Philadelphia City Council President Darrell L. Clarke unveiled an ambitious proposal Monday that he said would create up to 10,000 jobs over 10 years by investing in energy improvements to municipal buildings, schools, small businesses, and low-income homes.

But he and officials from the Philadelphia Energy Authority, the plan's architects, were unable to say how it would be paid for or would work. He said a more detailed plan would be prepared over the next six months.

"I'm just so optimistic this is going to happen," he said when asked for specifics at a news conference in City Hall packed with reporters and people from the energy sector. "I don't want to come off sounding like Donald Trump and not give you full answers. ... These folks up here know what they're talking about and know what they're going to do. So this is going to be good. Trust me."

The strategy calls for $1 billion in investments, public and private, over the next decade. It includes retrofitting 25,000 low-income homes and apartments, and 2,500 neighborhood small businesses.

The improvements to School District buildings would save an estimated $24 million a year in energy costs, according to the Philadelphia Energy Authority, an independent municipal agency that would oversee the plan. The authority was created in 2010 by Council under Clarke's direction.

Energy improvements to municipal buildings are often paid for with bonds, and Clarke said that was an option. He also mentioned seeking investments from companies that would be repaid out of the savings in utility costs.

There is more uncertainty about how the program would work in the private sector, where, for example, low-income homeowners might prefer to spend their money on a critical home improvement rather than energy-efficient windows. Emily Schapira, vice chairwoman of the Energy Authority, recognized that challenge and others, but said, "They are all solvable.

"Yes, there are a lot of challenges," she said. "None of them are insurmountable. They are all things we will have to specifically tailor the program to solve."

The 10,000 jobs the plan was estimated to create include the initial workforce to complete the energy improvements; those who make products for those improvements; and those employed because the savings from those improvements have been invested back into the economy.

"The bottom line is, we need to get started now," Clarke said. "We're literally watching dollars fly out of the window every day because of the inefficiencies associated with [city] facilities."

Mayor Kenney, who attended the news conference, expressed his willingness to work with Council and applauded some of the initiatives, saying infrastructure investments in city libraries and recreation centers are "long overdue." But he also detailed efforts already underway to retrofit city buildings and made clear that the plan was Clarke's own, thanking the Council president for inviting him to "his first major policy proposal of this new administration."