> Oh, and also batteries such as the tesla power wall can only be charged and discharged about 1000 times before they have lost a lot of capacity.
Powerwall's cycle life is much better than 1000. The Powerwall warranty guarantees 70% capacity after 10 years of daily cycles (i.e. 3650 cycles). This means they expect the capacity to be substantially above 70%.
> The Powerwall warranty guarantees 70% capacity after 10 years of daily cycles (i.e. 3650 cycles). This means they expect
... to have pulled some corporate restructure which leaves a bankrupt legal entity responsible for the warranty claims before they start costing any real money.
I think 12 years is an underestimate. Lithium-ion batteries will degrade, but they still have usable capacity. There are Tesla Roadsters still going strong, 15 years in. And the battery cell chemistry has since shifted to LFP, which has longer cycle life.
Furthermore, I would expect that an industrial battery is treated better than an EV. Optimal cooling/charging/discharge rates likely have a large impact on longevity.
Yes, Your phone or laptop though... that we dont have regulations that at least require manufacturers to give users the option to not charge to 100% is beyond me.
Many billions of batteries and thus billions of devices needlessly scrapped.
We need all the renewables we can get, and I think you can have both -- utility-scale and rooftop. Rooftop solar (and battery storage) just needs to be cost efficient to offset the rising cost of electricity and make it a good return on investment.
The "attacks on net metering" are merely acknowledging that the proportion of renewables on the grid is high enough that balancing grid supply and demand is becoming an issue. I'm a big proponent of rooftop solar, but the reality is that 1:1 net metering just doesn't make sense once there's a critical mass of solar installed (the duck curve problem). This is not a problem unique to California or the US. If you look at other places with high solar adoption (Australia, EU), you'll find even stricter policies like negative feed-in tariffs: the utility will charge you for exporting solar to the grid.
Battery storage is a solution to that problem, but that's where prices are still too high. I'm actually surprised that battery storage is not mentioned in the article, because that's a critical component of allowing solar/wind to grow further.
I agree about home batteries being too expensive, hopefully prices will come down with scale.
But the part about battery degradation is not true. Tesla Powerwall has a 10 year warranty[1] with 70% capacity retention. This means that Tesla has data showing that the battery will have higher capacity than 70% after those years. That's a lot of cycles and a lot of renewable energy that the battery will provide in its lifetime.
There's a reason why Tesla picks 10 years (8 years for car batteries) as a warranty period. Ask yourself: why 8 years and not 10 for cars? Why 10 years and not 15 or 20 years for home batteries? It's not arbitrary.
Battery degradation is not linear. It's not like: 10 years = 70%, 20 years = 40%. It's probably closer to 20 years = 20 % capacity left. The decay becomes exponential-like after a relatively linear period of roughly 10 years.
The Tesla warranty will fall under "first life" in the image in the link above.
So batteries (even Tesla Powerwalls) do degrade and do degrade to the point where you need to replace them a bunch of times during lifetime of a house.
Tesla and other car makers set their warranties at the mandatory minimums. Why would they offer more when they don't have to and consumers find them long enough and/or other car makers aren't competing on warranty length? That doesn't tell you anything about battery longevity.
Edit: Does my MacBook Pro die after 1 year when it's applecare warranty is over?
The mandatory minimums? Got a source of the mandatory minimum for cars (US and/or EU) as well as power walls?
The fact that other car makers aren't competing on warranty length seems to me to prove my point, but you seem to think it doesn't? What I mean is: if battery degradation for cars isn't that bad after 8 years, then why are other brands not offering significantly longer warranties to compete with the Tesla one?
Not sure about the competition argument anyway, since Tesla didn't have any competition initially and arguably still doesn't have real competition (depending on what features of the car you value most).
Edit: Does my MacBook Pro die after 1 year when it's applecare warranty is over? --> Pretty close yes IMO. My personal experience is that my laptop and phone battery capacities degrade very fast after 1 year and need to be replace after about 2 years, 3 years if you really really push it and are OK with constantly charging.
RE: MacBook Pro dying close to a year right after it's warranty it over --> well now you're just trolling. My iPhone 15 pro battery still maintains 100% battery health a year after its manufacturing date. It obviously won't need replacing in 1-2 more years even if I "really really push it and are OK with constantly charging". I used an iPhone XS until last year after it was about 5 years old, 5x longer than your supposed device-dead date. I don't think this is unusual.
Dynamic tariffs (aka real-time or wholesale plans) are becoming more common in the UK an EU. These are usually priced by 30-min periods and announced 24h in advance. More modern utilities will offer apps that control when your car is charged (in exchange for cheaper rates). But I agree, optimizing this is fun too. I'm building support for configuring Tesla Powerwall systems based on dynamic tariffs.
If you have the option, the best time to charge your car would be during the day when there is abundant solar.
In the long run, it makes sense to consume power when renewables can supply it, instead of having to store it in a battery and use it later.
In the short term however, renewables can't scale up in demand, so you're actually likely to require that the load is served from dispatchable power, which is probably either gas, hydro, or battery.
I don't think there's really any good time to charge it then. If solar was ever underutilized, I would assume there would be no gas in the mix at that point in time, but there is no such time.
On gridstatus, you can see how much renewable power is being curtailed (purposefully lowering output below what could be produced): https://www.gridstatus.io/live/caiso
Its... several GW in the middle of the day recently. So, this suggests charging EVs during this time would actually allow for better utilization of available renewables.
Another metric you can look at is if the grid scale batteries are currently charging or not. If they are charging, this suggests there is excess capacity available (or at least inexpensive capacity). The hours when grid batteries are charging are probably also good hours to charge EVs.
Powerwall's cycle life is much better than 1000. The Powerwall warranty guarantees 70% capacity after 10 years of daily cycles (i.e. 3650 cycles). This means they expect the capacity to be substantially above 70%.
We posted an analysis of Powerwall capacity retention: https://www.netzero.energy/content/2025-02/powerwall-analysi...