
British households choosing ‘100 per cent renewable’ electricity tariffs may be being misled – and a new online tool shows how
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Across the UK, many British households are choosing electricity tariffs marketed as ‘100 per cent renewable’. One quick Google search brings up a list of many of these allegedly ‘clean’ tariffs – such as those offered by E.ON, So Energy and 100 Green.
More often than not, households are paying a premium price for the promise of cleaner power.
While the label of ‘100 per cent renewable’ might suggest all the electricity used is from renewables such as wind or solar, the reality of how the grid actually works is complicated – making the reality of these ‘clean’ tariffs far more planet-polluting than you might think.
In essence, the electricity system operates in real time. Supply must match demand every second, even when renewables are not available. For example, on a dark and still winter evening, other sources such as gas or nuclear power fill the gaps that wind or solar may have otherwise met.
To circumvent this reality – and to still be able to say they are ‘100 per cent renewable’ despite not being so – suppliers work with annual aggregates. Essentially, if a supplier uses fossil-fuelled power one day, they are still legally able to claim being ‘100 per cent renewable’, so long as they purchase enough renewable energy on other days to balance it out.
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This approach satisfies the regulatory requirements defined by Ofgem – the energy regulator for Great Britain – and it was a balance that previously seemed appropriate when renewables were scarce and needed support to meet demands.
However, now renewables are frequently abundant on the grid – so it’s easy for suppliers to buy renewable energy when it’s plentiful without making meaningful changes to their supply for the rest of the year.
Although some suppliers are close to using 100 per cent renewable power, currently no suppliers in the UK hit the top mark.

But how is it possible to tell what energy your provider is using? Thanks to a new online tool – Matched – it is easy to see. Matched surveys 25 of the UK’s top energy providers, providing ratings updated every hour throughout the year using public data.
The results shed a light on otherwise alleged ‘100 per cent renewable’ tariffs. Take the example of E.ON from earlier, marketing a clean tariff. In reality, it ranks as one of the worst, sitting at 17th place with a mix of 26 per cent renewable energy and 74 per cent non-renewable.
Below, you’ll find the current rankings for energy companies across the UK, ordered by those using the highest percentage of renewable energy, to the least:




