TerryE

Octopus Agile (Time of Use) tariff

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Posted (edited)

Not sure where to put this, but I thought that this might be useful for other members considering switching to a ToU tariff. 

 

I've been considering moving my Home system to  use a ToU tariff and Octopus seems to be the only supplier offering one ATM.  My main concern was that they have a spreadsheet for historic pricing for 2019, but no hard data on current pricing on their website.  You can't get access to their forum until you have an account, which is a bit of a problem if you want the data to make an informed switch.  Luckily they do offer and document a REST API where you can query the ToU tariff data.  I used this to pull the data for the last 2 years, and aggregated this for time-of-day by Month.  I've attached the quick and dirty scripts (minimum effort to write) that I used for this as a starting point if anyone is interested in doing this themselves.  I used httpie and rs (because Octopus did and I couldn't be bothered to recode these; you can just sudo apt-get these utilities on most linux distros.)  I've also added the main summary graphs below.

 

My main conclusions are as follows:

  • Electricity prices are rather high at the moment (winter; an increased demand due to Covid home working; and possibly a Brexit hike), and in my case I have a 24 month fixed E7 tariff from OVO which isolates me from this hike, and so the rates will need to fall somewhat for it to be worthwhile for me to switch.
  • However the ToU tariff is cheaper in comparison to current single rate and E7 "flexible" tariffs, so long as you can stick to some basic rules:
    • Use the Midnight - 6AM window as much as possible for high-load stuff.
    • Avoid the 15:30 - 18:30 peak demand pricing where practical and move as much daytime use out of this window.  About the only use we have in this window is for "always on" devices and cooking and this is rarely more than 1 kWh during this window. 
    • The price can fall considerably on an infrequent basis (11:00 - 14:30 on sunny days in the summer; anytime the wind is blowing).
  • If you have a Home automation system and use the daily price forecast API, then you can reduce your electricity overall costs further.  Analysing our past usage E7 saves us about £15 / week in the winter months and a ToU tarrif would increase this saving to £20-25.
  • Be aware that you need a converted SMETS1 or a  SMETS2 meter fitted to allow your smart meter to be switchable between suppliers.  In our case, we have SMETS1 meter that is due to be converted in by July. (This OVO form post gives the back story.)

 

Hope this is useful.

 

622952001_MonthTrend.png.10e96aee7d6e3863ff0a090bfa3f604a.png

 

These are all calendar monthly aggregates by 30-min pricing slot.  Min and Max are the usual definition; the remainder are averages over different time windows. 

19885952_ToDbymonth.png.74610936fad95d96a18d830d6cd17fe3.png

 

Get-tariffs

#! /bin/bash
BASE_URL="https://api.octopus.energy"
PRODUCT_CODE="AGILE-18-02-21"
TARIFF_CODE="E-1R-${PRODUCT_CODE}-C"
TARIFF_URL="$BASE_URL/v1/products/$PRODUCT_CODE/electricity-tariffs/$TARIFF_CODE/standard-unit-rates/"
W=~/Desktop/agile

for ((i=0; i<$2; i = i+1)) ; do 
  START=$(date -d "$1-01 $i months" +%Y-%m-%d)
  END=$(date -d "$START 1 months" +%Y-%m-%d)
  MON=$(date -d $START +%y-%m)
  echo Processing $MON
  http $TARIFF_URL period_from=="${START}T00:00Z" period_to=="${END}T00:00Z" page_size==1490 | \
    jq -r '.results[] | [(.valid_from|capture("^........(?<m>..)T(?<t>..:..)")|"\(.m) \(.t)"), (.value_exc_vat|tostring)] | join (" ")' | \
    sort > $W/agile-tariff-$MON.lst
done

Aggregate Tariffs

#! /bin/bash
W=~/Desktop/agile
for ((i=0; i<$2; i = i+1)) ; do 
  m=$(date -d "$1-01 $i months" +%y-%m)
  perl -ne '
    my ($h,$m,$v) = /.. (..):(..) (.*)/; my $i = 2*$h+$m/30; 
    $tot[$i] +=$v; $cnt[$i]++; 
    END {foreach (0..47) {printf("%.2f,",$tot[$_]/$cnt[$_]);}; print "\n";}' \
    $W/agile-tariff-$m.lst
done

 

Edited by TerryE
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It's that afternoon (dinner time) rip off period that kills it for me.

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4 minutes ago, ProDave said:

It's that afternoon (dinner time) rip off period that kills it for me.

Time I am at work.

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I believe that I could save quite a lot on one of these tariffs as the majority of my energy use is overnight. I can easily avoid the peak period too. I just need Octopus or another supplier to start rolling out smart meters for 3 phase. It’s one reason why I haven’t gone down the ASHP route as this type of tariff better suits maximising usage during the cheapest tariff periods whereas an ASHP is better left to run throughout the day when it needs to I believe. 

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I’m on this and should be on the Agile Outgoing by tomorrow. I’m using the cheaper overnight rates for the Sunamp and  UFH. Here’s today and tomorrow’s prices. 
 

They release the following days prices at around 16:00. PV is starting to offset the peak periods. Batteries one day should help even more, charging at the low rate and using at the peak rate. 

9898008E-0901-4A6A-A023-B2A06CC36C3D.thumb.png.41610c1bfef7c42ba68527adfa9a8351.png

 

78FB128A-F13F-4732-BB61-90AA34A89665.thumb.png.c22da1e7029cf3cddb69261eda623e3f.png


 

 

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1 hour ago, newhome said:

I just need Octopus or another supplier to start rolling out smart meters for 3 phase

 

Octopus installed one for us in October last year.  Not convinved about ToU tarrif, think flat import/export is just so much easier if you have a fair amount of PV.

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Posted (edited)
3 hours ago, newhome said:

I just need Octopus or another supplier to start rolling out smart meters for 3 phase.

 

I had to do a search of you past posts to get the backstory.  A 24 kW boiler on for ~2hrs  a day: this is a peak single circuit load of 96A.  This seems to be case of mega-over-sizing to me.  Obviously whoever sized your system took no cognisance of your SAP calculations, and ended up costing you a lot of unnecessary expense and running cost / maintenance uplift. Split milk, I guess, but it must piss you off. 🙁

 

Out of interest, the maximum we've drawn in any ½hr slot (out of the 40 months that I have been capturing and logging smart meter data) is 4.6 kW and only 2% of the 30slots are over 3 kW (e.g. always-on load + one of the SunAmps on + Willis + washing machine, say). 

 

2 hours ago, Russdl said:

[Octopus] release the following days prices at around 16:00. PV is starting to offset the peak periods. Batteries one day should help even more, charging at the low rate and using at the peak rate. 

 

I already run daily queries in Node-RED to get weather forecast data and the  previous day's usage.  Running one in the evening using the REST API to pull down the following day's prices is straightforward.  One thing that you screen grabs do underline is that I should histogram out the various slots to get an idea of micro-placement is worthwhile. 

 

I don't have PV, so can't justify any battery storage.  I can't justify a RoI based on ToU shifting alone.  

Edited by TerryE

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Posted (edited)

I've just had a play with a few approaches.  Recall that the way my heating calcs go, I compute how much heat I need the following day each midnight.  The best algo seems to be to split this into ½hr slots so let's say I need N slots tomorrow, then pick the N cheapest slots in the next day's ToU tariff and run the heating during these slots whenever they are.  Depending on the month this can reduce my heating bill by 25-60%, so cancel my comment about the OVO E7 tariff being cheaper.

 

PS.  The price can go negative, so I need to think about what I do on these days! :) 

Edited by TerryE
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Very interesting indeed Terry.  Thank you.  Just (as in yesterday) switched.

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Went live with Agile last week. Cost saving against standard tariff (Octopus Flexible) is 35% for the first four days.

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4 hours ago, TerryE said:

I've just had a play with a few approaches.  Recall that the way my heating calcs go, I compute how much heat I need the following day each midnight.  The best algo seems to be to split this into ½hr slots so let's say I need N slots tomorrow, then pick the N cheapest slots in the next day's ToU tariff and run the heating during these slots whenever they are.  Depending on the month this can reduce my heating bill by 25-60%, so cancel my comment about the OVO E7 tariff being cheaper.

 

PS.  The price can go negative, so I need to think about what I do on these days! :) 

This is something I'm thinking a lot about at the moment. Currently at the planning stage and likely to have a heat pump and lots of PV, and since right now we're waiting on Architect and QS I need something to occupy my mind:

  1. Start out with conventional controls (thermostat for house and hot water cylinder), running through a transfer switch to the heat pump. That way if the homebrew smart controls don't work, it's easy to fall-back on something which does.
  2. On the alternative branch, have something like a Raspberry Pi which does the following:
    1. Pulls the next 24 hour pricing from the Octopus API (or another API in future as more tariffs come out). This includes the outgoing prices - the PV array will be facing SW so at least in summer we would probably be exporting during the evening peak which is worth something like 12p/kWh on the Agile version of outgoing.
    2. Uses some sort of third party site to predict generation over the next 24 hours - e.g. https://solcast.com/rooftop-solar/
    3. Takes some sort of assumption about demand (say 500W normally, 1kW during the evening peak) and decides if we would be importing or exporting during a period, then assigning the appropriate price to that time period.
    4. Take a rough estimate for the required run time to provide the heat needed for the floor and hot water - duplicating what you've done previously, essentially.
    5. Assign heating and hot water to the two cheapest continuous blocks over a 24 hour period (one each for heating and hot water, maybe two at most for heating in the middle of winter - don't want to cycle in half hour segments to chase a few pence of savings with a heat pump).
    6. Having some sort of interrupt to turn the heating off when temperature hits the target would be nice - not mandatory, but may allow for finer temperature control/badly screwed up programming.
  3. In terms of what we need to plan for, it should actually be pretty easy to implement - big hot water tank (Mixergy would be nice but they don't seem to give anybody else access to their resistor switch data), heat pump of some sort, and LAN + power connections nearby.

Does this look reasonably sensible, or am I missing something major? The heat pump is primarily because active cooling is a hard requirement for us, and any savings are likely to be pretty modest as a result - I figure the heating demand is likely to be ~600 kWh of electricity per year, plus a bit more than this for hot water. I'd be doing this primarily for the satisfaction rather than any sort of financial reason as a result.

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Those of you that are switching/have switched to a ToD tariff, can you keep a good record of your usage as well as the price (I assume the 'app' does that).

Will be interesting to see what the overall savings are, once meter rental and VAT is added on.  My power is coming it at 15p/kWh, but the last week, now that the heating is off, it is 18.6p/kWh, but my daily mean has gone from 23.8 kWh (87% night rate) down to 10.55 kWh (65% night rate), but that will almost halve in the net months.

While it hurts to pay the high day rate to EDF, generally (this winter was a bit of an exception) my usage is very low.

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1 hour ago, pdf27 said:

Mixergy would be nice but they don't seem to give anybody else access to their resistor switch data)

Can you expand? Mixergy has API and is also available with Modbus interface.

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56 minutes ago, Dan F said:

Can you expand? Mixergy has API and is also available with Modbus interface.

Digging through the published manuals it looks like a closed system - you can connect to Agile through their app, but as far as I can dig through the manuals (pretty sparse TBH) if you aren't doing so you've only got a fairly dumb on/off switching control. I can't find any mention of Modbus apart from one of your forum posts, or of an accessible API.

The ideal would be to be able to read the state of charge and temperature off the API - they clearly do this themselves so the hardware supports it, but I can't find anything in the public domain that suggests it's possible for third parties to do so. While monkeying about with it would be really interesting, it's too complex for me to take on.

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24 minutes ago, pdf27 said:

Digging through the published manuals it looks like a closed system - you can connect to Agile through their app, but as far as I can dig through the manuals (pretty sparse TBH) if you aren't doing so you've only got a fairly dumb on/off switching control. I can't find any mention of Modbus apart from one of your forum posts, or of an accessible API.

The ideal would be to be able to read the state of charge and temperature off the API - they clearly do this themselves so the hardware supports it, but I can't find anything in the public domain that suggests it's possible for third parties to do so. While monkeying about with it would be really interesting, it's too complex for me to take on.

 

There is an API (they gave me documentation), it does depend on their cloud service though (as does app).  Alternativley, there is a Modbus controller available with no internet dependency.  I also have Modbus documentation, but I beleive a different hardware controller is required for this, I am in the process of confirming,.   Via Modbus you can set heat source, target charge percentage, target temperature and well as read temperatures.

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2 hours ago, pdf27 said:

This is something I'm thinking a lot about at the moment. Currently at the planning stage and likely to have a heat pump and lots of PV, and since right now we're waiting on Architect and QS I need something to occupy my mind:

  1. Start out with conventional controls (thermostat for house and hot water cylinder), running through a transfer switch to the heat pump. That way if the homebrew smart controls don't work, it's easy to fall-back on something which does.
  2. On the alternative branch, have something like a Raspberry Pi which does the following:
    1. Pulls the next 24 hour pricing from the Octopus API (or another API in future as more tariffs come out). This includes the outgoing prices - the PV array will be facing SW so at least in summer we would probably be exporting during the evening peak which is worth something like 12p/kWh on the Agile version of outgoing.
    2. Uses some sort of third party site to predict generation over the next 24 hours - e.g. https://solcast.com/rooftop-solar/
    3. Takes some sort of assumption about demand (say 500W normally, 1kW during the evening peak) and decides if we would be importing or exporting during a period, then assigning the appropriate price to that time period.
    4. Take a rough estimate for the required run time to provide the heat needed for the floor and hot water - duplicating what you've done previously, essentially.
    5. Assign heating and hot water to the two cheapest continuous blocks over a 24 hour period (one each for heating and hot water, maybe two at most for heating in the middle of winter - don't want to cycle in half hour segments to chase a few pence of savings with a heat pump).
    6. Having some sort of interrupt to turn the heating off when temperature hits the target would be nice - not mandatory, but may allow for finer temperature control/badly screwed up programming.
  3. In terms of what we need to plan for, it should actually be pretty easy to implement - big hot water tank (Mixergy would be nice but they don't seem to give anybody else access to their resistor switch data), heat pump of some sort, and LAN + power connections nearby.

Does this look reasonably sensible, or am I missing something major? The heat pump is primarily because active cooling is a hard requirement for us, and any savings are likely to be pretty modest as a result - I figure the heating demand is likely to be ~600 kWh of electricity per year, plus a bit more than this for hot water. I'd be doing this primarily for the satisfaction rather than any sort of financial reason as a result.

 

I was planning to do roughly the same,  but given we have a lot of PV and expect to export at least twice of what we import over the year, the 11p export, 11p import Telsa Tariff just seems like a much simpler approach.   Maybe we could save more via manually controlling everything, but it's very hard to know if this would be the case, I doubt it though as 11p export is unavailable via any other tariff that I know of.  Also not seen anything for 11p for peak usage either.

 

Caveat is that to get this tariff you need a powerwall, and the lead time on these isn't great.

 

 

 

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11 hours ago, TerryE said:

Obviously whoever sized your system took no cognisance of your SAP calculations, and ended up costing you a lot of unnecessary expense and running cost / maintenance uplift. Split milk, I guess, but it must piss you off. 🙁


Well I can only blame my husband as he sized it! The only good thing is that I really only need to run it once a day so the Agile tariff would suit me very well, especially when the price goes negative 🙂

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15 hours ago, Dan F said:

 

Octopus installed one for us in October last year.  Not convinved about ToU tarrif, think flat import/export is just so much easier if you have a fair amount of PV.


They are apparently not installing them in my area. I’ve been on the list for well over a year and I’ve been told that the wait will be long. I have no PV just a not working Solar thermal system so ToU would work for me well. I accept that it’s not for everyone however. I’m on a flat rate tariff at present @ 12p for heating and 12.5p for other use (I have 2 meters currently). 

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1 hour ago, Dan F said:

I was planning to do roughly the same,  but given we have a lot of PV and expect to export at least twice of what we import over the year, the 11p export, 11p import Telsa Tariff just seems like a much simpler approach.   Maybe we could save more via manually controlling everything, but it's very hard to know if this would be the case, I doubt it though as 11p export is unavailable via any other tariff that I know of.  Also not seen anything for 11p for peak usage either.

 

Caveat is that to get this tariff you need a powerwall, and the lead time on these isn't great.

There's also the assumption that the tariff will be available for an extended period of time into the future, which I'm not very comfortable with. Taking that approach I also struggle to make the numbers stack up against a standard 15p import/5p export type tariff: all of the benefit of having a battery apart from backup power in an outage is baked into the unit cost, and for the predicted costs and usage the cost of that backup is pretty high, particularly if I end up with a non-Tesla electric car in future. Charging at 11p/kWh is expensive.

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1 hour ago, pdf27 said:

Charging at 11p/kWh is expensive.

That is about the same energy price when gasoline is a quid a litre.

You obviously get better efficiency from an electric motor compared to an ICE.

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2 hours ago, newhome said:


They are apparently not installing them in my area. I’ve been on the list for well over a year and I’ve been told that the wait will be long. I have no PV just a not working Solar thermal system so ToU would work for me well. I accept that it’s not for everyone however. I’m on a flat rate tariff at present @ 12p for heating and 12.5p for other use (I have 2 meters currently). 

WOW  Who is offering 12.5p for all uses 24/7 in Scotland?

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2 hours ago, pdf27 said:

There's also the assumption that the tariff will be available for an extended period of time into the future, which I'm not very comfortable with.

If the tariff is no longer available,  you'd just switch back Octopus Agile wouldn't you.   What would the issue be?

 

2 hours ago, pdf27 said:

Taking that approach I also struggle to make the numbers stack up against a standard 15p import/5p export type tariff: all of the benefit of having a battery apart from backup power in an outage is baked into the unit cost, and for the predicted costs and usage the cost of that backup is pretty high,

I guess it comes down to how much you'd import/export over the year, also how much you want to fiddle around (or automate) use/charging based on an agile tariff.

 

For us (without a electic car) this tarrif would mean a payment of approx £600 a year.  With the agile tarriff, I'm not even sure how I'd start to calculate what the annual cost would be, because it all depends on dynamic pricing, ability to schedule usage/charging as well as the maximum charge/discharge rate of battery.   Have you managed to estimate costs of agile tariff in any way?

 

2 hours ago, pdf27 said:

particularly if I end up with a non-Tesla electric car in future. Charging at 11p/kWh is expensive.

Agree 11p/kWh charging is expensive. But, if you export more than you import over the year, then the other way to think about it is simply that your summer excess is covering your winter usage?

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55 minutes ago, ProDave said:

WOW  Who is offering 12.5p for all uses 24/7 in Scotland?

I was looking the other week as I’m due to change and neon reef were 12.something all units and I have a North East Fife postcode.

they only do electricity but I’m fine with that and will look for gas elsewhere. Appreciate you don’t have gas.
 

 

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27 minutes ago, TonyT said:

I was looking the other week as I’m due to change and neon reef were 12.something all units and I have a North East Fife postcode.

they only do electricity but I’m fine with that and will look for gas elsewhere. Appreciate you don’t have gas.
 

 

Tempting. they are offering me 12.9p per kWh and 19p standing charge.

 

But how long will they last before they go bust at that price and I am lumped on some random substitute supplier.

 

And why does nothing like this ever come up on the price comparison sites?  last time I looked there I was offered nothing under 16p

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