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Best Energy Providers [UK]

JAR897

Member
Jun 11, 2020
197
171
Nottingham
Hi all,

With M3P due to arrive next week and lockdown assisting time to review, I'm looking at my gas & electricity provider and wondering if I'm on the best deal for the "new normal" (Details below).

With this in mind, can anyone suggest any tips/advise for energy providers - specifically considering the following;
  • I intend to charge the car a few evenings per night, and so something like an Economy 7 may be beneficial, however...
  • ...New normal also likely means I'll be at home a lot more, and so day-rates will be important too (Gas specifically in winter)
  • I'm based in Nottingham, currently paying c. £500 per annum in electricity (but this is currently excluding car charging)
I've heard good things - on this forum and elsewhere - on Ovo energy and Octopus energy, too. I also don't currently have a smart meter - So keen to understand if any benefit from an EV charging perspective?

Apologies, as I know this isn't a money-supermarket forum! But hopefully some experience of household bills related to EV charging!
 

Adopado

Active Member
Aug 19, 2019
4,907
3,724
Scotland
You will very likely need a smart meter to access the best EV charging options. I presently use Octopus Go which is 5p per kWh for a 4 hour period 0.30 to 4.30. Other Octopus users are on their Agile plan which is a super-variable (by the half hour) pricing scheme that can go even lower in some instances but can be higher too. I don't know about gas ... wish I had the option!

You will get £50 from Octopus if you go with them and quote somebody's referral code ... you only have to ask somebody on this forum ...
 

Adopado

Active Member
Aug 19, 2019
4,907
3,724
Scotland
Thanks all - Look like British Gas are quoting the best standard saving, but Octopus and Ovo are offering decent Economy 7 rates - I wonder if Economy 7 will be more cost-effective?

It depends on your particular pattern of consumption ... it varies but the most flexible options are going to require a smart meter (which can be fitted free by your chosen supplier of course).

The rules of this forum state that you shouldn't put your referral codes, Tesla or otherwise, in your signature ...
 

Dilly

Active Member
Feb 24, 2020
2,536
2,014
Norfolk
I’m with Octopus Go at £0.1345 & £0.0476 peak and off peak plus VAT. Peak rates may vary by location standing charge is 25p per day.
Having solar, I use next to no grid power during spring and summer and charge off peak late autumn & winter.
At this time of year the standing charge is the greater portion of my bill.

it comes down to how many hours off peak charge you need based upon daily miles driven. The Octopus 4 hour off peak window will give you a third of a full charge (28Kwh) that’s roughly 80 miles or more.
For a longer charge, economy 7 will give a longer off peak window I believe.
 

Jeeves

Member
Feb 12, 2020
611
355
UK
To make a choice, you really need to understand your pattern of consumption in relation to charging. It turns out that this is quite easy to estimate if you know how long your journeys are likely to be and how many per day on the days you would travel most. There are lots of posts discussing real-world Wh/mile on here.

Prior to the crisis, it was not unusual for me to need 55+kWh per night during the week (especially on cold days), but I didn’t know that before I got the car. To be candid, all the EV terminology was bewildering to me until I had owned one for a bit and began to understand how things worked.

My high consumption meant that the 4 hours/night of cheap electricity tariffs were less attractive to me, and I ended up moving from EDF’s EV tariff that I thought was good before owning the car to Agile Octopus after learning about it here because I could easily avoid the peak window of 16:00–19:00. That turns out to have been a sensible decision because the rates I’m paying are much lower than even EDF’s off-peak rate. Luckily, more time at home during the day in the new normal makes that even more so.

Whilst it make sense to optimise your bills, I think one can get a bit obsessive about it. The difference between EDF and Octopus usually equates to a couple of quid a night at most. Don’t get me wrong, I would rather the money in my pocket than the power company’s. I’m just suggesting that there is no need to rush. The real saving is likely to be in comparison with fossil fuels if you are new to EVs. Even if I had stayed on EDF, I would have saved a great deal in comparison with diesel for my old car.
 
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TM3P1

Member
Jun 16, 2020
38
32
Solihull
To make a choice, you really need to understand your pattern of consumption in relation to charging. It turns out that this is quite easy to estimate if you know how long your journeys are likely to be and how many per day on the days you would travel most. There are lots of posts discussing real-world Wh/mile on here.

Prior to the crisis, it was not unusual for me to need 55+kWh per night during the week (especially on cold days), but I didn’t know that before I got the car. To be candid, all the EV terminology was bewildering to me until I had owned one for a bit and began to understand how things worked.

My high consumption meant that the 4 hours/night of cheap electricity tariffs were less attractive to me, and I ended up moving from EDF’s EV tariff that I thought was good before owning the car to Agile Octopus after learning about it here because I could easily avoid the peak window of 16:00–19:00. That turns out to have been a sensible decision because the rates I’m paying are much lower than even EDF’s off-peak rate. Luckily, more time at home during the day in the new normal makes that even more so.

Whilst it make sense to optimise your bills, I think one can get a bit obsessive about it. The difference between EDF and Octopus usually equates to a couple of quid a night at most. Don’t get me wrong, I would rather the money in my pocket than the power company’s. I’m just suggesting that there is no need to rush. The real saving is likely to be in comparison with fossil fuels if you are new to EVs. Even if I had stayed on EDF, I would have saved a great deal in comparison with diesel for my old car.

Completely agree with this. I had no idea before I recently got my EV how cheap it would be in electricity to run (even on my rather expensive Shell Energy tariff). I have basically gone from using £180 in petrol a month in the BMW M3 to about £40 in electricity (15.7p /kWh daytime and economy 7 10.7p /kWh). Sure I will save another £10/month on Octopus go...but suddenly the rush to change energy supplier and spend £60 in exit fee is not so appealing. It will happen but I can take my time choosing the best option that works for me!
 

JAR897

Member
Jun 11, 2020
197
171
Nottingham
Octopus Go is currently 15p/8p on/off peak respectively. Amazingly, EDF GoElectric is incentivising at just 12p(!!) standard (single rate) which is very compelling for me - I think it might work out c. £100 more expensive over a 12 month period, but is much lower risk given (1) more time at home means on-peak costs would be more significant and (2) allows me to charge any time without thinking about on/off peak prices etc.

Resources:
EV Energy Tariffs: home tariffs designed for EV drivers - Zap-Map
EV Tariff - Energy for Your Electric Car and Home for Less
 
Agree and second @Jeeves comments above. In my situation, I was with British Gas (elec only) and found that Octopus Go was cheaper even with my 'normal' usage pre-lockdown and pre-EV so I decided to change to Go anyway as I would be saving money even before owning an EV. They installed the smart meter today (no cost) and there are no cancellation fees with Octopus so was a win-win for me. Once I have the M3 I will likely use most of the 4hrs per night of the low rate as I will be doing about 2000 miles per month.

Also as @TM3P1 mentions, the saving between Diesel and Electric meant that even if I didn't change, it would be a big saving.
 

JAR897

Member
Jun 11, 2020
197
171
Nottingham
Thanks everyone - super useful.

It’s worth doing the maths to understand the miles and equivalent KwH requirements as mentioned in order to determine the best option.

eg. For me, I’ll likely do 400-500 miles per week, and therefore need an estimated 1.5 charges @ 50KwH per week. With a 7KwH TWC I’ll therefore need a 10hrs charge once or twice a week. From this requirement I then worked out the split of “on peak” and “off peak” charging required, and actually concluded that Octopus Energy’s 5p per KwH for 4hrs per night (leaving 6hrs at a higher rate) was actually less cost effective than 10hrs at EDF’s GoElectric rate which is valid for 9pm-7am plus all weekend.

I can share the maths tomorrow if useful for others? but in short, absolutely right, do the maths based on individual needs to find the absolute best deal - but ultimately the saving between EV tarring options is minimal (c. £100) vs the savings from diesel to electric (£24 for 500 miles per week vs £100 per week in my BMW!! = £300 per month saving)
 

Mr Miserable

Well-Known Member
Supporting Member
Jul 8, 2019
5,734
11,108
UK
The savings from changing to a suitable tariff can be considerable. The key word here is suitable as there are many tariffs out there that may turn out to be totally unsuitable for you. It very much depends on your pattern of consumption.
If you have gas, don't assume a dual fuel tariff will work out better. Gas is very cheap at the moment and is likely to remain so for some time. So the first step to reduce your overall energy bill at the moment, is to look at your gas bill. There are some big savings to be had by moving to another supplier. Use a comparison site and don't ignore the whole market option rather than limiting your choice to just those suppliers that pay the comparison site. (I use SO Energy for my gas as the £40 referral bonus made the overall annual cost the cheapest.)
Since you now have an EV, you can expect a larger electric bill. Unless you have workplace charging the best place to charge will be at home and the best time to charge will be at night whilst you are sleeping. It's worth remembering that no matter what your tariff is you will still save money compared to what you will have spent on petrol or diesel, however why spend 15p per kWh when your next door neighbour may be paying 5p per kWh (or less) to charge their car.
Of the electricity suppliers Octopus has a variety of tariffs, some of which don't require a smart meter or economy 7 meter, which are extremely competitive. Octopus don't lock you in either so you can change tariffs or leave them completely at any time without penalty - not many allow that. Octopus Go (smart meter) gives you 4 hours each night at 5p per kWh.
You will hear a lot about Octopus Agile - this is a tariff with half hourly changing rates that reflect the wholesale market price. You need a smart meter to get this (smart meters are not being fitted at the moment and there will be a large backlog) and the headline is that at certain times the price can go negative (a sunny and windy weekend will do the job). The penalty is that between 1600-1900 the price can be as much as 35p per kWh. If you have a battery to tide you over this period you are laughing otherwise putting the kettle on during this period could wipe out the savings you made at other times. So this tariff is not for everyone but for those who have the flexibility to adjust their consumption pattern daily to maximise use during the cheaper periods the savings can be dramatic and addictive.
For those with the more traditional lifestyle (going to work in the morning and coming home in the evening M-F and weekends off) the EDF Go Electric tariff may be more attractive. It offers a long off-peak period from 9pm to 7am M-F and all weekend at 8p per kWh.
I did a spreadsheet with various electricity tariffs last year. You can play around with the consumption figures depending on the peak/off peak periods to get an idea of the monthly costs. I haven't checked whether the tariffs are still valid, so do check before making a final decision. You can see that some companies offer 'EV' tariffs that can work out to be extremely expensive and 'green energy' is worthy of a thread of its own as there are varying shades of green energy, some of which are very expensive.
Ecotricity offer discounts to their network of 'electric highway' chargers however the consensus of opinion on this forum at the moment is that they tend to be extremely unreliable.
An EV is more expensive to buy than an ICE but much cheaper to run. It can be incredibly cheap to run if you select the right tariff for your circumstances.
 

Jeeves

Member
Feb 12, 2020
611
355
UK
How many journeys make up that 4-500 miles a week? What would a typical travel day be like?

You might be too optimistic on the required kWh, especially in winter if the car doesn’t have the chance to warm up. I often do 110-130 miles in a day as two trips on rural roads. In winter, the battery is just getting properly warm by the time I arrive and stone cold again before coming back, so I never got anywhere close to the theoretical maximum efficiencies. Use of the cabin heater meant I tended to average 345 Wh/mile at best but often much worse when I chose to enjoy the performance characteristics of the car. That meant I tended to need 45-60 kWh a night, effectively from 15–25% to 80 or 90% each day. That’s what pushed me to Agile.

There is plenty of debate about charging habits on here, but the consensus seems to be that you should only regularly charge to 80 or 90% each night for battery longevity. If you want to do a long trip, it’s OK to charge higher, but you need to leave immediately so the battery isn’t sitting for long at a high state of charge. Maybe I’m cautious, but I like to have a bit of charge in reserve because chargers are in short supply on my regular routes, and I often must divert around jams. Consequently, I don’t like planning to go much below 20% on arrival unless I’m on the way to a supercharger.

Another winter factor to consider is pre-heating for defrosting, comfort and battery pack warming. The battery pack warming reduces the limited regen period and makes it more efficient in the cold. This uses up quite a bit of the charge you build up overnight because pre-heating uses more than the 7kW you can get off the wall, but getting into a warm defrosted car is a fantastic luxury on a dark, cold morning.

Apologies if you already knew all this, but the 300+ mile range advertised is for people driving like saints for long distances in a Californian climate using the entire battery capacity. Real-world Blighty is a bit different.

Consumption is markedly better in warmer weather, but it seems you should plan on routinely using only 60–80% of the battery capacity and be pessimistic about efficiency. Depending on the journeys you intend to make and how you drive, this might mean charging more frequently and putting a lot more juice in than you anticipate. Won’t cost you much more, it might even reinforce the decision you seem to have made on electricity supplier too, but you should know what to expect.

Charging practices and range seem to provoke fierce debate here. Not what I intend, but no doubt someone will be along shortly to contradict me. FWIW, I’m just sharing my personal, real-world experience of the car you are about to get and love driving (probably faster and harder than you imagined).

If you haven’t watched any, Bjørn Nyland’s YouTube videos teach you lots about charging, range and climate.
 

Bigknd

Member
May 14, 2020
27
14
Bristol
Octopus Go is currently 15p/8p on/off peak respectively. Amazingly, EDF GoElectric is incentivising at just 12p(!!) standard (single rate) which is very compelling for me - I think it might work out c. £100 more expensive over a 12 month period, but is much lower risk given (1) more time at home means on-peak costs would be more significant and (2) allows me to charge any time without thinking about on/off peak prices etc.

Resources:
EV Energy Tariffs: home tariffs designed for EV drivers - Zap-Map
EV Tariff - Energy for Your Electric Car and Home for Less

Another one for EDF GoElectric got the car through Drive Electric and EDF were offering 11.91p all day tariff and 5000 free miles so no brainier for me ;)
 

JAR897

Member
Jun 11, 2020
197
171
Nottingham
How many journeys make up that 4-500 miles a week? What would a typical travel day be like?

You might be too optimistic on the required kWh.

The 300+ mile range advertised is for people driving like saints.

Thanks for the info - It's a whole new world for me so any advice useful! Personally (and perhaps naively) I'm not *too* concerned with battery longevity - I'm on a 3yr lease - but intend to charge to 90% c. 2-3 times per week. I did the calculations on a cautious (2,000 KwH of charge) and pessimistic (4,000 KwH of charge) on top of my usual usage - I'll share my logic below should it be helpful for anyone else.

Step A: Data gathering
  1. Record single-rate KwH rates for both EDF (12.03p) and Octopus Go (14.61p)
  2. Record multi-rate on-peak/off-peak KwH rates for EDF (17.64p/8p) and Octopus Go (13.45p/5p)
  3. Record KwH Gas rates for EDF (2.62p) and Octopus Go (2.55p)
  4. Record Daily Electric/Gas standing charge for EDF (22.89p/27.35p) and Octopus Go (20.05p/17.85p)
The result from doing just this comparison would be that Octopus Go offers a more competitive rate, however...

Step B: Calculate KwH Usage
  1. First, understand pre-EV electricity usage (for me, 2,000 KwH last 12 months)
  2. To calculate KwH increase from EV, I first assumed 50 KwH per charge (c. 20KwH 'in the tank') and 270mi per charge.
  3. I assumed, therefore, I would need 1.5x charges per week based on avg. 400 mi per week, and 48 weeks of the year (50 x 1.5 x 48 = 3,600 KwH).
  4. I then rounded this up to the nearest 1k, to total a 4,000 KwH increase in KwH (equating to 6,000 KwH total when adding last 12 months).
On the single-rate tariffs, the clear winner here would be EDF based on a lower single-rate KwH rate (6,000 x 12.03p = £721 vs Octopus Go £876).

Step C: Calculate on-peak / off-peak usage
  1. This is where things get interesting. First, you need to understand the 'split' (on- vs off-) for the different tariffs. For EDF GoElectric this is 2100 - 0700 (10hrs) plus all day Sat & Sun. For Octopus Go this is 0030 - 0430 (4hrs).
  2. Next, I needed to calculate how the 6,000 KwH would be split between on- and off-peak. First, I needed to understand EV charge time, which is based on a 7KwH Tesla Wall Charger and a 50KwH requirement would be c. 7hrs.
  3. I am now ready to calculate KwH split: I did this in two phases; first the previous 12 months (2,000 KwH) and secondly the new EV charging (c 4,000 Kwh). The key factor here is the duration of off-peak rates.
  4. As the EDF off-peak rate lasts 10hrs plus weekends, and average charge takes under 10hrs, I was able to allocate 100% of the 4,000 EV-related KwH charging to the off-peak rate. I also shifted some of the previous 12 months (2,000 KwH) into off-peak based on an estimated on- vs off-peak usage (excluding EV charging). This resulted in 1,200 KwH on-peak and 4,800 KwH off-peak for EDF.
  5. For Octopus Go, only 4hrs (57%) of the 7hrs of charge would qualify for off-peak charging. Thus, I calculated 57% of the 4,800 KwH off-peak usage from EDF (equal to 2,736 KwH) as Octopus Go's off-peak usage, and therefore a further 3,264 KwH on-peak use.
Step D: Calculate on-peak / off-peak usage cost
  1. Now I know the Usage and Cost of on- and off-peak KwH, the calculation is simple.
  2. EDF was £211 (17.64p x 1,200 KwH) on-peak and £384 (8p x 4,800 KwH) off-peak. Octopus Go was £439 (13.45p x 3,264 KwH) on-peak and £136 (5p x 2,736 KwH) off-peak. Totals therefore before Gas and before Daily standard charges were £595 (EDF) vs £575 (Octopus Go).
  3. Of course, you then need to factor in Daily Standard Rates (Gas+Electric standard rate x 365) plus Gas KwH usage (KwH x Gas rate). This bought the totals to £1,120 (EDF) and £1,064 (Octopus Go)... A £60 saving for Octopus, right?
Step E: External factors & contingency planning
  1. So now we have four options on the table: (a) Single-rate EDF (£1,246), (b) Single-rate Octopus Go (£1,346), (c) Multi-rate EDF (£1,120), (d) Multi-rate Octopus Go (£1,064). Clearly option D is the most cost-effective, but there are some assumptions we need to consider also...
  2. I first calculated the risk variance on the two multi-rate tariffs by calculating the variance between the single- and multi-rate tariffs (£126 for EDF and £283 for Octopus Go), dividing by the day rate and then dividing by 50 KwH for a full charge. This gave me the number of times I could charge fully outside of the off-peak rate without it resulting in a higher cost than simply sticking with the single-rate variation of the tariff. It was 14 charges for EDF and 39 charges for Octopus (albeit Octopus 'on-peak' is a much wider duration of time. One point for Octopus, one point for EDF.
  3. I also considered the flexibility of the off-peak hours: All weekend is favourable as I'm home quite a lot, but a higher on-peak rate from EDF means if I'm home more the risk of cost creeping up is higher. One point for Octopus.
  4. The on- vs off- usage is currently an estimate, and therefore understanding the single-rate costs is important as a 'back-up' rate. One point for EDF.
Step F: Make a God-damn decision already(!)
  1. Ultimately then ladies and gentlemen, where I got to is exactly where I started: The difference between rates (even considering the single-rate and multi-rate variances) is only £300, which is a drop in the ocean versus the cost-saving of petrol/diesel vs electric!(Quick maths for me is c. £3.5k per year saving!).
  2. The lowest possible option for me is Octopus Go on a multi-rate, however the single-rate is the highest possible option. With point E4 above regarding lowest single-rate option (EDF) I am leaning towards that - Whilst it's potentially £60 more expensive at it's he's (comparing multi-rates of EDF £1,120 vs Octopus Go £1,064), there's also a potential £100 risk (comparing EDF £1,246 vs £1,346 Octopus Go).
  3. Ultimately, in the 'new normal' usage is unknown - And so opting for the lowest on-peak is the least risky option. That is EDF single-rate at 12.03p.
Decision made: EDF single-rate (12.03p any time) with a smart-meter install to understand 'actual' on- vs off-peak usage: which may then push me towards either EDF (immediate switch) or Octopus Go (after 12 months fixed). The best balance of cost-effectiveness coupled with de-risk of estimated usage for the next 12 months.

Hope that helps anyone looking to do the same calculations and logic. Feedback on logic welcome!
 

Chalks99

Member
Nov 4, 2019
314
115
UK
Thanks for the info - It's a whole new world for me so any advice useful! Personally (and perhaps naively) I'm not *too* concerned with battery longevity - I'm on a 3yr lease - but intend to charge to 90% c. 2-3 times per week. I did the calculations on a cautious (2,000 KwH of charge) and pessimistic (4,000 KwH of charge) on top of my usual usage - I'll share my logic below should it be helpful for anyone else.

Step A: Data gathering
  1. Record single-rate KwH rates for both EDF (12.03p) and Octopus Go (14.61p)
  2. Record multi-rate on-peak/off-peak KwH rates for EDF (17.64p/8p) and Octopus Go (13.45p/5p)
  3. Record KwH Gas rates for EDF (2.62p) and Octopus Go (2.55p)
  4. Record Daily Electric/Gas standing charge for EDF (22.89p/27.35p) and Octopus Go (20.05p/17.85p)
The result from doing just this comparison would be that Octopus Go offers a more competitive rate, however...

Step B: Calculate KwH Usage
  1. First, understand pre-EV electricity usage (for me, 2,000 KwH last 12 months)
  2. To calculate KwH increase from EV, I first assumed 50 KwH per charge (c. 20KwH 'in the tank') and 270mi per charge.
  3. I assumed, therefore, I would need 1.5x charges per week based on avg. 400 mi per week, and 48 weeks of the year (50 x 1.5 x 48 = 3,600 KwH).
  4. I then rounded this up to the nearest 1k, to total a 4,000 KwH increase in KwH (equating to 6,000 KwH total when adding last 12 months).
On the single-rate tariffs, the clear winner here would be EDF based on a lower single-rate KwH rate (6,000 x 12.03p = £721 vs Octopus Go £876).

Step C: Calculate on-peak / off-peak usage
  1. This is where things get interesting. First, you need to understand the 'split' (on- vs off-) for the different tariffs. For EDF GoElectric this is 2100 - 0700 (10hrs) plus all day Sat & Sun. For Octopus Go this is 0030 - 0430 (4hrs).
  2. Next, I needed to calculate how the 6,000 KwH would be split between on- and off-peak. First, I needed to understand EV charge time, which is based on a 7KwH Tesla Wall Charger and a 50KwH requirement would be c. 7hrs.
  3. I am now ready to calculate KwH split: I did this in two phases; first the previous 12 months (2,000 KwH) and secondly the new EV charging (c 4,000 Kwh). The key factor here is the duration of off-peak rates.
  4. As the EDF off-peak rate lasts 10hrs plus weekends, and average charge takes under 10hrs, I was able to allocate 100% of the 4,000 EV-related KwH charging to the off-peak rate. I also shifted some of the previous 12 months (2,000 KwH) into off-peak based on an estimated on- vs off-peak usage (excluding EV charging). This resulted in 1,200 KwH on-peak and 4,800 KwH off-peak for EDF.
  5. For Octopus Go, only 4hrs (57%) of the 7hrs of charge would qualify for off-peak charging. Thus, I calculated 57% of the 4,800 KwH off-peak usage from EDF (equal to 2,736 KwH) as Octopus Go's off-peak usage, and therefore a further 3,264 KwH on-peak use.
Step D: Calculate on-peak / off-peak usage cost
  1. Now I know the Usage and Cost of on- and off-peak KwH, the calculation is simple.
  2. EDF was £211 (17.64p x 1,200 KwH) on-peak and £384 (8p x 4,800 KwH) off-peak. Octopus Go was £439 (13.45p x 3,264 KwH) on-peak and £136 (5p x 2,736 KwH) off-peak. Totals therefore before Gas and before Daily standard charges were £595 (EDF) vs £575 (Octopus Go).
  3. Of course, you then need to factor in Daily Standard Rates (Gas+Electric standard rate x 365) plus Gas KwH usage (KwH x Gas rate). This bought the totals to £1,120 (EDF) and £1,064 (Octopus Go)... A £60 saving for Octopus, right?
Step E: External factors & contingency planning
  1. So now we have four options on the table: (a) Single-rate EDF (£1,246), (b) Single-rate Octopus Go (£1,346), (c) Multi-rate EDF (£1,120), (d) Multi-rate Octopus Go (£1,064). Clearly option D is the most cost-effective, but there are some assumptions we need to consider also...
  2. I first calculated the risk variance on the two multi-rate tariffs by calculating the variance between the single- and multi-rate tariffs (£126 for EDF and £283 for Octopus Go), dividing by the day rate and then dividing by 50 KwH for a full charge. This gave me the number of times I could charge fully outside of the off-peak rate without it resulting in a higher cost than simply sticking with the single-rate variation of the tariff. It was 14 charges for EDF and 39 charges for Octopus (albeit Octopus 'on-peak' is a much wider duration of time. One point for Octopus, one point for EDF.
  3. I also considered the flexibility of the off-peak hours: All weekend is favourable as I'm home quite a lot, but a higher on-peak rate from EDF means if I'm home more the risk of cost creeping up is higher. One point for Octopus.
  4. The on- vs off- usage is currently an estimate, and therefore understanding the single-rate costs is important as a 'back-up' rate. One point for EDF.
Step F: Make a God-damn decision already(!)
  1. Ultimately then ladies and gentlemen, where I got to is exactly where I started: The difference between rates (even considering the single-rate and multi-rate variances) is only £300, which is a drop in the ocean versus the cost-saving of petrol/diesel vs electric!(Quick maths for me is c. £3.5k per year saving!).
  2. The lowest possible option for me is Octopus Go on a multi-rate, however the single-rate is the highest possible option. With point E4 above regarding lowest single-rate option (EDF) I am leaning towards that - Whilst it's potentially £60 more expensive at it's he's (comparing multi-rates of EDF £1,120 vs Octopus Go £1,064), there's also a potential £100 risk (comparing EDF £1,246 vs £1,346 Octopus Go).
  3. Ultimately, in the 'new normal' usage is unknown - And so opting for the lowest on-peak is the least risky option. That is EDF single-rate at 12.03p.
Decision made: EDF single-rate (12.03p any time) with a smart-meter install to understand 'actual' on- vs off-peak usage: which may then push me towards either EDF (immediate switch) or Octopus Go (after 12 months fixed). The best balance of cost-effectiveness coupled with de-risk of estimated usage for the next 12 months.

Hope that helps anyone looking to do the same calculations and logic. Feedback on logic welcome!
Don't forget to factor in Daily Charge cost (not of the car but for provider to supply electricity)
 

VanillaAir_UK

Well-Known Member
Jun 17, 2019
8,959
6,553
Surrey, UK
eg. For me, I’ll likely do 400-500 miles per week, and therefore need an estimated 1.5 charges @ 50KwHkWh per week.

I don't know what car you have ordered, but if you had a LR AWD and worked on 300-350Wh/mile in winter, you will probably be ballpark energy needs. So worse, but not uncommon case at 350Wh/mile especially if driving on faster roads, 140-175kWh/week, at 70% battery usage (20-90%), thats around 55kWh electricity per charge used including losses. So 3-4 charges per week if you are not time limited. But if you are time limited to say 4 hours / night, you will be only able to get around 40% charge, approx 30kWh electricity consumption, maybe 27kWh usable. In which case, thats 5 - 7 charges per week. Based upon real world maths, at 350Wh/mile.

At 300Wh/mile, you may get away with one less charge. Likewise, warmer times, you will do better. Worth noting, 'winter' does not mean sub zero temperatures, it means typical conditions you get 6 months of the year.

Real world efficiency. Most trips in data below are not motorway speeds. Worse case figures above are more biased to take motorway speeds into account.
SharedScreenshot.jpg
 
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I would be doing similar miles as you but I am intending to plug the car in each night rather than eeking as much from the battery as I can and fill up twice a week (as you would do with an ICE car). Generally the idea is that one would plug the car in whenever it is at home (which doesn't necessarily start charging). The car or smart charger will will start the charge based on how you have set it up (ie cheap off peak time or departure time). Therefore you will be charging smaller amount each night and starting each day at your 80% or 90% setting.
 
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