They also noted that Appalachian Power ratepayers have had no prior investments in the Mitchell plant, but have had a stake in the Amos plant.
"We consider it relevant and important that Appalachian Power already owns (most of the Amos plant)," the commission's order said. "Virginia ratepayers already have made substantial investments in the Amos units."
The Virginia commission also echoed environmentalists' concerns, citing the risks associated from a lack of diversity in Appalachian Power's power-generating fleet. The commission said approving both acquisitions would raise Appalachian Power's percentage of electricity produced by coal-fired plants to 87 percent by 2017.
Byron Harris, director of the West Virginia Consumer Advocate Division, said the Virginia decision mirrored what his office told commissioners here.
"We think that acquiring both of these plants is just too risky," Harris said. "I think Virginia made the right decision, and I hope our commission does the same."
Harris said this was the first multi-state case he could recall in which Virginia regulators made their decision before their counterparts in West Virginia.
He said West Virginia could still approve the purchase of both plants - Appalachian Power does have the right to appeal the Virginia decision - but he didn't feel it was likely.
"They could still issue the order approving the full transaction, but it is kind of a moot point at this point," Harris said.
In addition to the power plant transfer, Virginia regulators also approved the proposed merger of Appalachian and Wheeling Power. They said they believed the merger of the two companies would be "neutral and potentially positive" for ratepayers.
West Virginia regulators are expected to rule on the transfer and merger cases in the coming months.
An Appalachian Power representative did not immediately respond to a request for comment.
Contact writer Jared Hunt at busin...@dailymail.com or 304-348-4836.