Scottish Power chief Keith Anderson said families would find rising prices 'extremely difficult'.
Mr Anderson said: "The average wage in Scotland is somewhere between £31,000 and £32,000. If the energy price goes to £2,900, that means every person on an average salary will be defined as being in fuel poverty."
He added: "We need to be realistic about the gravity of the situation - around 40% of UK households, potentially 10 million homes, could be in fuel poverty this winter." However, Mr Anderson said a £10bn tariff-reduction fund could be paid for by adding £40 a year to all household energy bills for the next decade.
This applies if their remaining income is insufficient to maintain an acceptable standard of living, defined as being at least 90% of the UK Minimum Income Standard, a set of criteria drawn up by the Centre for Research in Social Policy at Loughborough University.based on essentials such as food, clothes and accommodation, as well as "other costs required to take part in society".by 2040.