> 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%.
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.
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.
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.
Tesla Powerwall is probably the most commercially successful home battery. It comes with a warranty guaranteeing 70% capacity after 10 years, which is not to say it has a 10 year lifetime. It's still early to determine its actual lifetime, but the battery technology is also rapidly improving due to the EV transition.
- What is your energy usage and peak demand during that time?
Peak demand is a big factor: a single Tesla Powerwall 2 for example has 13.5 kWh of capacity but only 5kW of continuous power. A heat pump or AC can exceed that, which is why many people stack multiple batteries to be able to power their homes. (The new Powerwall 3 can supply more power.)
https://pv-magazine-usa.com/2026/02/25/solar-and-storage-to-...