I got an estimate for a solar installation on a south-facing roof in London. The system would have ~3kW of panels with ~10 kWh of battery, with a cost of around £8,500.
Estimated annual savings are £600-£700, with a battery lifespan of 10-15 years. Using these figures and oversimplifying a little, the system will be paid off in 12 years, leaving 3 years of clear profit to the tune of £2,100.
Now let’s compare this to taking that same £8,500 and simply putting it into a low-risk investment with an average of 5% over the same 15 years. The final amount comes out at £17,670. That’s a profit of £9,170. I know which option I would choose.
There’s an entire industry of domestic solar in the UK but the numbers just don’t add up. What am I missing?