As a yet-tiny market of electric cars is ramping up surely but slower than initially hoped for, there are those who say compressed natural gas (CNG) is also a viable alternative for U.S. transportation.

Among them are a coalition of close to half of the U.S. state governments that have told American carmakers to make natural gas-powered vehicles, saying their agencies will buy them for state fleets.

The thrust was poignantly outlined on Wednesday this week, when Oklahoma Gov. Mary Fallin met with automobile manufacturers and dealers, and purchasing officials from more than a dozen states in Oklahoma City, Bloomberg reports. As the governor for one of the most ready to go CNG states, she was joined by 22 states collectively grouped to solicit bids for the purchase of natural gas-powered vehicles for state fleets.

“We’re serious. We’re ready to buy natural gas vehicles now,” said the Oklahoma governor. “We all know that natural gas is a cleaner form of energy. It’s an abundant form of energy. It’s a less expensive and cheaper form of energy, one that will not only create American-made jobs, it will be good for our national security and economic security.”

The thrust for more natural gas vehicles available for purchase by states has been led by Fallin as well as Colorado Gov. John Hickenhoper. Their goal is to promote the natural gas industry and among the states that have joined them are natural gas producing states including Texas, Wyoming, West Virginia and Pennsylvania.

Strengthening the natural gas industry, Fallin said, “will help provide our states with money back into our local economies, money back into our state budgets, which will be beneficial for those governors who are participating in this.”

The states have joined to issue a Request For Proposal. Responses from auto manufacturers and dealers are due Sept. 7, and purchasing officials expect award a contract by Oct. 5. The contract calls for 60 compact sedans, 850 mid- to full-size sedans, 400 half-ton trucks and 480 three-quarter ton trucks, all natural gas powered.