Co-operative Energy has become the latest supplier to announce inflation-busting price increases, heaping more strain on cash-strapped households.
The supplier, which launched in May, says gas and electricity prices will rise by 18% and 11%, respectively, from 3 November.
The company blames the increases on rising wholesale energy costs (what it pays for energy), charges for distribution and levies to fund energy investment.
All the big six energy companies have recently announced a second round of price hikes after bills went up over the winter.
Co-operative Energy's business development manager Nigel Mason says: "The last thing we want to do is put up our prices and we have held off for as long as we possibly could, but unfortunately we are affected by the same pressures as the rest of the energy industry."
This week at the Labour Party Conference, shadow business minister Gareth Thomas called for more mutual energy companies to be set up in an effort to combat rising domestic bills.