Renewable energy supplier Good Energy, which has had an advert banned for claiming its electricity contains no carbon dioxide, has said it can be “difficult to manage simplicity against detail”.

While the company accepts this week’s Advertising Standards Authority (ASA) ruling, it believes the ASA may not be being consistent over adverts for other fuels and said it would continue to investigate the decision.

Earlier this week the advertising regulator upheld a complaint about Good Energy’s website advert wording which stated: “An average unit of electricity in the UK (a kilowatt hour or kwh) results in 360g of carbon dioxide (CO2) emissions and 0.007g of radioactive waste. But the electricity we supply contains 0g of CO2 and no radioactive waste.”

A complainant challenged the message as misleading, saying Good Energy makes use of biomass energy that can produce more CO2 than coal when burnt.

Responding, the firm said the claim was based on the same calculation methods and results adopted by the government and pointed to a 2010 Department for Business, Energy and Industrial Strategy (BEIS) report stating that biomass fuels were considered a form of renewable energy.

It also shared fuel mix information from BEIS, stating that renewable energy sources produce 0g/kWh of CO2 compared to coal which produced 925g/kWh of C02.

However, the ASA noted 2011 research from the Department for Environment, Food and Rural Affairs (Defra) on consumer understanding of green terms, which found most respondents often interpreted “zero carbon” as “emits no carbon”.

Although accepting consumer understanding can change over time, in this case – regardless of the energy being from a renewable source – the ASA thought they were also likely to interpret the claim as meaning no C02 was produced throughout the electricity’s whole life cycle, including generating and transporting it.

In a statement, the energy company, which supplies around 200,000 customers, accepted the ruling regarding the clarity of calculating and expressing CO2 emissions and confirmed it had taken the necessary measures to comply.

“We always aim to be as fair and straightforward as possible in our communications and have historically reported on CO2 emissions based on guidance from the Greenhouse Gas Protocol and UN in respect of carbon reporting.

“However, it can sometimes be difficult to manage simplicity against detail. We also believe that the ASA may not be consistently considering this type of advertising for other fuels and will be continuing to investigate how they have come to this opinion.

“We will take this ruling as an opportunity to extend our efforts at transparency further, as we believe it is positive that we use the UN guidelines in our calculation and will provide wider clarification to customers going forward.”

Good Energy, one of the UK’s largest Feed-In Tariff providers, says it aims to “break the stranglehold of the big, old-fashioned energy generators”.

It added: “We look forward to seeing how it [the ruling] is applied not just in renewables, but across the energy sector.”