Should I bother with a battery? 14 February 2022 at 4:35PM edited 14 February 2022 at 4:37PM in Green & ethical MoneySaving 35 replies 1.4K views

michaels

1961Nick said:

For anyone on Octopus Go or Go Faster the case for battery storage has never been stronger.

The latest price is 7.5p/30p for Go & it should reflect the prevailing market as it isn't capped.

Charging for 4 hours per night on Go will yield a discharge of 11.35kWh. The cost of that will be about 9p/kWh after factoring in round trip losses. The savings are therefore 11.35 x 21p (30p - 9p) = £2.38/day... or £870 pa.

The capital cost of the equipment required is;

6 x US2000C @ £720ea = £4320 (or 4 x US3000C @ £1020 = £4080)
Sofar ME3000 = £700 (?)
Installation = £350

ROI = is just under 6 years for the US3000C (£5130/£870)... & that's without factoring in any of the solar output you harvest!

Of course all this is dependant on energy prices remaining at 30p/kWh after April 1st & Octopus keeping the huge differential between the on & off peak Go tariff.

Would there be options for faster charge and discharge so that you could have a larger battery and still fill it in 4 hours?

Most importantly, does anyone know where Octopus go pricing is likely to go in the coming months?!

JKenH

michaels said:

1961Nick said:

For anyone on Octopus Go or Go Faster the case for battery storage has never been stronger.

The latest price is 7.5p/30p for Go & it should reflect the prevailing market as it isn't capped.

Charging for 4 hours per night on Go will yield a discharge of 11.35kWh. The cost of that will be about 9p/kWh after factoring in round trip losses. The savings are therefore 11.35 x 21p (30p - 9p) = £2.38/day... or £870 pa.

The capital cost of the equipment required is;

6 x US2000C @ £720ea = £4320 (or 4 x US3000C @ £1020 = £4080)
Sofar ME3000 = £700 (?)
Installation = £350

ROI = is just under 6 years for the US3000C (£5130/£870)... & that's without factoring in any of the solar output you harvest!

Of course all this is dependant on energy prices remaining at 30p/kWh after April 1st & Octopus keeping the huge differential between the on & off peak Go tariff.

Would there be options for faster charge and discharge so that you could have a larger battery and still fill it in 4 hours?

Most importantly, does aayone know where Octopus go ricing is likely to go in the comping months.

Octopus Go will be 7.5p for the cheap rate and around 30p for the rest of the day depending on region). I am on Octopus Go Faster  (5cheap hours in a block you select between around 8.30 pm to 6.30 am) and have just been looking at my options. Go Faster would therefore give you a longer charging period but at a slightly higher rate. 

I received this from Octopus. 

“For the new Go Faster rates, the day rate would be 29.82p/ kWh and the night rate would be 8.25 p/kWh as you get 5 hours (rather than 4 hours) of off-peak energy. You should get an email confirming your new rates shortly.”

Verdigris

That's interesting. 5 hours in the evening would be good for running the heat-pump at full blast when you actually need some heat.

michaels

JKenH said:

michaels said:

1961Nick said:

For anyone on Octopus Go or Go Faster the case for battery storage has never been stronger.

The latest price is 7.5p/30p for Go & it should reflect the prevailing market as it isn't capped.

Charging for 4 hours per night on Go will yield a discharge of 11.35kWh. The cost of that will be about 9p/kWh after factoring in round trip losses. The savings are therefore 11.35 x 21p (30p - 9p) = £2.38/day... or £870 pa.

The capital cost of the equipment required is;

6 x US2000C @ £720ea = £4320 (or 4 x US3000C @ £1020 = £4080)
Sofar ME3000 = £700 (?)
Installation = £350

ROI = is just under 6 years for the US3000C (£5130/£870)... & that's without factoring in any of the solar output you harvest!

Of course all this is dependant on energy prices remaining at 30p/kWh after April 1st & Octopus keeping the huge differential between the on & off peak Go tariff.

Would there be options for faster charge and discharge so that you could have a larger battery and still fill it in 4 hours?

Most importantly, does aayone know where Octopus go ricing is likely to go in the comping months.

Octopus Go will be 7.5p for the cheap rate and around 30p for the rest of the day depending on region). I am on Octopus Go Faster  (5cheap hours in a block you select between around 8.30 pm to 6.30 am) and have just been looking at my options. Go Faster would therefore give you a longer charging period but at a slightly higher rate. 

I received this from Octopus. 

“For the new Go Faster rates, the day rate would be 29.82p/ kWh and the night rate would be 8.25 p/kWh as you get 5 hours (rather than 4 hours) of off-peak energy. You should get an email confirming your new rates shortly.”

I am on the ovo v2g trial until mid June so can't switch electricity supplier until then so am at the mercy of rate changes up till then.  Can't see the day rate only being the same as the post April cap with a cheaper night rate, there is always a trade off - currently the day rate is 10p more than the cap.

AS a big electricity user it seems to make sense to go for storage and time-shifting, problem is my leaf 24kwh battery is not big enough, can only shift about 2-3 kwh per day on average after own use of the car and round trip losses using the V2G kit from the trial as V2H.

Options seem to be:
1) Batteries - 12kwh cost about 5.5k and last ?10 years
2) Bigger battery leaf 40kwh - but then have to offset higher annual depreciation compared to current leaf and also any value on having a newer car with a better range but deduct any peak use when the car is out from potential savings.  This could also give about 17kwh per day storage
3) Possibly left field but second 24kwh leaf which will give a similar 12kwh of storage to the batts, two 24kwh leafs may depreciate less per year than one 40kwh big battery leaf.

One possible advantage of (3) is that if leccy prices go back to historic levels I can just sell one of them whereas options (1) and (2) I am locked in.

Petriix

Octopus Go/Faster are fixed tariffs and therefore not subject to the price cap. If they needed to be higher then they would be already. They put the peak rate up to ~ 30p in January when the regular price cap was ~ 22p.