Council-owned supplier Bristol Energy has posted an £11.2 million loss in the year to 31 March 2018.
The financial documents posted on Companies House show that after tax, the total loss posted for the financial year was £11,205,533.
In response to the figures, the company says the losses outlined are “in the range” of what was expected.
A spokesperson said: “During the financial year 2017/18, Bristol Energy’s residential customers on supply grew by over 62,000 customers.
“We doubled our business customers supply volume, turnover increased nearly fourfold and the company’s gross margin grew by over £3 million.
“The losses outlined in our latest accounts are in the range of what was expected as we continue to build on the solid position we’ve established within the sector.
“It has been a tough 12 months for the energy retail market due to market and regulatory conditions, with wholesale energy prices hitting a ten-year high this year.
“Despite these challenges we’re continuing to attract new customers and grow our business sustainably – thousands are joining us every month – and we’re helping to tackle fuel poverty in the city with our fuel good fund.”
Peter Haigh, Bristol Energy’s managing director, stepped down from his role shortly before Christmas.
Haigh, who helped launch the company in 2015, will be replaced by Bristol Energy’s finance director Marek Majewicz as interim managing director.
The council-backed energy supplier announced in August last year that it was increasing its standard variable tariff (SVT) for the first time in its history due to “increased uncertainty”.
Bristol Energy has previously said it expects to be in the black by 2021.
It received a fresh £2 million injection of funds from its local authority parent on 30 July 2018.