
How Edison uses water to store excess power - adventured
http://www.latimes.com/business/la-fi-big-creek-20150823-story.html
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amelius
> State regulators in October 2013 set a target for utilities to bring 1,325
> megawatts of new storage online by 2024. It would take more than six times
> Eastwood's 200 megawatts of hydro storage to meet that goal.

Shouldn't storage be measured in Joules instead of Watts? Or are we talking
about the maximum power output of such facilities? (In which case, the more
important number of the actual storage is missing here.)

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sopooneo
Could they have been mixing up megawatts and megawatt-hours? Regardless,
personally, I despise the ubiquitous usage of *watt-<time> over joules.

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dredmorbius
Why?

After all, a Watt is simply a Joule/second.

Watts are how we measure power. A Watt second (joule) isn't particularly
useful. A watt-hour (or kWh or MWh) makes sense for many industrial processes.

Otherwise we're talking 3600 Joule / kilojoule / megajoule quantities (seconds
per hour).

Or multiples of 86,400 per day.

Sensible units aren't always decimal.

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ZeroGravitas
Is there any good write-ups on how pumped hydro has responded to the new
reality of cheap noontime solar power? Naively it would seem that they could
double their effectiveness by running two pump-discharge cycles per day.

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jessriedel
What are the costs of using hydro energy storage in places not affected by the
drought, and just sending the energy over transmission lines? Obviously this
results in substantial loss along the lines, but those costs might be very
acceptable stop-gaps if droughts are sufficiently rare. I just have no idea
what the orders of magnitude are.

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keithpeter
UK National Grid transfers power from North to South reflecting the population
density gradient (not because of drought!). The Wikipedia article on National
Grid will give you a ballpark figure on line losses and distances involved.

 _" There is an average power flow of about 11 GW from the north of the UK,
particularly from Scotland and northern England, to the south of the UK across
the grid. This flow is anticipated to grow to about 12 GW by 2014.[12]

Because of the power loss associated with this north to south flow, the
effectiveness and efficiency of new generation capacity is significantly
affected by its location. For example new generating capacity on the south
coast has about 12% greater effectiveness due to reduced transmission system
power losses compared to new generating capacity in north England, and about
20% greater effectiveness than northern Scotland."_

[https://en.wikipedia.org/wiki/National_Grid_%28UK%29](https://en.wikipedia.org/wiki/National_Grid_%28UK%29)

Another quote I can't resist...

 _" Following the unauthorised but successful short term parallelling of all
regional grids by the night-time engineers in 1937, by 1938 the grid was
operating as a national system."_

Imagine hacking the electricity supply for a whole country?

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tedunangst
What does that last quote mean?

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keithpeter
Good question. I've been googling and found nothing.

I think it means that they had regional power grids running with emergency
links between them (nearest neighbour basis?) already in case a large part of
the generating capacity in one region was lost or in case a site near the
boundary of one region became disconnected from that region's main line.

One night they decided to try to activate all the inter-regional links so that
power from all the power stations was available across the whole country. I
got confused by the 'in parallel' bit, but then you would hardly be connecting
them in series!

The grids would have been 3-phase and the frequency was controlled to be near
exactly 50 Hz, but then you would have to synchronise the phase of each pair
of grids before you made the link active... Any electrical engineers around?

This historical incident would make a good magazine article I think.

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wcchandler
If I had money to invest, this is why I'd be dropping it into commercial
battery backup manufacturers. Losing the ability to store electricity will
cause greater discrepancy in costs during peak hours and non-peak hours.
Instead of just maybe $0.03 per Mwh between peak and non-peak we might start
seeing $0.05-$0.10 differences. It won't even be about being able to sell the
energy BACK during peak times, it'll be so companies have more control over
the costs of this utility.

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jkot
Similar plant is near my home in Central Europe. It uses the same turbine to
generate electricity and push water up 1,670 ft (reversing turbine). Startup
time from zero to 650MW is 150 seconds.

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vermontdevil
Perhaps another benefit for having a desalination plant. Create fresh water to
be pumped into these hydro storage facilities?

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elektromekatron
It seems to work well in Scotland, but then there aren't exactly the same
drought problems.

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

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keithpeter
There are quite a few pumped storage schemes in UK [1]. We have the advantage
of the national grid (and a smaller country!) so we can have a mix of base
load stations and spin up higher cost peak demand stations. Pumped storage
allows some base load power to be stored against demand peaks.

[1] [https://en.wikipedia.org/wiki/Pumped-
storage_hydroelectricit...](https://en.wikipedia.org/wiki/Pumped-
storage_hydroelectricity)

