Let There Be Light (and a Battery to Catch It)

It’s funny, isn’t it? The sun comes up every morning – free, inexhaustible, and surprisingly reliable – and yet we still have national energy policies written as though we’re Victorian mill owners with a vested interest in coal dust and candle wax. Meanwhile, out here in the Cotswolds, something quietly revolutionary is happening behind the net curtains and roof tiles since I installed my solar batteries in March.

Take a couple of days ago, for instance – 6th April. While the world argued about nonsense, my battery was getting on with it. The PV array started generating just after about 9am, peaking gently about 1pm like a polite guest. The load – that is, what the house actually needed – was fed straight from the solar as long as it lasted. The excess? Into the battery it went, greedily guzzling the surplus like a squirrel prepping for winter.

Come sunset, the magic kicked in. Instead of leeching from the grid like some vampire Victorian terrace with a halogen habit, the house simply sipped from its own reserves. The battery discharged through the evening and into the night, quietly powering kettles, routers, and whatever else hums away in the darkness. Not a single watt was drawn from the grid during that stretch – not until the battery dipped below its 20% threshold in the wee hours. The 20% is to extend battery life - discharge it fully and you reduce its life.

I track all this in real time using the Fox ESS app – a rather elegant tool that turns energy use into something almost artistic. I can see exactly when the solar kicks in, how much goes into the battery, and when it returns the favour. Frankly, it’s more informative than anything Ofgem’s put out in the last decade.

It's interesting to be able to see graphically that I get more sun in the afternoon than I do in the morning. This is due to the solar panels facing slightly west of due south. The rise in generation in the morning is quite steep as the sun moves from east to west, whereas the decline is slower after 1pm, as the panels are in the sun for longer.

And yes – I’m seriously considering adding a third battery (I currently have 2 batteries giving me 9.5kWh capacity, which get to 100% capacity now on a sunny day, and it's not even midsummer). Why wouldn’t I? There’s more solar being generated than I can store at present, and wasting it feels like throwing away hot water in a drought. A third battery would mean more independence after sundown. It’s not just about savings – it’s about principle. Why fund a creaky, centralised system when you can power your own home on your own terms? Diverting the excess into a battery, rather than the grid, makes no difference to my feed-in payments - I'm remunerated for what I generate, not what I export.

I'm also tempted to add more solar panels, just to increase the available charge for the battery. As far as I understand it, that wouldn't necessarily affect my feed-in status, providing the new panels are wired to prioritise battery charging and not export. But the regulations are so byzantine you almost need a solicitor and a sacrificial goat to interpret them. Still, if it lets me store more sunshine and rely even less on the grid, then why not?

On top of that, I’m looking to switch to Octopus Energy. Not out of loyalty – I’ve got none left when it comes to utility companies – but because they’re one of the few outfits offering agile tariffs that make sense for someone who’s generating and storing their own power. Unlike the usual suspects, who penalise you for not needing them, Octopus actually encourages you to play smart. Time-shift your loads, sell back your excess at peak, and suddenly the economics tip further in your favour.

In essence, I’ve decoupled from the grid’s worst instincts. No need to spike demand when prices surge and fossil fuels fire up. No need to bankroll someone else’s gas-fired inefficiency. Just harvest daylight, store it, and use it on my own terms. The system is elegant – the very opposite of the bloated, centralised energy model we’re still shackled to.

Now, if you squint at the following graph – that scatterplot of self-sufficiency versus generation – a clear pattern emerges. The more I generate, the less I need from outside. It's not linear, of course – diminishing returns and all that – but the curve doesn’t lie. We're gliding towards true independence. It’s local, it’s clean, and it works.

So why, one wonders, isn’t every roof in Britain doing this? Why are we still subsidising North Sea exploration instead of slapping panels on council houses and sticking batteries in basements? Why the obsession with "big energy" when "small energy" is quietly outperforming it in real-world use?

Perhaps the answer lies in who profits. It certainly isn’t the householder who’s tied to a variable tariff and told to "use less at peak times." It’s time we flipped that on its head. Let people generate, store, and manage their own power – and sell the surplus, if they wish. Not as a favour to the grid, but because it’s bloody common sense.

And so, as the sun sets each evening over this fine Gloucestershire village, I’ll continue drawing power not from some anonymous gas turbine in Essex, but from yesterday’s sunshine – neatly packaged, stored, and unleashed when needed. I'd like ot be able to unplug my solar battery when we're going away in the motorhome and take it with us.

If that’s not the future, I don’t know what is.