Speaking in Leeds after meeting Eastern, Yorkshire Electricity, Scottish Power and Manweb - the first to allow customers to switch suppliers from 14 September - Mr Battle hailed competition as "a consumer-led revolution in energy".
But he urged companies to ensure that their contractors were fully open about prices. He said: "A market can only work with genuinely fair price information.... Sales representatives should make it clear to customers that the market is open to competition and that a number of suppliers may offer deals to customers.
"I would like them to hand over a clear written statement of the tariff options their company is offering the customer, and a comparison between these and the equivalent prices from the local company. ... Finally, they should make it clear to the customer that if they want independent information or advice they should call the Offer helpline. The number of the helpline should be on the statement given the customer."