Tipping point for when to charge (public) or use petrol

[AndrewA]

Folks, I'm interested to know what your 'tipping point' is when you would use a public charger to charge your PHEV? PHEVs make a lot of sense when you get a cheap tariff at home. I'm on Intelligent Octopus Go, so charge at home regularly at £0.07 per kWh, which can make local motoring as cheap as 2p/mile.

I'm going out on some longer journeys in the coming weeks, and was wondering if I bother to use a public charger. I did use some public chargers in Europe recently, at £0.34 kWh in The Netherlands. Based on my calculations, I think above that cost is about the level when it becomes not worth it, cost-wise, to use a public charger.

For example, if a public charger is £0.34 kWh/hour and I use all of the charge on electric-only mile, the cost per mile works out at about 11p per mile.

Based on my own calculations, if I fill the car up with petrol at an average cost of £1.34/litre then I think the Leon VZ2 I have costs ~13.3p per mile to run (obviously linked to my lifestyle, short journeys <30 miles are almost always done on electric so these petrol costs are for longer journeys on trunk roads).

Ergo, if the public charger is £0.34 per kWh/hour, I use it for a marginal (rather small) cost benefit.

However, if I use one of our many overpriced UK public chargers, even at £0.50/kWh hour (which is not that high in a UK context) the electric-only miles would cost 17p per mile, assuming I can squeeze 30 miles out of it (which is realistic - indeed I once got 32 miles on a round trip between Shrewsbury and Ironbridge avoiding the M54).

The point at which the pence per mile of electricity use goes above petrol is about 40p/kWh.

So in conclusion, with a 2021 Leon PHEV, I feel that there is no point using a public charger more expensive than 40 p per kilowatt hour - which rules out most of the UK network of public chargers...

Any thoughts or experiences which differ from mine?

I want to use the EV part of the car as much as possible, but there's a point where it's not economical to charge.

 

[Tell]

Well I know the oil boiler conversion factor for central heating which seems to turn out similar to the gas one. The issue you got with Octopus on Agile for me is to grab the cheap spells for water heating using the immersion heater. Anyhow oil you divide the litre price ship a decimal place. Rule of thumb takes into account boiler efficiency. Currently a kilowatt costs 7p in oil and seems to be similar to gas. So if electricity prices are above 7p per kilowatt use fossil fuels ⛽️ if below use electricity. Let you twiddle with for a petrol engine.

Complicating factor I have solar and get paid 15p kilowatt exported. A night you can ignore that....my fun calculations. At night if Octopus Agile is less than 7p then its electricity for water heating. Day time you have to cogitate (solar tumble drier etc). We save circa 20% on Agile against their standard best deal tariff.

No EV or hybrid at the moment. I reckon for local shoppings and days out I could use Agile / solar to keep the battery charged up. There are car chargers that split the solar production between export and charging the car. Don't have a house battery. Bit non plussed by them. The EV battery will be the only battery. V to * offers you to power up the house off the car battery in an emergency. Quite common in Ireland with their storms.

I will get an EV not a hybrid at some stage so wont have the luxury of filling with fossil fuels and your trade off. The oil burner I'm keeping going for the time being. Electricity prices are too high, the country led by recent Governments fumbling nuclear energy investment and the lack of gas storage in the UK to bridge summer and winter prices. Not very bright energy planning in the UK. They probably relied on coal too much unlike the French. It's all turned rather political as some can't get their head around net zero, climate change, green energy generation, battery storage, tidal energy etc. Not the yarn they want to spin to keep their funders in order to deliver their carbon use agenda.

For local use home charging is cost effective. If you were using your car daily on business / communing I can see charging away from home isnt cost effective. Its the mix of local use against away from home use. I use to do 120 mile daily round trips, I can see the hassle of electric only for that. Holidays one can cope. A lot of hotels now have EVs chargers so you would carefully pick those. I see the Osprey centre in Wales has banks of chargers with powerwalls inside. Charging times are getting better.

I can give you some solar figures. 11 panel system covers our house electricity for six months of the year. The export is in balance with the import. Winter months that changes. Talking about ~£90 of electricity a month. Nice to have zero electricity bills in the summer and shoulder months. No gas here, oil for heating. Clearly an EV will eat into that but I reckon one can grab cheap Agile not to make much of an impact. Perhaps I need more panels with an EV. Pay back period is about 11 years. Microinvertor system. Strings ones are cheaper. Give you a shorter payback period.

 

[Mupwangle]

I'm the same. So far the only charger we've used away from the house is my wife's work which is pretty much to a penny the same as petrol, but it is coming from solar and a wind turbine (there's one on site) so it's cleaner. Most of the places we end up aren't big on choice so it's normally not worth it.