Alistair Buchanan, chief executive of Ofgem, said that the service was an ideal "additional route" for energy customers to have their complaints resolved without immediately switching providers after bad service.
He added: "The ESO has made good progress in its first year, but suppliers must communicate more effectively the benefits of the scheme, which can award customers up to £5,000 in compensation when a complaint is upheld."
Ofgem's research has come after it unveiled a new energy rating system designed to help household and business electricity customers last week.
The new system has been created to help the public make informed decisions on the most energy efficient services and products in the UK.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.