Virginia regulators estimate that consumers may have to pay significantly more for electricity under Gov. Ralph Northam's plan to reduce air pollution by joining a carbon cap-and-trade program with other states.

State Corporation Commission staffers told a legislative hearing Thursday that the average residential customer would have to pay $7 to $12 more each month.

Northam's office disputes these numbers, saying the cost would likely be less than $1 a month.

Northam has pushed Virginia to join the Regional Greenhouse Gas Initiative and the state air pollution board is set to vote on final regulations this spring.

The cap-and-trade program among Northeastern and mid-Atlantic states mandates emission reductions in the power sector.

Republicans have tried unsuccessfully to block Northam from joining RGGI without legislative approval.