Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.

The ASA and CAP’s Climate Change and the Environment (CCE) project is in place to respond to the ongoing climate crisis, and to take action to ensure that environmental claims in advertising are not misleading or irresponsible. Updates about our work in this area are published here.  

Ensuring claims do not mislead

The basis of environmental claims must be clear, and unqualified claims can mislead if they omit material information (Rule 11.1). Broad claims relating to renewable energy that are not qualified, for example “Live the life you want - without harming your world”, are more likely to breach the Code (Good Energy Ltd, 22nd June 2005). Absolute claims must be supported by a high level of substantiation, while comparative claims such as "greener" or "friendlier" are more likely to be justified and supportable with evidence (Rule 11.3). Marketers must also base environmental claims on the full life cycle of the advertised product, unless the marketing communication states otherwise, and must make clear the limits of the life cycle (Rule 11.4). See ‘Environmental claims: General “Green” claims’ for further guidance.

As with all sectors, marketers should hold robust evidence to substantiate all objective claims (Rule 3.7). Also, if a significant division of scientific opinion exists or evidence is inconclusive, that should be made clear to readers: marketers should not suggest that their claims command universal acceptance if they do not (Rule 11.5).

Marketers also should be aware that ambiguous environmental claims can mislead. For instance, the ASA considered consumers were likely to understand the claim “the UK’s leading 100% renewable electricity supplier” by Good Energy to mean that the company had more customers on their renewable tariff than their competitors. However, the claim was intended to mean that Good Energy were the only company who offered solely renewable tariffs. The ad was ruled as misleading by the ASA in the absence of comparative evidence supporting the claim as it would likely be understood. (Good Energy Ltd, 7th August 2013).

It is also worth noting that even statements of intent or aspirational claims regarding environmental credentials can be problematic if they are not sufficiently qualified, or supported by a clear organisational plan of how to achieve them. For example, in 2011 an ad for Spark Energy featured the claim “Over the next few years, we will be obtaining secure renewable fuel sources”. Because Spark Energy’s renewable sources were only secured for a few months, and their plans beyond then only extended for up to a year, the ASA considered that the unqualified claim was likely to mislead. (Spark energy Ltd, 20 July 2011).

Renewable energy initiatives

Marketers communicating about renewable energy initiatives should be careful to avoid giving a misleading impression about the wider environmental impact of the business, particularly where the business is otherwise responsible for a significant amount of ongoing emissions or environmental harm.

Ads highlighting renewable initiatives may need to include “balancing information”, when omitting it could otherwise mislead consumers about the initiative’s significance, relative to the company’s overall activities. Businesses in higher-emitting sectors, such as fossil fuel companies and those who finance the industry, need to be particularly careful in this respect.

In 2023, the ASA investigated a complaint against an ad for an energy company, that stated “Renewable hydrogen, another alternative to reduce emissions. At Repsol, we are committed to renewable hydrogen as an energy source […]”. The ASA considered the ad’s focus on renewable hydrogen, combined with imagery associated with lower-carbon energy, such as solar panels, EVs and wind turbines, created the impression that renewable and lower-carbon energy formed a significant part of Repsol's current business. However, the ASA found that Repsol's renewable hydrogen activities were still at an early stage and not yet operating commercially, while large-scale oil and gas production and exploration formed the vast majority of its business interests. Because the ad did not include qualifying information about the proportion of Repsol’s overall business model that comprised lower carbon energy, the ASA concluded that it omitted material information and was likely to mislead consumers (Repsol SA, 18 October 2023).

Similarly, the ASA investigated three ads for Shell relating to lower carbon actives such as renewable electricity, offshore wind power and electric vehicle charging. It considered the ads misleadingly suggested that these products comprised a significant proportion of the energy products Shell invested in and sold in the UK. As oil and gas investment and extraction still made up the vast majority of Shell’s business, material information should have been included that made clear the proportion Shell’s lower-carbon energy products relative to its overall activities (Shell UK Ltd, 7 June 2023).  

See further CAP guidance on claims about environmental initiatives in Greenspeaking with confidence - Environmental claims in advertising.

Renewable electricity source claims

“Renewable electricity” is the term used to describe electricity generated from renewable non-fossil energy sources such as wind, solar, geothermal, wave, tidal, hydro-power, biomass, landfill gas, sewage-treatment-plant gas and biogas.

Most electricity generated from renewable sources is distributed through the National Grid. The amount of electricity taken from the National Grid by consumers of renewable electricity products is generally equal to the amount of electricity fed into the grid from renewable sources. However, marketers should ensure that they do not misleadingly imply that the electricity generated from renewable sources is delivered directly to their customers from those sources if that is not the case. Claims such as "100% renewable electricity" can be acceptable without further qualification, provided the claims can be substantiated and do not imply energy is supplied directly to consumers. (Woodland Trust t/a Woodland Trust Energy, 11th December 2013).

There’s no precedent by way of ASA rulings that requires marketers to always make clear that renewable energy is derived from the National Grid. But, where there is the potential for ambiguity, or an ad could misleadingly imply that energy is provided directly from a renewable source, marketers are urged to include more information about the source of the energy - provided that qualification does not contradict the overall message of the ad. For example, an ad could make clear that electricity is distributed via the National Grid with a claim such as “renewable electricity is supplied to the National Grid, which in turn supplies your home”, or similar.

In 2023, the ASA considered a complaint challenging whether claims were misleading in three ads for Shell, including “In the South West 78,000 homes use 100% renewable electricity from Shell”. The complainant was concerned the claims misrepresented the number of homes that purchased 100% renewable electricity from Shell Energy, and implied that Shell Energy directly supplied energy to those homes in each region. The ruling noted that each ad included the claim “Shell Energy’s renewable electricity is supplied by the National Grid and certified by Renewable Energy Guarantees of Origin, matching electricity bought with the equivalent amount from 100% renewable sources”. In both a TV and a YouTube ad, this qualification featured on-screen during the ads’ opening shots, while it was included directly below the headline claim in a poster ad. The ASA considered that the ads all made clear that the electricity was supplied via the National Grid rather than directly, and also that Shell had substantiated the figures about the volume of homes. So, the ruling concluded that the ads were not likely to mislead in that regard. (Shell UK Ltd, 7 June 2023).  

In 2010, the ASA also ruled against an ad in a magazine for Good Energy which featured the claim “[…] all the energy we supply on behalf of domestic customers is certified 100% renewable. This means producing and using energy locally; making it a visible part of the local community; and reconnecting people with the source of their energy.” The ASA considered the claim was ambiguous, but the overall impression of the ad was such that it was likely to be interpreted as misleadingly suggesting Good Energy supplied 100% renewable energy directly to consumers. (Good Energy Ltd, March 2010).

Renewable energy in domestic settings

Marketers should take care not to mislead about the financial savings that renewable energy products can deliver in households, or the amount of energy that those products can generate. Where such claims are made, marketers should include all information likely to be considered material to understanding the claim for consumers, such as cost modelling assumptions and specific tariffs on which claims are based, or the need for purchasing extra equipment like batteries, or installation fees.

The CAP Code states that price claims such as “up to” must not exaggerate the availability or amount of benefits likely to be obtained by the consumer (Rule 3.22). Additionally, the ASA is likely to have regard to the Competition and Markets Authority guidance on ‘Marketing green heating and insulation products: Consumer law compliance advice for businesses’ (the CMA Guidance). It states that “up to” claims, including price claims and other “up to” claims, should reflect that at least a significant proportion of consumers would be likely to achieve the stated outcome. Where relevant, they should also reflect the range of factors that impact product performance. Also see CAP guidance on ‘Prices: General’.

In 2026, the claim “shrink electricity bills by up to 94% in your first year” in an ad for solar panels was ruled misleading. The ASA considered the marketer had not provided sufficient evidence to demonstrate that a significant proportion of consumers could realistically achieve that level of savings in the first year. The ASA also found that key assumptions behind the modelled figure had not been disclosed in the ads, and the ad omitted material information such as the need for a battery and specific tariffs. (Centrica Hive Ltd, 04 March 2026).

Another ad for solar panels was also found to mislead due to omitting material information and insufficient evidence. The ad stated “Drastically Reduced Bills: Generating your own electricity significantly reduces dependency on the grid, insulating you from rising costs”. The ASA considered the ad failed to include information such as the factors that influence savings and the conditions or individual circumstances under which reductions could be achieved. (GGRS Energie Ltd, 26 November 2025).

Additionally, in 2010, a marketer of solar panels was found to have exaggerated the claimed savings by conflating bills for both gas and electricity. Because solar panels would not offset costs associated with gas consumption, for example central heating, the ASA ruled the ad misleading (Solar Fusion, 25th August 2010).

The ASA have also ruled against ads with savings claims for other lower carbon domestic products, such as heat pumps.  In an ad for British Gas, the ASA noted the claim “Save up to £546” depended on undisclosed modelling and tariff assumptions as well as customer circumstances. Because the ad omitted such material information, and the marketer had not provided adequate evidence demonstrating a saving of £546 could be achieved by a significant proportion of consumers, the ASA concluded the ad was misleading. (British Gas Services Ltd, 04 March 2026).

Renewable output claims

Claims in ads about the output of renewable electricity producing sites should also be demonstrably true.

When claims refer to the future output of a specific site, such as a wind farm, the predicted output should be calculated using site specific data. If a claim is based on an estimated output but not on historical data (for example, for a proposed site) that fact should be made clear to consumers. Definitive claims about the output of sites that are not based on site-specific data are likely to be problematic (Druim Ba Sustainable Energy Ltd, 31 October 2012).

In 2012, the ASA also ruled the claim “The electricity generated as a result of the project will, on average be enough to power 3,670 Craven District households*" was misleading. The ASA considered the claim had used definite, and not conditional, language. It was also not clear that the claim was an estimate, based on an average capacity factor rather than data specific to the proposed site. (Energiekontor UK Ltd, 30 May 2012).

Marketers describing the output of a given site by stating the number of homes that could be supplied by that site should not imply that the electricity is delivered directly to those homes. When calculating the number, an up-to-date average electricity consumption figure published by a relevant authoritative body should be used.

For further guidance, see also entries on ‘Environmental Claims’ in the ‘Resource Library’, including:

 

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