Charging costs

[StackH]

I'm assuming a lot of us will have read this: Electric car charging costs nearing petrol prices for some - RAC

Is anyone getting cold feet about their order (assuming this is their first EV)? I'm fortunate to be able to home charge, and even at the current standard variable price (I'm with Octopus) of 26p per kwh it's still a fair bit cheaper than filling up my current ICE car, although the gap has narrowed a bit. But some of the rapid charger prices are looking a bit eye watering at the moment if I were to go on a long journey.

Bizarrely, the Octopus EV tariff looks really cheap overnight, but significantly higher than variable during the day - which is when most of my electricity is consumed. Some quick man maths shows that the EV tariff would be far more expensive than just charging on the variable rate.

Just wondered if anyone else has looked into it?

 

[Jomarkh]

I managed to move most of my high wattage white goods to run during the over night slot and now less than 50% is on the peak rate.
It is not just the charging cost you need to consider with an EV as the service and running cost are less than an ICE and better for the environment.

 

[MundaneMatt]

I have an my EV since July 2021, and have used public chargers since. We're about to buy a new build (I know, yuck) which has an EV charger attached to it already.
I worked out that the EV would use the most energy across the whole house, so it makes sense to me (although I know this is not the same for everyone) to go for the Octopus Go tariff as the highest use will need the lowest per unit cost.
I worked out my mileage for the year, worked out my mpkWh and therefore how many kWh I would use against the normal house usage and looked at what else could be moved to the middle of the night (high usage items) like the washing machine, dishwasher etc.

 

[Jomarkh]

What EVSE does the new build have?

 

[ph79]

I'm with EON at similar rate and like you will be able to charge form home and will be my first EV. When i looked i came to same conclusions that low rate wouldn't compensate for higher daytime rate. I think 6/12 months down the line i will review because a lot of companies are not encouraging switching now anyway. Its a shame that one of the things that could attract more people to EV's has now been diluted but long term its the way to go and hopefully the other benefits will offset any initial increase in charging cost.

Having had a quick ride in the MG4 on Saturday it felt really fun and so I'm 100% keeping the faith and looking forward to becoming one of those smug people that people hate when they preach about how EV's are the way forward!

 

[MundaneMatt]

What EVSE does the new build have?

It comes with a Rolec. But I work for Pod Point, so if it turns out to be tripe I will have it taken off and can get a free one installed by work.

 

[StackH]

It is not just the charging cost you need to consider with an EV as the service and running cost are less than an ICE and better for the environment.

Very true - I'm currently running a Merc A class and the service costs from a dealer are scandalous.

 

[Tig170]

I'm assuming a lot of us will have read this: Electric car charging costs nearing petrol prices for some - RAC

Is anyone getting cold feet about their order (assuming this is their first EV)? I'm fortunate to be able to home charge, and even at the current standard variable price (I'm with Octopus) of 26p per kwh it's still a fair bit cheaper than filling up my current ICE car, although the gap has narrowed a bit. But some of the rapid charger prices are looking a bit eye watering at the moment if I were to go on a long journey.

Bizarrely, the Octopus EV tariff looks really cheap overnight, but significantly higher than variable during the day - which is when most of my electricity is consumed. Some quick man maths shows that the EV tariff would be far more expensive than just charging on the variable rate.

Just wondered if anyone else has looked into it?

I must admit I was concerned about this, mainly as almost all EV tarrifs with cheap overnight home charging (I think only octopus is left at present?) disapperad since the start of 2022. I was sort of lucky in that I got onto the 2 year fixed interchangeable (GoElectric single-rate. GoElectric 98. GoElectric 35), but am sort of unlucky?? as my smart meter won't connect to the DCC (Data Communications Company) correctly - still the EDF EV team have been reasonably okay, and are still trying to get me up and running. GoElectric single-rate works well over the summer, when daytime usage is low.

... guess how much it was this time last year (I'm not on this rate btw)

• Power rate peak/off-peak: 17p/4.5p
• Standing charge/day: 31p
• Contact: EDF Energy

... gosh! talk about how times have changed!

 

[tsedge]

I did the sums for us and with 10,000 miles a year it works out a bit more expensive to have Octopus Go and the cheap night rate, but the difference was small AND that assumes that we don't time-shift the biggest-using appliances to the night time. If we do that, it will actually be cheaper because the night rate is so cheap. So we're going to see how much we can shift to the night time and then switch if it is worth it.

To get the calculation right, you need to work out how many miles a year will be done FROM home (not en-route charging) and whether your average daily charge will fit into a 4 hour night-time slot.

If your mileage is low and if you don't want to mess around changing when you put on the washing machine, tumble-drier, dishwasher, etc... then sticking with a normal tariff will probably be cheaper.

 

[johnnyc]

I did the sums for us and with 10,000 miles a year it works out a bit more expensive to have Octopus Go and the cheap night rate, but the difference was small AND that assumes that we don't time-shift the biggest-using appliances to the night time. If we do that, it will actually be cheaper because the night rate is so cheap. So we're going to see how much we can shift to the night time and then switch if it is worth it.

To get the calculation right, you need to work out how many miles a year will be done FROM home (not en-route charging) and whether your average daily charge will fit into a 4 hour night-time slot.

If your mileage is low and if you don't want to mess around changing when you put on the washing machine, tumble-drier, dishwasher, etc... then sticking with a normal tariff will probably be cheaper.

Totally disagree with this sorry. I’ve done a tremendous amount of research into this, and if you are ‘average’ hone use according to Cornwall insights etc you are looking at using 2900kwh a year - which is about 8kwh a day.

If you have an EV, and are able to get an EV tariff and load shift heavy usage items - the savings can be huge! I’m talking £1000 on average.

But it all depends on the tariff and the usage, everyone will be different - hence why I came up with a spreadsheet that will work out your TOTAL energy usage including house and charging. It’s all about the average rate, not the high or low.

You need to be able to shift about 25-30% of your usage into the night rate which if you have an ev is pretty easy (I’m at about 65% into the night with EV and load shifting).

but quick bit of maths, based on my usage now;

So I’m putting 28kwh into the car at 7.5p twice a week at night which is £2.10. If I I was SVR (@28p) that is £7.84.

I use 8 kWh per day in the house - 2kwh of these are washing machine and dishwasher - I put these on during the cheap rate so cost £0.15, if it was SVR it would be £0.56.

Then I use 6kwh at 40p which is £2.40, if it was SVR it would be £1.68.

So total cost usage for me is £2.10+£0.15+£2.40 = £4.65 per day for 36kwh which averages at 12.66p/kwh.

If it was SVR at the exact same usage it’s £10.08 for 36kwh which obviously averages 28p/kWh.

Now if I average this over the week, I would use 104 kWh 2 days at (36kwh and 5 at 8 kWh) if that’s the SVR (28p) it would be £29.12.

With octopus go it’s (4.65*2)+(2.55*5) = £22.05 which is an average rate of 21.2p.

So total savings over the year of £367 - based on the current SVR rate. When it goes up in October - the savings (or rather money not having to be spent) will be greater. So another 6p saving per night unit used so come October and onwards - a saving of £700 for my usage.

More if you charge more than twice a week.

But as I said everyone Is different and it will affect people differently!

If you (or anyone wants me sheet) you can download it freely here.

Time of Use Tariff vs SVR July 2022 Prime V4.1 copy 2.xlsx

Shared with Dropbox

www.dropbox.com

 

[tsedge]

Totally disagree with this sorry. I’ve done a tremendous amount of research into this, and if you are ‘average’ hone use according to Cornwall insights etc you are looking at using 2900kwh a year - which is about 8kwh a day.

If you have an EV, and are able to get an EV tariff and load shift heavy usage items - the savings can be huge! I’m talking £1000 on average.

But it all depends on the tariff and the usage, everyone will be different - hence why I came up with a spreadsheet that will work out your TOTAL energy usage including house and charging. It’s all about the average rate, not the high or low.

You need to be able to shift about 25-30% of your usage into the night rate which if you have an ev is pretty easy (I’m at about 65% into the night with EV and load shifting).

but quick bit of maths, based on my usage now;

So I’m putting 28kwh into the car at 7.5p twice a week at night which is £2.10. If I I was SVR (@28p) that is £7.84.

I use 8 kWh per day in the house - 2kwh of these are washing machine and dishwasher - I put these on during the cheap rate so cost £0.15, if it was SVR it would be £0.56.

Then I use 6kwh at 40p which is £2.40, if it was SVR it would be £1.68.

So total cost usage for me is £2.10+£0.15+£2.40 = £4.65 per day for 36kwh which averages at 12.66p/kwh.

If it was SVR at the exact same usage it’s £10.08 for 36kwh which obviously averages 28p/kWh.

Now if I average this over the week, I would use 104 kWh 2 days at (36kwh and 5 at 8 kWh) if that’s the SVR (28p) it would be £29.12.

With octopus go it’s (4.65*2)+(2.55*5) = £22.05 which is an average rate of 21.2p.

So total savings over the year of £367 - based on the current SVR rate. When it goes up in October - the savings (or rather money not having to be spent) will be greater. So another 6p saving per night unit used so come October and onwards - a saving of £700 for my usage.

More if you charge more than twice a week.

But as I said everyone Is different and it will affect people differently!

If you (or anyone wants me sheet) you can download it freely here.

Time of Use Tariff vs SVR July 2022 Prime V4.1 copy 2.xlsx

Shared with Dropbox

www.dropbox.com

Thanks. As you say this depends on your usage. Our home use is 17kWh per day, so rather different. That is in part because we run a hot tub and have a large detached house. Thanks for showing your calculations, that will help other people work out their usage and what is best for them.

 

[tsedge]

Oh and I believe that the average usage often quoted by the analysts is the 'median' (middle value), not the 'mode' (most common). And I've see other "average" quotes that are much higher. YMMV.

 

[johnnyc]

Thanks. As you say this depends on your usage. Our home use is 17kWh per day, so rather different. That is in part because we run a hot tub and have a large detached house. Thanks for showing your calculations, that will help other people work out their usage and what is best for them.

Yup! A hot tub would do that! haha! But you have options with that…just heating up during the night time and when you use it? Rather than all the time? That may help?

Although - I don’t have a tub (no matter how much I try to persuade my wife!) so I don’t know how they work…

 

[tsedge]

Yup! A hot tub would do that! haha! But you have options with that…just heating up during the night time and when you use it? Rather than all the time? That may help?

Although - I don’t have a tub (no matter how much I try to persuade my wife!) so I don’t know how they work…

Trouble is our model doesn't have a remote control and we like to use it in the early evening, so without a home battery it is tricky. The tub adds 50% to our electricity bill and we have insulated below and around it and added a thermal cover. It used to be fairly cheap to run but recently has been costing a lot more but more than my life is worth to take it away!

 

[Collected]

wonders if you can run a hot tub off vehicle to load.
Solar panels and a storage battery are the way to go, but you’ll be waiting as long as you would for a ZS

 

[tsedge]

wonders if you can run a hot tub off vehicle to load.
Solar panels and a storage battery are the way to go, but you’ll be waiting as long as you would for a ZS

You certainly could, it is about 2.5kWh peak load. But it is where the energy comes from. Can’t really seem myself going to Tescos daily for free energy just to heat the tub up.

Solar not an option for us as plan to move within 3 years so payback period doesn’t work out.

 

[Jonhklee]

Octopus go works if you time shift your electricity usage to the cheap overnight rate. I now heat my hot water tank using smart immersion heater timer @7.5p/kWh instead of capped gas at 10.5p/kWh gas. It’s More efficient btw. Plus I move my dehumidifiers to cheap rates at full blast for 4hrs, dishwashers, washing machines, etc….then use heated clothes rails to dry clothes instead of tumble driers.
It averages out to be around 12-15p/kWh that way!! Gas bills tumbles to using it for central heating only. The 54kwh day was with MG5 charging an extra 50%.

 

[Robf]

You certainly could, it is about 2.5kWh peak load. But it is where the energy comes from. Can’t really seem myself going to Tescos daily for free energy just to heat the tub up.

Solar not an option for us as plan to move within 3 years so payback period doesn’t work out.

If you were on Octopus Go you can charge the car at 7.5p/kw and then heat up the hot tub any time you want via the car?

 

[tsedge]

In theory, yes. In practice they are 30 metres apart on different sides of the house.

 

[Collected]

What could possibly go wrong?