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.


In 2021 the ASA and CAP launched a Climate Change and the Environment (CCE) project, to respond to the ongoing climate crisis and take action to ensure that environmental claims in advertising are not misleading or irresponsible. Updates about our work in this area are published here.  

The project consists of several strands, including:

  • Sector-specific reviews, focusing on previous ASA work on these issues, common claims in ads for these sectors, and any recent legislation or developments in understanding of their environmental impacts
  • Research into consumer understanding of different types of environmental claims
  • Targeted investigations, to establish new precedent and take action against advertisers who use green claims in a way that is likely to mislead or cause harm
  • Updates to our existing resources, and creation of new educational material

Please see the updated CAP Advertising Guidance on The environment: misleading claims and social responsibility in advertising, and the new e-learning module that covers the rules on Climate Change and the Environment

While this advice represents the current position, the ASA’s CCE project is actively reviewing our approach to these issues, which may lead to further rulings and updates to this guidance.

Claims about the output of a renewable electricity producing site should be demonstrably true.

If the ad makes claims about 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. That can be done by stating “estimated output” or by making the output claim conditional, for example “could produce up to …”. 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).

Marketers may describe the output of a given site by stating the number of homes that could be supplied by that site but should not imply that the electricity is delivered directly to those homes. When calculating the number, the Copy Advice team recommends using an up-to-date average electricity consumption figure published by a relevant authoritative body, such as that recommended by Ofgem of 3.3 MWh.

Comparisons, such as comparing the amount of emissions with those produced by a car, are likely to be acceptable if the comparison makes clear the specific model of car used (RWE Npower t/a Npower Renewables, 21 February 2007).

Marketers of energy from renewable sources often want to make claims about the beneficial effect to the environment, usually expressed as a reduction of carbon dioxide emissions, compared with electricity from conventional sources. If they make conditional claims such as "It is estimated that the Brightenber Hill wind farm could save more than 7,741 tonnes of CO2 each year*", marketers should be able to show that that estimate has been based on the relevant capacity factor and that figures used are representative of the current UK electricity-generating mix (Energiekontor UK Ltd, 30 May 2012).

See other entries on Environmental claims: General and Environmental claims: Marketing of electricity from renewable sources General


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