The Philadelphia City Council is hiring an energy consultant to get a second opinion on Mayor Michael Nutter's plan to sell the city's gas company. 

Concentric Energy Advisors will analyze all the proposals submitted to the city to buy Philadelphia Gas Works, the biggest publicly-owned gas utility in the nation. Nutter wants to sell PGW to to UIL Holdings Corp., a New England firm, for $1.86 billion.

The consultant will also look at how PGW could leverage its current resources.

Council President Darrell Clarke says the contracts with Concentric Energy Advisors, which are worth at least $425,000, do not duplicate the Nutter administration's previous work of vetting possible buyers.

"As a separate branch of government, it's our responsibility to make sure that what was submitted is appropriate," he said. "We would also like to look at the possibility of maximizing one of the city's most significant assets, be it public or private. The reality is that there is a golden opportunity for this to produce jobs."

If Council doesn't approve the sale by mid-July, UIL can bail on the deal.

Michael West, a spokesman for UIL, says he is comfortable with Council's decision to retain a consultant.

"As we understood it, this was going be a part of the process," he said. "We remain confident in the merits of our bid proposal."