MONTPELIER -- The Vermont Public Service Board has approved a merger of the state's two largest power companies, with the parent company of Green Mountain Power taking over Rutland-based Central Vermont Public Service Corp.

With its approval, the board also OK'd a hotly debated provision allowing a $21 million repayment to CVPS ratepayers to come in the form of investments in energy efficiency and weatherization.

And it approved provisions limiting the merged company's control of the Vermont Electric Power Corp., the company that manages the high-voltage backbone of Vermont's power grid.

The $21 million repayment had become a big issue in this past legislative session, with some lawmakers saying the money should be paid directly to ratepayers. It was owed from a ratepayer bailout of the then-financially-troubled CVPS a decade ago.