California is also going negative quite often now. Instead of dropping prices and encouraging usage during those times they curtail. The utility model is completely broken.
As A CA resident living under the thumb of PGE I have to say that nothing shocks me any more.
The current PGE rates basically redline a whole portion of the state.
Gray Davis got run out of town on the back of Enron's nonsense. The fact that there is abject lack of fall out from the current pricing is, outrageous.
in most of US the cost of residential power is almost entirely in the delivery, not the generation. If folks knew how much they were being fleeced they'd lose their minds.
Or, California just needs to increase its battery storage capacity some more. (This week they announced storage systems now already have over 10,000 megawatts in capacity — "about 20% of the 52,000 megawatts the state says is needed to meet its climate goals.")
That will be a tough game to chase long term as batteries need to be removed and replaced regularly. Assuming the storage capacity needs continue to grow, CA would need to replace larger and larger stocks of batteries on the scale of 5-15 years depending on what kind of warranty the battery manufacturers are providing.
And for lithium batteries, maintaining an overcapacity drastically increases the lifetime by reducing the depth of the cycle. e.g., you get vastly more cycles at %50 DoD vs %80. This would increase the lifespan to be many decades
California isn't exactly known for water management practices, though sure there are storage systems that use kinetic potential as a battery. In theory that can be used at very large scales, if the water and elevation is available for use.
Is be really curious how the math works out with regards to how much water would be required for say 3 days of use in LA. That may even be an over estimate of storage needs given how few rainy days they get.
The California Environmental Quality Act (CEQA) makes it extremely difficult to build new pumped storage facilities. It's possible in principle but will take many years to get through the construction permits and inevitable lawsuits.
California is already planning a giant off-river reservoir that will be dependent on pumping to fill. If it could be set up to kick in instead of curtailment it could be a win win.
That is assuming all batteries are lithium-ion, but the state is going for a larger mix of storage tech.
As just one example, iron-air batteries:
> The CEC is supporting this project through its Long Duration Energy Storage (LDES) program, a fund dedicated to accelerating the implementation of non-lithium technologies offering 8+ hours of energy storage. Form Energy will use the grant funds to develop and operate the project, and PG&E will provide land and an interconnection point at the substation site.
For some reason grid storage reporting always seems to use a power metric instead of storage metric, which makes no sense to me. I've seen this in a half dozen stories, and found that even the government reports do this. I think it stems from someone reusing a column to represent both storage and power across generators and batteries.
> For some reason grid storage reporting always seems to use a power metric instead of storage metric
Grid scale batteries are used primarily for real time demand management, and therefore their most relevant property is how much immediate power they can output and for how long. If they were only described in terms of energy (i.e MWh) without separating the power and time components, then it wouldn't be clear how much immediate value they could provide to the grid.
It's analogous to how in an EV the max horsepower is determined in large part by the power output rating of the battery, but the range is related to the the energy capacity.
>their most relevant property is how much immediate power they can output and for how long.
You listed two properties there.
Only one of these two properties is present in a figure that is solitarily presented as "10,000 megawatts."
We can tell this because only one property is presented.
And because it is a very-clearly ambiguous and singularly-useless instance of a unit that sees frequently-erroneous use, we do not know if this singular figure relates to "how much" or if it relates to "how long."
It probably relates to one of them, I'd suppose.
However... we do know that it cannot relate to both things, as-presented. The singular property presented can't even be extrapolated to relate to both things.
> The singular property presented can't even be extrapolated to relate to both things.
Both things aren't equally important.
The energy capacity of the battery isn't provided for the same reason that coal plants don't specify the size of their coal piles or hydro plants don't specify the potential energy storage capacity of their reservoirs.
Power is the most relevant property to the real time operation of the grid, and the specification of power (and not energy). The grid operators need to know how much power a battery (or other generation source) can provide, and for how long. That tuple <power, duration> what any dispatchable energy source ultimately bids onto the real-time electricity markets.
The energy storage capacity of a battery is a function of what energy market it is designed to fit into.
For example, a battery that primarily functions in the frequency regulation market (modulation of supply and demand every few seconds) doesn't need a lot of storage capacity, but needs high power output. In contrast, a battery that shifts supply over the course of a single day might need more capacity (4 hours).
From the grid operator's perspective, the storage capacity is an implementation detail of the particular power source, or at least a secondary consideration.
It's a measure that makes perfect sense for conventional electricity production: 10,000MW of aggregated coal generation can hypothetically produce 10,000MW more-or-less indefinitely, as long as it keeps being fed things like fuel, water, and maintanence.
But it doesn't make any sense at all, by itself, for energy storage: A net 10,000MW battery might be able to produce 10,000MW, but for how long can that output be sustained? Unlike a group of coal plants, it absolutely cannot do this indefinitely; at some point, that battery will become completely discharged.
It takes at least two figures to describe a working bucket of energy (whether that bucket is Lithium cells or pumped storage or whatever): The capacity (megawatt-hours is a fine figure here, and units like Joules also work), and the maximum input/output (and plain megawatts works fine for this part). Using only one figure doesn't really describe anything at all.
I don't know when or why we stopped doing this, but it's misinformative in a way that leads to a bad generalized understanding of the these concepts with the populace that is actually paying for all of this stuff.
Its fine as long as the amount of time it can provide rated output is longer than it time it takes to bring replacement generation capacity on line.
I don't care how long my UPS will actually last as long the holdover time is long enough to cover the time it takes to deal with all of the foreseeable problems in starting up the backup generator.
I don't think that grid-scale batteries are working with consumers on the grid in the same way that your home UPS is with you in your house.
Perhaps most-obviously: Consumers who are suddenly running on grid-scale batteries have no idea that this is a thing that is happening. There's no signal for them to shut their stuff off -- automated, or not.
It's a whole different paradigm than your UPS under your desk is: With your UPS, your system(s) receive a signal that things are running on local battery, and you've elected to configure things to use that signal to order an automated shutdown.
But, again: That doesn't happen with the grid-scale batteries under discussion -- at all. You're comparing apples to dildos here.
(Which is not to say that grid-scale batteries offer new opportunities for power cuts, because the opposite of that is true. It is instead just to say that unknowingly using grid-scale batteries is nothing like monitoring a local UPS is.)
I mean during the great texas power outage natural gas plants ran out of fuel because of supply issues that were not typically supply issues it would be more honest if every power plant also listed it's on hand 'fuel battery'. Now I'm sure they may do this with ERCOT, but it's not something typically reported.
Why, sure. It would be good to know how long a conventional generator can keep running when everything around it has gone wrong. For coal, for instance, that might be represented by the mass of the piles of coal that are normally on-hand -- or by the electricity (in MW-h, say) those piles of coal should be able to produce. Having this information close by would seem to be a good thing for an organization like ERCOT, so as to be factored into their emergency playbook.
But that's still a different case than a battery, wherein: Even if everything is going right, using energy from a battery must eventually cause it to become depleted.
It's never like a coal plant that (ideally) consumes fuel at one end, and spits out electricity at the other end as a continuous process. A battery, in this context, can be in a charging or a discharging state, but it can never be in both of those states at the same time -- using a battery is not at all a continuous process.
Best I can guess is batteries are rated by name plate power. And raw capacity is about 3-4 times that.
Wouldn't surprise me if there is a bunch of finkie dinkie technically driven accounting stuff around how fast and how deep a charge and discharge cycle they're willing to do vs price. Not to mention adding supply effects the price as well.
Your link claims that curtailment is largely due to congestion - "when power lines don’t have enough capacity to deliver available energy". Dropping prices will not help with that?
The current PGE rates basically redline a whole portion of the state.
Gray Davis got run out of town on the back of Enron's nonsense. The fact that there is abject lack of fall out from the current pricing is, outrageous.