Semis Are Getting Greener: EPA/NHTSA’s ‘Phase 2’ Emissions Standards Explained
When we talk about increasing fuel efficiency standards, usually we are referring to either light-duty vehicles (small trucks, passenger cars, etc.) or averages across a brand’s entire fleet (as is the case with CAFE standards). However, increasing standards are not just for the light-duty cars out there—the Environmental Protection Agency and the National Highway Traffic Safety Administration jointly proposed new standards for medium- and heavy-duty vehicles back in 2015, which at the time accounted for around 20% of greenhouse gas emissions and oil use in the US despite only accounting for 5% of all vehicles on the road. A large part of this is the transportation industry, which currently consumes more than 70% of petroleum in the US.
So, to look at this a little more clearly, the US Energy Information Administration has put together a report looking at the impact that the proposed “Phase 2” standards would have when they would take effect for Model Years 2021-2027.
The most basic effect is that, of course, fuel economy would rise by 28% from 2017 to 2027 over the Reference case, leading to a drop in oil consumption—an estimated 22% less than otherwise. In particular diesel consumption is estimated to drop 18%. By 2040, new vehicle fuel efficiency is expected to average 10.6 miles per gallon gasoline equivalent (a 33% improvement over the Reference case). This rising fuel economy would also lead to a shift away from vehicles powered by natural gas or propane, since the lower conventional gas/diesel prices would take away a lot of the incentive to buy the more expensive CNG or propane vehicles.
In addition, the new standards would force the redesign of trailers as they currently are to create lower rolling resistance and improve aerodynamics. This, coupled with a required reduction in each category of medium- and heavy-duty vehicle would lead to a large reduction of emissions, starting at a cumulative 3% reduction of 1,200 million metric tons between 2021 and 2040 and ending up at a reduction of twice that percentage in 2040.