Kansas City, Kan. ? The Kansas City, Kan., School District has added 47 buses that run on an alternative fuel — compressed natural gas –rather than imported diesel.

District officials say the buses are expected to cut fuel costs by more than one-third and significantly reduce maintenance costs.

The compressed natural gas vehicles represent half of the district’s largest buses and will replace one third of its fleet.

The Kansas City Star reports that the $7 million project was paid for in part by a $4 million Department of Energy grant. The district covered the remaining costs.

A federal tax credit will pay for 50 cents per gallon of natural gas. Overall, the district expects to see a $1 per gallon cost savings in compressed natural gas versus diesel.