I have noticed in youtube videos that many people who get a home battery don’t feel it is worth the money. They say that it would have been better to buy extra solar panels, and use the grid as a battery.
First Solar panels are very cheap. Right now solar panels are less than $100 for 100 Watts. This means that you can easily buy solar panels that can provide you with the amount of power you use each day. The payback for this is quick. Even with a professional installation, most people get a payback in a few years.
When you add a home battery like a Tesla Powerwall2 or Sonnen things get more interesting. They are expensive, usually from $10-15k and while they help you save money, the pay back period is much longer. So let’s take for example a $15k Sonnen. If you pay $200 a month without solar, and buy solar and a Sonnen, how long will it take to pay back? Now the payback number can jump to 15-20 years. This means that you are betting that energy prices are going to rise in the future and/or want to be prepared for emergencies.
Let’s take the emergency preparation out of the equation. Given that utility companies are installing more renewable power and coal is decreasing, due to solar being cheaper, it seems reasonable the future will have cheaper power. Right now there are companies that give you the opportunity to buy renewable power, and I would expect that to increase in the future. The present/future will have more choices, and I think at a lower price point than currently. We have seen energy prices drop with the Pandemic, and I am not confident they will return to their former price points.
If you look at it in this way, a home battery isn’t worth it. Personally I feel a home battery is worth it, since there are always problems and there is no guarantee that prices will decrease. It seems reasonable to lock in the current prices, and if the prices get cheaper, then that is a helpful thing for society/environment.
There are more arguments that can be made about this. A breakthrough in power might be possible with cheap battery storage, or fusion power. However let’s not count on those. Let’s try to make the most reasonable decision we can with what is available to us. To me, a home battery and solar power are a winning combination.