A very frequently asked question. Usually the answer is “no”.
On a side note, if you’re replacing your gas guzzler with an electric car (EV) on the other hand, you could kill two birds with one stone. EVs have got a huge battery which can be used to store your solar, and use it in your own home, or export it in times of demand. On average cars sit idle 95% of the time, so the rest of the time their batteries can be used to even out intermittent renewable energy sources.
Firstly, what are the reasons for wanting batteries? Most commonly they are:
- Use more of your own solar (for financial benefit)
- Use more of your own solar (for environmental benefit)
- Independence from the grid, and electricity retailers
- Energy storage in case of black out
Batteries don’t really offer good solutions to any of these reasons usually, except for the last in some cases.
1. Use more of your own solar (for financial benefit)
Unfortunately, when you crunch the numbers, getting batteries doesn’t usually add up financially. It may at some point in the future for some people, but for now you’re usually better off getting solar on its own. This is dependent on the feed-in-tariff (FIT) you can get in your particular area, but generally a FIT is enough to make selling the power to the grid a better financial decision than buying a battery to store the solar.
2. Use more of your own solar (for environmental benefit)
This one doesn’t add up as long as there is demand for renewables when it is produced. Batteries are unnecessary (and have their own built in carbon footprint) when you can simply put your excess solar into the grid, and buy energy when you need it. The grid is a very efficient way of distributing energy and meeting supply and demand. Although a caveat to that is that grid operators do need battery storage to help even out the intermittent nature of renewables in some areas - in which case the carbon cost of producing, transporting and disposing of the solar panels + battery storage is likely to still be considerably less than the fossil fuel equivalent.
3. Independence from the grid, and electricity retailers
The issue with this one can get a bit technical, but in short you need a huge amount of batteries to be ”off-grid”. There’s a big difference between having a small battery bank in order to use the energy your solar systems produced during the day, at night, than having enough energy storage to last you through 3-4 low sun days in the depths of winter. The cost of going fully off grid is usually astronomical, and requires a lot of changes to how you use power. The only time it makes sense is if you don’t have access to a grid.
Also, as per above, I’m not really a believer in this reason. I think we should support the grid, it’s really quite efficient. If we need to add storage to the grid to support renewables, by all means, but I think that is far preferable to every house being a micro grid - which is incredibly inefficient.
4. Energy storage in case of black out
This one is the only one that regularly adds up, but only if you are in an area with a crappy grid, or you are running a business and really can’t afford to be in candle lights or have the fridge off for a couple of hours.
Here’s some further reading which might help clear up some other questions.
Hope that helps.