Solar Panels UK - is it worth it?

[Avendit]

Are you meaning you are buying some off peak and no peak (sorry if I'm being thick)?

'Coz with PV and Battery wouldn't that be the norm once out of deep Winter?

I have to go back to January when I was routinely using "some peak", since 01-Feb I drew some peak on 08-Feb (PV=3.3kWh), 10-Mar (6.6kWh) and 11-Mar (5.6kWh) (**), and before 14-Feb I drew a piddly bit for an hour-ish before Off Peak started most days, but basically I have survived on Off Peak and PV since 01-Feb.

Last night Tesla prediction charged PW to only 30% (actually it charged to 45%, but started discharging long before end of Off Peak such that it finished Off Peak @ 30% ... it has been doing that, I assume on the basis of "overcharge and then check prediction is still optimistic as end of Off Peak approaches", I've wondered why not "Charge to minimum and top up later in Off Peak if prediction worsens")

(**) 48 panels

Yea, reached that transition point to only buying off peak for us. But that is 'only' 19 panels and a 10kw battery, and a heat pump.

It's frustrating that the green techs don't balance very well. I did manage to make the HP 1/3rd more efficient this year by tweaking software, but it fundamental gets less efficient when it gets colder, when you need more heat and the panels are producing less to help. Means we have 2-3 months of paying ~£250 over winter then almost a 0 bill the rest of the time.

 

[Drew57]

It's frustrating that the green techs don't balance very well. I did manage to make the HP 1/3rd more efficient this year by tweaking software, but it fundamental gets less efficient when it gets colder, when you need more heat and the panels are producing less to help. Means we have 2-3 months of paying ~£250 over winter then almost a 0 bill the rest of the time.

Those sort of numbers have been holding me back from getting a heat pump.

We have paid £157 for gas one month this winter with only one other +£100 & this is with two gas boilers. Since state retirement age the winter payment covers almost all gas usage. PV/FIT/batteries put us in positive territory for electricity as well so I can’t see that a Heat Pump would make any sense for our situation (especially as 10 weeks/yr we are visiting family overseas during the colder months).

 

[Avendit]

Those sort of numbers have been holding me back from getting a heat pump.

We have paid £157 for gas one month this winter with only one other +£100 & this is with two gas boilers. Since state retirement age the winter payment covers almost all gas usage. PV/FIT/batteries put us in positive territory for electricity as well so I can’t see that a Heat Pump would make any sense for our situation (especially as 10 weeks/yr we are visiting family overseas during the colder months).

Depends on your house and desired comfort levels. That's us maintaining 21 degrees most of the day in a 5 bed house. If we hadn't done insulation and the heatpump and just left the (old) gas system in place we would be paying £1000 a month just now.

Seasonal co-efficience of performance is the magic number for heat pumps. It's how much energy you use to move the heat into your property - if it's 3, then for every kWh of electricity, you get 3 KW of heat, averaged over the year. If you can beat the ratio of gas: electric prices, then you are quids in. But it's not really about being cheaper (although it can be, some installs can hit a cop of 4.5), it's about not burning Dino juice while not being any more expensive, and being more comfortable.

Heat pumps and their installers are still going through a massive learning curve. If you have a working, efficient boiler then run that I to the ground - better HP's or easier installs will be available later. But if you need a new system anyway, absolutely consider it. Just make sure to get a heatgeek qualified designer for the system.

 

[spon88]

We run 5 A2A units with 2 external heat pumps. They cover us easily for all but the coldest days in Dec/Jan when the COP falls away and we run the gas boiler for a few hours instead. That's a cost consideration as gas on Octopus tracker has been very cheap and just beats the ASHP when it starts to go below freezing. That said, we only spent a total of £160 on elec/gas in Dec/Jan. We'll probably break even this month and then be making money on export over the next 6 months. Depending on Flux rates, we should be negative on gas/elec for the year. 4 bed house, 10.1 kwp PV, 19kwh batteries.

PV, good battery storage capacity, ASHP and IOG has made heating costs effectively go away. If you do go the ASHP route, take a look at A2A - arguably a lot more versatile and much more forgiving to install than A2W. You don't get the Govt grant at the moment though.

 

[Pete UK]

We run 5 A2A units with 2 external heat pumps. They cover us easily for all but the coldest days in Dec/Jan when the COP falls away and we run the gas boiler for a few hours instead. That's a cost consideration as gas on Octopus tracker has been very cheap and just beats the ASHP when it starts to go below freezing. That said, we only spent a total of £160 on elec/gas in Dec/Jan. We'll probably break even this month and then be making money on export over the next 6 months. Depending on Flux rates, we should be negative on gas/elec for the year. 4 bed house, 10.1 kwp PV, 19kwh batteries.

PV, good battery storage capacity, ASHP and IOG has made heating costs effectively go away. If you do go the ASHP route, take a look at A2A - arguably a lot more versatile and much more forgiving to install than A2W. You don't get the Govt grant at the moment though.

What’s the average price on the Octopus gas tracker?
Would you say it’s a lot cheaper than the standard Octopus gas tariff I’ve been on since switching to Octopus last summer?
I’m guilty of ignoring the gas costs as I’ve been mainly focussed on my electricity

 

[spon88]

What’s the average price on the Octopus gas tracker?
Would you say it’s a lot cheaper than the standard Octopus gas tariff I’ve been on since switching to Octopus last summer?
I’m guilty of ignoring the gas costs as I’ve been mainly focussed on my electricity

Just under 4p per unit I reckon. Currently 4.1p here but often under 4p. That's probably jinxed it! However, warmer weather on the horizon. So yes, for the 6 months or so we've been on it, a lot cheaper. One thing to note is that you can switch away without penalty i believe but they don't let you back on for 9 months. We use very little gas and have an Eddi for hot water as contingency, so we're happy sticking with it.

 

[Drew57]

I've been on Tracker for Gas for a couple of years. Only seen just above 5p/kWh once or twice early on & that was very briefly. For this winter it has been as low as 2.8p and as high as 4.7p, mostly in the 3-3.9p range.

Even if prices did rise above the fixed threshold they would have to stay there for quite a long time to negate the considerable savings (cannot rejoin Tracker for nine months after leaving)

This site illustrates prices for the past two months on a rolling basis (South Wales, regions vary slightly). Octopus Tracker tariff v Energy Price Cap 2024.

 

[Pete UK]

Thanks @spon88 @Drew57

Much appreciated. Presumably there is less chance of it spiking up in summer?

Sent the email to swap. Should have done that 9 months ago

Better late than never.

 

[thewishy]

Much appreciated. Presumably there is less chance of it spiking up in summer?

Generally, yes. Geopolitical incidents (Ukraine, Gaza) will spike it a little in the summer, but it's not until there is supply uncertainty and winter looming that things get really spicy

 

[ACarneiro]

Thought about it but the current Loyal tariff is just under 6p
As I tend to be fairly risk-averse, I don’t think the uncertainty is worth it for a couple of pence per kWh, especially when I have moved most of my energy usage to electricity.

 

[WllXM]

I must say I have a big issue with Tracker Gas, not once they have correctly billed be for my actual daily consumption.
Instead they take two readings a month apart, and then apply an 'industry standard' profile to spread this monthy consumption into estimated daily figures.

Meaning it's not a proper individualised weighted average.

As long as tracker stays reasonably within the same range it's not a terrible issue, even if I consider that I'm not being billed as accurately as they could (because with my smart meter they DO have daily readings if they wanted to bother).
But in the event of large day-to-day swings where you'd want to reduce gas consumption on a particularly expensive day, you would still be billed on an average basis and would not make any savings.

 

[Pete UK]

we use quite a lot of gas, so it’s worth a try, we’ve got gas CH, cooker and a couple of gas fires.
Even when we ‘don’t use any’ in the summer it’s still about £3 a day - presumably for hot water cylinder heating.

Since joining Octopus flexible;
Aug £89
Sept £88
Oct £165
Nov £340
Dec £370
Jan £460
Feb £326

So I guess 4p/4.1p a unit would make a fair difference to us in winter instead of the 7p we’re currently on. Summer probably wouldn’t matter too much.

The price varies per day doesn’t it? Not like electricity where it changes every half our on some tariffs?

 

[Avendit]

we use quite a lot of gas, so it’s worth a try, we’ve got gas CH, cooker and a couple of gas fires.
Even when we ‘don’t use any’ in the summer it’s still about £3 a day - presumably for hot water cylinder heating.

Since joining Octopus flexible;
Aug £89
Sept £88
Oct £165
Nov £340
Dec £370
Jan £460
Feb £326

So I guess 4p/4.1p a unit would make a fair difference to us in winter instead of the 7p we’re currently on. Summer probably wouldn’t matter too much.

The price varies per day doesn’t it? Not like electricity where it changes every half our on some tariffs?

And 'leccy on top of that . And people were commenting on my power bills as a heat pump user!

 

[Drew57]

I must say I have a big issue with Tracker Gas, not once they have correctly billed be for my actual daily consumption.
Instead they take two readings a month apart, and then apply an 'industry standard' profile to spread this monthy consumption into estimated daily figures.

Meaning it's not a proper individualised weighted average.

As long as tracker stays reasonably within the same range it's not a terrible issue, even if I consider that I'm not being billed as accurately as they could (because with my smart meter they DO have daily readings if they wanted to bother).
But in the event of large day-to-day swings where you'd want to reduce gas consumption on a particularly expensive day, you would still be billed on an average basis and would not make any savings.

Yes I thought that. Octopus do this any month that even a single half hour slot is missing and that happens quite often with our gas smart meter.

We spend up to 3 months/yr with our family in the USA and in October/November Octopus averaged our usage even though for 3 weeks we were away and those were actually the highest pence/kWh rates (so by averaging we actually paid for energy on those days & it was at the higher rates whereas our actual later usage would have been at a lower rate, And of course the 'cheaper' days recorded less usage because the average moved it to the days we weren't there!).

When I queried this and Octopus downloaded the 'missing' days it resulted in a credit of £1.02 so although 'averaging' may cost slightly more, when it happened similarly on a billing period we were at home the difference was only £0.09.

Hardly worth bothering about & on the bill I received on Monday 'averaging' must have worked slightly in my favour this time. I may therefore only challenge whenever we have been away for several weeks....or not bother at all.

 

[Pete UK]

And 'leccy on top of that . And people were commenting on my power bills as a heat pump user!

I think for a most of the year “all electric house” you’re doing very well TBH.
Don’t forget that’s all your car fuel as well.

It isn’t easy with these big old solid wall properties.

We’ve been effectively 100% off peak usage since end of June last year, and even exporting a (tiny) bit of excess in the winter evenings and just a couple of days we used some peak around Christmas time. We are break even cost wise on a daily basis right now for import/export. Which should turn into a net gain from now on.

I think my electricity bill will be net zero over the year. So it’s just the gas bills. I’m still pondering a heat pump though. And moving onto Gas tracker should bring the gas bills down 35% ish.

 

[phil4]

I must say I have a big issue with Tracker Gas, not once they have correctly billed be for my actual daily consumption.
Instead they take two readings a month apart, and then apply an 'industry standard' profile to spread this monthy consumption into estimated daily figures.

Meaning it's not a proper individualised weighted average.

As long as tracker stays reasonably within the same range it's not a terrible issue, even if I consider that I'm not being billed as accurately as they could (because with my smart meter they DO have daily readings if they wanted to bother).
But in the event of large day-to-day swings where you'd want to reduce gas consumption on a particularly expensive day, you would still be billed on an average basis and would not make any savings.

My meters are hopeless always missing half hours lots here and there... but at the end of each month I get a single page table, or each days use, cost and so totalcost.

eg:
22nd Feb. 2024 58.650 p/thm 3.61 p/kWh 28.64 kWh £1.03
23rd Feb. 2024 58.100 p/thm 3.59 p/kWh 28.91 kWh £1.04
24th Feb. 2024 58.800 p/thm 3.62 p/kWh 28.97 kWh £1.05
25th Feb. 2024 58.800 p/thm 3.62 p/kWh 28.17 kWh £1.02

I've never seen them fudge a figure.

 

[Pete UK]

Yeah, these “smart” meters can be a bit dodgy.
I’ve had them replaced at least 3 times. Took ages of messing about. They worked for a week or two then didn’t .

The last ones seem ok after they added the extra aerial on the electric meter, despite the signal being good before!

I guess them being down in the cellar and with (certainly for us) thick walls, hills, all the inverters, batteries, the mesh WiFi, TVs, cameras, computers, phones, iOT tech, kicking out signals all over the place, maybe it’s that and electrical interference. Despite the meters being on a different frequency.

 

[WllXM]

My meters are hopeless always missing half hours lots here and there... but at the end of each month I get a single page table, or each days use, cost and so totalcost.

eg:
22nd Feb. 2024 58.650 p/thm 3.61 p/kWh 28.64 kWh £1.03
23rd Feb. 2024 58.100 p/thm 3.59 p/kWh 28.91 kWh £1.04
24th Feb. 2024 58.800 p/thm 3.62 p/kWh 28.97 kWh £1.05
25th Feb. 2024 58.800 p/thm 3.62 p/kWh 28.17 kWh £1.02

I've never seen them fudge a figure.

Yes, but unless you are extremely lucky, my point is your consumption figures shown above (28.64 kWh, 28.91 kWh, 28.97 kWh, 28.17 kWh) are oddly consistent.
They are in fact based on a scale and do not reflect your actual usage for that particular date.

Have you tried looking at days where you were away and turned the thermostat off, for which you would expect a consumption of near zero?
I bet you would still find a 'normal day' usage figure there.
Essentially they take your monthly usage, and divide it by 30 days, but with a bit more fudge to account for seasonal temperatures variations observed and whatnot.

In a nutshell, these figures are estimates, and the only 'real one' is the monthly total. At least that's how it is for me.

Again, it's fine as long as the day tariff doesn't have big swings within a billing period. But if it does, then it might be unfair.

 

[phil4]

Actually you're spot on... if I look at Hugo I get the following from the DCC:
22nd - Octopus 28.64, Hugo: 31.72
23rd - Octopus 28.91, Hugo: 34.86
24th - Octopus 28.97, Hugo: 49.10
25th - Octopus 28.17, Hugo: 28.04

Yeah, I think I'll keep quiet about that.

I never have days when we're away, so can't really use them.