Republicans say they envisioned the $5 billion in the infrastructure act for climate-friendlier school buses would replace older polluting diesel buses with a mix of ones that run on electricity, compressed natural gas or propane.

But nearly all of the first batch of funding the Environmental Protection Agency has given out to school districts around the country has gone to help schools buy electric buses, according to the agency’s data…

Experts and Democrats say districts are asking for electric buses in greater numbers because they cost less to operate than other kinds of buses and have a greater impact on the environment. And as the cost of batteries goes down, that will add to the savings that electric buses bring, said Chris Hendrickson, faculty director of Carnegie Mellon University’s Traffic 21 transportation research institute.

Additionally, Hendrickson said, while buses that run on compressed natural gas or propane pollute less than those on diesel, they still use internal combustion engines that send greenhouse emissions into the air.