Cost of running an EV

MojoMaker

Hi all. Just about to order my first EV and I've been doing the usual number crunching pre-purchase - of course it's not going to change my mind at all, but something stood out I just want to cross check here.

My own old diesel yoke gives me about 700kms for €70 diesel at today's prices (was €50 in January - ugh). Looking at public fast charging EV rates on the m-way network, 45c per kw/h, my new 77kw car will cost €35 to fully charge, and that will be good for 350kms fingers crossed. So basically €70 to charge the EV for the same 700kms I get from my diesel.

Am I missing something? Even on a slow charge at home at 22c per kwh it will still be 50% as expensive to run the EV and quite far from the quantum savings promised in the early days of EVs.

Thud

what is your nightsaver electricity rate?

innrain

https://www.boards.ie/discussion/2058248483/cost-of-running-an-ev

There are few bits here but the first is that of course we're departing from the early days. The promises were for those days. Nobody said it is going to last forever. However, there are still benefits but they might diminish in time. Like mentioned above night rate charging is way cheaper than the 45c/kWh. (you need to do some shopping around) Some charge their cars using the electricity they produce. I doubt diesel can be produced in the back garden. The long therm estimates for the electricity prices have a downwards slope while the oil is on the opposite direction. Then there are the benefits of driving an EV which are beside the fuel price.

MojoMaker

You think electricity will be going down in price over the long term? Hmm.

Switching to night rate electricity pushes up the day rate to make it actually more expensive overall if you have a household that runs a lot during the day, so that's not really a runner. I can imagine similar for folks that won't/can't charge overnight.

The chap in the dealer even had the suggestion for me that I'd be looking at around €6-7 to charge the car, the reality is at least €22 and probably more like €30 as a median. That's for 350kms optimistically, again as a median.

The other benefits accepted, yes indeed, and were some of the initial drivers. I think the vendors are conveniently glossing over the actual realities of the cost of power now.

Are there any free public chargers left in the country or have they all switched over to being managed by a charging (€€) network of one form or another?

Furze99

I've been paying electricity bills for many years and using a variety of household equipment powered by electricity. I've always understood it to be a relatively expensive way to heat or move things. EVs may have various benefits in terms of some reduction of fossil fuel use, but I fully expect the eventual running costs to be not dissimilar to what we expend now on personal transport. No such thing as a free lunch. And always remember, the state needs our taxes to run the place.

KCross

https://www.boards.ie/discussion/2058248483/cost-of-running-an-ev

On the road charging is expensive. You wont save money there.

The savings are in home charging which is typically 90%+ of your charging but, of course, YMMV.

Also, once you get an EV you also get a day/night electricity tariff so you pay <10c/kWh, not the 22c you mention. You pay an extra 2c for your day rate and an extra ~€70 on standing charge but you still save money overall... which is directly proportional to the amount of miles you drive.

So, that begs the question.... will you be charging it at home each week?

How many km's per year will you be driving?

How many unit of electricity do you use per year right now?

We can tell you exactly what you will save then even with the higher day rate.

ted1

You are paying to much for electricity. Hence your maths are off

crisco10

https://www.boards.ie/discussion/comment/119148197#Comment_119148197

I wouldn't be so quick to dismiss night rate because of the increase in day rate. The "payback" ratio for the increased day rate (and standing charge) of a day/night meter is somewhere in the region of 20% to 30% of your electricity on night rate.

With very little effort (i.e. just setting timers on dishwasher and clothes machine to come on at 630am), we moved about 20% of our usage to night rate. Then we got EV, which solely charges at night. That's brought us to about 55% night rate usage. So even with the more expensive day rate, we are significantly better off.

And that's for a house that is full all day. I wfh, my wife is a stay at home mum and 2 kids not in creche. (eldest goes to ECCE for 3 hours in the morning is all). So plenty of daytime usage too.

My night rate is ~10c/kWh. so full charge of 77kWh battery is indeed €7.70 so dealer isn't miles off. I've done about 3000km so far in my Ioniq 5, charging at home over night, and with a small bit of free public charging here and there (Lidl, Public Parks etc). Total cost about €60. So definitely still in the honeymoon period cost wise!

https://www.boards.ie/discussion/comment/119148208#Comment_119148208

I do agree that the taxes will change at some point, can't be just the VAT on electricity and a flat €120 motor tax forever. In terms of efficiency for "moving things", an electrical drivetrain is far more efficient than an ICE at getting the power from the fuel transferred into motion.

PGE1970

I'll have to change my car next year - my work part pays so it's a new car every five years.

I was leaning towards EV but I haven't ruled out a petrol as my annual km is about 25,000km per annum.

I'll be keeping a close eye on this thread!

Good post OP and very interesting replies so far for someone like me who is new to all this!

MojoMaker

Hmm. Standard 24hr electricity rate is from 20c (Bord Gáis) to 50c per kwh right now. My current domestic rate of 22c looks to be on the low side to be honest.

The night rate meter is worth looking at for sure, I was told day rate would be higher than just a 2c penalty so I'll check that out.

I see this on Electric Ireland's website:

1. The day/night meter unit rates with Electric Ireland are: 18.52 cent per unit (day), 9.15 cent per unit (night). VAT @13.5% included.

That looks promising, but as an EI customer I'm a bit annoyed.

crisco10

https://www.boards.ie/discussion/comment/119148372#Comment_119148372

The Electric Ireland rates have crept up a bit since May 1st. Think Day / night is 21c / 10.4c but 24hr rate is 19.7c. So actually on that sample, the increase in day rate is less than 2c.

Tenshot

Looking at public fast charging EV rates on the m-way network, 45c per kw/h, my new 77kw car will cost €35 to fully charge and that will be good for 350kms fingers crossed. So basically €70 to charge the EV for the same 700kms I get from my diesel.

Something I don't see discussed much is that your 77 kWh car will generally keep 30% of the battery in reserve to preserve its life, so the 350 km range is being generated with only 70% of its capacity. 77 * 70% * 2 = approx 108 kWh. At night-time rates of, say, ~12c/kWh that will only cost you €13 to get your 700 km range. Using expensive street charging gets you to €48 which is a reasonable saving over diesel but not outstanding.

(The downside of this is that as your battery's capacity deteriorates over time, a drop from 100% to 80% capacity will reduce the useful capacity from 70% to 50%, which reduces your range from 350 km to 250 km, rather than the 280 km you might have expected.)

On the day/night rate, we switched when we got our EV but when I did the calculations, we should have switched years ago -- even without the EV, our usage pattern meant it saved us almost 20% on each bill. Your mileage may vary, of course.

slave1

Jesus, get your facts straight mate, 30% reserve!!!!!!!

KCross

https://www.boards.ie/discussion/comment/119148452#Comment_119148452

Something I don't see discussed much is that your 77 kWh car will generally keep 30% of the battery in reserve to preserve its life,

Thats way off unless there is some EV out there that does that.

Some examples...

Gen 1 Leaf.... 24kWh battery and 22kWh usable

ID.3... 62kWh battery and 58kWh usable

The above is all very typical for any EV I've seen, so more like 5-10% is hidden from you, not 30%.

with only 70% of its capacity. 77 * 70% * 2 = approx 108 kWh. At night-time rates of, say, ~12c/kWh that will only cost you €13 to get your 700 km range.

This calculation is way off too. Regardless of whether the hidden amount is 5% or 30% you dont get to use that hidden amount so you dont have to charge it either, so its not costing you money. You seem to be adding the hidden buffer into the charging costs... thats not how it works unless I'm missing your point?

If you car has 58kWh usable and has a WLTP range of 400km's then 58kWh is all you have to charge the car with to go from 0-100% (there will be ~5% charging losses through heat). Basically, you dont use the total battery capacity figure to calculate your charging cost. You only use the usable capacity (plus charging losses).

KCross

https://www.boards.ie/discussion/comment/119148372#Comment_119148372

After the latest round of increase we are all paying high prices but I'm paying around 22/11c for day/night at the moment and you are paying 22c all day long. Without changing any of your behaviors other than just switching providers you will be up money as you will be getting half price electricity for 9hrs a day. The extra standing charge isnt that big. Add an EV to the mix and you will be saving alot of money relative to diesel.

Your starting point is to look at your stats...

How many km's do you drive a year?

How much electricity do you use per year right now?

Its easy to calculate from there. Share those figures with us and I'll give you a worked example for your stats and you'll know exactly whats what then.

MojoMaker

Thanks!

So in 2021 Electric tells me I used 2126kwh over the year. Using their comparison tool it seems I am tracking from January to use 10% less electricity from month to month (that's great, but I haven't changed any habits or changed any devices so I wonder why my consumption is less).

I drive 24K kms annually.

Just emailed EI to ask about why I'm paying more than the declared 24hr rate, and I got an automated reply:

"Thank you for contacting Electric Ireland.

We are experiencing reduced capacity across all contact channels, resulting in longer wait and response times than normal. We are currently taking a minimum of 8 days to respond to emails. We apologise for any inconvenience caused and are doing our best to serve you as soon as possible."

MakersMark

https://www.boards.ie/discussion/comment/119148713#Comment_119148713

Are you changing your car to try to save money, or would you be changing it anyway?

If the former, then you won't be saving anything at all.

If the latter, then assuming you were going to spend 45k to 50k or more on a new diesel, you may well be better off with a new ecar.

KCross

https://www.boards.ie/discussion/comment/119148713#Comment_119148713

Some assumptions I need to make here to calculate the figures so you can rework the calculations if you wish but it should still be reasonably accurate

Diesel: €1.90/l and assuming an average of 6l/100km (seems about right for your 700km's for €70)

Electricity: 22c/11c (day/night) and assuming all your charging is at home at 11c/kWh.

EV: Assuming an average of 20kWh/100km (including charging losses). Its hard to give an accurate figure here as it depends on whether you do alot of motorway driving or not but its a good ballpark figure to use as a yearly average (possibly even too high).

So, for your 24k km's...

Diesel: 1440 litres @ €1.90/lt = €2736

EV: 4800kWh's @ 11c = €528

Savings: ~€2200/yr!!!! The modest increased standing charge becomes irrelevant and your are still getting all your daytime electricity at 22c (what you are already paying).

So, your electricity bill (excluding levys) is currently €467. That will go to ~€1k but you will then also have the option of shifting some of your existing appliances/usage to the cheaper rate by turning on dryers/washer etc between 6-8am so it will bring you additional savings on top of the €2200.

crisco10

https://www.boards.ie/discussion/comment/119148713#Comment_119148713

Quick calc incoming...

So Electricity costs are below (assuming you 100% home charge overnight, and that you continue to use 100% of 2021's electricity consumption at Day Rate). So basically, 2126kWh at Day rate, and (24000km * 18.9 kWh/100km /100) = 4500kWh at night rate

If you kept your diesel, you're electricity bill becomes, i.e. 2126kWh at day rate.

So basically, the car would cost you approximately €600 per year in increased electricity bills (comparing €666 to €1248). For 24000 km. How far does €600 worth of diesel get you? 6000km?

MojoMaker

Was going to change anyway, the impetus now being the extreme fuel inflation which shows no sign of abating. It seems wrong to even contemplate a new diesel, and while petrol/hybrids may be an outside runner, again the hydrocarbon factor still sticks around.

I know, spend €€€€€ to save € etc - but purely isolating the monthly running costs - you're saying there's no savings at all?

AFOL

Tesla app tells me I have spent 8e on charging in the last 31 days and I have covered about 1000km in that time. I charge every 3-4 days between 2am and 5am (this lets me add 30% charge at a time) and my rate is about 6c/kwh during those off peak hours.

MakersMark

https://www.boards.ie/discussion/comment/119148800#Comment_119148800

No, if you're changing anyway, and you get the right electricity rates, you'll save a lot of money.

MojoMaker

https://www.boards.ie/discussion/comment/119148801#Comment_119148801

This is interesting. Can you program the home charging station to just operate on certain time intervals - i.e. to match the night rate boost hours? A 30% top-up nightly would probably do me grand to be honest.

AFOL

https://www.boards.ie/discussion/comment/119148834#Comment_119148834

Yup... you can either do it on the charger end, or on the car end. I have the car set to only start at 2am and set a limit of +30% etc...

My wife has a PHEV (Cupra) and can also do the same within the car menus

Edit: looks like my rate is 5.25/kwh for those hours

KCross

https://www.boards.ie/discussion/comment/119148834#Comment_119148834

Can you program the home charging station to just operate on certain time intervals

Every EV has that.

ted1

https://www.boards.ie/discussion/comment/119148850#Comment_119148850

Except it doesn’t work for the ID range. So we use the charger ;)

CuriosityKilledtheCat

Just jumping in here.

I'm currently with Bord Gais on 24-hour rate - works out at 14.16 c/kWH (+ VAT) after discounts are factored in so €16.07 all in. Assuming 77kw battery, am I right in saying my charge should cost no more than about €12?

I will be able to charge at home and I also work overnight in a place where I will be able to charge for free so I am figuring that most weeks, I may not even need any home charge. My work commute is approx 50km each way - 4 days per week and with a good few shorter work related trips during the week. If I have a long journey and range anxiety strikes, there are ICE cars within the family that I can drive instead.

I am currently driving 2.5l hybrid, costing me about €100/week in petrol so potential savings of approx. €300/month to go towards new car payment. Had planned to change in the near future anyway so going fully electric seems a no-brainer to me if my figures are correct. Road tax saving is not much and really current car has cost me very little apart from regular servicing.

Am I missing something?

CuriosityKilledtheCat

https://www.boards.ie/discussion/comment/119149747#Comment_119149747

Oops 16.07c not €16.07🙄

John_Rambo

https://www.boards.ie/discussion/comment/119148800#Comment_119148800

You said in your opening post "Even on a slow charge at home at 22c per kwh it will still be 50% as expensive to run the EV" no matter what way you negatively word it, it's still half the price!

Is the Tax cheaper? Is it better for your families health? Is it better for the environment? Will it be cheaper to service?

Also, we started running out of fuel the day the first barrel was opened. Diesel is dead for us, it's back where it belongs, in trucks and tractors.

It's all good man! You're going to love it, enjoy the new car & best of luck with it.

Tenshot

| Your 77 kWh will keep 30% of battery in reserve

That's way off unless there is some EV out there that does that

Fair enough. My 2017 Outlander does indeed do that - it has a 13.8 kWh battery but my nightly charge (with the car showing 0%) is typically 9 kWh, which is actually a bit less than 70% of the nominal capacity; the battery is over four years old now so is slightly diminished. From new, it was around 9.5 kWh to charge from empty, as measured on a Zappi.

No doubt battery management is improved on newer EVs with larger batteries. You mentioned 22 of 24 kWh usable with a Gen 1 Leaf; some Googling suggested an early e-Golf gets about 20 kWh usable on a 24 kWh battery. (Maybe someone with a suitable charger could post some real-world figures for a modern EV with a larger battery size, fully charging from as close to empty as you dare and comparing that to the official battery capacity.)

| With only 70% of capacity, 77 * 70% * 2 = 108 kWh

This calculation is way off too. Regardless of whether the hidden amount is 5% or 30% you don't get to use that hidden amount so you don't have to charge it either.

That was actually the point I was making. It shouldn't take 77 kWh to charge a battery rated at 77 kWh gross because it should never be fully discharged; the rated mileage takes this into account. So, I was reducing the energy needed to 70% of that, to reflect 30% of it being kept in reserve. If only 15% is kept in reserve, then it would be 77 * 85% * 2 = 130 kWh of energy to fully charge the battery twice (to reach 700 km of range). That would increase the charging cost at night rates from €13 to €15, which is about €7.50 for each full charge.

I think the confusion is whether quoted battery sizes are gross capacity or usable capacity. All the figures I've seen are gross capacity (because it makes them sound bigger) but maybe this practise has changed more recently.

John_Rambo

https://www.boards.ie/discussion/comment/119151113#Comment_119151113

Jaysus, and I thought I did a good bit of research before buying!! You got a degree in research.