Renewable gas and electricity supplier Green Energy is hiking electricity prices by around 9% on average, while gas prices will fall by 5% meaning dual fuel customers face an increase of about 1.5%.
The supplier, which has around 30,000 customers, is set to hike bills for those on its variable energy tariffs from Monday 1 May.
It's also set to withdraw its 'Still' variable tariff and will move those customers onto its 100% renewable gas and electricity 'Sparkling' tariff.
This is the latest in a long line of recent price hikes by energy suppliers. If you're among the 66% of customers still on a standard tariff, it's likely you're overpaying so check now to see if you can lock in a cheap deal via our Cheap Energy Club.
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What the withdrawal of the 'Still' tariff means for customers
If you're on Green Energy's 'Still' variable energy tariff, and you pay by direct debit, you'll be transferred automatically to the supplier's other variable deal its 'Sparkling' tariff.
If you pay by cash or cheque, the supplier is sending letters to explain what to do next.
The 'Sparkling' tariff is currently about £15/year more expensive than the 'Still' deal for dual fuel customers.
Meanwhile, customers on Green Energy's time-of-day 'Tide' tariff who pay different rates for electricity depending on when they use it won't be affected, as prices are frozen until March 2018.
What does Green Energy say?
A Green Energy spokesperson said: "It has been a long-held wish of this company to be able to offer solely 100% renewable energy.
"The market seems to have reached the point where we can purchase renewable at no price premium, so we have taken the liberty of transferring our direct debit 'Still' customers onto the 'Sparkling' tariff to reflect the quality of the energy going into your tariff."