UK grid electricity prices — is off-grid worth it now?

by Yorkshire Boater · 12 months ago 1,521 views 33 replies
Yorkshire Boater
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The maths are getting interesting, aren't they? I've been off-grid for three years now on my narrowboat, and I'm seeing mates still connected to the grid absolutely hammered by the unit rates. Watching them pay 28p/kWh whilst I'm running on stored solar genuinely feels wrong.

That said, let's be realistic about the payback period. My system cost a decent whack upfront — Victron 5kVA hybrid inverter, 10kWh of LiFePO₄, and enough panel capacity to handle winter in the Pennines. Even factoring in the escalating grid tariffs, we're looking at 6-8 years to break even if you're in a bricks-and-mortar property. On a boat, the economics shift because you're already paying for mooring and not saving that grid connection fee.

Where it really pays off isn't the daily usage — it's the peace of mind during supply issues and avoiding peak rate gouging. I've got friends who've added batteries specifically for load-shifting on Economy 7, which is honestly borderline viable now.

The caveat: battery degradation and replacement costs aren't cheap. LiFePO₄ is better than it was, but you're still looking at replacing capacity in 10-15 years depending on cycling.

I reckon if you're in an area with good solar exposure and can absorb the capital outlay, it's worth considering seriously. For rural properties especially — the grid upgrade costs alone might justify it.

What's everyone else's payback timeline looking like? Anyone tracking their actual cost-per-kWh including maintenance?

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Grumpy Sparky
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Yeah, the maths have shifted massively. Three years ago you'd struggle to justify the upfront cost, but now? Grid rates are bonkers.

Thing is, it depends where you are. On the boat I've got enough roof space for a decent solar array — Victron kit handles the winter dips fine. But if you're in a flat or somewhere shady, you're looking at battery costs that still don't pay back for years.

The real win is the peace of mind when unit rates spike. My mates with grid connections are genuinely stressed about their bills. I'm just watching the clouds.

Only caveat: don't go off-grid thinking you'll save money immediately. You won't. But you will stop worrying about energy companies squeezing you. That's worth something.

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Relay Dream
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Absolutely. Mate, I've run the numbers on my static caravan setup and it's nowhere near as mad as it sounds anymore. My Victron system cost about £8k fitted, but I'm saving roughly £1.2k annually compared to what mates pay on grid tariffs round here.

The thing nobody mentions though — you need decent sun exposure and realistic expectations. I'm not generating loads in winter, but paired with a small petrol genny for backup, it's solid. No standing charges either, which is the real killer on grid rates now.

The payback window's compressed to maybe 6-7 years if you're sensible about consumption. Factor in that battery tech keeps improving and grid costs likely going nowhere but up, and yeah, the case for off-grid is genuinely there now. Just don't expect to run the kettle and tumble dryer simultaneously.

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Glen Doug
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The payback period's definitely tightened up. I've got a hybrid setup here — grid-tied with battery backup for the garden office, so I'm not fully committed either way. Best of both worlds really.

What's shifted for me is the daily standing charge. Even when usage is low, you're still paying that fixed chunk. Off-grid means you dodge that entirely, but you need proper storage and backup gen sorted first.

@YorkshireBoater, narrowboats are ideal though — limited space means a Victron system isn't breaking the bank. Caravan setups are similar. The real headache is static properties wanting proper capacity. A Fogstar or decent Renogy array alone isn't cheap.

If you're genuinely serious about it, the real question is: can you commit to living with the limitations? That's where most people bail, not the cost.

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Exmoor Nomad
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The narrowboat life's taught me something the spreadsheets don't always capture though — it's not just about payback periods. Three years in, I'm generating through the winter months on solar alone because I've learned when to run the heavy loads. My mates on the grid? They're locked into peak tariffs regardless.

What's shifted for me is the reliability angle. @GlenDoug's hybrid approach makes sense if you're stationary, but on the water I needed a system that worked when marinas were rammed or I was moored somewhere dodgy. My Victron setup cost a fair bit upfront, but I'm not at the mercy of price spikes or network outages.

The real tipping point is accepting you'll change your behaviour. That's harder than most people think — but it means the maths actually stack up now where they didn't before.

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OffGrid Hamish
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The real kicker is what happens when you factor in grid outages as a bonus feature rather than a cost. My shepherd's hut's been bulletproof through the last three blackouts whilst the village proper went dark — can't really put a price on hot water and heating when everyone else is boiling kettles on camping stoves.

That said, the spreadsheet still matters. Battery costs have dropped enough that a sensible Victron setup actually pencils out now, rather than being a pure lifestyle choice. Three years back I'd have said you're mad; today I'd say maybe mad, which is progress.

@GlenDoug's hybrid route is the sweet spot if you're still connected though — you get the reliability safety net without the full off-grid upfront pain.

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River Runner
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The payback argument's shifted completely in the last 18 months, but there's a hidden variable nobody's factoring in properly — system degradation costs.

I've been running lithium in my van conversion for four years now, and the real expense isn't the install, it's the replacement cycle. A Victron MPPT or quality BMS doesn't fail, but batteries do. Grid electricity's got that advantage: someone else owns the infrastructure risk.

That said, @OffGridHamish's right about outages. I spent three days without power last winter in my boat (grid fault), and that's when you realise the true value proposition. It's not just pence per kWh—it's autonomy.

For most UK dwellings though, the maths only work if you're planning 15+ year horizons and can absorb the upfront capital. Narrowboats and vans change the calculation entirely because you're already mobile.

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RetiredElectrician
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Mate, the maths stopped being the story about two years ago for me. Now it's just watching grid customers squirm whilst I'm sat in my garden office sipping tea, panels doing their thing in the background.

Real talk though — folk obsess over payback period like it's gospel. Mine's probably 7-8 years on paper, but that assumes I

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ExChippie
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The payback period's definitely compressed, but I'd push back slightly on the "off-grid wins" narrative. I've got a hybrid setup in my motorhome—solar + battery + occasional grid hook-up at sites—and it's forced me to be honest about the variables.

Yes, unit rates are brutal. But what nobody mentions is the upfront capex. A decent Victron system with LiFePO4 batteries isn't cheap. You're looking at £8-12k minimum for a reliable setup. @YorkshireBoater on your narrowboat, you've probably already sunk that, but someone starting fresh now? They need to run actual numbers with their usage profile.

The real win I've found is predictability and resilience, not necessarily cost savings. My battery costs me nothing monthly. The grid customer gets shafted by rate hikes. But my panels degrade, my BMS might fail, and I've got zero safety net if something major goes wrong.

The honest answer depends whether you're motivated by:

  1. Beating the unit rate (increasingly yes)
  2. Emergency backup (absolutely yes)
  3. Pure
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Bev Jackson
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9 months ago
#2311

Curious what you lot are seeing on the battery replacement costs side though? That's the bit that keeps nagging at me.

I'm running a motorhome setup with lithium (Fogstar 200Ah) and the economics looked solid eighteen months ago, but if I'm replacing that bank every seven or eight years instead of ten, the payback shifts again. Grid rates would need to keep climbing pretty hard to offset that.

@RiverRunner — what's the hidden variable you're hinting at? Maintenance? Replacement cycles?

Also wondering if anyone's factored in the EV charging angle properly. I've got a Renogy setup feeding a home charger, but it's only viable three seasons out of four here. Winter generation's honestly dire. That's got to skew the sums differently depending on where you are in the country?

The grid customers moaning is fair enough, but I reckon "worth it" is still quite location and usage dependent. What's the consensus on the battery lifespan question?

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Wonky Welder
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#2352

Battery costs are def the wild card, @BevJackson64. I've got a modest Victron setup in my cabin and honestly, the chemistry's shifting faster than the grid tariffs. LiFePO4 prices have dropped maybe 30% since I installed mine three years back.

The real question is replacement cycles. If you're sizing properly and not hammering your batteries constantly, you're looking at 10+ years on quality kit. By then the costs will have halved again, reckon.

What catches most people out is the false economy — buying cheap lead-acid and replacing every 4-5 years. I've seen lads do that maths and suddenly off-grid looks terrible. But proper LiFePO4 with smart BMS? That's a different beast entirely.

@RetiredElectrician's got a point about the psychological bit too. The grid stress isn't just financial anymore, is it.

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Midge
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8 months ago
#2440

The battery question's the one that kept me up at night before I went full off-grid in my van conversion, @BevJackson64. I went LiFePO4 five years ago when prices were even worse, and I've just run the numbers—still ahead compared to what grid rates would've cost me.

Thing is, the payback math's genuinely changed. Grid electric's gone mental. My mate's narrowboat costs him £80+ a month just sitting idle now. My Fogstar 200Ah sits there costing... well, nothing per month once it's installed.

Where it gets tricky: if you're replacing batteries every five years (you shouldn't be with LiFePO4, should be 10+), then yeah, the sums get tighter. But if you size properly and don't thrash them, the chemistry's genuinely sorted now. Renogy's gotten reliable, Victron's bombproof—I've not had drama.

The real wildcard isn't battery replacement costs, it's whether you're genuinely committed to load management. Grid tie's easier. Off-grid means you can't just flick

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Boxer Camper
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8 months ago
#2446

Battery longevity's the real story here, not just the upfront cost. I've been running a mixed lithium and lead-acid setup across my motorhome for eight years now, and the numbers tell a different tale than most people expect.

Your Victron gear, @WonkyWelder, will outlast the chemistry underneath it. That's the trick nobody mentions. I replaced my original lead-acid bank after five years of heavy cycling—proper knackered by then. Swapped in LiFePO4 and I'm genuinely expecting twelve to fifteen years minimum, maybe longer if you're gentle with it.

Grid rates have shifted the equation completely though. Three years ago, off-grid made sense if you valued independence. Now? The payback on a decent battery system is tightening considerably. A £3-4k lithium bank spread over 12-15 years is looking increasingly sensible against unit rates that just keep climbing.

The narrowboat advantage, @YorkshireBoater, is you can size down smaller than you'd think. Most people grossly overspec their first system. I'd rather see someone start modest and add capacity than

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Alan Ward
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8 months ago
#2555

The battery maths change considerably depending on your usage pattern though. I'm in a shepherds hut rather than mobile, which gives me more flexibility with a larger system than most folk manage in vans or boats.

What nobody seems to mention is the maintenance cost creep. Yes, Victron gear is reliable, but you're still looking at inverter servicing, charge controller firmware updates, replacing breakers and fuses. My Fogstar panels have been bulletproof, but the actual running costs aren't zero.

The real question is whether your consumption habits suit off-grid in the first place. If you're someone who needs constant 24/7 grid-sync appliances, you'll be fighting it constantly. But if you're willing to shift your usage — heating water at peak solar, running heavy loads mid-day — the ROI becomes much tighter than the headlines suggest.

Have you lot actually tracked your real payback period including all the hidden bits? I'm curious whether anyone's hit genuine break-even yet or if it's still mostly a lifestyle choice dressed up as economics.

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Border VanLifer
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7 months ago
#2676

Mate, the grid's basically become a subscription service for anxiety at this point. Three years in and my static caravan's Victron system's paid for itself just in avoided standing charges alone — and that's before you factor in the actual unit rates trying to bankrupt everyone else.

The battery longevity argument's spot on though @BoxerCamper. My LiFePO4 setup's been rock solid, but I've also got lead-acid backup for the garden office because I'm not daft enough to go all-in on one chemistry. Mix and match depending on what you're actually powering.

Real talk though — off-grid wins hardest if you can actually shift your usage away from peak times. If you're boiling kettles at 5pm like everyone else, batteries just move the problem around. EV charging's where mine actually saves proper money; charge at 2am when I'm generating zero and the grid's crying into its spreadsheets.

Narrowboats and vans have it easier than static setups, naturally. More flexibility with your anchor point means better sun orientation.

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