A new bill in the U.S. Senate would amend Corporate Average Fuel Economy rules to encourage production of a new class of natural-gas vehicles with "reserve" gasoline tanks.

As demonstrated in a drive of prototype vehicles earlier this year, the range-extended natural gas cars would run for perhaps 60 miles on natural gas.

They're envisioned to be filled from a home refueling device connected to the natural-gas line in a private residence, avoiding the need to build a nationwide natural-gas fueling infrastructure.

Such cars would burn natural gas in their engines, but a small gasoline tank would provide "range extension" for longer trips or where natural gas was not available--in the same way the gasoline range extender of a plug-in electric Chevrolet Volt provides travel beyond that car's 38 miles of electric range.

No such cars are planned for production today, but the natural-gas industry has proposed that such designs would allow natural gas to be used as a vehicle fuel for the bulk of a car's daily miles without the loss of cargo space required to fit the larger tanks permitting a car to run a few hundred miles on the fuel.

The bill, S.1355, would treat such vehicles as "dedicated natural-gas vehicles," which are assumed to run 100 percent of the time on natural gas, and are not subject to limits on how many CAFE credits can be earned.

It also amends CAFE standards to let such vehicles be treated equally to electric vehicles, which natural-gas-vehicle advocates feel have been unduly favored by current EPA policy.

In contrast, "bi-fuel" vehicles--which would include aftermarket natural-gas conversions added to pickup trucks, including a version of the 2014 Ford F-150 pickup truck with a natural-gas readiness package--are assumed to run 50 percent of the time on each fuel.

And, there are limits to the number of CAFE credits permitted to manufacturers for such bi-fuel vehicles.

The bill was introduced by Senator Jim Inhofe [R-OK], and cosponsored by senators Mark Begich [D-AK], Roy Blunt [R-MO], and Robert Casey [R-PA].

Natural gas, largely produced in the U.S., emits fewer pollutants per mile than gasoline and is favored by energy-security advocates over gasoline produced from imported oil.

Senator Inhofe is noted for his consistent denial of climate change on the floor of the U.S. Senate and elsewhere.


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