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Are high day rate time of use tariffs better than the variable rate?

johnnyc

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This is a long read but it might help people who have an Electric Vehicle if they think the variable is their best or only option - Just been going through some figures for some mates to help them out with energy etc and it’s based on their rough usage (6500kwh/year -split between 3500 for charging and 3000 for everything else) and the following tariffs:

Their existing tariff (edf @13.67p/kWh) which ends very soon,
Staying on The standard variable
Octopus Go @ 7.5p/35p
EDF go electric 98 @ 20.65/41.81
EdF go electric 35 @ 4.5p/44.69p
Right…let’s see….

Usage - 6500 kWh

If we say driving is just over half of the usage - say 3500 kWh, that would leave 3000kwh for home use which would equate to about 8.2kwh a day.

Current EDF Fixed @ 13.6p

So with edf at a fixed rate of 13.6p - 6500kw x 13.6 = £884

884/6500kwh = 13.6p average unit cost

Standard Variable Tariff - capped at 28p until October (expected rise to be about 40p)

Standard variable until October is 28p/kWh so 5 months worth of electric would be roughly 2708 kWh so 28p x 2708kwh if we then look at the variable from October onwards (say 7 months) it’s looking to be 42% more expensive so - about 40p/kWh. So we will say 3792kwh @ 40p = £1516.8

Add those figures together and that’s

£1526.8+ £884 = £2400

£2400/6500 = 36.92p average unit cost.


Octopus Go

4 hours of cheap electric if we charge the car during this entire period - 3500 x 7.5p. If we can shift 3kwh of usage into this period too (low estimate for washing machine and dishwasher) and that’s 5 times a week that’ll work out at about 780 kWh (3kwh x 5 x 52). Which will leave 2200 kWh at the more expensive rate of about 35p.

Therefore:

(Car charging) 3500kwh x 7.5p = £262.5

(Washing machine & dishwasher shift) 780kwh x 7.5p = £58.50

(Everything else) 2200 x 35p - £770

Total on octopus go - £1091

1091/6500 = 16.78p average unit cost.


No fees to leave and will probably be on the variable gas tariff (or tracker gas which is interesting But there’s also the tracker tariff which is really interesting as it is priced at the next day wholesale price - at the moment it’s capped at 11p/kWh (which is obviously higher than the price cap at the moment), but recently (due to it being summer and usage is lower) it’s been between 2-6p/kWh…it may be worth going on that during the summer as theoretically it should be cheaper than the price cap tariff…then in October when demand is high, you’ll be protected by the 11p cap - which theoretically should be the same as the variable price cap.



Octopus Intelligent (if you have a tesla or compatible car)

2 Extra hours of the cheap price, so will work out cheaper than go does!

EDF Go 98

No point in me working out what the edf go 98 one will be - as the cheaper price (even though there is more time) is higher than the average price on Octopus Go - so you’ll never get it down as low as that. Even if you used 6499 kWh at the cheap rate on edf and 1 kWh on the more expensive rate - you’d be getting an average of 20.2 per unit. But it’s all about the averages and this average is probably going to be cheaper than the variable rate now, and definitely cheaper than the variable rate in October.

EDF Go Electric 35

Car charging) 3500kwh x 4.5p = 157.5

(Washing machine & dishwasher shift) 780kwh x 4.5p = £35.1

(Everything else) 2200 x 44.69p - £983.18
Total on EDF Go Electric 35 - £1,175.78

£1,175.78/6500 = 18p average unit cost.


But you’ll have exit fees to pay if you want to leave early and will have to take the high gas tariff which is 13p/kWh at the moment.


Figures above are charging the car twice a week roughly (maybe a little more than twice a week) about 67kwh a week so, maybe 10 hours of charging as opposed to 8, the more you charge the car though (or put more into the cheap time) the lower your average price per kWh becomes 🙂



If you don’t load shift anything and only charge the car during the cheap times on octopus (so keep your washing machine on during the day time etc) total cost would be about:

3500kwh x 7.5p - £262.5

3000kwh x 35p - £1050

Total without switching washing machine (no load shifting) to cheap time on octopus go - £1312.50


Average price per kWh is therefore 20.19p - and if you applied this (no load shifting) to the other tariffs, octopus would be a little lower than edf Go Electric 35, way lower than edf 98, way lower than the price cap now, and half the price of the price cap in October!!! 😱😱😱



Standing Charge added on

Variable = 45p x 365 = + £164.25

Octopus Go = 47.84p x365 = + £174.62

Edf 98 = 48.23p x365 = + £176

Edf 35 = 48.23p x365 = + £176



It’s all Back of fag packet calculations - but it’s a good starting point for anyone who is thinking that staying on the variable is the cheapest option for them if they have an EV.

Obviously it all depends on usage and these figures won’t necessarily be indicative of your own usage - but I thought it was worth putting out there as some people get scared by the high day prices of the time of use tariffs and think they are better off on the variable as it’s a lower price. As I said this won’t suit everyone as everyone’s usage is different - but hopefully it might help one or two! :) It’s always worth doing your own calculations!!

The sharing of referral codes in the forum is banned (which is absolutely the correct decision by admin), but if you think that octopus is the better tariff for you, and you did want a refferal code (to get £50 free credit), mine is below in my signature - and if you’re reading this on mobile and can’t see my signature - you can always PM me! 😀
 
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Your findings are similar to my own, in that as long as you can charge for approx. 6 hours (~40kwh) a week on average, you'll break even on Go compared to the variable.

Load shift and/or charge more and you'll save money. Fix now and if the cap goes up (which it will) and come October you'll save money even if you don't charge your car.
 
This is a long read but it might help people who have an Electric Vehicle if they think the variable is their best or only option - Just been going through some figures for some mates to help them out with energy etc and it’s based on their rough usage (6500kwh/year -split between 3500 for charging and 3000 for everything else) and the following tariffs:

Their existing tariff (edf @13.67p/kWh) which ends very soon,
Staying on The standard variable
Octopus Go @ 7.5p/35p
EDF go electric 98 @ 20.65/41.81
EdF go electric 35 @ 4.5p/44.69p
Right…let’s see….

Usage - 6500 kWh

If we say driving is just over half of the usage - say 3500 kWh, that would leave 3000kwh for home use which would equate to about 8.2kwh a day.

Current EDF Fixed @ 13.6p

So with edf at a fixed rate of 13.6p - 6500kw x 13.6 = £884

884/6500kwh = 13.6p average unit cost

Standard Variable Tariff - capped at 28p until October (expected rise to be about 40p)

Standard variable until October is 28p/kWh so 5 months worth of electric would be roughly 2708 kWh so 28p x 2708kwh if we then look at the variable from October onwards (say 7 months) it’s looking to be 42% more expensive so - about 40p/kWh. So we will say 3792kwh @ 40p = £1516.8

Add those figures together and that’s

£1526.8+ £884 = £2400

£2400/6500 = 36.92p average unit cost.


Octopus Go

4 hours of cheap electric if we charge the car during this entire period - 3500 x 7.5p. If we can shift 3kwh of usage into this period too (low estimate for washing machine and dishwasher) and that’s 5 times a week that’ll work out at about 780 kWh (3kwh x 5 x 52). Which will leave 2200 kWh at the more expensive rate of about 35p.

Therefore:

(Car charging) 3500kwh x 7.5p = £262.5

(Washing machine & dishwasher shift) 780kwh x 7.5p = £58.50

(Everything else) 2200 x 35p - £770

Total on octopus go - £1091

1091/6500 = 16.78p average unit cost.


No fees to leave and will probably be on the variable gas tariff (or tracker gas which is interesting But there’s also the tracker tariff which is really interesting as it is priced at the next day wholesale price - at the moment it’s capped at 11p/kWh (which is obviously higher than the price cap at the moment), but recently (due to it being summer and usage is lower) it’s been between 2-6p/kWh…it may be worth going on that during the summer as theoretically it should be cheaper than the price cap tariff…then in October when demand is high, you’ll be protected by the 11p cap - which theoretically should be the same as the variable price cap.



Octopus Intelligent (if you have a tesla or compatible car)

2 Extra hours of the cheap price, so will work out cheaper than go does!

EDF Go 98

No point in me working out what the edf go 98 one will be - as the cheaper price (even though there is more time) is higher than the average price on Octopus Go - so you’ll never get it down as low as that. Even if you used 6499 kWh at the cheap rate on edf and 1 kWh on the more expensive rate - you’d be getting an average of 20.2 per unit. But it’s all about the averages and this average is probably going to be cheaper than the variable rate now, and definitely cheaper than the variable rate in October.

EDF Go Electric 35

Car charging) 3500kwh x 4.5p = 157.5

(Washing machine & dishwasher shift) 780kwh x 4.5p = £35.1

(Everything else) 2200 x 44.69p - £983.18
Total on EDF Go Electric 35 - £1,175.78

£1,175.78/6500 = 18p average unit cost.


But you’ll have exit fees to pay if you want to leave early and will have to take the high gas tariff which is 13p/kWh at the moment.


Figures above are charging the car twice a week roughly (maybe a little more than twice a week) about 67kwh a week so, maybe 10 hours of charging as opposed to 8, the more you charge the car though (or put more into the cheap time) the lower your average price per kWh becomes 🙂



If you don’t load shift anything and only charge the car during the cheap times on octopus (so keep your washing machine on during the day time etc) total cost would be about:

3500kwh x 7.5p - £262.5

3000kwh x 35p - £1050

Total without switching washing machine (no load shifting) to cheap time on octopus go - £1312.50


Average price per kWh is therefore 20.19p - and if you applied this (no load shifting) to the other tariffs, octopus would be a little lower than edf Go Electric 35, way lower than edf 98, way lower than the price cap now, and half the price of the price cap in October!!! 😱😱😱



Standing Charge added on

Variable = 45p x 365 = + £164.25

Octopus Go = 47.84p x365 = + £174.62

Edf 98 = 48.23p x365 = + £176

Edf 35 = 48.23p x365 = + £176



It’s all Back of fag packet calculations - but it’s a good starting point for anyone who is thinking that staying on the variable is the cheapest option for them if they have an EV.

Obviously it all depends on usage and these figures won’t necessarily be indicative of your own usage - but I thought it was worth putting out there as some people get scared by the high day prices of the time of use tariffs and think they are better off on the variable as it’s a lower price. As I said this won’t suit everyone as everyone’s usage is different - but hopefully it might help one or two! :) It’s always worth doing your own calculations!!

The sharing of referral codes in the forum is banned (which is absolutely the correct decision by admin), but if you think that octopus is the better tariff for you, and you did want a refferal code (to get £50 free credit), mine is below in my signature - and if you’re reading this on mobile and can’t see my signature - you can always PM me! 😀
Excellent work, this is a perpetual dilemma.
I did post a link to a simple easy to use spreadsheet I created a while back for this same purpose that anybody can use.
Link is in the post below (it will take you direct to the link) and is also attached again below. if anyone wants to try their own figures. Click on the link and it will download the spreadsheet for you to use, just overwrite the default figures in green.

 

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Excellent work, this is a perpetual dilemma.
I did post a link to a simple easy to use spreadsheet I created a while back for this same purpose that anybody can use.
Link is in the post below if anyone wants to try their own figures.

Indeed it is! I was trying to explain to my friends how it’s all about the AVERAGE price per kWh, but they couldn’t see past the high day time rate - stating that it’s going to cost them more to be on Go (or any time of use tariff) as opposed to the standard variable as the price for that was obviously lower than the high day price of a time of use tariff.

After laying out all the figures - I think it helped them to see that they would be massively in benefit of a time of use tariff like octopus go, or edf go electric 35.

It probably makes sense to switch to one now even if you hardly charge the car as the higher day rate (as it stands) will be cheaper than the variable price in October.

Crazy times we live in! I just hope My calculations can help someone who really needs the help - as well as everyone else who can benefit.

Obviously usage will affect the figures - but I think the figures are reflective of ‘average-ish’ usage data - well everyone I’ve spoken to has roughly this usage! 😂😂😂

All about the averages! Get more usage into the cheaper rates and the average price comes down :)
 
I agree with your figures above. But, 3500 kWh of car charging is around 12,000 miles. Although 12,000 miles is my average yearly mileage, only about half of this is home charging in my case, with the remainder being at Tesco and rapids. Once the home car charging is reduced to around 1700 kWh, the average price per kWh on the Octopus Go or EDF Go35 increase.
In my case, the EDF Go98 is slightly cheaper than the other 2 options. This is because I have to run dehumidifiers for about 10 hrs per day in my house plus some underfloor heating early morning and late evening. The long cheap rate of the EDF Go98 is ideal for this. As you say, every house is different and to get the best rate requires modelling for your own usage pattern.
 
I’d argue that taking into account charging losses and efficiency etc - that 3500kwh will give between 10,000-12,000 miles - but yes that’s what my figures are based on as that’s our (and my friends Yearly usage) - which then begs the question - why do people feel the need for an EV to have a range of 500 miles before they would consider one? 12,000 miles a year equates to 32 miles a day.

Anyways, back on point - point proven with the time of use tariff (be it EDF go electric 98 or octopus go) being cheaper than the standard variable rate - even taking into account the much higher day rate :)

I’m just hoping this post will encourage some to look at their own usage patterns and decide that even though time of use tarrifs have a higher day rate, they you shouldn’t be scared of it…it’s all about the AVERAGE rate :)
 
I agree with your figures above. But, 3500 kWh of car charging is around 12,000 miles. Although 12,000 miles is my average yearly mileage, only about half of this is home charging in my case, with the remainder being at Tesco and rapids. Once the home car charging is reduced to around 1700 kWh, the average price per kWh on the Octopus Go or EDF Go35 increase.
In my case, the EDF Go98 is slightly cheaper than the other 2 options. This is because I have to run dehumidifiers for about 10 hrs per day in my house plus some underfloor heating early morning and late evening. The long cheap rate of the EDF Go98 is ideal for this. As you say, every house is different and to get the best rate requires modelling for your own usage pattern.
You could use the spreadsheet above to compare the 2 tariffs as it uses your own figures for daytime and off-peak usage, times are unimportant.
 
I went through this lot last week when the reminder came (bit of a shocker that was), wish your post had been a few days earlier would have saved me a headache. Good job though much better than all my scraps of paper 😁

It didn’t seem as though the EDF go35 was open to new sign ups when I tried looking at their site unless it was just down at the time.

I recently added Solar/battery storage so this makes it a tad harder for us to work out given it’s too early for us to have any historic month on month figures to base anything on, currently by rotating 2 EV’s between commute & running about were only having to charge from grid 3 days/month rest of the time we seem to be managing to run off grid (probably been a lucky start), don’t see that lasting much past September though but keeping my fingers crossed.
 
I went through this lot last week when the reminder came (bit of a shocker that was), wish your post had been a few days earlier would have saved me a headache. Good job though much better than all my scraps of paper 😁

It didn’t seem as though the EDF go35 was open to new sign ups when I tried looking at their site unless it was just down at the time.

I recently added Solar/battery storage so this makes it a tad harder for us to work out given it’s too early for us to have any historic month on month figures to base anything on, currently by rotating 2 EV’s between commute & running about were only having to charge from grid 3 days/month rest of the time we seem to be managing to run off grid (probably been a lucky start), don’t see that lasting much past September though but keeping my fingers crossed.
Theoretically you won’t ever need to pull from the grid during the expensive part if using a battery, and if Solar too means your figure should be At most an average of 7.5p/kWh!

So if you went with my figures of 6500 kWh, the maximum really you will ever pay is 6600 x 7.5p = £487.5 for EVERYTHING. If you were on the standard variable from now 5 months at 28p = £758, 7 months at 40p = £1516.

Total for Standard variable = £2274! Meaning a saving of AT LEAST £1800 - add in the solar and it’ll be at least another £200 saved if not more - and then selling back to the grid…I had better get some panels myself!
 
This is a long read but it might help people who have an Electric
Best solution is to invest in a battery system (solar if possible) with a capacity to cover daily usage then go on Octopus Go and fill up that battery for domestic use bringing all usage to 7.5p/kw
Peak/daily rate becomes irrelevant
 
Best solution is to invest in a battery system (solar if possible) with a capacity to cover daily usage then go on Octopus Go and fill up that battery for domestic use bringing all usage to 7.5p/kw
Peak/daily rate becomes irrelevant
Yup indeed! Totally agree with this - it’s what I’m looking to do myself - but not everyone has the upfront cash (or the installers as they’re all so busy!)
 
I went with a 12kwh battery system would recommend that as a minimum, typical household usage is probably 8-10khw/day our 6kva solar array tends to generate between 6-32kwh/day march-may so has been providing hot water via a Solar Iboost and charges a car a couple of times a week. Dropped really lucky with the install as I enquired on a Friday and they started the install the following Wednesday as I had scaffolding up from another job. If your figures are anything like payback should be about 5yrs (Not including what we’re saving on the cost of diesel)
 
Wish my payback was the same, I guess location, size of roof etc. are not in my favour and companies were quoting me estimated payback of nearer 15 years then the inverter will need replacing.

That was just over £10k for 3kw solar array and 8kw battery system.
 
I’ve come up with a stupidly complicated and massive spreadsheet which was based on my initial calculations (couldn’t sleep last night!) I’ll try upload it somewhere! Or I can always input your figures if you want! :)
 

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Wish my payback was the same, I guess location, size of roof etc. are not in my favour and companies were quoting me estimated payback of nearer 15 years then the inverter will need replacing.

That was just over £10k for 3kw solar array and 8kw battery system.
5yrs was a bit tongue in cheek but as the energy prices go up it seems to be getting more and more realistic.

Given the opportunity I figured the money was just better spent on the system to gain some independence wrt my EV / Home energy costs than simply handing it to the energy companies each month.

Would be interesting to know how many others are going down this route, quite a few would be my guess judging by how busy the solar installers seem to be.
 
I’ve come up with a stupidly complicated and massive spreadsheet which was based on my initial calculations (couldn’t sleep last night!) I’ll try upload it somewhere! Or I can always input your figures if you want!

Great summary much easier to see all the figures in a tabular form.
 
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