Anyone still weathering it out with Agile?
@jamespetts I agree it's extremely hard to calculate ROI on batteries as it will also see changes in usage patterns as well as opening up tariff options.
Factors include
- EV? Usage? Charger?
- Solar panels? Size?
- Inverter charge/discharge rates?
- Batteries? Size?
- ASHP? size? Usage?
- Automation options including HA, WonderWatt Homely etc?
In my case
- EV? Yes Usage? Around 2000kWh/pa. Charger - zappi
- Solar panels yes Size 8.5kw
- Inverter charge/discharge rates? Only 2.6kWh
- Batteries? Size 24.6kWh
- ASHP yes size? 16kw Usage: 6000kWh/pa. Weather compensation controls
- Automation options including HA, WonderWatt Homely etc? Yes. WonderWatt
- I crank up heating of house and hot water at night on cheap rates
- Solar probably produces around 6500kWh/pa (not optimal orientation etc). Endeavour to export majority
Usage: say 6k ashp, 2k ev, 2k all other usage Inc lighting, cooking.
Import: say 3k kWh/pa at cheap rate overnight for later force export as well as filling batteries for own usage + charge ev + run ashp
Expected TOTAL imports 13000kWh @ 8p Intelligent Go = £1040
Expected TOTAL exports 6500kWh @ 15p = £975
Expected Net cost £65 for 1 year usage in 2025
So I conclude the batteries are a no brainer for me. But I could not have assumed that in advance. Charge/discharge rate is a significant barrier to maximising but newer installations are likely to be better especially if part of a setup such as Tesla, GivEnergy All-in-one etc
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
@tim441 As you say Tim, very difficult to quantify any savings or ROI even, for a battery; I have often wondered about the savings I make from my solar PV - the figures might be very different with or without a battery. Without a battery, I might quantify my solar ‘gain’ at 25 pence per kW/h as I would not likely be using a TOU tariff but a fixed one. As I do have a battery (Tesla 27kW/h Powerwall), I opted for Cosy and pay ~ 13 pence per kW/h and let the battery take the strain. But wait! I am only showing a solar ‘gain’ of ~13 pence per kW/h now!?😉. In fact, my exported energy realises 15 pence per kW/h with Octopus Outgoing Fixed (at the moment anyway!) Oh, now my brain hurts! Regards, Toodles.
Toodles, heats his home with cold draughts and cooks food with magnets.
@toodles I guess it all comes down to import averages. Which is going to be impacted by ToU tariff, time-shifting usage etc.
In my case I'm importing vast majority at night at 7p/kWh... for own usage and filling batteries.
In summer using batteries to force export + maximise solar export.
In winter using batteries to supply home ... and refill during day from solar (if any excess) + any bonus cheap slots.
I think I should keep the average for year sub 8p as a result. But with max exports it's a game changer.
When I was on Agile in 2024 the average was around 12 or 13p I think. But far less exports as the round trip was not worthwhile.
Tracker in 2023 was a decent saving vs fixed or standard contracts.
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
We are still on agile and it works ok'ish to charge the EV. But the way the market is working I am not sure we will stick with it for long. We have HA but without PV I suspect our consumption will benefit from the predictability of a lower overnight rate.
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