The U.S. EPA final rule for emission standards for cars and gasoline made E10 the new federal emissions test fuel, finalized specifications for E85 test fuel for flex-fuel vehicles (FFV) and left the door open for vehicle manufacturers to request approval for alternative certification fuel, such as E30, for vehicles optimized for that fuel. 

“It’s not the greatest thing since sliced bread; but at least there’s dough in the machine,” said Advanced Biofuels USA’s vehicle emissions expert, Robert Kozak, in a press release. In other words, the standards, known as Tier 3 rules, don’t contain everything the ethanol industry could have hoped for, but it did include some positive elements.

The final rule requires that all Tier 3 light duty and chassis-certified heavy-duty gasoline vehicles be certified on E10. The test fuel will be used for new vehicle certification, assembly lines and in-use testing. The EPA considered a change in the volatility of the fuel, or pounds per square inch (psi) Reid Vapor Pressure, but ultimately concluded that an RVP of 9 psi should be maintained for the E10 test fuel.

General Motors addressed the fact that E10, rather than straight gasoline, is now the new test fuel. “We commend EPA for selecting a certification fuel that is representative of in-use fuels,” the company said in a prepared statement. “This allows OEMs (original equipment manufacturers) to optimize vehicle performance to an actual fuel that our customers use nationwide.”

In addition, finalizing specifications for an E85 emissions test fuel for FFVs will help resolve uncertainty and confusion, the EPA said. The agency also said that it intended to finalize in-use fuel quality standards for E51 to E83 and possibly E16 to E50 as well but wasn’t able to do it in time to include it in this final rule. “As the number of flex-fuel vehicles in the in-use fleet increases, it is becoming increasingly important that all fuels used in FFVs, not just gasoline, meet fuel quality standards,” the EPA said. “A lack of clarity regarding the standards that apply to fuels used in FFVs could also act to impede the further expansion of ethanol blended fuels with concentrations greater than 15 volume percent, which is important to satisfying the requirements of the RFS2 program.”