About 7 years ago I did a post looking into the costings of buying battery storage to go with our solar panels. I came to the conclusion that the cost of batteries would have to halve before they would pay for themselves.
Since then the cost of batteries have continued to come down and the cost of electric has gone up (Thanks to the Russians invading Ukraine). So, nearly 3 years ago (2023), I decided to get some through a scheme which aimed to cut the cost of buying and installing batteries via a bulk buy initiative.
In the end, I got two Pylontech US3000 batteries installed with a total usable capacity of 6.4 kWh plus a Solis inverter for £5000. Still not cheap, but just manageable.
[Note: Both Pylontech and Solis are Chinese companies - A sign of the times].
Based on the energy savings we got in the first year of use over the previous year we saved about £410. So, assuming everything stays the same, it'd take just over 12 years for them pay for themselves. That's not bad, as long as they exceed their 10 year warranty of course.
Batteries, as my previous post pointed out, are the answer to the annoying fact that it's often impossible to use all the energy your solar panel generate, so you end up selling the excess back to the grid for a pitiful rate (Currently just over 5 pence a kWh) when compare to what they charge us (Currently over 28 pence).
Of course, that assumes your batteries can store all the excess....we probably use about 6 kWh a day and the batteries can store about 6.4 kWh, which basically means anything more than 12.5 kWh of solar energy in a day still finds it's way back to the grid. On a good day, that's up to 6 kWh.
Anyway, back to the money saving aspects.
A little known fact about these systems is that you can program the inverter to get the batteries to store electric from the grid when the price is cheaper. For example, we have an Economy 7 plan, which means we get electric at a cheaper rate at certain hours during the night. We can therefore tell the inverter to use any spare capacity in the batteries to store that cheaper rate electric.
Now, that's not such a clever idea in the summer because you'd rather be storing the free electric coming from your panels, but it's great for the gloomy winter months. I worked out that we can save a further £51 over the winter, which brings the pay back time down to just under 11 years.
Whether that trick is possible with all inverters, I don't know. It also assumes you're sufficiently tech savvy to do the necessary setup. Solis provide manuals and, more importantly, videos that take you through the process.
I've been looking at current battery prices and a US3000 would now cost around £820. You'd also have to get an inverter and an installer, but I'd guess that a similar system would now cost between £3k to £4k. Even better value.
When you factor in the volatility of energy prices these days - As I write this, the US and Israel are attacking Iran, pushing up natural gas prices - Solar battery storage is certainly something to consider if you can afford the upfront cost.
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