U-M researchers problem USPS EV environmental research


A brand new College of Michigan research finds that making the swap to all-electric mail-delivery autos would result in far larger reductions in greenhouse fuel emissions than beforehand estimated by the US Postal Service (USPS). (Earlier put up.)

In its evaluation of the potential environmental impacts of the Subsequent Era Supply Automobile program, the Postal Service underestimated the anticipated greenhouse fuel emissions from gasoline-powered autos and overestimated the emissions tied to battery-electric autos, in response to U-M researchers. The U-M crew’s paper is revealed in Environmental Science & Know-how.

Our paper highlights the truth that the USPS evaluation is considerably flawed, which led them to dramatically underestimate the advantages of BEVs, which might have impacted their decision-making course of.

—Maxwell Woody, lead creator

The NGDV program requires the acquisition of as much as 165,000 new mail supply vans over the following decade. The Postal Service mentioned in February that no less than 10% of the brand new mail vans can be electrical. However following sharp criticism from many quarters, the company upped that quantity in July. (Earlier put up.)

Although the Postal Service now says no less than 40% of the brand new supply autos can be electrical, the issues within the USPS environmental evaluation stay and have to be addressed, mentioned Woody, a analysis space specialist on the Heart for Sustainable Methods, which is a part of the U-M Faculty for Surroundings and Sustainability.

The brand new research takes a second take a look at the 2 delivery-vehicle situations the Postal Service evaluated in its 340-page Closing Environmental Influence Assertion on the NGDV venture.

That doc in contrast the anticipated environmental impacts of a supply fleet with 10% battery-electric autos and 90% gasoline-powered vans (referred to as the ICEV state of affairs for internal-combustion engine autos) to a fleet with 100% battery-electric autos (referred to as the BEV state of affairs).

The U-M researchers performed a cradle-to-grave life-cycle evaluation of the 2 situations and reached some vastly totally different conclusions than the Postal Service did.


Woody et al.

The U-M crew decided that:

  • Lifetime greenhouse fuel emissions below the ICEV state of affairs can be 15% larger than estimated by the Postal Service, whereas emissions tied to the BEV state of affairs can be no less than 8% decrease than estimated by the company.

  • When anticipated enhancements to electrical autos and future electrical-grid decarbonization are factored in, a completely electrical USPS supply fleet would end in as much as 63% decrease greenhouse fuel emissions than the company estimated, over the lifetime of the fleet.

  • An all-electric fleet would cut back lifetime greenhouse fuel emissions by 14.7 to 21.4 million metric tons of carbon dioxide equivalents when in comparison with the ICEV state of affairs. The USPS estimate was 10.3 million metric tons.

The Postal Service has not commented on the U-M research.

In February, the company introduced it had accomplished the environmental evaluate for its Subsequent Era Supply Automobile program and was transferring forward with plans to begin buying the brand new vans. At the least 10% of the supply autos can be zero-emissions electrical fashions, whereas the rest can be powered by gasoline.

In response, attorneys normal from 16 states (together with Michigan), the District of Columbia and a number of other environmental teams sued the mail company to dam the unique buy plan or to drive the Postal Service to purchase extra electrical vans. The company later pledged to impress no less than 40% of its new supply fleet.

The authors of the brand new research say the principle causes their findings differ considerably from the USPS outcomes are:

  • The U-M research consists of greenhouse gases generated all through a supply automobile’s lifetime, together with the mining and manufacturing of supplies, automobile meeting, automobile operations and repair (often called use-phase emissions) and end-of-life disposal. The Postal Service evaluation seemed solely at use-phase emissions.

  • The brand new research consists of projections of how electrical-grid emissions are prone to change over the estimated 20-year service lifetime of next-generation supply autos, as renewables more and more change fossil fuels. The USPS evaluation didn’t tackle this issue, which is called grid decarbonization.

  • The U-M research makes use of a extra correct technique to calculate automobile working emissions, one which depends on gasoline financial system and gasoline combustion depth charges. The USPS evaluation of projected working emissions was based mostly on estimated per-mile emissions charges.

Whereas our emissions outcomes and USPS emissions values are on the identical order of magnitude, the small print of the USPS FEIS appear to have important miscalculations and range tremendously from the established literature on automobile LCAs.

—Woody et al.

Research senior creator Greg Keoleian, director of the U-M Heart for Sustainable Methods, mentioned the brand new findings counsel the Postal Service must be deploying electrical supply vans at a fee a lot larger than 40%. The failure to take action exposes a scarcity of sustainability management by the company, he mentioned.

Finally, the USPS determination about next-generation supply autos was based mostly extra on value than climate-altering greenhouse fuel emissions, Keoleian mentioned. The company estimated that an all-electric supply fleet would have a complete value of possession about $3.3 billion larger than a fleet with simply 10% electrical autos.

Nonetheless, the not too long ago signed US “Inflation Discount Act” consists of $3 billion to assist the US Postal Service meet zero-emission automobile objectives: $1.29 billion for the acquisition of zero-emission supply autos and $1.71 billion for infrastructure to assist these autos.

The work was supported by Ford Motor Co. via a Ford-College of Michigan Alliance Venture Award, by the Accountable Battery Coalition and by the U-M Faculty for Surroundings and Sustainability.


  • Maxwell Woody, Parth Vaishnav, Michael T. Craig, and Gregory A. Keoleian (2022) “Life Cycle Greenhouse Fuel Emissions of the USPS Subsequent-Era Supply Automobile Fleet” Environmental Science & Know-how doi: 10.1021/acs.est.2c02520


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