Negative bill?

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Stinsy
Posts: 3484
Joined: Wed Jun 02, 2021 1:09 pm

Negative bill?

#1

Post by Stinsy »

As with a lot of you I've been playing with the concept of buy at 7p sell at 15p. And this has taken the edge off my bills. Aided by the cephalopod's generosity WRT additional cheapslots and limited by my 3.6kW inverter, small battery, as well as fitting it around the wife, 3-kids, and dog.

My system has been to have 3x battery charging periods (0000-0300, 0600-0900, and 1800-2100) powered by gamed cheapslots, 2x forced discharging periods (2100-0000, and 0300-0600), and have the battery cover my usage from 0900-1800. This doesn't just happen in the background, we have to try to use the vast majority of our energy in the charging periods (running appliances, heaters, etc.), use as little as possible in the forced discharge periods and to respect the 3.6kW inverter limit in the daytime.

On Monday I thought I'd try something new. It was forecast to be sunny and we've just reached the time fo year when, if the sun does shine, it hits the panels and generates significant power. So I set the inverter to force-discharge from 0900 to see how long the battery would last with a bit of solar help.

Here is the result:

ImageImage


Expenditure including standing charge was £4.54, income was £4.83 so positive for the day. Not too shabby even if it was aided by 8.6kWh of solar!
Last edited by Stinsy on Wed Feb 26, 2025 9:11 am, edited 1 time in total.
12x 340W JA Solar panels (4.08kWp)
3x 380W JA Solar panels (1.14kWp)
6x 2.4kWh Pylontech batteries (14.4kWh)
LuxPower inverter/charger

(Artist formally known as ******, well it should be obvious enough to those for whom such things are important.)
Yuff
Posts: 554
Joined: Sat Dec 31, 2022 1:18 pm
Location: East Midlands

Re: Negative bill?

#2

Post by Yuff »

I charge my batteries when the heating is on and export when they aren’t apart from a 2 hour window through the night when I’m charging a car, heating the hot tub DHW etc
Batteries don’t last long enough from 10.30am - 4.30pm so I top them up in the middle of the day so I can export a little bit more.
Heat pumps are on 8-10 hours a day at the moment and use 6-8 kWh whilst on. Results from 24th are


Image

Image
Mitsubishi Ecodan
ASHP 8.5kW x 2
12 x 460w Solar panels
9.5kWh GivEnergy
Batteries x 2
EVs x 4 240 kWh Batteries
Ripple 5.8 kW PV 0.547 kW Whitelaw Brae
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Joeboy
Posts: 8947
Joined: Mon May 31, 2021 4:22 pm
Location: Inverurie

Re: Negative bill?

#3

Post by Joeboy »

24th Feb cost me 8p to run the show. I'm OK with that :D
15kW PV SE, VI, HM, EN
42kWh LFPO4 storage
7kW ASHP
200ltr HWT.
73kWh HI5
Deep insulation, air leak ct'd home
WBSx2
Low energy bulbs
Veg patches & fruit trees
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nowty
Posts: 6293
Joined: Mon May 31, 2021 2:36 pm
Location: South Coast

Re: Negative bill?

#4

Post by nowty »

24th Feb was a negative energy bill for me (minus £0.24), :mrgreen:

Leccy cost £6.50, Gas cost £0.36, Export rebate £7.10

Image

And yesterday 25th will likely come in at over minus £3.50 once the saving session is included. :xx:
18.7kW PV > 110MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 33MWh generated
7 Other RE Coop's
105kWh EV storage
90kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 530 m3
Lincs Robert
Posts: 236
Joined: Fri Mar 11, 2022 7:48 pm
Location: Lincolnshire

Re: Negative bill?

#5

Post by Lincs Robert »

This is all good stuff.

Ive just had a look at mine and can report that my YTD import cost is £250 and export is £258! That includes charing the car.

Looking at a day to day basis doesn't really work for me as I essentially charge the car at random as and when the fancy takes me, so I’m dead chuffed with the result in this dreary period.

Ive noticed a distinct increase in solar peaks in the last few days, with it peaking @ 10kW for a few mins yesterday. So I’m hoping for significant export opportunities moving into the spring & summer as the batteries fill earlier in the day. I only started this export malarky at the start of December.

A lot of change in one season for me. A return to having an EV after an absence of a couple of years, significantly increased solar and battery capacity and now exporting to boot.

Bring it on ……
SporranMcDonald
Posts: 71
Joined: Thu Feb 16, 2023 10:29 am
Location: East Hampshire

Re: Negative bill?

#6

Post by SporranMcDonald »

1st Feb 2024 - 31st Jan 2025 Overall increase in Credit Balance . . . . £200 approx. i.e, OctopusEnergy are paying me for my fulsome excess export.

During that period . . .
- Gas disconnected / Meter removed.
- A 2nd Air-to-Air HP unit fitted. ( I only ever use one at a time and this new 4kW one is the favourite.)
- Woodburner not used this winter. Now for emergency use only.
- HP(s) used for much longer periods during the winter, as they are now the only space-heating method. . . . . and very comfortable too !!
4 kWp Solar PV : 50%/50% SE/SW : Solis Hybrid 3.6 : Pylontec 9.6 kWh
5 kW & 4kW Air-to-Air Mitsubishi Heat Pumps
GF + KH Coops : OctopusCollective : Triodos : Energy4All
No Car : bicycles : bus & train
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Stinsy
Posts: 3484
Joined: Wed Jun 02, 2021 1:09 pm

Re: Negative bill?

#7

Post by Stinsy »

SporranMcDonald wrote: Wed Feb 26, 2025 2:18 pm 1st Feb 2024 - 31st Jan 2025 Overall increase in Credit Balance . . . . £200 approx. i.e, OctopusEnergy are paying me for my fulsome excess export.

During that period . . .
- Gas disconnected / Meter removed.
- A 2nd Air-to-Air HP unit fitted. ( I only ever use one at a time and this new 4kW one is the favourite.)
- Woodburner not used this winter. Now for emergency use only.
- HP(s) used for much longer periods during the winter, as they are now the only space-heating method. . . . . and very comfortable too !!
My DD is still £100 and that just about covers it. We've still got a gas meter and combi doing our DHW, we also have a 5-bed house to heat and 2x EVs. So I've been OK with the £100.

However, I'm hoping to do much better for the rest of the year.
12x 340W JA Solar panels (4.08kWp)
3x 380W JA Solar panels (1.14kWp)
6x 2.4kWh Pylontech batteries (14.4kWh)
LuxPower inverter/charger

(Artist formally known as ******, well it should be obvious enough to those for whom such things are important.)
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Joeboy
Posts: 8947
Joined: Mon May 31, 2021 4:22 pm
Location: Inverurie

Re: Negative bill?

#8

Post by Joeboy »

I think we've all made leaps & bounds over the last couple of years bouncing off each other with ideas? Sporrans progress is brilliant!

I've only been exporting since Sept 24 but can see the benefits of last year's installed extra solar already. I have to keep reminding myself it's still Feb not April. It's very nice indeed.

I'm £1 per month DD with £140 left in the VB.
£54 of that gone this month. I think I'll make it to June 25 fan1&2 payment without topping up🤔

Image

Image
15kW PV SE, VI, HM, EN
42kWh LFPO4 storage
7kW ASHP
200ltr HWT.
73kWh HI5
Deep insulation, air leak ct'd home
WBSx2
Low energy bulbs
Veg patches & fruit trees
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nowty
Posts: 6293
Joined: Mon May 31, 2021 2:36 pm
Location: South Coast

Re: Negative bill?

#9

Post by nowty »

Last year was my first full year on export, my energy bill for combined gas and leccy was circa minus £850, but excluding the saving sessions about minus £450. Almost all leccy house and 2 EVs.

I reviewed my 2024 usage here,
https://camelot-forum.co.uk/phpBB3/view ... 440#p54440
18.7kW PV > 110MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 33MWh generated
7 Other RE Coop's
105kWh EV storage
90kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 530 m3
User avatar
Joeboy
Posts: 8947
Joined: Mon May 31, 2021 4:22 pm
Location: Inverurie

Re: Negative bill?

#10

Post by Joeboy »

6th April 2022 was the last time I paid a real power bill. A few tenner dd's until i twigged to the £1 dd possibility. Nearly 3 years with the yoke off, that has went swiftly!
15kW PV SE, VI, HM, EN
42kWh LFPO4 storage
7kW ASHP
200ltr HWT.
73kWh HI5
Deep insulation, air leak ct'd home
WBSx2
Low energy bulbs
Veg patches & fruit trees
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