Posted by: @jamespa

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Posted by: @editor

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I’d be interested to hear the feedback and consensus on the tariffs we discussed recently and if you agree:

I watched it.  I found it an interesting discussion but Im not sure how much sense it would make to someone coming at this from a 'standing start'.  Thats largely, I think, a feature of the format.  An unscripted discussion between several people is not particularly good, in my opinion, at conveying the comparative information between different tariffs and for whom they may be good/poor.  Obviously thats just a personal opinion but I could imagine coming away confused rather than enlightened.  It might be worth trying to get some feedback from some people who havent given lots of thought to the matter in advance.

In answer to the question in the title I'm currently on EON Next Drive.  This gives 7 hours Midnight - 7am at 6.7p/kWh in return for about a 10% uplift on the day rate.  Its fixed price for one year until Dec 2025

The reasons for choosing this were:

• I dont have a battery (and cant make the business case pay to get one) but I do have solar panels
• I do have an EV.  The cheap rate period applies to whole consumption but they reserve the right to check if you have an EV
• The tarrif is simple so I dont need complex automations, special hardware or a battery to take advantage of it - unlike the current Octopus offerings
• Because the night time import rate is less than the export rate, I dont have to consider using excess solar power to 'displace' consumption that otherwise could be postponed to night time.  So Year-round I can just put on my EV and high capacity items at night wherever I can and it will work out cheaper even though I am self-consuming less
• Although I could get my heat pump energy cheaper (15p/kWh) with the OvO heat pump add on, once I take into account the cost for charging the EV and OVOs very low export rate, the EON tarrif works out cheaper overall

My average unit rate excluding the energy used by my EV and ignoring the solar panels - ie assuming all electricity used is imported, works out at 19.3p.  To calculate this figure I first allocate all energy used by the EV to the cheap rate (because its only charged between midnight and 7am) and then work out the average for the rest.

So it works for me which doesn't mean it works for anyone else!

Im assuming that I may well have to switch suppliers every year until tariff patterns stabilise!

Interesting to hear how that works for you.

We have a heat pump and solar, but no battery and we are on Octopus Cosy.

We load shift as much as possible into the three cheap rate Cosy slots, and minimise usage at peak rate times. We operate an overnight switch off for the heat pump (and off between peak rate 4-7pm).

Our average import price over winter (Dec-Feb) has been ~19-20p so identical to @jamespa above despite our very different tariffs and approaches.

As we don't have an EV, the very cheap overnight tariffs are not available to use, but I don't think they'd work so well for us anyway. The heat pump is the major use for us, and I want less heat overnight when it's cheap, not more, so without a battery (or EV) I'm not sure we could make that work.

We had previously been on Octopus Agile, but moved away from that as prices increased in December. I agree with @jamespa point above about not needing complex automations, and have found the Cosy tariff far easier to manage with the 3 regular cheap rate slots.

We try to stay on top of tariff developments, as that seems to have the most affect on our bills, more so than any running tweaks or performance/efficiency changes we can make to the running of heat pump (assuming it's already running reasonably well)

Posted by: @old_scientist

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Interesting to hear how [EON Next Drive] that works for you.

We have a heat pump and solar, but no battery and we are on Octopus Cosy.

We load shift as much as possible into the three cheap rate Cosy slots, and minimise usage at peak rate times. We operate an overnight switch off for the heat pump (and off between peak rate 4-7pm).

Our average import price over winter (Dec-Feb) has been ~19-20p so identical to @jamespa above despite our very different tariffs and approaches.

As we don't have an EV, the very cheap overnight tariffs are not available to use, but I don't think they'd work so well for us anyway. The heat pump is the major use for us, and I want less heat overnight when it's cheap, not more, so without a battery (or EV) I'm not sure we could make that work.

We had previously been on Octopus Agile, but moved away from that as prices increased in December. I agree with @jamespa point above about not needing complex automations, and have found the Cosy tariff far easier to manage with the 3 regular cheap rate slots.

We try to stay on top of tariff developments, as that seems to have the most affect on our bills, more so than any running tweaks or performance/efficiency changes we can make to the running of heat pump (assuming it's already running reasonably well)

 

I haven't yet bothered optimising the heat pump cycle, I just leave it on 24*7.  I did my calculations to get to 19.3p per kWh from mid Nov - mid Feb.  The night time usage is slightly depressed when its very cold by the fact I have 'quiet mode' in operation during the period, but it nevertheless worked out OK.  Im now getting the (slightly unexpected) bonus that the solar is taking up some of the daytime heat pump load, thus tipping the balance towards the cheap rate.  

I do think its rather difficult to be certain what the optimum tariff is, but for sure the standard tariff isn't optimum for me and several others are an improvement, to the tune of several £100 per annum.  When I did the calculations that I based the decision on, Next Drive was the one that worked out cheapest and, when combined with its simplicity, the choice became easy.  I will re-run them in December when the fixed price period expires, although I could exit this import rate without penalty, it would reduce my export rate to 4p for the whole year, so its not worth considering a mid-term switch unless something extreme happens.

@jamespa. You are on the same tarrif as me 😀 .  My average on the import comes to about 10p but the house is well insulated and only needs heat in the 7 hours on the ev tarrif. Sometimes the upstairs does kick in the afternon but for just a   very short time and it only runs  5. Very small radiators.

Over the past few years I've moved from Octopus Standard >> Tracker >> Agile >> Intelligent Go

Noting setup includes;

16kw ASHP from 2020

8kw Pv Solar from 2021

24.6kwh batteries from 2021

E/V from 2023

Due to inverter charge/discharge rate of just 2.6kwh I thought tariffs like Agile or IOG might be a problem. However I was wrong - in my case these tariffs were much better and charge/discharge rate reduced ability to maximise without being a big problem.

Annual ASHP usage 5800kwh

Annual imports circa 9000kwh (some imports used for later forced exports at higher rates e.g. during Saving Sessions)

Annual usage inc self production solar circa 12000kwh

Annual exports circa 3000kwh

Annual solar production circa 6000kwh

My use of Octopus Intelligent Go (IOG) which gives a minimum of 6 hours at 7p overnight and a fair daily rate. However they also give extra slots during the daytime hours - also at 7p. Afaik they use this to help balance grid. By maximising daytime slots + batteries I can import almost all requirements at cheapest rates except on coldest days when I may need some imports at day rates. I export at 15p using Octopus "Fixed" which is currently set at 15p but terms have been varied and this may change.

So far I'm not round trip importing at 7p and exporting at 15p - with my slow inverter and round trip losses I'm not sure I can make a lot. But will consider further.

I use @WonderWatt to manage my batteries to get filled not only from the overnight slots but also it recognises the daytime slots which easily justifies the cost for me as it would be almost impossible to manage manually.

More importantly use of the overnight 7p to fill batteries will mean that I expect to export a larger proportion of solar production. Something to review at year end.

Note IOG requires smart meter with compatible E/V and ideally compatible charger. Coupled with batteries offers best savings.

So IOG may not be an option for some people but hopefully the principle encourages others to review ToU options.

2023 Tracker ave 19p

2024 Agile ave 12p

2025 IOG ave looks like 8p

@tim441 looks like a fantastic set up! 👌

@andris cheers! I got lucky in a way that the heat pump installation during covid was at a competitive price and benefitted from more generous RHI grant.

Solar and batteries were OK pricing as it was before lithium shot up (albeit falling back since - not sure batteries reflect that properly?). I installed more batteries than seemed necessary on paper - worked out well with enhanced ToU tariffs available.

EV thankfully is contract hire so not my problem for 2nd hand values or decline of battery.

If installing now it would benefit from:

- higher output solar panels

- fast inverter charge/discharge rates

- better battery options inc integrated emergency power supply from variety of manufacturers.

- Bigger capacity as standard

Etc. So it's never too late! And forums like this help a lot with guidance.

OE have informed me today that they have now completed the integration of IOF with Tesla Powerwalls. I wonder if anyone out there has looked at or gone for this tariff please?

I have 27kWh of storage and produce ~ 6 MWh of solar energy annually. During the heating season, we consume some 20 - 40 kWh of energy daily with the heat pump - I feel it is probably better at present to be on the Cosy tariff where we pay ~13 pence per kWh and leave the grid-charged battery to take the strain for the other 16 hours of the day. At present, our best performance from solar is approx. 20 kWh on a sunny day. Our domestic needs take approx another 15kWh per day.

I feel that once the temperature rises so that the ASHP is only consuming ~ 10 kWh or less. in a day, the solar might be providing 30 kWh plus per day, the IOF tariff may be a better balance. What does anyone think please?

Regards, Toodles.

Posted by: @toodles

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OE have informed me today that they have now completed the integration of IOF with Tesla Powerwalls. I wonder if anyone out there has looked at or gone for this tariff please?

I have 27kWh of storage and produce ~ 6 MWh of solar energy annually. During the heating season, we consume some 20 - 40 kWh of energy daily with the heat pump - I feel it is probably better at present to be on the Cosy tariff where we pay ~13 pence per kWh and leave the grid-charged battery to take the strain for the other 16 hours of the day. At present, our best performance from solar is approx. 20 kWh on a sunny day. Our domestic needs take approx another 15kWh per day.

I feel that once the temperature rises so that the ASHP is only consuming ~ 10 kWh or less. in a day, the solar might be providing 30 kWh plus per day, the IOF tariff may be a better balance. What does anyone think please?

Regards, Toodles.

That's great news!

I've not done a detailed analysis, but when I took a quick look, IOF looked like a good choice once you become a next exporter (so probably around the time the heating goes off). You can charge the battery from solar, and export the excess at ~22-23p per kWh. Knowing your average monthly usage and average monthly generation/export, it should be fairly easy to model in a spreadsheet.

During heating season, where solar generation is much less, locking in the cheap Cosy rates seems a clear win to me.

@old_scientist Between 16:00 - 19:00, the export rate rises to 29.97p (present rate in my area today anyway). Now, pity I can’t have Cosy import and peak rate export on IOF!!! 😉 Regards, Toodles.

Posted by: @toodles

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@old_scientist Between 16:00 - 19:00, the export rate rises to 29.97p (present rate in my area today anyway). Now, pity I can’t have Cosy import and peak rate export on IOF!!! 😉 Regards, Toodles.

Given the rates are approximately 23p/30p, I'm assuming IOF would fully discharge your battery each evening during the peak at 30p, and then you'd import at 23p overnight (instead of just using your stored energy) gaining you 7p per kWh. The battery can then recharge from excess solar during the day with any excess exported, and the cycle repeats.

It should be possible to model that scenario versus a simple Cosy/SEG scenario to see how much usage/generation is required for the cross over point (we can probably assume a fixed average daily usage)

@old_scientist The OE guidelines mention that their control over the Powerwall would discharge it down to 20% during the peak demand time. As I am permitted to discharge at 10kW, those three hours would enable me to export ~ 21.6 kWh plus whatever solar might be produced for perhaps at least 1.5 hours of that exporting period. I might have an export opportunity of ~ 24 kWh, which at current rates = £7 or so.😀 There are a number of variables of course, not least weather! During the day, my domestic needs might require ~15 kWH; my solar panels might produce 40 kWh plus on a sunny day so it looks like a possible project! Regards, Toodles.

I have now written to OE for clarification on the algorithm used for the charge / discharge levels and how this affects the ability to ‘save’ the solar energy to export during the peak time. IE, is the battery grid charged to full capacity or only partially grid charged to allow for solar energy to be used to charge it - this saving on the amount of grid imported energy. Regards, Toodles.