A business consortium that includes Lockheed Martin and Barclays bank plans to invest as much as $650 million over the next few years to slash the energy consumption of buildings in the Miami and Sacramento areas. It is the most ambitious effort yet to jump-start a national market for energy upgrades that many people believe could eventually be worth billions.

Focusing mainly on commercial property at first, the group plans to exploit a new tax arrangement that allows property owners to upgrade their buildings at no upfront cost, typically cutting their energy use and their utility bills by a third. The building owners would pay for the upgrades over five to 20 years through surcharges on their property-tax bills, but that would be less than the savings.

The consortium is led by a company called Ygrene Energy Fund of Santa Rosa, Calif., which has already won an exclusive contract to manage a retrofit program for a half-dozen communities in the Miami area, with the city expected to join in a few weeks. It is in the late stages of completing a contract with Sacramento, and is seeking deals in other cities.

State and city officials are optimistic they may have found a way to tackle one of the nation’s biggest energy problems — waste in older buildings — without new money from Washington. If enough building owners sign on, private capital would be put to work paying for retrofit projects that promise to save local businesses money while creating thousands of new construction jobs.