WASHINGTON (AP) — Republicans on the Senate Energy Committee say they are concerned that President Barack Obama's nominee to be the nation's top energy regulator has views they consider to be outside the mainstream.

Specifically, Republicans said they were troubled by a comment by former Colorado regulator Ron Binz that natural gas may be a "dead end" fuel.

Republicans also said they were concerned that Binz was not truthful when he assured them that he was not part of a coordinated effort by a green-energy group and a Washington lobbying firm to boost his nomination to chair the Federal Energy Regulatory Commission.

Alaska Sen. Lisa Murkowski, the panel's top Republican, told Binz she was not convinced that his views were "compatible with FERC's mission" to regulate interstate transmission of electricity, oil and natural gas.

Binz told the panel he had spoken "inartfully" at a March forum and said he fully embraces use of natural gas, at least for the next two decades.