British Gas has already committed £350m to a new billing system, and a summit of energy companies and industry regulator Ofgem will be held in June to discuss proposals for integrated data transfer. Energywatch last week said up to two million people have received inaccurate bills in recent years.
Earlier this year it was revealed that problems in transferring customer data had left British Gas £13m out of pocket and about 10,000 of its customers awaiting a year's worth of bills.
The news put the spotlight on the deregulated energy industry's inability to transfer customer information between suppliers due to a lack of common data formats.
In a joint statement, British Gas, Npower, Powergen and Scottish Power announced "their collective commitment to drive improvements in billing accuracy, by working to repair and fix industry processes and improve data quality".
They said, "With many millions of consumers having switched electricity and gas suppliers since liberalisation of the markets in the late 1990s, some data inconsistencies in the information held on some customers has been swapped among all participating suppliers."
Analyst David Bradshaw of Ovum said, "The energy companies need to get their heads together and it seems like that is what they are doing. This reinforces the need for any consumer-based company to have clean customer information."
There are about 30 electricity suppliers in the UK. When consumers transfer their custom between these firms, a number of organisations between the user and the new supplier need to harmonise the data that is transferred.
For each electricity company there is a data collector, data operator and data aggregator. The complexity of the data is huge, especially as much of it is old and resides in legacy systems.
Transferring data between companies is costly. It currently takes about six weeks to transfer customers between suppliers, and mismatches usually have to be resolved manually.