CHICAGO (CBS) — The Chicago City Council’s Budget Committee has given preliminary approval for a $160 million plan to convert most of the city’s outdoor lights to LED technology.

Rebecca Scheinfeld, the Chicago Transportation commissioner, said the city will save $10 million per year using the more energy-efficient LED lights and smart technology. She couldn’t, however, say how the rest of the costs will be covered.

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“The budget department and CFO are committed to identifying those resources on an ongoing basis – it’s a four year implementation expectation, so that will cross over multiple fiscal years,” Scheinfeld said.

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And there are still questions about how the project will be financed.

“If you do a $160 million contract, there’s got to be a breakdown somewhere more specifically of how much out of TIF (Tax Increment Financing), which TIF is it coming from and how much, generally, are we going to talk about bonding out here,” said Ald. Scott Waguespack.

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The plan passed with those questions unanswered.