EV Discussion thread

JKenH

Let’s be honest about how much charging your car on Octopus Go actually costs.

I think we tend to underestimate the true cost of charging at home on tariffs like Octopus Go. Very few, if any, EV forumites or journalists ever point out that while you can charge more car much more cheaply on an EV tariff you need to take into account the effect on the rest of your electricity bill.

If you are the average electricity user (no EV) with a domestic consumption of 3000kWh on a standard cap tariff your bill will be around £990 

If you go out and get an EV and do 8000 miles all charged at home and switch to Octopus Go (40p/12p) your new bill will be £1200 for domestic use plus (for ease of calculation let’s say 4 m/kWh = 2000 kWh) your EV charging will cost £240 so your new bill is £1430. So compared to your original £990 bill those 8000 miles are actually costing you £440 or 22p/KWh.

Of course, unless you are only using your EV as a second car or you have a very large battery EV, not all your charging will be at home. If you only charge 6000 miles at home then your cheap rate charging falls to £180, your total bill becomes £1360 and your 6000 miles of home charging (1500kWh) are adding £390 to your bill or 26p/kWh.

Now the reality is most people who are going out and buying EVs, particularly new or nearly new ones are perhaps a little more affluent than average and probably have a higher domestic electricity usage than the typical user. If you have 4000kWh of domestic use that would cost £1320. If you then get an EV and switch to Octopus  and Go and use 1500kWh at home your total bill will become £1780 (4000kWh@40p plus 1500kWh@12p) so in effect you are paying an extra £460 for that 1500kWh or 30.67p/kWh.

Yes, EVs can work out very nicely for those of us who have solar panels or batteries and low electricity usage but the typical new EV buyer now is unlikely to fit that profile and may not benefit as much. 

thevilla

JKenH said:

Let’s be honest about how much charging your car on Octopus Go actually costs.

I think we tend to underestimate the true cost of charging at home on tariffs like Octopus Go. Very few, if any, EV forumites or journalists ever point out that while you can charge more car much more cheaply on an EV tariff you need to take into account the effect on the rest of your electricity bill.

If you are the average electricity user (no EV) with a domestic consumption of 3000kWh on a standard cap tariff your bill will be around £990 

If you go out and get an EV and do 8000 miles all charged at home and switch to Octopus Go (40p/12p) your new bill will be £1200 for domestic use plus (for ease of calculation let’s say 4 m/kWh = 2000 kWh) your EV charging will cost £240 so your new bill is £1430. So compared to your original £990 bill those 8000 miles are actually costing you £440 or 22p/KWh.

Of course, unless you are only using your EV as a second car or you have a very large battery EV, not all your charging will be at home. If you only charge 6000 miles at home then your cheap rate charging falls to £180, your total bill becomes £1360 and your 6000 miles of home charging (1500kWh) are adding £390 to your bill or 26p/kWh.

Now the reality is most people who are going out and buying EVs, particularly new or nearly new ones are perhaps a little more affluent than average and probably have a higher domestic electricity usage than the typical user. If you have 4000kWh of domestic use that would cost £1320. If you then get an EV and switch to Octopus  and Go and use 1500kWh at home your total bill will become £1780 (4000kWh@40p plus 1500kWh@12p) so in effect you are paying an extra £460 for that 1500kWh or 30.67p/kWh.

Yes, EVs can work out very nicely for those of us who have solar panels or batteries and low electricity usage but the typical new EV buyer now is unlikely to fit that profile and may not benefit as much. 

Or you could simply check your average price per kWh on your Octopus Go monthly bill.....

michaels

JKenH said:

Let’s be honest about how much charging your car on Octopus Go actually costs.

I think we tend to underestimate the true cost of charging at home on tariffs like Octopus Go. Very few, if any, EV forumites or journalists ever point out that while you can charge more car much more cheaply on an EV tariff you need to take into account the effect on the rest of your electricity bill.

If you are the average electricity user (no EV) with a domestic consumption of 3000kWh on a standard cap tariff your bill will be around £990 

If you go out and get an EV and do 8000 miles all charged at home and switch to Octopus Go (40p/12p) your new bill will be £1200 for domestic use plus (for ease of calculation let’s say 4 m/kWh = 2000 kWh) your EV charging will cost £240 so your new bill is £1430. So compared to your original £990 bill those 8000 miles are actually costing you £440 or 22p/KWh.

Of course, unless you are only using your EV as a second car or you have a very large battery EV, not all your charging will be at home. If you only charge 6000 miles at home then your cheap rate charging falls to £180, your total bill becomes £1360 and your 6000 miles of home charging (1500kWh) are adding £390 to your bill or 26p/kWh.

Now the reality is most people who are going out and buying EVs, particularly new or nearly new ones are perhaps a little more affluent than average and probably have a higher domestic electricity usage than the typical user. If you have 4000kWh of domestic use that would cost £1320. If you then get an EV and switch to Octopus  and Go and use 1500kWh at home your total bill will become £1780 (4000kWh@40p plus 1500kWh@12p) so in effect you are paying an extra £460 for that 1500kWh or 30.67p/kWh.

Yes, EVs can work out very nicely for those of us who have solar panels or batteries and low electricity usage but the typical new EV buyer now is unlikely to fit that profile and may not benefit as much. 

So 100% of your non-ev charging is done during the day rate period?  Not how it works in our house, we use 40kwh+ between midnight and 5AM which includes car charging and V2H battery charging and then ideally less than 1kwh at peak rate.  Obviously we run big loads like dishwasher and washing machine at night but with a 4.5p off peak unit rate we also heat the immersion tank with electricity rather than 10.3p per unit gas during this window as well.

The in car display claims we get 4.4 - 4.6 miles per kwh which serendipitously makes it 1p per mile although I fully accept there are charging losses.

As above, we use 95% plus of our electric on the 4.5p rate so the 45p rate for the remainder is not too frightening.  Our fix has another 18 months to go.  We are lookign at getting a bigger battery leaf so we can run our heating using a heat pump also at 4.5p per unit (2p or less per kwh once the efficiency factor is included) and we will also then be able to ditch our ice which we currently keep for about 2000 miles of journeys per year that our outside the range of a leaf 24/when we need two cars, the leaf does the other 12k of our annual mileage.

shinytop

Spies said:

EV deniers are the same ones that would happily have our nation burn coal instead of investing in renewables. 

EV deniers   

JKenH

michaels said:

JKenH said:

Let’s be honest about how much charging your car on Octopus Go actually costs.

I think we tend to underestimate the true cost of charging at home on tariffs like Octopus Go. Very few, if any, EV forumites or journalists ever point out that while you can charge more car much more cheaply on an EV tariff you need to take into account the effect on the rest of your electricity bill.

If you are the average electricity user (no EV) with a domestic consumption of 3000kWh on a standard cap tariff your bill will be around £990 

If you go out and get an EV and do 8000 miles all charged at home and switch to Octopus Go (40p/12p) your new bill will be £1200 for domestic use plus (for ease of calculation let’s say 4 m/kWh = 2000 kWh) your EV charging will cost £240 so your new bill is £1430. So compared to your original £990 bill those 8000 miles are actually costing you £440 or 22p/KWh.

Of course, unless you are only using your EV as a second car or you have a very large battery EV, not all your charging will be at home. If you only charge 6000 miles at home then your cheap rate charging falls to £180, your total bill becomes £1360 and your 6000 miles of home charging (1500kWh) are adding £390 to your bill or 26p/kWh.

Now the reality is most people who are going out and buying EVs, particularly new or nearly new ones are perhaps a little more affluent than average and probably have a higher domestic electricity usage than the typical user. If you have 4000kWh of domestic use that would cost £1320. If you then get an EV and switch to Octopus  and Go and use 1500kWh at home your total bill will become £1780 (4000kWh@40p plus 1500kWh@12p) so in effect you are paying an extra £460 for that 1500kWh or 30.67p/kWh.

Yes, EVs can work out very nicely for those of us who have solar panels or batteries and low electricity usage but the typical new EV buyer now is unlikely to fit that profile and may not benefit as much. 

So 100% of your non-ev charging is done during the day rate period?  Not how it works in our house, we use 40kwh+ between midnight and 5AM which includes car charging and V2H battery charging and then ideally less than 1kwh at peak rate.  Obviously we run big loads like dishwasher and washing machine at night but with a 4.5p off peak unit rate we also heat the immersion tank with electricity rather than 10.3p per unit gas during this window as well.

The in car display claims we get 4.4 - 4.6 miles per kwh which serendipitously makes it 1p per mile although I fully accept there are charging losses.

As above, we use 95% plus of our electric on the 4.5p rate so the 45p rate for the remainder is not too frightening.  Our fix has another 18 months to go.  We are lookign at getting a bigger battery leaf so we can run our heating using a heat pump also at 4.5p per unit (2p or less per kwh once the efficiency factor is included) and we will also then be able to ditch our ice which we currently keep for about 2000 miles of journeys per year that our outside the range of a leaf 24/when we need two cars, the leaf does the other 12k of our annual mileage.

As I said

Yes, EVs can work out very nicely for those of us who have solar panels or batteries and low electricity usage but the typical new EV buyer now is unlikely to fit that profile and may not benefit as much. 

Perhaps I should have said “Octopus Go” rather than EVs but hopefully most will understand what I was saying.

There will be some new EV buyers who will be getting batteries or using V2G/V2H, but my point was they will not be the typical EV buyer so the case for Octopus Go will depend on just how many hours of EV charging they do overnight and what their usage is for the other 20 hours of the day.  In your case Octopus Go works very well for you, but I am sure you would agree you don’t have a typical usage pattern. Yours is what some might refer to as an “edge case”.

You ask “ So 100% of your non-ev charging is done during the day rate period?” My observations were in general terms rather than based on my own usage/situation but as you ask I will afford you the courtesy of responding:

I don’t have any non-EV charging. I am on a 5 hour Go Faster tariff from 01.30 to 06.30 currently paying 13.3p/5.5p. My background consumption over those hours is approx 180 watts so 0.9 kWh over the 5 hours. I don’t have gas so in winter I use an immersion heater on a timer rather than oil to provide around 5-6kWh of DHW but for around 8 months virtually all my DHW is provided by the iBoost. In winter I also use 0.5kWh of cheap rate electricity to heat my insulated urn. We very occasionally put the tumble dryer on overnight but only for towels and most of the time I take advantage of solar or the Octopus Power Hour.

I no longer have an EV so I doubt it would be worth my while to stay on Go Faster once the rates go to 40p/12p.

If I did stay on Go Faster I would also charge my 2 Poweroak 2.4kWh PPS overnight as there is a potential saving of 28p/kWh less round trip losses. (I don’t charge them overnight atm as the saving of 7.8p/kWh doesn’t cover the degradation on the batteries -£500/kWh /2500 cycles. Neither does solar but it is closer and I hate to see it wasted being on deemed export).

If I come off Go Faster, I can heat some of my DHW by oil and when the iBoost can’t provide enough for the other tank it will get a top up (up to 3 kWh on SVT rates). Being on an SVT rather than peak rate will save us on cooking (all electric).

Prior to getting solar or an EV and our ASHPs our usage was 6900kWh pa. Solar and energy savings initiated by the solar installation brought it down to around 3500-4000kWh (around 10kWh per day). That 6900 kWh  might be seen by many on here as a very high usage but I imagine most EV buyers will be relatively affluent and hence have higher than average electricity consumption so will need to do the sums. 

I’m not saying Octopus Go is a bad tariff; it isn’t,  but some people tend to just look at the cheap rate and forget that they pay a higher rate on 20 out of their 24 hours electric consumption to compensate. I am suggesting people do the sums carefully and check if it really is cheaper than being on an SVT. It is for you and many on here but not for everyone.

michaels

We certinly aren't low users, with the car and immersion and solar use I suspect our usage may be towards 15k pa.

I know the v2h helps but even without we have managed to shift about 60-70% of our non ev usage to night rate.

The pont being on your calcs I think you should not assume 100% day rate for the non ev usage and that will change the maths

JKenH

michaels said:

We certinly aren't low users, with the car and immersion and solar use I suspect our usage may be towards 15k pa.

I know the v2h helps but even without we have managed to shift about 60-70% of our non ev usage to night rate.

The pont being on your calcs I think you should not assume 100% day rate for the non ev usage and that will change the maths

I take your point, once an EV user has a dual rate tariff there will be opportunities to move some usage off peak, such as dishwashing, washing machine and tumble dryer (if they have timers) but we can’t assume everyone will be as keen a MSEr as we are and want the hassle. When it’s washday here my wife will often do 4 loads during the day and tumble dry 2 loads of towels. Trying to fit that into off peak usage will cause a lot of marital friction. It’s possible but not necessarily probable.

I think most people will just carry on as normal without the  change of routine we enjoy. 

PS: my son has an EV and Octopus Go but doesn’t use the cheap rate for anything other than EV charging. He has a combi boiler so can’t even heat his water. I think his behaviour would be regarded as nearer the norm than that of the majority of us on this forum.

Grumpy_chap

I do think that the examples of cost to run an EV that assume very low power costs (IIRC 5.5p/kWh was referenced a few posts up thread) are disingenuous and possibly counter-productive in making the case for an EV.
The very low overnight charging rates do require an element of life-style adjustment to avoid higher day-time rates.  Not everyone can make these adjustments and not everyone will be willing to make the adjustments.  Having made the adjustments, the cost of cheap overnight charging still needs to reflect the uplift incurred in daytime tariff.

There was another poster a while back that regularly posted the costs for running an EV on the basis of all energy being free by virtue of using only solar power.
The majority of the population do not have solar power (and any such claim to free power would need to consider the capital cost contribution and the fact that free power could be used for other purposes or sold to grid if not used to charge the EV).  

The promotion of EVs on the basis of very cheap charging (whether time-of-use or solar) is quite possibly of decreasing merit as the new-comers that still need convincing are less likely to be as adaptable as the early adopters.

The case for EV stands up far better and is far more persuasive if based upon normal domestic tariffs, with a footnote that solar or some adjustments to habits with ToU-tariff could make the case even stronger.
That gives a far more universal forecast.

(At the extreme, there was something in the press recently about people being paid per kWh to use night energy.  No-one seems to have suggested - yet - to charge the car at night and drive during the day just to create battery capacity to charge again and get paid again next night.  It would be preposterous!)

The cost of like-for-like acquisition of an EV (compared to ICE) continues to remain a cost challenge.

Exiled_Tyke

I would imagine that in time if EV take up becomes significant we'll end up with TOU tariffs merely penalising peak evening use and there'll be very little discount for night time charging as everyone will be doing it.   So this game playing with tariffs will be simplified.

Of course the issue here is what happens to electricity prices compared to petrol?   Electricity has skyrocketed recently but increased renewable production could help to level this.  EV batteries will be a massive aid in smoothing the peaks and troughs of unpredictable production which could help stablise prices (as Martyn has previously asserted).  As we become less dependent on oil, I hope we will see the difference in running an ICE and an EV will become clearer again.

I agree that  right now,  consumers need to be quite savvy to make sure EV is financially beneficial (but as mentioned already that's not the sole reason for going down this route).   However, with continued RE investment and sound government policy (if we get a sane government ever) then we should have a great EV future.  It is after all the only way forward. 

Grumpy_chap

New Hyundai, looks nice:
https://www.honestjohn.co.uk/news/new-cars/2022-11/2023-hyundai-ioniq-6/