Mayor Jerry Sanders has authorized the hiring of New York investment adviser Lazard Ltd. to provide advice on a financing plan for an estimated $800 million football stadium for the San Diego Chargers, according to a mayoral spokesman.

According to the spokesman, Sanders provided a rough estimate of an annual debt service the city would contribute: $38 million, which would cover about half the cost.

Sanders identified the new stadium consultant as George Bilicic, Lazard’s head of power, energy and infrastructure. The contract has yet to be worked out. Its cost will be up to $250,000, contingent on a deal being worked out between the city and the Chargers, said Sanders spokesman Darren Pudgil.

The city hired another stadium consultant last year at a cost of $160,000.

The team has recently been trying to get the city to combine a planned expanded Convention Center with a new stadium, and using tax revenue from both projects to pay annual debt service on lease revenue bonds to be issued by the city.

Earlier this week, the City Council approved a financing agreement that calls for establishing an assessment district that would increase the hotel room taxes on visitors from 1 to 3 percent to pay for the estimated $550 million cost for an expanded Convention Center.

Mark Fabiani, the Chargers special counsel on the stadium issue, said the vote on the center’s financing plan is only preliminary and needs other approvals, including one from the California Coastal Commission, which is likely “to turn down the whole project anyway.”

— Mike Allen