The rev of a gasoline engine is a sound that is becoming less prominent among cars on the street, and now school buses.

With the growing popularity of electric vehicles, more bus barns are going green, in part, due to the fact that school districts in the long run, could possibly save some green.

Knox County Schools Superintendent Andy Turgeon has three electric buses, and not even two years into ownership, he’s already seeing substantial returns.

Right now, we’re seeing savings of $5,000 -$6,000 a year between the energy cost and the fuel cost of each bus," Turgeon said

But while the investment sounds like a great opportunity to some districts, others still have reservations.

"Another thing that goes into account, and again this is my understanding visiting other schools, our shortest bus route is an hour and 20 to an hour and 25 minutes" said Dr. Heath Halley, superintendent of the Putnam County School District. "We are geographically one of, if not the largest bus route schools in the state of Missouri, and we have been for the last 30 years."

Because its school buses are relatively new vehicles, the Putnam County School District would not qualify for the EPA’s Clean School Bus Program.

This program allows qualifying school districts to trade in their old buses for zero- or low-emission school buses.

But even if they did qualify, Dr. Halley would need more answers.

When we look at it, there are a lot of great ideas, but you know on the flip side of that, a lot of times with these ‘green’ ideas, there’s a lot of carbon footprints that goes along with that," Halley said. "And you know, I’m not the expert, I’m an old science teacher, so I look at those things and then have conversations, and right now, we don’t feel like it’s the best fit for us.

For Turgeon, he has his questions as well, but his questions are more about the future of the Knox County bus barn.

So, you know, some day will it all be electric? Quite possibly, very likely, but there’s some things that have to happen before we get to that point," Turgeon said.