HOUSTON, March 21 (Reuters) - Permitting reform,

including around the development of power transmission

infrastructure, will be needed to support growth in renewable

energy, NRG interim CEO Larry Coben said on Thursday.

"It's a tremendous issue," he said, pointing to difficulties

around interconnection, which are the rules that new electricity

generators must follow to connect to the electric grid.

It can take up to four years to move a project through the

interconnection process, according to the American Clean Power

Association.

(Reporting by Liz Hampton in Houston)