Electric car + solar panels

Fritz68

So I've bought a full electric car.. would it also be worth putting solar panels on my house roof?? I'm not sure exactly how it works now with the payments for the power you generate.
Kind regards
Fritz68

ElefantEd

You don't get very much (if anything) nowadays  for electricty generated through solar panels - the Feed in Tariff scheme closed last year to new applicants. However solar panels do generate electricity that you can use yourself, so you don't have to pay an electricity supply company for the energy. Unlikely to be financially worthwhile in the short term, but in the long term it will eventually break even - you can work out when by comparing your electricity bill (how many units of energy you use and their cost) against how much the panels will generate each year. For reference, our 3kW system generates about 2600 units per year.

As far as the car goes, most people charge at night (ie when they aren't using the car), so unless you have a storage system for the energy generated by the panels you wouldn't be able to use it to charge your car.

couriervanman

And the storage batteries are not cheap

AdrianC

This isn't really a motoring question - the PV/FiT and the EV are different things.

You'd probably be best off here -> https://forums.moneysavingexpert.com/categories/green-ethical-moneysaving
or here -> https://forums.moneysavingexpert.com/categories/in-my-home-includes-diy-moneysaving

Mickey666

Fritz68 said:

So I've bought a full electric car.. would it also be worth putting solar panels on my house roof?? I'm not sure exactly how it works now with the payments for the power you generate.
Kind regards
Fritz68

The days of good deals to sell generated electricity seem to be over, which has really reduced the financial viability of domestic PV generation.  It’s basically a large capital outlay for a long term break even point, depending on your lifestyle.  People working away from home all day will not be able to make full use of the generated power unless they also buy batteries for storage, which is an additional cost.  Without batteries, PV panels are useless for charging an EV overnight.  The economics change if you consume most power during the daytime but even then a system that is adequate in the summer will be marginal during the winter months.  Sure, a system could be sized for winter requirements, but it will be far more expensive for no significant gain in the summer leading to even longer break-even timescales.
ElefantEd’s example of 2600 units per year from a 3kW system is a helpful guide.  2600 units would cost less than £400 to buy from the grid, which is around £7.50 per week, so the savings on electricity bills are not exactly transformative.
It’s not easy (or cheap) being green.

Herzlos

ElefantEd said:

As far as the car goes, most people charge at night (ie when they aren't using the car), so unless you have a storage system for the energy generated by the panels you wouldn't be able to use it to charge your car.

Yeah, you wouldn't be charging the car from the panels directly unless during the day. However if you're using the panels to power the house during the day, you're still going to be saving money which would be more noticeable as the electric car will increase the electric bill.

It'll certainly save you money *eventually*, but it'll depend on where you live (longitude and facing) - a South facing bungalow on the Dorset coast will generate more electricity than an East facing terrace in the Highlands.

Bluebell1000

We have solar panels, 3.57kWp system generating approx 3100 units per year. So far we have been able to charge our EV for free from approx March (when we got the car) to mid Oct using solar power. With the charge point on our house, we use solar matching to send excess daytime solar generation into the car, but as it has a minimum of 1.2kW we will rarely reach that kind of peak generation for long in winter. With the panels the max we can get into the car on a nice sunny day using only 'free' electric is about 10kWh (about 40 miles). That's fine for our mileage, and the car is parked at home a lot during the day, but it's not going to be viable for everyone. 

Belenus

Should the bonnet, roof and tailgate of electric cars be made out of solar panels?

AdrianC

Belenus said:

Should the bonnet, roof and tailgate of electric cars be made out of solar panels?

It's been tried.
https://blog.toyota.co.uk/introducing-new-prius-plug-in

They aren't nearly big enough, even before you get to any other issues.
https://www.inverse.com/article/34253-elon-musk-tesla-cars-solar-roof

Doesn't stop people throwing it about in their latest hare-brained crowdfunder, though...
https://sonomotors.com/

facade

A solar panel is around 20% efficient, so a 1m x 1m panel would produce around 200W- at noon, in high Summer. It would need a massive fold out flat roof, that could be continually angled to maximise the area facing the Sun.

Herzlos

Belenus said:

Should the bonnet, roof and tailgate of electric cars be made out of solar panels?

It would provide some charge, if you kept it somewhere bright enough, but probably not enough to make it self sufficient unless you were a really low mileage user.

For example: a 4mile/kwh car generating 200w would need about 75 minutes sunlight to gain a miles range.