The COVID-19 pandemic changed the American grocery business and how consumers shop. Online orders and deliveries boomed, and grocers adapted to filling orders quickly, often at small, automated warehouses called micro-fulfillment centers. Researchers at the University of Michigan and Ford studied how the changes affect the amount of greenhouse gas emissions generated during grocery shopping and what customers can do to reduce their carbon footprint. 

The research team used computer modeling to determine emissions for a 36-item grocery basket transported to a customer via 72 different traditional and e-commerce paths. The analysis included the impacts of micro-fulfillment centers, refrigeration, vehicle automation, and last-mile transportation. They found:

• The most emissions are released by a customer who shops in-store and drives an internal combustion engine pickup truck to the site. Switching to an electric vehicle — sedan, SUV, or pickup truck — for in-store shopping reduced emissions by 39% to 51%.
• All home delivery options tested in the models produced fewer emissions than in-store shopping with an internal combustion engine as transportation.
• Cutting the frequency of shopping in half reduced emissions by about 44%.

Some modern delivery innovations proved beneficial for reducing emissions: 

• An autonomous sidewalk robot the size of a suitcase produced the least emissions of any pathway for delivering the 36-item basket. 
• Drones had the least carbon emissions for a single item delivered to a customer who lives near a micro-fulfillment center.

A lot of the emissions from grocery store operations are caused by lighting, refrigeration, and HVAC. The researchers concluded that using micro-fulfillment centers is more efficient and reduces emissions by up to 67% compared with traditional shopping.