> 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.)
My guess would be the limiting factor is actually the capacity of the turbines, not that of the reservoir, in which case it makes sense to talk about watts. I agree that it is a weird way to talk about it though?
"The 1.3 gigawatts is a capacity target, because different storage technologies have different rates at which they can accept and discharge energy, and the mandate aims to be technology-neutral."
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.
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.
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.
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."
"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?
I love how it's the engineer's job to keep everything running, but not to do anything too forward-thinking, lest management get all uppity that it wasn't their idea.
Right, so it seems to me that a ~20% loss is acceptable in order to weather the occasional drought. So I don't think the droughts and their interference with the hydro power storage are super important.
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.
Their original grid was actually more like a bunch of little grids with no connections except a few for emergency use only. The night time engineers apparently just said fuck it, lets make it one big grid and turned those emergency connections into normal connections.
Off-peak time for California is probably also off-peak time for anywhere else that can buy electricity from California. If they don't have the option of storage, they do try sell excess capacity, to the extent that other markets are willing to pay for it. They say this in TFA:
"The first tool currently available is to find electricity generators to submit bids to reduce their output, Greenlee said. If that doesn't work, then there's an effort to export the electricity elsewhere — often at negative prices, which means power generators pay someone to take their electricity."
The article is kind of mis-representing the purpose of the system: it wasn't built to store energy from renewables, but rather, to even out demand spikes on the grid. Losing a system like this just means that they've lost a tool for managing fluctuations on a short-term basis. They have to resort to selling excess power at low-demand times (possibly at a loss), or disconnecting generators in order to keep the grid stable. They'll do whatever is most cost-efficient, but both options are probably inferior to the storage system. A big ol' capacitor like this gives the grid manager an extra margin of safety before having to do something drastic to keep things stable.
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.
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.
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.
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.)