Hello @tim441, I have been collating details to compare Cosy and Agile and had intended to let the figures run for a further three months as I changed to Cosy from Agile on the first of July so only have three months for comparison as yet - but for what it is worth, I’ll do an interim here.

But first (as they say) I’ll provide my salient details and last year’s stats. Sorry that they may be in a different format and order to yours but I have to grossly magnify the page to read it and consequently, it is very tedious to scroll back and forth noting order and format.

My system:

8.1 kWp of PV with Enphase IQ7 microinverters. (Not optimally placed and with some chimney and tree shading at various times.)

Tesla Gateway with 27 kWh’s of Powerwall storage; able to import/export at 10 kWh.

No vehicle (visually handicapped - keep death off the roads!).

All electric household with:

Daikin 8kWh monobloc ASHP.

Sunamp Thermino ePC210 DHW system.

MyEnergi Eddi.

Induction hob, 2 x combi Microwave Cookers, Air Fryer, Slow Cooker, Breadmaker, Heavy Cast Iron Cookware various, Washing Machine, Heat Pump Tumble Dryer.

The usual array of Network and WiFi thingery plus HiFi equipment etc.

According to my Enphase app, the figures for 2023:

PV Production 7.4 MW

Exported 3.5 MW

Total imported 6.7 MW

Nett Imported 3.2 MW

Consumption 10.7 MW (N.B., the ASHP was not commissioned until mid-February so I am still working on meaningful consumption figures for an all-electric home. (Gas heating and DHW until mid-Feb) 

I have used figures from Agileprices.co.uk for the comparison, it must be understood that there are statistics and statistics of course! I  have taken the ‘Average Off Peak’ figures for July, August and September though I am uncertain how they arrive at these actual prices. I am assuming that they are representative of the HH rates a diligent consumer might use in an average day by adhering to just the lower priced HH’s and avoiding all other times each day.

They show:

July 15.9 pence per kWh

August 13.5 p p kWh and 

September 17.2 p p kWh.

Taking the average of these three figures gives an averaged average(!) of 15.63 p p kWh. for July - September on Octopus Agile.

I swapped to Cosy on July 1st. and the unit cost was 11.2p p kWh during that time (it has risen approx 10% from 1st October) My export rate is 15p. p kWh fixed and I try to export as much of my self generated as I am able.

I will leave the reader to discern whether Agile or Cosy might be the cheaper to use for their needs. I only use the 8 cheapest hours in each day to keep my Powerwalls charged and am effectively ‘off-grid’ for the other 16 hours each day. It works for me anyway.

My intention is to update the figures when I have the full 6 month’s worth of stats. Regards, Toodles.

@toodles many thanks for the comprehensive reply!

In terms of Agile I have no doubt you would significantly improve on the Agile average due to your usage of batteries with great capacity and high charge rate capacity.

Using my pathetic capabilities due to inverter charge rate I managed an average of 10.62 for those 3 months - using my actual bills. We had some nice low rates from time to time....

Lets swap notes again around year end!

@tim441 Yes, could be more meaningful by then, there is also the ‘bonus’ of Savings Sessions and the short notice high value 1 or 1.5 hour sessions - they can allow me to export 10 kWh or more and Octopus paid £4.50 per kWh at one time last winter! Rewards, Toodles.

@toodles yes, I managed to get about £180 on savingssessions last winter - even with my slow discharge rate... plus switching off ashp.

it will be interesting to see if they run it with similar structure this year or make some changes

@tim441 Last year I ‘netted’ about £400 that way so I hope they keep it similar in its’ workings. Toodles.

This is a really interesting thread. 

Could I get some thoughts from the sharp minds here on my scenario? 

13kW Grant ASHP with additional 3kW immerser/volumiser

5.46kW solar array

10kW battery

I’m on Octopus tracker for Import and the 15p export tariff.

I just can’t figure out whether Agile or Intelligent is going to be better for me than Tracker. I’m about to order an EV through my work’s salary sacrifice scheme. Would 7p per hour overnight for charging the car also mean that I would get to run my ASHP overnight at 7p per hour? That could be a game changer in winter. 

@marvinator80 what rate will your inverter charge/discharge?

If its low.. you may not get max from cheap slots?

In case it helps I recently posted a tarrif model in this thread https://renewableheatinghub.co.uk/forums/postid/36428

You may be able to adapt the assumptions to your case (which isn't so different to mine).  

I reached the conclusion that, for me, battery doesn't pay (I don't have one).   You already have one so start from a different place but the model, which fundamentally is designed to compare tarrifs, may still help.

My understanding of intelligent go is that you do get overnight electricity at 7p, I think it says that clearly on the website.  Assuming you mean 10kWh when you say 10kW, you should be able to charge your battery during this period. If your ashp is correctly sized at 13kW, then most of the time it will be delivering 6kW which at a cop of 3 will consume 2kW so your battery will last 5hours.

@tim441 hi Tim. It’s a 5KW inverter but if I’m understanding things correctly that shouldn’t be an issue as I want to charge the car, power the house/ashp and ideally charge the battery overnight at the 7p rate which would be from the grid. The battery isn’t being discharged at all during this 6 hour period. 

car will only need charged a few times a month and often not a full charge. 

@jamespa thanks James. 

Makes sense and charging the battery overnight at 7p per hour would be a nice bonus but not the be all and end all.

i get the impression from Octopus spending some time on the Octopus website today that you need to have a particularl battery (GivEnergy) to link it to their system. Mine is an AmpiHome, from a Dutch company Ampowr. 

Posted by: @marvinator80

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Makes sense and charging the battery overnight at 7p per hour would be a nice bonus but not the be all and end all.

i get the impression from Octopus spending some time on the Octopus website today that you need to have a particularl battery (GivEnergy) to link it to their system. Mine is an AmpiHome, from a Dutch company Ampowr. 

You could well be right.  I didn't look into it that far because I fail Octopus Intelligent Go at the first hurdle.  Although I have an EV its only compatible with Intelligent Go if I also have a compatible charger, which I don't.  In fact I don't have a 'charger' at all just a 13A socket and no need for a higher charging rate than that supplies.

That said, given that the tarrif says that 7p/kWh applies to everything between the specified hours, I suspect this is a function of the battery control system not of Octopus.  Octopus will just see it as another house load that isn't a car, so if your battery can draw power on a timed basis then that should do the job.