Independent, Expert EV Reviews & Advice Since 2006
Electric Nation V2G Marie Hubbard

Save money on energy bills by charging your EV using solar power

Energy prices are rising but there’s still a way to drive a car with minimal running costs, by using solar panels to power an electric car.

Of course solar power only works efficiently when the sun is shining, and you may not be able to charge an EV at that time, so storing the energy from solar in a battery in your home is also an important part of the solution.

Here’s a quick introduction to solar power and battery storage solutions.

Solar panels have been increasing in popularity, largely due to the money households save on their energy bills. It’s estimated that almost one million households in the UK now have solar panels installed – reducing their reliance on the grid.

Solar batteries store the excess energy generated from solar panels, instead of letting it go back to the National Grid. This energy can then be used to power your home – or your EV – during times of the day when your solar panels don’t generate enough electricity.

Solar batteries reduce dependency on the National Grid electricity you use and enable you to store the energy that your solar panels generate.

Currently, solar batteries cost anywhere between £1,800 and over £9,000. The reason for such a wide price range is that it depends on the capacity of the solar batteries, chemical composition, and the battery’s life cycle. For a ballpark figure, a solar panel system to support the average family of three people would cost around £6,000.

When solar panels were first introduced they were fairly expensive but as they have become more widespread, their price has become more affordable (solar panel prices have nearly halved over the past decade). This is also expected to happen with solar batteries, but as with any new technology, it takes some time for this to happen.

There are two types of chemical materials that are most commonly used for solar batteries – lithium-ion and lead-acid. If both types have the same storage capacity of 4kWh, lithium-ion batteries have a cost of around £4,000, whilst lead-acid batteries only cost around £2,000.

Although the initial cost of lithium-ion batteries is double the cost of lead-acid batteries, lithium-ion solar batteries have proven to be more cost effective than their lead-acid counterparts because of their long-term usage and higher cycle life.

Lithium-ion batteries typically have a life cycle (complete charge/discharge cycles) of 4,000, compared to a 1,800 life cycle for lead-acid. Also the usable capacity of lithium-ion batteries is 90% whereas lead-acid is only 50%.

Solar panels typically have around a 20 to 30-year lifespan, but there’s just a five to 15-year lifespan for solar batteries.

The return on investment for solar batteries depends on your household’s electricity consumption and the price of energy. But one thing that’s guaranteed when you have a solar battery is that your reliance on the grid is reduced, and your energy bills will reflect this. The average household will make a profit on their solar panels set-up – and with the price of electricity at an all-time high, the time it takes for solar panels to pay for themselves is at an all-time low

Households in England, Wales and Scotland could benefit from a Smart Export Guarantee (SEG) tariff. The SEG allows you to sell back your renewable energy generated from your solar panels that’s sent back to the grid.

Two of the best companies for their SEG tariffs include Tesla and Octopus Energy – the two with the highest paying rates. Tesla offers 11p per kWh and Octopus Energy offers 7.5p per kWh. However Tesla (administered by Octopus) requires you to purchase a Powerwall 2 solar battery – costing £9,000.

The battery only has a 10-year warranty, therefore it may need to be replaced for an additional £9,000 around half way through your solar panels’ 20 to 30-year lifespan.

With Octopus Energy you’ll make 7.5p per kWh of energy that you send back to the grid. It should be noted that this is only available to its own customers and the rate for other households is set at 4.1p per kWh.

If you don’t have a solar battery you’ll lose about 50% of the power your solar panels generate.

So if you want to install this technology, where do you start if you’re looking for independent advice? One option is to visit the Federation of Master Builders website to find out the best solar panels and if you want your solar panel costs worked out.

Image from the Electric Nation V2G project.