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Solar system savings - sense check
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Thank you for that but most FiT suppliers don't pay a decent rate for metered export and those that do only do so for their supply customers. Even the beloved Octopus only pays 4.1p per kWh if you're not with them for import. Try your sums with that number instead of the assumed 15p per kwhReed0
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Reed_Richards said:Thank you for that but most FiT suppliers don't pay a decent rate for metered export and those that do only do so for their supply customers. Even the beloved Octopus only pays 4.1p per kWh if you're not with them for import. Try your sums with that number instead of the assumed 15p per kwh
On 'negotiated' exports, you can choose any supplier for the export part, typically you get the best deals by going with the same one you buy your imports from (I'm with Octopus).
You can still keep your FIT generation payments with whoever they were already with (I'm with Ecotricity, not the best in terms of speed but I couldn't be bothered to switch away).
On 'standard tariff' exports these are paid by your FIT supplier at the rate specified by Ofgem which increases at RPI. You can freely switch between these options once per year.
No one has ever suggested taking a derisory rate like 4.1p; that would be very stupid and isn't really worth discussion. It really feels like you're arguing for the sake of it while continuing to ignore the clear point I've made.1 -
Petriix said:Qyburn said:It's not that complicated, on a deemed export tariff any electricity you use instead of exporting is free.
You generate 4000kWh per year.
You self consume 1,500kWh for normal usage.
Scenario 1:
You divert 2,000kWh to your hot water via an iboost.
You export 500kWh.
You earn (2000 x 6.79p) £135.80 for deemed export payments.
Scenario 2:
You import 2,000kWh (either gas or off-peak electricity) at 7p per kWh to heat water costing £140.
You export 2,500kWh.
You earn (2500 x 15p) £375 for a net gain of £135.
That's the whole point.
So if you are on Deemed Export, you would receive the same payment from a generation of 4,000kWh whether you used it or not.0 -
Qyburn said:So if you are on Deemed Export, you would receive the same payment from a generation of 4,000kWh whether you used it or not.And that's *exactly* what Petriix calculated in Scenario 1. Deemed export of 50% of 4000kWh, despite 2000kWh being diverted and actual export being only 500kWh.Scenario 2 is for metered export (without diversion) of 2500kWh.
N. Hampshire, he/him. Octopus Intelligent Go elec & Tracker gas / Vodafone BB / iD mobile. Ripple Kirk Hill member.
2.72kWp PV facing SSW installed Jan 2012. 11 x 247w panels, 3.6kw inverter. 34 MWh generated, long-term average 2.6 Os.Not exactly back from my break, but dipping in and out of the forum.Ofgem cap table, Ofgem cap explainer. Economy 7 cap explainer. Gas vs E7 vs peak elec heating costs, Best kettle!3 -
@Petriix, I could never think of a reason for separating the generation payment from the export payment but I suppose speed of the generation payment is a perfectly good one.
You say:On 'negotiated' exports, you can choose any supplier for the export part, typically you get the best deals by going with the same one you buy your imports from (I'm with Octopus).
I'm not arguing with your sums, I never have; I just didn't think the benefits of metered export were pertinent to @Qyburn's comment . But I am only aware of two suppliers that pay a decent rate for export, the second of these only quite recently, and I believe that changing from deemed export to metered export with either of them is by no means trivially easy. Either that or I have been particularly unlucky.Reed0 -
SuzeQStan said:Grandad2b said:
We still have to get a handle on battery round trip efficiency - how much can you expect to get out for every kWh you put in?
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That's higher than some other people I've asked - I was told typically 10 - 15% but more when the battery is close to fully charged.
We estimate a ‘round trip’ lost of about 20% for the battery charge in / out. So the 7p per kwh we charge the battery during cheaper TOU works out more like 10p per kWh by the time we hav stored & used itGrandad2b said:
We still have to get a handle on battery round trip efficiency - how much can you expect to get out for every kWh you put in?
Lancashire
PV 5.04kWp SW facing
Solar Battery 6.5 kWh
🐙 Intelligent Go
Mortgage freedom January 2024 - paid off 7 years early by making overpayments where we could.0 -
SuzeQStan said:
That's higher than some other people I've asked - I was told typically 10 - 15% but more when the battery is close to fully charged.
We estimate a ‘round trip’ lost of about 20% for the battery charge in / out. So the 7p per kwh we charge the battery during cheaper TOU works out more like 10p per kWh by the time we hav stored & used itGrandad2b said:
We still have to get a handle on battery round trip efficiency - how much can you expect to get out for every kWh you put in?
I think we'd also need to replace the existing inverter.
Obviously everyone's situation is different and what doesn't make sense for one household may be exactly right for another.2 -
Absolutely - we game the heck outta our battery - even so it probably still won’t pay us back cos we bought it when batteries were more expensive.Lancashire
PV 5.04kWp SW facing
Solar Battery 6.5 kWh
🐙 Intelligent Go
Mortgage freedom January 2024 - paid off 7 years early by making overpayments where we could.0
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