Ofgem has opened investigations into British Gas, E.On and Npower over their roll-out of advanced electricity meters to business customers.
The regulator said it will investigate whether the three suppliers took “all reasonable steps” to install the meters after finding they had the lowest completion rates.
Under the Government’s scheme, which began in 2009, suppliers had to take all reasonable steps to fit 155,000 business customers with the meters by April this year.
Ofgem said its assessments found the roll-out was only 75% complete in electricity, compared with 86% in gas.
British Gas, E.On and Npower had the lowest completion rates in electricity, accounting for more than half of the 40,000 meters still waiting to be installed.
Ofgem said a number of other suppliers did not roll out the new meters to all eligible customers, and it would keep the possibility of action against them under review.
The Government has estimated that businesses will save around £40 million a year by using the meters, which are designed to offer better and timelier information about energy consumption.
Rachel Fletcher, senior partner for Ofgem’s markets division, said: “We are disappointed in the overall performance of the majority of suppliers concerning the roll-out of advanced meters to business customers.
“These new meters offer real benefits to customers including saving money through reduced energy consumption and ending estimated billing.
“Regulatory and government programmes are not optional and failure to meet these in a timely way causes consumer harm. All suppliers can and must learn the lessons from the roll-out of meters for business customers and apply them to the domestic smart meter roll-out.”
Ofgem said it monitored suppliers’ progress throughout the roll-out and repeatedly reinforced the need to deliver on time.