Octopus Agile

Newbie_John

MP1995 said:

Potential negative afternoon Thursday and a cheap weekend for those that like to plan in advance.

Let's try again long term forecasting 😅
Sunday->Monday night looks at the moment as one for possible 0p prices..

NedS

matt_drummer said:

NedS said:

matt_drummer said:

NedS said:

MP1995 said:

Weather,power demand and geopolitical issue to name but a few. It all affects energy prices.

The July tracker formula is the final nail in the coffin for most. All the risk and  maybe 10% cheaper over a year.

If Agile follows suit my best alternative is cosy. (Always have a plan B and a plan C and know what it will cost you)

I have been evaluating the new updated Cosy tariff since they changed the rates and added another 2h low priced period 10pm-midnight.

For those with large batteries, it seems like a no-brainer as they should be able to fill their boots on the 11p cheap slots and never need to import on the daily rate or peak rate.

For those without batteries, it's a lot more difficult to compare with Agile, as our usage is time-shifted based on 30min pricing, which may be different between the two tariffs. In summer we would be unable to take advantage of the afternoon cheap rate slot, as first we would need to use the 3kW of solar we are generating, which has a value of 15p if exported. The other two slots would only receive minimal usage.

In autumn and spring Cosy could work if we can use the cheap slots to put sufficient heat into the house in those 8 hours, and heat the DHW.

Winter looks a lot more challenging, as ASHPs like to run low and slow 24/7 and are not really designed to ramp up for 8h when prices are cheap and then switch off during peak periods, so at best we may turn the heating off (or down) between 4-7pm, but that still requires running for 13h at the standard daily rate and 8h at cheap rate so likely cheaper than Agile for 8h per day and more expensive for 13h per day, with both having a peak rate slot 4-7pm to be avoided.

As I said, for those with large batteries, they could potentially run at 11p/kWh

I have 38 kWh of usable battery storage, 13.60 kW of solar panels and a heat pump. The cosy tariff with 15p per kWh export is perfect for me. I will rarely import at over 11p per kWh and on an annual basis I pay nothing.

My heat pump is very efficient and I just run it continuously. This means it runs at somewhere between 400W and 600W most of the time and minimises imports outside the cheap periods.

Octopus Cosy tariff is perfect for me and our house.

I really don't think there is any way to run cheaper. Obviously I am ignoring the cost of the stuff to make it possible but I have spent the money and that is that!

Exactly Matt, large batteries totally work in your favour.

Can I ask - what is your heat loss figure, and what is the minimum battery size you think you would need to see you through to the next cheap Cosy slot?

I'm guessing the fact your ASHP is only drawing 400-600W helps - mine draws 1kW minimum and maybe up to 2kW in Winter (crudely calculated as 1kW input with a COP of 3 in winter gives 3kW output, and our heat loss is around 6-7kW). We will find out in our first winter!

With 6h gaps between the cheap Cosy slots, I think I'd need a 13kW battery as a minimum, recharging 3 times per day to see me through, and even then I suspect I'd be drawing from the grid outside of the cheap slots. Plus with a 3.6kW inverter, I'd only be able to put 10.8kW into the battery in the 3h cheap slots, so would likely need a bigger inverter to fully utilise a battery over 10kW. Maybe a 9-10kW battery and 3.6kW inverter would do the job 90% of the time and we can hope for a mild winter

I think you need to remember that your heat pump would not be running from the batteries for 8 hours a day. Whilst your batteries are charging at the maximum rate possible you heat pump is also drawing its power at the cheap rate and not utilising the batteries.

As Cosy Octopus is now,  the batteries and solar only have to support the heat pump for 16 hours a day.

So, maybe on a bad day, I need the batteries to supply 16 kWh for the heat pump and whatever the rest of the house needs outside of the cheap slots. Perhaps 25 kWh so three batteries would suffice assuming no solar. With 6 Kwh a day on average from solar it is down to 19 kWh from the batteries so I could in theory make do with half of what I have and still run entirely from the cheapest rate. But, it probably won't always be enough

I am often tempted by Agile just for the fun of it, but I think it requires more attention that I am prepared to commit to.

I think if you can get through the day only drawing from the grid during the cheap Cosy slots, you've already won the game as you are averaging 11p per kWh, which is always going to beat Agile at present.

This will be my first winter, so I have no real idea yet on our usage / numbers, but I'm interested in adding batteries so we can achieve the same. Once we have a winter under our belts, and I have some real data, I should have a clear idea as to what we will require in terms of battery capacity and inverter sizing.

Telegraph_Sam

I  confess to never having gone into the battery debate in anything like the detail as described in the above few posts. Having forked out for the solars 11 years ago, my further queries about adding a battery came to an abrupt halt when I learned the costs. The payback or amotisation period was simply not economic.
No doubt the costs of the techology have fallen since then but I would still require to be convinced before making the jump.

NedS

Telegraph_Sam said:

I  confess to never having gone into the battery debate in anything like the detail as described in the above few posts. Having forked out for the solars 11 years ago, my further queries about adding a battery came to an abrupt halt when I learned the costs. The payback or amotisation period was simply not economic.
No doubt the costs of the techology have fallen since then but I would still require to be convinced before making the jump.

The use cases are also changing all the time with the introduction of new tariffs, so it's no longer simply a case of storing and utilising excess solar which would otherwise be exported.

Telegraph_Sam

That  ("..simply a case of ..") is more or less how I understood it then - and more or less how I would see it now !

MP1995

NedS said:

MP1995 said:

Weather,power demand and geopolitical issue to name but a few. It all affects energy prices.

The July tracker formula is the final nail in the coffin for most. All the risk and  maybe 10% cheaper over a year.

If Agile follows suit my best alternative is cosy. (Always have a plan B and a plan C and know what it will cost you)

I have been evaluating the new updated Cosy tariff since they changed the rates and added another 2h low priced period 10pm-midnight.

For those with large batteries, it seems like a no-brainer as they should be able to fill their boots on the 11p cheap slots and never need to import on the daily rate or peak rate.

For those without batteries, it's a lot more difficult to compare with Agile, as our usage is time-shifted based on 30min pricing, which may be different between the two tariffs. In summer we would be unable to take advantage of the afternoon cheap rate slot, as first we would need to use the 3kW of solar we are generating, which has a value of 15p if exported. The other two slots would only receive minimal usage.

In autumn and spring Cosy could work if we can use the cheap slots to put sufficient heat into the house in those 8 hours, and heat the DHW.

Winter looks a lot more challenging, as ASHPs like to run low and slow 24/7 and are not really designed to ramp up for 8h when prices are cheap and then switch off during peak periods, so at best we may turn the heating off (or down) between 4-7pm, but that still requires running for 13h at the standard daily rate and 8h at cheap rate so likely cheaper than Agile for 8h per day and more expensive for 13h per day, with both having a peak rate slot 4-7pm to be avoided.

As I said, for those with large batteries, they could potentially run at 11p/kWh

As I said we have a plan B if they meddle with the Agile formula

We have a spreadsheet and how it would work for us.

We have an ASHP and what we do on agile is stop it for three hours 4-7pm because we have a very efficient home it makes no difference except missing that expensive period. We did this last winter.

We do not have grid connected solar and batteries (I didn't want to confuse issue but I have started a home brew little system just this past couple of weeks with old farmers solar panels and a couple of ecoflows) but they are not part of this or my calculations from last winter on Agile and running our heat pump with no battery or solar.

So at the current cosy rates and knowing our usage down and mixing in some 7kwh of cooking during peak during the week (we eat out two evenings and at least one takeaway a week so thats probably over estimating) we have come up with the following

15.44p kwh

Compare that to Agile for this year it's averaging at 13.5p kwh again without batteries and solar.

The 2 extra cosy hours have made the gap closer.

@matt_drummer why don't we just call it economy 8 

matt_drummer

MP1995 said:

@matt_drummer why don't we just call it economy 8 

Maybe because it is a tariff that is only available to heat pump owners?

MP1995

matt_drummer said:

MP1995 said:

@matt_drummer why don't we just call it economy 8 

Maybe because it is a tariff that is only available to heat pump owners?

The best thing to happen is that cosy6 customer complain they can't run their ASHP as cheaply as Octopus said they could and they make it an e10 product..

Have you seen you can add your Daikin on the octopus app?

matt_drummer

MP1995 said:

matt_drummer said:

MP1995 said:

@matt_drummer why don't we just call it economy 8 

Maybe because it is a tariff that is only available to heat pump owners?

The best thing to happen is that cosy6 customer complain they can't run their ASHP as cheaply as Octopus said they could and they make it an e10 product..

Have you seen you can add your Daikin on the octopus app?

MP1995 said:

matt_drummer said:

MP1995 said:

@matt_drummer why don't we just call it economy 8 

Maybe because it is a tariff that is only available to heat pump owners?

The best thing to happen is that cosy6 customer complain they can't run their ASHP as cheaply as Octopus said they could and they make it an e10 product..

Have you seen you can add your Daikin on the octopus app?

Yes, I gave Octopus access to my heat pump data via their app as soon as it became available last year

Newbie_John

Next days look really good:
https://emoncms.org/ukgrid