternoon A/C
electricity and shut it down as everyone starts to go home.

Instead of having the peaker plant be at ~20% capacity from 12-2, ~60%
capacity from 2-5 and ~30% capacity from 5-7 you get to run 0% from 12-2,
80-100% from 2-5 and 30% from 5-7. Two hours of runtime saved per day is 600
hours per year. Turbine rebuilds aren't cheap; a buddy of mine is a private
jet pilot and they have to put away between $500 and $2500 per hour that
engines are running for overhaul at either 1000 or 2000 hour intervals. And
that's for the kind of small engines in a 6-12 seater business jet. I'd wager
that 20MW (~20,000 HP) natural gas turbines are substantially more.

~~~
sliverstorm
You wrote a very long post about the benefits. Thank you, but I already
understand that. This _really_ doesn't address my post in the slightest!
Unless I'm just thick as a brick here.

~~~
jonmrodriguez
I think msandford is thinking that you think that this system would charge-
cycle a car more than once per day, and if you do think this, he's addressing
it by pointing out that the car would be charge-cycled only once per day, or
less given that the system wouldn't need to utilize every car on a given day.
So this extra <= 1 charge cycle per day shouldn't "murder" the battery
longevity (or at least murder is way too strong of a word) compared to normal
daily driving.

~~~
msandford
Yes I was getting to that in a roundabout way. It wasn't very clear. You're
going to have two charge cycles per day driving to and from work probably, and
one or less for the V2G scenario. So it doesn't seem terribly murderful on
battery life to me. Should have made that a lot more clear.

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eigenvector
The biggest obstacle, in my opinion, to vehicle-to-grid (V2G) applications is
distribution utilities. All utilities have comprehensive procedures for
studying and approving connection of distribution generation resources to
their networks (rooftop PV, small CCGT, etc.). These take in account the
maximum possible output of the generation asset as well as how they will
behave under fault conditions.

They're already quite stingy about approving customer-owned DGs (because there
is little or no financial benefit to the utility) - I can only imagine how
they'll feel about people connecting a generator they don't control, at
locations and times they can't predict, with the ability to disconnect them
arbitrarily and drive away.

In order for V2G to become a reality, utilities will need far more advanced
software and metering infrastructure to perform real-time load-flow analysis
of their systems and determine if/how to dispatch connected EVs. At present
few utilities even have the metering infrastructure to enable that kind of
intelligent control, let alone the supervisory control software.

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EEGuy
>[eigenvector]... utilities will need far more advanced software and metering
infrastructure

...and as I take it from other discussion, re-design, -engineering and
replacement of some distribution station equipment and software to allow net
power flow upstream when a substation's downstream DG exceeds downstream load,
presently taken to be a fault condition.

A DG participation fee payable to the utility for infrastructure development
and upgrades seems reasonable to me in light of these considerations.

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coin
Do they factor in the fact that battery capacity diminishes with each
discharge/charge cycle?

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EEGuy
This "Vehicle to Grid" idea has been around for a while. The article cites
some progress (a trial program in SoCal).

It's noted that using one's car to contribute to grid stability may void
current battery warranties, about which the article notes:

"Innovators in the field are gradually convincing car manufacturers of the
potential to create a "value proposition for the car owner" and thus boost
sales, Gage said. Ultimately, however, carmakers may be put at ease by
experiments being conducted by the military."

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fit2rule
Recently there have been quite a few debates on the subject of
solar/alternative-energy users feeding power back onto the grid .. and the
latest story seems to be that power companies are attempting to fight off the
impending doom of self-powered individuals by stating that 'it costs too much
to update the grid to allow everyone to push to it, so these alternative-
energy users should pay a hefty fee to upgrade the grid'.

Well, this story seems to point to the solution: put batteries in all the
things! If its going to cost more to feed power back to the grid, then why not
just make everything in your home store its own local power supply ..

To some extent, I'm already doing this - pretty much every electronic device
in my house uses rechargeable batteries. So maybe the campaign by the
utilities against feeding power to the grid is going to have the effect of
pushing everyone to localise their power needs even further, and instead of
pushing excess to an ageing, antiquated monopoly, us alternative-energy freaks
are instead going to foster the creation of a heftier market for battery-
protected devices. (I'd be quite happy to run my TV on battery power, if it
only had one in it, like my laptops and cell phones and toothbrushes do ..)

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malandrew
I would imagine that the best batteries would be reservoirs. Take two spaces
that hold water. One at high ground and one at low ground. Pump the water from
low ground to high ground when energy is plentiful and let it run through
generators when you need energy. Yeah, there is going to be energy loss, but
this approach should scale to the quantity of energy necessary to provide the
same amount of energy as a power plant for 12-24 hours.

~~~
willthames
Dinorwig power station in North Wales does this.
[http://en.wikipedia.org/wiki/Dinorwig_Power_Station](http://en.wikipedia.org/wiki/Dinorwig_Power_Station).

For a consumer though, a single KW (3.6MJ) of power would be generated by
moving 10m^3 (i.e. 10KL) of water 36m (approximating gravity at 10ms^-2). You
can tweak those numbers but you end up needing two sizable water tanks quite
far apart. Great if you have loads of land but not much use for consumer
storage.

Feel free to correct any flaws in the calculations, I'd be much happier if I
were off by an order of 10 or more.

~~~
malandrew
There's a second benefit to this approach in that you could use potable water
tanks and fully sealed piping. This would provide many people with water to
use in the event of an emergency. Obviously they would need to balance the
needs of water with its utility as a way to store energy, but so long as you
conserve both in the event of a disaster, you should be able to replenish what
you've used via rainwater if the system is set up to collect rainwater and
filter it (except in dry areas or during a drought of course).

How long would 1 KW last for the average household, and, if 1 KW is not
enough, how many cubic meters of water would the average household have to
store?

~~~
willthames
How long 1 kilowatt hour would last is a difficult question - depends on how
efficient the home is and what tasks need to use that energy (for example, AC
is very expensive but tends to be needed most when solar energy is available).
Heating and cooling are most expensive.

Our energy usage in a not particularly well insulated home but in a
subtropical Spring averaged about 9kWh/day - so 1kWh (3.6MJ) wouldn't get us
far - it probably barely powers the fridge! However, you'd only need the
storage overnight, and use solar energy the rest of the time. In sunny climes,
at least.

Again, how much water depends on how much vertical drop, but it would likely
be a lot of water (if you sat one cubic tank with 4.4m sides on top of another
then emptying the top into the bottom would theoretically generate 1kWh)

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kineticfocus
It'll be interesting how the energy landscape gets defined in the near future.
Of note, there's a funded kickstarter that stores energy in residential
flywheels that appears to be another promising solution:
[http://www.kickstarter.com/projects/1340066560/velkess-
energ...](http://www.kickstarter.com/projects/1340066560/velkess-energy-
storage/posts)

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kimonos
One concern is that: Can they perform well like the fuel-powered cars?

