Move from petrol to electric - with solar

TonePeddler51

Hi, (Apologies if this in the wrong category as it's a bit of a hybrid!)

I currently have a perfectly reliable Octavia and love it. However, with household energy prices and car fuel costs, my head keeps running around the idea of getting an electric car.

My house is prime for solar panels (south facing roof, over half of my road already have them), and my dilemma is do I sell a car that works and services all my needs, to use that money for solar panels? Secondly, I'd then use a salary sacrifice scheme at work to get the electric car.

I was always taught not to replace something unless it was really needed, and I can't get my head around whether this is a good idea, or if I'm 'throwing away' a decent car too easily. As I type it, I do feel like I know the answer but any advice - especially from those who have done something similar - would be greatly appreciated. Thanks!

LukeB_92

It helps to separate the two decisions, because tying them together makes the maths harder to judge.

1. Solar on its own: look at payback from your actual daytime usage and export, not just the headline generation figure. A south-facing roof helps, but the best return is usually on electricity you use yourself. If the car will be at work during the day, it won't be soaking up much of that solar generation on weekdays.

2. The car on its own: if the Octavia is reliable and does everything you need, its depreciation from here is likely to be relatively low, and keeping it is often the cheapest form of motoring. Selling a known, reliable car is not throwing it away if you get a fair price for it, but you are giving up that low, predictable cost.

3. Salary sacrifice on its own: compare the total sacrifice cost over the whole term, and check what is included (insurance, maintenance, tyres) and what is not. Also check the effect on pension contributions and any other benefits calculated from salary, the benefit-in-kind tax on the EV, and what happens to the car / what charges apply if you leave the job early.

Try costing three options side by side over, say, three years: keep the Octavia without solar, keep the Octavia and add solar, and sacrifice scheme EV plus solar. Include fuel vs home charging (much of that charging may be overnight on your normal tariff, not from solar), servicing, insurance and the one-off solar cost. That usually shows whether it is the solar, the car change, or both that are actually paying for themselves, rather than one subsidising the other in your head.

Ectophile

I have solar and an electric car. But I don't attempt to charge the car off solar. It would need a long sunny day to charge the car. Any day that's cloudy or rainy isn't going to work, and there's so little sun in the winter that there's no chance.

Plus charging off solar isn't going to work if you drive the car to work during the day, or if you go somewhere at the weekend.

So I use the solar to power the house, and I have signed up for a cheap overnight EV tariff to charge the car. That way, the car charges while I am asleep.

Herzlos

There are a lot of variables that make it hard to figure out. For example, having an EV unlocks special EV tariffs that provide cheaper overnight electricity for longer than a solar/battery does. Most people tend to use the solar during the day to top up a battery or sell back to the grid, and charge their EV overnight at the cheap rate. That can get the costs down to about 8p/kWh which on newer EV's can mean as low as 2p/mile.

The biggest things to consider are how much you'd get for the car, what the solar setup would cost, what the new car would cost and how much you'd save on fuel.

If it's a good salary sacrifice deal and you do high-ish miles then you may find that the car almost pays for itself. If you do lower mileage it'll do almost nothing.

This tool will give you an indication of how much energy you could generate: https://re.jrc.ec.europa.eu/pvg_tools/en/

QrizB

Most people tend to use the solar during the day to top up a battery or sell back to the grid, and charge their EV overnight at the cheap rate. That can get the costs down to about 8p/kWh which on newer EV's can mean as low as 2p/mile.

That includes me.

Solar, battery, EV, EV tariff. My average electricity cost for the last year is under 10p/kWh, which (for 4000 kWh of import per year) is a £600 saving vs. the Ofgem-capped SVT.

EV fuel costs are around 2p/mile vs. 15p/mile for my diesel car (or 20p at current diesel prices), which for 8000 miles/year is another £1500/yr saved.

On top of that, from May to September my solar export payments were larger than my electricity bills.

mikrt

Have a look at battery only without solar. I charge mine up overnight @ 6.9p on intelligent octopus, and it supplies my whole house during the day. Along with 6 hours for ev charging.

Frozen_up_north

A friend recently installed 6 KW worth of panels on his south facing roof. He also added an 11 KWH battery. Cost overall was around £11,000. Installation was in July.

He was excited to keep his battery fully charged and was only paying the standing charge for electricity use during the summer and early autumn. He doesn't have an electric car.

Fast forward to current dull and rainy weather, his charging rate has dropped to a few hundred Watts at 10am and his battery is nearly totally discharged.

He is reluctant to change tariff as the unit rate is much higher than he currently pays on a fixed rate (not sure of the end date). So topping up using off peak electricity on a new tariff may not be too cost effective.

The panels + battery look great in summer, not so sure about later in the year.

TonePeddler51

Thanks all, lots of good advice for me to work through. I'm in the office two/three days a week but wouldn't need to charge there (~60 mile round trip) so could get away with cheap charging at home.

One thing on the scenarios is it's probably an all or nothing, mainly as the car being sold is going to finance the solar panels with the by-product meaning I'd be carless. Lots to think about!

QrizB

The panels + battery look great in summer, not so sure about later in the year.

A typical generation curve looks a bit like this (from PVGIS, other tools are available). This is for 6kWp of panels in Oxford, facing south.

Just over 6000kWh/yr generated, over 500kWh/month from March to September but dropping to only 200kWh in December.

He is reluctant to change tariff as the unit rate is much higher than he currently pays on a fixed rate (not sure of the end date). So topping up using off peak electricity on a new tariff may not be too cost effective.

There will be good days and there will be bad days, but even on bad days he won't be paying any more than he would have been without solar & battery!

DrEskimo

When I was offered salary sacrifice, the deals were awful. Far more expensive than just personal lease. I'm starting a new job so will see what their provider is like, but I'm not holding my breath it will represent good value for money, even as a HRT with childcare thresholds to consider.

Any reason you aren't considering just a used EV? I'm on my second used EV in 10-years now and been very happy with the cost of ownership. Far far less than leasing brand new.

Herzlos

https://forums.moneysavingexpert.com/discussion/comment/82161622#Comment_82161622

I've got a very similar setup and yeah, if there are 2 rainy/cloudy days in a row the battery drains and never recovers.

BUT I've moved to a flexible tariff where I can recharge the batteries overnight on a cheap rate (no EV so it's 14p/kWh rather than 8p, but it's still half the day time rate). There's a peak rate to avoid though, and a bit of guess work as to how much to fill the battery, the app does let me set levels based on the predicted weather the next day but I haven't been using that long enough to get an idea of accuracy.

There's not much expectation for solar to provide all the energy year round, but I'd expect that over the nicer months they should generate and sell back enough excess to cover most of their standing charges and offset a bit of the winter costs.