Drivers are failing to capture financial and CO2 savings from electric vehicle tariffs, a new study by renewable electricity company Good Energy claims.

Commissioned to coincide with the launch of the firm’s new EV Charge Tariff, the research shows that reducing carbon emissions and pollution is the most common motivation for people to choose a plug-in vehicle, cited by 48% of them, alongside saving money, also quoted by 48%.

Electricity tariffs designed for EV drivers can help here. Such tariffs often offer lower electricity prices during off-peak hours, typically at night, compared to standard tariffs. Requiring a smart meter, they enable customers to charge their vehicles when electricity demand is low, and renewable energy is high, saving money on energy costs.

But while 71% of EV drivers say they charge their vehicles at home using one of these tariffs, many are not getting the benefits they are looking for.

Good Energy warns that many energy suppliers claim to provide ‘100 per cent’ renewable electricity – including through their EV tariffs – while justifying their claims through Renewable Energy Guarantees of Origin (REGOs), which are often traded via a secondary market. This means suppliers can source energy from fossil fuel sources, and then buy certificates to label a tariff as ‘100% renewable’”.

Good Energy analysed the Matched Clean Power Index – the first platform that gives UK consumers the ability to see exactly how much of their electricity comes from renewable sources, hour by hour, all year – and found that of 11 electricity providers offering specialist EV tariffs, seven provide renewable electricity 33% of the time or less. According to the index, some providers of EV tariffs provide renewable electricity 0% of the time.

Good Energy also spotlighted its own performance in the index; for 2025/25, the business came out top, with a score of 88% renewable energy across 0.4 TWh of consumption.

Current regulation only mandates suppliers to match the total volume of renewable electricity certificates (REGOs) to the total annual electricity consumption, which means consumers may be using fossil-fuel electricity at lower renewable production times, even though they’re told they’re on a ‘100% renewable’ tariff.

Good Energy’s findings also suggest that many EV drivers are needlessly wasting money. At least 15% of them aren’t using EV tariffs, meaning they are missing out on off-peak savings. A further 7% didn’t know what kind of tariff they used.

Recent research from Easee suggests that charging an EV during peak times when electricity is at its most expensive costs a typical high-mileage driver using 40kWh per week around £372 extra per year.

And a Cornwall Insight report suggests that specialist off-peak EV tariffs can offer motorists average annual savings of up to £1,240 compared to petrol, rising to £1,780 for high-mileage drivers.

Such savings could become even more important following reports that the Chancellor is planning on introducing a pay-per-mile scheme which would charge drivers of electric cars 3p per mile – costing them around £250 a year on average.

But even some motorists with an EV tariff are losing out, as there are significant differences in the off-peak rates charged across these tariffs, from 6.5p/kWh to over 15p/kWh at the other end of the scale.

Good Energy has stepped in to help EV motorists with a new tariff that offers one of the most competitive off-peak rates available. Featuring overnight rates of 6.6p/kWh between midnight and 5am, the energy supplied is matched with 100% renewable electricity bought directly from Good Energy’s community of 3,000 generators across the UK. It’s open to both new and existing customers.

Donna Slater, head of propositions and pricing at Good Energy, said: “Our new EV tariff is for motorists who want peace of mind that their electricity is as renewable as it can be under the available infrastructure, and be able to charge their car overnight as cost-effectively as possible.”

Slater also said that customers deserve more transparency around how suppliers source renewable electricity, “which is one of the major roadblocks preventing British households and businesses from being able to play an active part in our net zero ambitions”.

“We’d like the Government to mandate a much higher level of transparency so that people and businesses can be assured that choosing a green supplier helps to create a greener energy system,” she stated.