The California Public Utilities Commission on June 21 turned down a proposal from San Diego Gas & Electric Co. to build a $639 million natural gas pipeline from Rainbow Station to Miramar, saying there is no need.

Southern California Gas Co. also wanted to build the 36-inch diameter line. Both utilities are part of Sempra Energy (NYSE: SRE).

The 47-mile long line is meant to replace a 16-inch line on roughly the same route, and would have increased capacity along the route.

Commissioners ruled the utility would not need the proposed line to improve safety or reliability.

In a statement, the commission said the utilities’ most recent natural gas supply forecast and the commission’s reliability standard for gas planning do not demonstrate that there is a need for the proposed pipeline.

In addition, the commission called on SDG&E to submit a hydrostatic test or replacement plan for the existing, 16-inch line.