Should we get more home battery capacity?

[Bam Bam]

We've got 9.5kwh of battery storage with our Givenergy system.

That has been fine until we've got our heat pump installed.

On cold winter days the battery seems to run out before getting round to the next cheap period.

I've obtained a quote from our installer as follows...

Extra battery
5.2kwh = £1904.17
9.5kwh = £2648.17

Pebbles is not convinced that it is worth getting more.

I think the pay off period will be about 10 years but that of course depends on tariffs and energy costs during that time.

Further advantages...

• Longevity: Additional battery would reduce the pressure on our existing battery and thus extend its life. It is currently doing around 1.5 cycles per day
• Backup capability: Extra battery would also make it more useful as a backup system since I'd keep more of a buffer in there.
• Environmental: Extra battery is helping the energy transition by shifting energy from low to high carbon times.

Export rate changes?
Octopus have today reduced their export payment rates (15p to 12p) and they will probably drop further.

However, the export rates will remain high in the evening peak.

Does this mean that...
1. Batteries will be more valuable as you can sell during the evening demand peak (for more) rather than the daytime
2. Batteries will be less valuable because you can't get as much arbitrage from filling up overnight and selling during the day.

Any thoughts?

 

[GaryMG4]

There was a report that HMRC was considering making income from arbitrage taxable.

 

[Giller]

We've got 9.5kwh of battery storage with our Givenergy system.

That has been fine until we've got our heat pump installed.

On cold winter days the battery seems to run out before getting round to the next cheap period.

I've obtained a quote from our installer as follows...

Extra battery
5.2kwh = £1904.17
9.5kwh = £2648.17

Pebbles is not convinced that it is worth getting more.

I think the pay off period will be about 10 years but that of course depends on tariffs and energy costs during that time.

Further advantages...

• Longevity: Additional battery would reduce the pressure on our existing battery and thus extend its life. It is currently doing around 1.5 cycles per day
• Backup capability: Extra battery would also make it more useful as a backup system since I'd keep more of a buffer in there.
• Environmental: Extra battery is helping the energy transition by shifting energy from low to high carbon times.

Export rate changes?
Octopus have today reduced their export payment rates (15p to 12p) and they will probably drop further.

However, the export rates will remain high in the evening peak.

Does this mean that...
1. Batteries will be more valuable as you can sell during the evening demand peak (for more) rather than the daytime
2. Batteries will be less valuable because you can't get as much arbitrage from filling up overnight and selling during the day.

Any thoughts?

Interesting. Solar and battery installed last May, 10.2 kWh battery fed from 12 panels through a 3.68 kWh inverter (max we can have in NI) and with off peak charging battery in winter months works well, but we don't have a heat pump.

Given your comments and everything I'd say go for it, just don't tell Pebbles I said that

 

[Bam Bam]

There was a report that HMRC was considering making income from arbitrage taxable.

Even if it is just credit on the account that you use at another time?

My understanding is that if you withdraw money from your energy provider then that is taxable income, though I haven't checked lately.

As things stand, we've just had our first bill in 11 months. £15.15.

Maybe with the heat pump now we will end up in credit over the full year, but I imagine we will break even at best.

 

[GaryMG4]

Even if it is just credit on the account that you use at another time?

Interesting point, as with most taxation it probably hasn't been thought through, I would imagine a credit is still benefit in kind. I had similar thoughts regarding me FiT payments, in a good year it could exceed the '£1000' limit although with 2 EVs the generation amount won't be above 120% of consumption so should be tax free but I wondered if I switched the FiT supervisor to Octopus and received credits whether it would count.

 

[Rolfe]

Seems to me one could make a good argument that any tax due should be able to be offset against the expenditure of installing the system.

 

[GaryMG4]

Seems to me one could make a good argument that any tax due should be able to be offset against the expenditure of installing the system.

Certainly would be the case if you were a business not sure there's anything in personal tax like that.