As early as 2013, the Central Ohio Transit Authority plans to switch to buses that run cheaper, cleaner and quieter on compressed natural gas.

A $4.4-million competitive grant from the U.S. Department of Transportation will help renovate COTA’s McKinley Avenue facility fueling station for CNG buses. The Southwest Ohio Regional Transit Authority in Cincinnati also received $1.9 million to replace diesel buses in its fleet.

Total costs for renovating the McKinley Avenue facility would be about $50 million over a period of three to five years.

“It will be a gradual evolutionary change, not a revolutionary change where we would do everything at once,” COTA president and CEO Bill Lhota said. “Our plan is to replace buses when we have to buy new coaches and we do that about every year.”

The new buses would cost more to buy, but less to fuel and maintain. COTA won’t retrofit any of its 300 diesel buses.

Most buses run on ultra-low-sulfur diesel, which costs COTA an average of $3.10 per gallon. In comparison, natural gas costs $1.13.

COTA’s project was among 46 selected nationwide through two funding programs aimed at reducing greenhouse gases and promoting clean fuels. The Federal Transit Administration reviewed 266 project applications.

“These grants and others like them will put thousands of Americans back to work building sustainable, energy-efficient transit vehicles and facilities across the country,” Transportation Secretary Ray LaHood said in a news release.

In 2007, COTA switched from a biodiesel blend to the ultra-low-sulfur diesel in an effort to save money and reduce emissions.

Last year, six hybrid buses were put into service, but they are even more expensive to purchase than coaches, which run on CNG.

Buses that burn CNG cost about $40,000 more and require new fuel pumps. Hybrid buses cost $230,000 more.

According to the American Public Transportation Association, nearly 19 percent of the nation’s buses run on compressed natural gas or other similar blends. But diesel accounts for more than 65 percent of the nation’s fleet.

Clean Fuels Ohio is supervising an $11-million federal grant which will convert bus fleets with natural-gas fuel pumps.