@dr_dongle we use Cosy (another octopus tarrif and together with the battery in January our average electricity price was 18p. So we used more on some days than the Cosy cheap periods (8hrs total) and battery discharge times ~8hrs on the coldest days. But overall not too bad.

Posted by: @tim441

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Octopus Agile has wholesale rates changing every 30 mins.

• Bigger faff factor to manage
• If you can manage correctly savings likely to be bigger
• Especially if peak avoided by using oil

I agree, we used to have agile but now with enough energy storage we never did better - with a simple 7p overnight "all weather" tariff. 

We use octopus agile for export (but just ignore the faff and focus on peak, with a completely local setup). Excluding EV charging, we can almost ignore the electricity bill. 

@tim441 all good intel. thanks, I'll check those out - the Web site wasn't offering either by default and really, both assume that you can re-timetable your consumption quickly. Agile definitely doesn't look like it is for the faint-hearted since "Agile prices can spike up to 100 p/kWh any time - although a typical household in Winter '22-'23 paid around 35 p/kWh average". 

I monitor my system closely via HomeAssistant and an ebus interface though I control it via the manufacturer's controller.  Currently the ASHP brings in the oil boiler via a bivalent point when the ambient temperature drops below -2 but a tariff-optimising option might be to bring on oil via HomeAssistant when the COP averaged over an hour or so drops below the break-even point (about 4 and corresponding to an ambient temperature of about 4 C). For further study...

@dr_dongle Agile can work very well. But probably better suited with battery. HA would help automate - you could switch to oil if Agile above (say) 25p. The spikes are few and far between. Personally would not be unduly concerned.

Tracker is very simple.

Cosy might suit but again udeally suited with battery storage. I suspect oil is cheaper than cosy peak rates.

@tim441 (apologies for potential topic drift into "Octopus Cosy Heat Pump Owners and Discussion" thread BTW).

For now the model from the utilities is clearly various ToU tariffs. As said on the other group "yes, but what will it all be next year .. or the year after?" That means more capital £££ from us for energy storage which assumes that the pattern won't change. Government seems fixated on outdated policies (see Mars's excellent video) and quoting figures that are mostly for new-builds and look good in publicity material but don't solve the problem of retro-fits to old properties.

I extrapolated Scottish Government's installation figures and it is telling me that they're going to miss their 2030 target by a factor of 10. A pointed letter to the Minister is on the way. (more topic drift so I'll stop there)

The trick with Agile is simply to avoid pulling from grid at the peak points. Do that and the average is far lower than 35p.

However, the only way to significantly timeshift purchase from usage is with a battery. I wouldn’t recommend Agile without one. In addition, because Agile is inherently variable, it’s not ideally suited to scheduling strategies, so works best in combination with an automation system of some sort. Home Assistant is ideal since it can work through a number of rules that cover all the likely scenarios and act accordingly. That’s what I do.

@majordennisbloodnok When I had solar panels being fitted, I had already considered having more than the one Tesla Powerwall as, in my opinion, tariffs were never going to allow for ‘anytime’ consumption without considerable cost penalties. Difficulties of supply aside, I was very pleased to have the 27kWh capacity available when the heat pump is running; virtually all of our grid power is ‘downloaded’ during the 8 cheapest hours of the Cosy tariff. Some arbitrage during the summer helps here and there too. Regards, Toodles.

Exactly, @toodles. You have the battery necessary for the timeshifting but not the automation system for the automated horse trading. I know you do sometimes do a bit of that manually, but not enough to make Agile the best fit for you.

@dr_dongle 

Yes, the model is TOU, even if sometimes they market variations based on owning a specific type of device (EV included). But whereas some are very simple to make use of, others like agile may appear to require HA or "AI" capability, with all the time that goes into it. Quick observation of agile export rates led me to conclude the main daily variation is peak time. A few hundreds of pounds off the yearly electric bill, just by making use of the spare 8-9kwh battery space has been a great reward for the effort I put into getting a BESS! 😀 

@dr_dongle I had a phone call yesterday from an 80yr old talked into installing a very expensive Heat Pump system to her converted barn.

She'd have been better installing an LPG system boiler as her Electricity has gone from £120 to £350 with Solar too. Previously on top of electricity, she had 2x Gas fires running from 47kg LPG.

I do not see the logic due to R32 dropping to 2:1 as you say, at the exact time efficiency is low and demand is high.

Running A2A here, below 2 degrees it gets switched off and we run boiler for the night.

However - my first suggestion is that she is with British Gas who are offering half price electricity 00:00 - 07:00 and 13:00 - 16:00.

She is installing a Smart Meter and switching to that tariff which is available and no suggestion of being withdrawn.

Best I can suggest in your scenario is a large battery pack (30kwh) and Inverter to cope and charge while cheaper, to buffer the more expensive hours.

Other than that, colder nights for sure run the oil boiler as I've recommended to this lady look to sticking an LPG 'assist' boiler for those times the very expensive Auxiliary Heater kicks in or efficiency is very low.

At the end of the day, crunching 27p per kwh at 2 to 1, is almost 3x the price of Gas. Yeh, yeh, its only a few weeks of the year but my, these weeks can sure kill other savings.

I'm all for CO2 reduction but the reality is, sometimes it is cheaper and better for the Grid to push some heating load to on-site Gas burning - a hybrid system.

EDF are about to offer Heat Pump tariffs asking for pre-registration. We're with EDF and have had 16hrs of unlimited lovely free Sunday electricity since September.

Over £1200 of Sunday electricity credited over the last 12months.

Each Sunday we get 165kwh to 200kwh free leaving £20 to pay for the rest of the week. If you want £50 to switch to EDF, drop me a line as not sure I can post it here.

Take a look at BG or EDF for HP and even better with Sunday Saver.

Sundays here are crazy, washing, drying, heating, EV, house batteries and 4x dehumidifiers running to keep house bone dry and warm for free. Once a week we drop humidity to 40% - all for free.

Octopus are losing their edge now they are giving others access to Kraken.

@diverted-energy Thank you and the others for that information and there is a lot there to digest.  An immediate takeaway is that there are a lot more tariffs out there than a superficial search would suggest.

Taking what I know I did one simple comparison assuming I did absolutely no time shifting and had constant electricity use 24/7. I then used that to calculate an effective per unit rate. It is artificial but I thought the results were interesting.

On this basis

My current OvO tariff was 15p/kWh 24x7 with a cap that I just avoided this year but as of today that has been withdrawn and I don't know of a replacement. Their undiscounted SVR is 27.01p/kWh.

Cosy Octopus starts out at 29.22 p/kWh but comes down to 27.91, somewhere between their fixed and tracker rates. The peak rate hours accounted for 40% of the figure.

EDF Heat Pump tracker starts at 27.69 (probably, they are a bit coy) but this then comes down to 25.19. The "free Sunday" rate is hard to compare since free hours have to be earned by avoiding standard and peak rates elsewhere.

British Gas starts high at 31.50 but drops to an effective rate of 24.94 due to having 10 hrs/day cheap rate and no peak rate.

I haven't included standing charges or switching penalties yet but with no energy storage actually British Gas doesn't look too bad. My heat pump power consumption hour by hour is all over the place but I should be able to refine that via HomeAssistant. If going to BG I would for instance stop putting the house on a lower setback overnight and store a bit of heat in the house fabric..

All this has to be compared with an effective rate for oil at about 7p/kWh though between March and November the better COP means that the ASHP wins. I just need to cover the really cold snaps.

A really worthwhile discussion, thanks again everyone.

Posted by: @dr_dongle

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My current OvO tariff was 15p/kWh 24x7 with a cap that I just avoided this year but as of today that has been withdrawn and I don't know of a replacement. Their undiscounted SVR is 27.01p/kWh.

Cosy Octopus starts out at 29.22 p/kWh but comes down to 27.91, somewhere between their fixed and tracker rates. The peak rate hours accounted for 40% of the figure.

I was a bit surprised with the rates you mentioned being close to 30p, so I had a quick look at octopus and in my area, this is what the attractive part is: 

Cosy rate (04:00 - 07:00, 13:00 - 16:00, 22:00 - 00:00) 14.05p / kWh

But clearly you need to have some battery storage to take see the benefit.

Such a system would mean your average rate for all consumption can be very close to it...