WASHINGTON, Jan 11 (Reuters) - Democratic Senator Jay Rockefeller of West Virginia will announce later on Friday that he will not seek a sixth term in the Senate in 2014, according to a Senate Democratic source.
Rockefeller, 75, is chairman of the Senate Commerce, Science and Transportation Committee. He is scheduled to make an announcement at 11 a.m. EST (1600 GMT) in Charleston, West Virginia, about his future plans, according to his office.
The liberal Democrat, whose full name is John D. Rockefeller IV, is the great-grandson of the famous oil tycoon who became a billionaire in the late 1800s.
Senator Rockefeller has been a strong supporter of organized labor and was an active participant in healthcare reform initiatives, including President Barack Obama's successful effort in 2010.
Rockefeller also has been a protector of West Virginia's coal industry, an important economic force in his impoverished state. In 2009 and 2010, Rockefeller urged the Senate to take a careful approach to climate change legislation that would have aimed to reduce the use of carbon-emitting fossil fuels, such as coal, over the long-term.
That legislative effort ultimately sputtered in the Senate.
Instead, Rockefeller promoted a system that would have permanently stored carbon dioxide industrial emissions underground - a commercially unproven technology.
Republican Representative Shelley Moore Capito has been weighing a run for Rockefeller's Senate seat for a while.