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Discussion Starter · #1 ·
Hi All,
Could someone kindly help me to chose the EV tariff?
I have two tariffs one from British gas and another one from EDF.

British gas:
Off peak times are from 12MN to 5AM
Off peak rates- 12p,
Peak rate- 39.365p
Standing charge-45.86p

EDF:
Off peak times are from 1AM to 8AM.
Off peak rates- 6.90p
Peak rate- 47.31p
Standing charge-45.86p

Thanks in advance for any advice.
 

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Discussion Starter · #5 ·
I don't get it...12p Vs 6.9p

What's there to choose?

If you have no other considerations but the EV charging... There is no contest.
With EDF the off peak rates are for 7 hours whereas with British gas 5 hours. However, the peak rates with EDF is 47.31 vs 39.365 with British gas. Hence, seeking the advise.
 

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Discussion Starter · #6 ·
You will need

The problem is that most people do have other considerations as they will have day time use every day, but may only be charging the car once a week...

The question can only be answered when you know the full details of EV charging frequency and amount along with use during the peak period...

Factors like solar and a home battery also make a difference.

For example, we have a Tesla Powerwall 2 and so we use 100% of our electricity at the low rate, the peak rate is irrelevant for us so the low rate is the only consideration, but that isn't the same for everyone.
Thanks Mark for giving some clarity. I don't have solar or home battery.
With regards to the EV charging frequency, I'm yet to receive my first EV car(Niro EV4) within the next week. My weekly mileage is around 220miles.
 

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Discussion Starter · #10 ·
So that will probably be twice a week, and around 60kW in total allowing for losses.

The remaining piece of the puzzle is how much will you typically use (kWh) for the rest of the house in the peak periods for each of those tariffs?
With EDF for remaining 17 hours of peak rate/day I would say around 40-45kW per week as I could use the electricity for using washing machine, shower,etc between 6am and 8am.
However, with British gas it may go up as its only 5 hours of off peak and it is only till 5am.
 

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Discussion Starter · #12 ·
Roughly how many miles per week do you drive in your EV(s)? Do you know how many kWh you typically use per week/month for that? (If not you could estimate using the long-run kWh/mi you are getting.)

(ah just seen you don’t have the car yet. 220 miles per week, at say 3.75mi/kWh (kona might get 4 or more but it depends how you drive, how long journeys are, temp, etc.) is 60kWh/week for EV charging.)

How much electricity does the rest of the house use per week? If you have a smart meter you might be able to find out from your current provider’s customer online system. If you don’t then you could look at recent bills (and then subtract out any kWh you think went on home EV/PHEV charging - presumably none in your case?) to get a rough idea.

Now run those numbers through the two different tariffs to see which costs more, assuming you can do all your EV charging overnight during the cheap rate. Which comes out to the highest total?

Note that if you get a 7kW chargepoint then even 5 hrs is long enough to add 35kWh which is 130 miles of range. If you use a ”granny” charger cable then you’ll only be adding ~10kWh in 5 hrs, which is more like 40 miles of range, whicy might mean having to do 10% or so of the EV charging at the higher rate if you go with BG, depending on how evenly split the miles are between days.

Then you can think about whether you can time shift other electrical loads (dishwasher, washing machine, electric underfloor heating, immersion heater - heating water with cheap overnight electric is cheaper than gas at current prices) to the overnight period - and whether you could do more time shifting with the longer cheap rate period?
Thanks for the detailed explanation. Much appreciated. I will check my bill and do the maths. Thanks
 

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Discussion Starter · #13 ·
If possible you need to estimate your current electric usage using your meter, info you get from your supplier or just past bills. If you guesstimate how much of that is in the period that will be peak rate under the new tariffs, you can then estimate the total cost under each of the new tariffs of both your existing electricity usage and the new consumption for the car.

Off topic but very pleased to see there are competitors to Octopus again in the off-peak EV charging market. These tariffs look competitive with Go now.
Thanks, will check the past bill as suggested.
 

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Discussion Starter · #15 ·
I haven't read all the replies to this thread, so apologies if I am repeating something already stated: We use Octopus Go, and one of the advantages is it's not explicitly limited to overnight EV charging. We tend to also run dishwasher / washing machine between 12.30 - 04.30 as well.

It's not clear to me if the tariffs shown above are explicitly tied to EV charging, or not, but worth double checking that as well.
No its not tied to EV charging. I could use for other purpose as well.
 
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