as a potential owner of a solar home with large (DIY) powerwall type storage: I am not a fan of this idea. I know how cycle life and cycle depth affects the overall lifespan of LiIon, LiPo and LiFePo4 type batteries. I want to control how many times my home cycles its batteries from full down to 10-15%, how deeply it can discharge, etc.
I do not want some remote agency controlling the discharge of my home battery, except in a miraculous future scenario where we invent batteries that are good for 20,000 deep cycles with <5% degradation over 20+ years.
If this usage means having to replace the batteries more frequently (or at all; for some people they might last a lifetime with typical use) will they subsidize the cost of replacement too?
Otherwise it's a losing proposition for the homeowner.
Would you accept the trade off for significant subsidies on installation?
also, but think the jury is still out on the power walls, there is evidence that Tesla batteries in Model S have much reduced battery degradation than previous experience would suggest. Which is interesting but needs more study
Nickle-Iron batteries have 50k+ deep cycle lifetime, though they are expensive and have numerous other drawbacks (poor efficiency, high self discharge). They are typically found in applications where cycle life matters more than any other parameter.
> except in a miraculous future scenario where we invent batteries that are good for 20,000 deep cycles with <5% degradation over 20+ years
That future may not be so miraculous since various flow and liquid salt batteries supposedly offer such properties. But you probably won't see them in homes since they only work economically at larger scales.
Build and deploy the homebrew system quickly if you want to avoid California Rule 21-style grid support mandates. Depending on where you live and how cooperative (!) your utility is it may already be too late. Good luck
Once off grid solar battery tech is mature it will transform the housing market. Hoping the utility bureaucrats and their captive politicians don't destroy this opportunity by commandeering our batteries
I have a hard time believing this. There's simply not enough lithium in the world to support every house having its own battery, let alone support all of the EVs coming into production.
Besides, there's genuine benefit being hooked up to the grid. I'll gladly pay the $10/month interconnection fee just to have that as a backup to my battery.
There is plenty of lithium. Reserves are low because until recently demand was low and so no one bothered to go and look for more. And then there is virtually unlimited lithium in the ocean, which costs more to get, but would still be a small part of battery costs.
The bigger problem is cobalt,but from what I understand people are working on various alternatives.
If you get one of these batteries with the main goal being backup power for your own home in case the grid goes down, why would you ever join such a program? Presumably, if you tie your battery to the grid, and there's some sort of issue with main backbone generation, the grid would pull from your battery for what it thinks is a temporary issue, after which all power would be gone, and now your backup has been drained.
This effectively means that the only people that would join are people who would be paid to do so, but then that introduces the question of whether it isn't simply cheaper and more efficient for power companies to just deploy larger scale batteries that they control, rather than pay random people to put them in their own - much more uncontrolled - homes.
The only answer I can think of is that people are using these batteries to avoid peak electric prices during the day, while charging it up when electricity is cheap. If that is your plan, and you don't care much about having electricity when the city goes black, you could join the program.
Batteries last longer when you don't use their full range, so if the grid can tap the first half it can get more recharge cycles than it owned a smaller battery, second you benifit if the grid goes down and some charge happens to be in the upper half. Making this a win / win.
Or if the odds of that are rather low, say 1/20 and the income is significant then you might gain benifits 95% of the time for 1/2 the cost of a 100% solution which is often a worthwhile tradeoff.
One thought that comes to mind is that household power outages are usually a result of a downed power-line, blown transformer, or similar. Your connection to the grid is lost, but the grid still has plenty of power.
In that case, you wouldn't put power back into the grid b/c your connection has been broken. You use the battery for your own power instead.
California has a major issue with Solar (duck curve). I think the goal would be to incentivize additional storage, so when the sun goes down and they suddenly need 8 GW, they can lean on the batteries as gas is ramping up to replace the lost power.
The exact same thing that would happen today if some hacker ramped up production from a natural gas plant. Either the rest of the grid would respond by ramping down production or voltage/frequency would go out of whack.
Seconded. This isn't a new issue with storage, as SCADA is used everywhere. Look up the article from Wired on the Ukrainian Grid Cyber Attack. They got into the utilities operations center and started remotely opening circuit breakers and took out many key substations and then DDOS the phone systems so customers couldn't call in and let them know what was going on. Horrifying stuff.
Makes sense. The one difference is see is the speed which you could ramp up the power and the amount of current you can draw.
Even the fastest gas plant presumably needs a few seconds to power up - enough time for the network to react. Additionaly, the maximum power and current it can deliver is generally known.
In contrast, the plan linked here basically proposes to build a giant distributed capacitor bank - with ever-growing capacity.
From what I understand, purpose-built large capacitor banks are used to generate very short pulses of enormously large currents - e.g. to power experimental lasers, railguns or similar.
Maybe my imagination runs wild here, but I see no reason a hacker with appropriate access couldn't do something similar - e.g. command all batteries to unload with the largest possible churrent at once and setup switches in such a way the current from all batteries is directed to a particular location.
I'm don't know what you could do with the resulting pulse but probably nothing good.
I like the european ancillary services model. In Switzerland for example (It's the one I know quite well), it's the TSO role to keep the grid stable; in this case Swissgrid.
Swissgrid then passes on the costs of this stabilization to the consumers.
This stabilization is made by 3 main services: primary, secondary, and tertiary control (the level indicates the response time: instantaneous, 10s, 15 min). Anyone can be a ancillary services operator if they are big enough (5MW of control), and if they respect certain rules (must be audited, etc.).
Then, when there is a need of control, a bid is created and the cheapest operators win the bid, effectively earning money (as a rule of thumb, you can earn ~20kCHF/year if you offer 1 MW of tertiary control power). It's much more for secondary.
This model effectively makes the industries want to stabilize the grid either by consuming more, or consuming less when there is a need of grid stabilization. I would really want to see how much tesla will earn with their site in belgium, because their marginal cost of control must be quite small.
Some cars (such as the Leaf) already supports this in a "vehicle-to-the-home" type system. I think the problem is largely bureaucratic and not technical.
Besides, I want my battery to last a long time, not necessarily be sacrificed to the grid.
Because of SGIP[1], you can basically get a powerwall for free right now in CA depending on the circumstances. However, the requirements for the program all but guarantees it will use up the life of your storage system.
Tesla's powerwall at least allows you to do things like set reserve levels to 15% or 30% to make sure you're not cycling your battery too aggressively, but if you don't meet the required 57 full discharges a year they'll disable features like this automatically. In other words you own it, but you don't control it.
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[ 3.2 ms ] story [ 41.7 ms ] threadI do not want some remote agency controlling the discharge of my home battery, except in a miraculous future scenario where we invent batteries that are good for 20,000 deep cycles with <5% degradation over 20+ years.
Otherwise it's a losing proposition for the homeowner.
also, but think the jury is still out on the power walls, there is evidence that Tesla batteries in Model S have much reduced battery degradation than previous experience would suggest. Which is interesting but needs more study
That future may not be so miraculous since various flow and liquid salt batteries supposedly offer such properties. But you probably won't see them in homes since they only work economically at larger scales.
Besides, there's genuine benefit being hooked up to the grid. I'll gladly pay the $10/month interconnection fee just to have that as a backup to my battery.
The bigger problem is cobalt,but from what I understand people are working on various alternatives.
This effectively means that the only people that would join are people who would be paid to do so, but then that introduces the question of whether it isn't simply cheaper and more efficient for power companies to just deploy larger scale batteries that they control, rather than pay random people to put them in their own - much more uncontrolled - homes.
The only answer I can think of is that people are using these batteries to avoid peak electric prices during the day, while charging it up when electricity is cheap. If that is your plan, and you don't care much about having electricity when the city goes black, you could join the program.
Or if the odds of that are rather low, say 1/20 and the income is significant then you might gain benifits 95% of the time for 1/2 the cost of a 100% solution which is often a worthwhile tradeoff.
Why do people join Uber or Airbnb?
So the user still enjoys - and pays for - the storage component while the utility enjoys and pays for the frequency reg.
In that case, you wouldn't put power back into the grid b/c your connection has been broken. You use the battery for your own power instead.
Even the fastest gas plant presumably needs a few seconds to power up - enough time for the network to react. Additionaly, the maximum power and current it can deliver is generally known.
In contrast, the plan linked here basically proposes to build a giant distributed capacitor bank - with ever-growing capacity.
From what I understand, purpose-built large capacitor banks are used to generate very short pulses of enormously large currents - e.g. to power experimental lasers, railguns or similar.
Maybe my imagination runs wild here, but I see no reason a hacker with appropriate access couldn't do something similar - e.g. command all batteries to unload with the largest possible churrent at once and setup switches in such a way the current from all batteries is directed to a particular location.
I'm don't know what you could do with the resulting pulse but probably nothing good.
Swissgrid then passes on the costs of this stabilization to the consumers.
This stabilization is made by 3 main services: primary, secondary, and tertiary control (the level indicates the response time: instantaneous, 10s, 15 min). Anyone can be a ancillary services operator if they are big enough (5MW of control), and if they respect certain rules (must be audited, etc.).
Then, when there is a need of control, a bid is created and the cheapest operators win the bid, effectively earning money (as a rule of thumb, you can earn ~20kCHF/year if you offer 1 MW of tertiary control power). It's much more for secondary.
This model effectively makes the industries want to stabilize the grid either by consuming more, or consuming less when there is a need of grid stabilization. I would really want to see how much tesla will earn with their site in belgium, because their marginal cost of control must be quite small.
PS: sorry for the english
Battery tech is still very immature though, and a significant persistent fire risk if damaged, as is the case with electric vehicles.
Besides, I want my battery to last a long time, not necessarily be sacrificed to the grid.
Tesla's powerwall at least allows you to do things like set reserve levels to 15% or 30% to make sure you're not cycling your battery too aggressively, but if you don't meet the required 57 full discharges a year they'll disable features like this automatically. In other words you own it, but you don't control it.
1. http://www.cpuc.ca.gov/sgip/