Millions of us choose renewable electricity tariffs to try to do our bit for the planet. But now the government is examining how energy firms describe their green tariffs in an effort to stamp out 'greenwashing'.
It says it will decide whether the current rules about what can be called a green tariff are fit for purpose.
Anne-Marie Trevelyan, Minister of State for Energy and Clean Growth, said: 'I want people to know that when they sign up to a green tariff, they are investing in companies that make a conscious choice to invest in renewable energy.'
Energy companies can label tariffs as 'green' or '100% renewable' even if some of the electricity they supply comes from fossil fuels.
That's as long as they offset the fossil fuel power by buying certificates called Renewable Energy Guarantees of Origin (REGOs).
So, for example, one energy firm's green tariff could be solely backed by REGO certificates, while another may own a solar farm or buy directly from renewable generators.
From looking at energy firms' websites, it can be tricky to tell exactly what you're buying.
The review of green tariffs will look at:
For example, you could be given information about the type of renewable electricity, where it was generated and when.
It has asked for evidence to understand the problems and help decide how it should change the rules about green electricity tariffs.
The government isn't alone in being concerned about how green tariffs are marketed. The Competition and Markets Authority (CMA) recently announced draft guidelines for businesses making 'green' claims, including energy companies, to reduce the risk of misleading consumers.
Sue Davies, Which? head of consumer protection policy, said: 'We know that consumers want to make more sustainable choices, so it's good that the government is investigating concerns that some suppliers appear to be 'greenwashing' their energy tariffs, which could risk misleading customers.
'We believe there needs to be greater clarity on how renewable electricity is defined and marketed. If the government concludes that firms are not being upfront and transparent about their green credentials, it should take action to ensure people can make informed decisions about where to buy their energy from.'
Regardless of the electricity tariff you choose, try these tips to reduce your energy use and cut your carbon footprint: