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Hydrogen vs. Battery
- Thread starter siry
- Start date
nwdiver
Well-Known Member
When it's ~10% it'll be time to start thinking about possibly looking into the potential of maybe getting storage... at some point
When it's ~10% it'll be time to start thinking about possibly looking into the potential of maybe getting storage... at some point
I don't know the scale of the numbers involved, but wouldn't having enough EVs charging during sunny hours effectively "soak up" excess PV power to some degree, if not all of it?
The Caltech system has adaptive charging, where power to all vehicles is controlled. Easily modified in software to simply wait till sunrise or whenever to begin charging.
Expand that out to where there are say 1 million vehicles sitting at work, plugged in, just waiting to soak up any/all available excess power.
Wouldn't that solve the need to curtail excess generation?
No need to build large amounts of battery storage for excess power. Tesla is already doing that by building 1000 storage units per day, commonly known as electric vehicles.
RT
nwdiver
Well-Known Member
Let's say those 1 million EVs are charged at 19.2kW L2, so that is extra 19.2GW that the grid needs to bear.
The peak load in CA's grid is around 50GW the last few years, so you are asking the grid to take extra 40% load, likely causing brownouts/blackouts.
If those 1 million cars can be charged off grid, then that probably will work. So it does make sense to add local, off grid, battery storage to soak up excess PV outputs, and charge EVs with that excess energy off grid.
nwdiver
Well-Known Member
Let's say the peak charge rate for most cars today is ~32A or 7.7kW (Because it is)
Let's say most cars charge off peak since it's cheapest (Because they do)
Let's say we use demand response and EV charging to improve grid stability (Because we can)
Let's say that if EVs are absorbing otherwise curtailed local generation it's not adding to the system peak (Because physics)
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Let's say 7.7kW/car and 1 million EVs, that is still 7.7GW, or 15% extra on top of 50GW peak load in CA the last few years.
Let's say excess PV power shows up at peak daylight hours(yes they do), so it looks like you are suggesting that daylight peak excess PV power needs to be stored somehow, and feed the EVs after dark off peak.
nwdiver
Well-Known Member
If the cars are using PV from distributed generation to avoid curtailment that's not adding to the peak....
Peak limitations are based on transmission and centralized generation constraints. If you're charging a car at noon on a sunny day especially in Southern California you're not using either...
Ties right in with the current discussion:
The rise of EVs could overwhelm the grid, but PG&E has a better plan
Private sector EV or EVSE manufacturers could manage the coming load by aggregating their customers to provide demand response services to utilities, SEPA reported. "There is already adequate charging infrastructure technology to incorporate real-time pricing, and use price signals to shift charging from peak demand periods to times when utilities have renewables over-generation," DNV-GL's Hill agreed.Private sector EV or EVSE manufacturers could manage the coming load by aggregating their customers to provide demand response services to utilities, SEPA reported. "There is already adequate charging infrastructure technology to incorporate real-time pricing, and use price signals to shift charging from peak demand periods to times when utilities have renewables over-generation," DNV-GL's Hill agreed.
The rise of EVs could overwhelm the grid, but PG&E has a better plan
Private sector EV or EVSE manufacturers could manage the coming load by aggregating their customers to provide demand response services to utilities, SEPA reported. "There is already adequate charging infrastructure technology to incorporate real-time pricing, and use price signals to shift charging from peak demand periods to times when utilities have renewables over-generation," DNV-GL's Hill agreed.Private sector EV or EVSE manufacturers could manage the coming load by aggregating their customers to provide demand response services to utilities, SEPA reported. "There is already adequate charging infrastructure technology to incorporate real-time pricing, and use price signals to shift charging from peak demand periods to times when utilities have renewables over-generation," DNV-GL's Hill agreed.
Why is it so hard for you to understand the contradiction between the highlighted statements ???
EVs are charged OFF-PEAK, because that is the cheapest!
Therefore, EV charging never adds a single milliwatt (mW) to the peak load let alone GWs.
Currently, peak demand is during the business operating hours, because thats when the large industrial users require the most energy, which happens to be when the sun is shining, so adding PV needs no storage. EVs are currently charging overnight, because that is off-peak usage and therefore lowest price.
IF at some future point, the amount of power generated by PV dominates total generation (instead of being a minuscule percentage as it is now), AND such generation is more than the demand at sunny hours, THEN power in those hours will become cheaper than overnight, since it is excess, therefore EVs will start charging in those hours. They are typically sitting in work-place parking lots at that time, so charging them then is very much feasible !
How does charging off peak have anything to do with "1 million vehicles sitting at work, plugged in, just waiting to soak up any/all available excess power"?
We were talking about using excess PV output during peak daylight hours to charge 1 million vehicles sitting at work, not off-peak after dark.
nwdiver
Well-Known Member
"Peak" in the context of usage as well as PV generation(e.g. hot clear sunny afternoons), both of which puts extra stress on the grid.
And in your context of "If there's excess power then by definition that's 'off peak'", for sure this type of 'off peak' at the middle of clear sunny afternoons cannot be cheapest, right?
nwdiver
Well-Known Member
That's simply not true unless you prefer burning fossil fuels for providing your base load over nuclear power and hydro.
When it gets dark, your PV supply is 0. If (with your numbers), nighttime demand is greater than 10 GW, you have to run generators at night. Unfortunately:
- You can't readily do that with nuclear, because nuclear power plants can't spin up and down that quickly.
- If hydro and wind can make up the difference, you're already wasting renewable power during the day (i.e. your renewable supply exceeds demand).
If, however, you store renewable power during the day and use it at night, you can reduce the difference in available renewable power so that nuclear generation can run at roughly the same levels at night and during the day, and you can then reduce the amount of power produced from fossil fuels.
nwdiver
Well-Known Member
If PV generation is 40GW and demand is >50GW..... where 'ya getting the energy for your battery???
The point is that it makes zero sense to store energy that could be used immediately.....
And 'base load' is 'non-sense'; It's defined as 'Power Available'. That includes everything.
Again, distributed generation is just a generic term that encompasses rooftop solar, storage, microgrids, etc, etc, that are not grid-tied(at least to the "main" grid).
These distributed generators do see their own curtailments, e.g. utilities impose "export limit" to throttle excess PV outputs to flood back to "main" grid.
Off-grid obviously means not adding to the peak. And by hitting "export limit", excess PV outputs are wasted if there is no local storage.
nwdiver
Well-Known Member
LOL.... where does the 'main grid' start??? The grid is the grid. There are numerous transmission bottlenecks. Point is that if you're charging 'off-peak' when there's a surplus of solar you're not stressing the grid. No one that uses words for what they mean would call that 'off-grid'.... I could be charging at home using solar from the roof of Wal-Mart a mile away and that's not putting stress on 'the grid'. That would be DG but I'm not 'off-grid'.....
How.... how if there is a surplus of solar.... how is making that surplus SMALLER causing INCREASED stress??????
The stress matter if the electrical connections between WalMart and your solar are bottlenecks.
That has happened around here on and off(and this is the heart of SV), e.g. on heat waves in the last few days, when local loads trip up transformers and fuses.
From other power sources. Let me break it down differently. Suppose you have
Day demand: 100-120 GW
PV: 40 GW
Nuclear: 60 GW
Fossil: 0–20 GW
Night demand: 60–70 GW
Nuclear: 60 GW
Fossil: 0-10 GW
Now store some of the solar and replace it with nuclear power.
Day demand: 100-120 GW
PV: 30–40 GW
Nuclear: 70–70 GW
Fossil: 0–10 GW
Storage: 10–0 GW
Night demand: 60–80 GW
Nuclear: 70–70 GW
Fossil: 0–0 GW
Storage: -10–10 GW
Notice that the fossil fuel load dropped in half during the day and to zero at night, the nuclear base load increased, and the only difference is the availability of storage.
Now I suppose one can argue over how much of this is actually storing nuclear power versus PV power, but that's kind of splitting hairs.
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