HOUSTON, March 21 (Reuters) -

The U.S. government needs to streamline permitting for

renewable energy projects, including development of power

transmission infrastructure and grid connectivity, to support

needed growth, executives said on Thursday at a conference in

Houston.

"It's a tremendous issue," said NRG interim CEO

Larry Coben, pointing to difficulties around interconnection,

the rules that new electricity generators must follow to connect

to the grid.

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

interconnection process, according to the American Clean Power

Association.

Coben lamented that it is much harder to move through

permitting processes in places like California than Texas.

States with fewer regulatory restrictions are going to

be the big winners in attracting renewable investment and

growth, said Andrés Gluski, CEO of utility firm AES Corporation ( AES ).

Hurdles around permitting have been discussed frequently

among executives attending the annual CERAWeek energy conference

in Houston Texas. Earlier in the week, U.S. Senator Joe Manchin

told participants that permitting reform "will get done."

The call for faster permitting comes as renewable

deployment is forecast to grow by as much as 17% to 42 gigawatts

this year, representing about a quarter of electricity

generation, consultancy Deloitte said in a report, citing U.S.

government figures.

"We've got to get infrastructure built, transmission lines

built. We've got to work through these kind of political forums

that are being used to stonewall and stop progress," said Chris

Womack, chief executive at utility firm Southern Company.