Solar Panel Help

GPKett

Hi,

I'm getting an Electric car through work and they are effectively giving me £1200 a year to cover the cost of electricity to charge the car. In my mind if i can generate this electricity myself through solar panels then this can be used to bring down the break even time for a solar panel / battery system. I’m not sure where to start on calculating the costs / break even time.

We live in a 4 bed detached in Northants. One of us will be at home every day for most of the day.

We have a disabled son who is getting older and is going to start needing more electric equipment at the start and end of the day so a battery would make sense? i can’t find any grants or anything for disabled children unless I have missed anything?

Using the energy calculator for a 4K system it comes out at a total yearly benefit of £437, generating 1908kWh / year. Not sure how to factor in a battery?

We are current on Eon Next variable rate at 32.4 p/kWh. Last years useage was 4543.5 kWh

These means I wouldn’t generate enough energy to cover standard useage let alone car charging?

Im not sure how to fit this all together to work out if its worth doing, if its worth getting a battery, and the break even time.

 

Any help much appreciated

 

Thanks Gareth

ABrass

GPKett said:

Hi,

I'm getting an Electric car through work and they are effectively giving me £1200 a year to cover the cost of electricity to charge the car. In my mind if i can generate this electricity myself through solar panels then this can be used to bring down the break even time for a solar panel / battery system. I’m not sure where to start on calculating the costs / break even time.

We live in a 4 bed detached in Northants. One of us will be at home every day for most of the day.

We have a disabled son who is getting older and is going to start needing more electric equipment at the start and end of the day so a battery would make sense? i can’t find any grants or anything for disabled children unless I have missed anything?

Using the energy calculator for a 4K system it comes out at a total yearly benefit of £437, generating 1908kWh / year. Not sure how to factor in a battery?

We are current on Eon Next variable rate at 32.4 p/kWh. Last years useage was 4543.5 kWh

These means I wouldn’t generate enough energy to cover standard useage let alone car charging?

Im not sure how to fit this all together to work out if its worth doing, if its worth getting a battery, and the break even time.

 

Any help much appreciated

 

Thanks Gareth

A 4kW system pointed south should generate in the region of 4,000kWh. Unless you're pointing way off South you should get more than 1,900kWh

You should look at how large your roof is, and how many panels you can fit. With an EV and half decent SEG rates then larger systems are much better value and pay back faster.

Find a PV installer locally and ask them how much you can fit on your roof.

Batteries can be good value but they have a slower payback than PV does.

Screwdriva

Welcome to GEMS, Gareth! 

As ABrass has shared, it will make the most sense to fix the max. # of panels on the roof, especially with an EV on the horizon. Also recommend a Zappi EV charger over other brands as it is PV compatible. I would keep the EV battery topped up and sell your excess PV generation to Octopus Energy via the Flux tariff.

Depending on where you are based, a 4kW Sharp panel system with SolarEdge optimizers and inverter w/ 20 year warranty should be installed for < £6K. This figure should help guide you as you review quotes from installers. 

Petriix

The biggest factor is switching to an EV tariff as that will potentially save you loads of money. If you're able to switch just 20% of your home usage into the off-peak window on Octopus Intelligent then you break even vs the standard rate (ignoring the EV) and anything over that will be a saving. Then the EV will run at around 3p per mile.

Solar will help, but I'd only count on using a maximum of 40% of what you generate without a battery, and solar EV charging will only actually save you 2.5p per kWh because you'll lose the 5p you might have earned for the export payment and you could have charged overnight for 7.5p.

You'll likely be looking at £5k for a 4kWp solar array plus £1k for a Zappi charger (or equivalent). Say you generate 4,000kWh per year, exporting 2,400kWh at 5p for £120 income, 600 kWh into the car saving £45 and 1,000kWh used by the home, saving £410, that's ~ 10 years to break even if prices stay as high as they are.

The battery calculations are complicated... It ultimately depends on how much of your usage is unavoidable peak use. You might find a battery makes sense if it's a high amount, otherwise just load-shifting will be better. Batteries are expensive so only make sense for unusually high peak users.