Well-to-Wheels Emissions of Greenhouse Gases and Air Pollutants of Dimethyl Ether from Natural Gas and Renewable Feedstocks in Comparison with Petroleum Gasoline and Diesel in the United States and Europe

Dimethyl ether (DME) is an alternative to diesel fuel for use in compression-ignition engines with modified fuel systems and offers potential advantages of efficiency improvements and emission reductions. DME can be produced from natural gas (NG) or from renewable feedstocks such as landfill gas (LFG) or renewable natural gas from manure waste streams (MANR) or any other biomass. This study investigates the well-to-wheels (WTW) energy use and emissions of five DME production pathways as compared with those of petroleum gasoline and diesel using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET^®) model developed at Argonne National Laboratory (ANL). The five DME pathways include 1) fossil NG with large-scale DME plants, 2) methanol from fossil NG with large-scale plants for both methanol and DME (separately), 3) LFG with small-scale DME plants, 4) manure-based biogas with small-scale DME plants, and 5) methanol from black liquor gasification with small-scale DME plants. This study analyzes DME production and use in the U.S. and Europe, and in two vehicle classes (light and heavy duty vehicles [LDVs and HDVs]). The WTW results show significant reductions in fossil fuel consumption and greenhouse gas (GHG) emissions by DME compared to gasoline and diesel if DME is produced from LFG and manure-based biogas. When methanol from black liquor is used for DME production, there are reductions in GHG emissions, though smaller than DME produced from LFG and MANR. Meanwhile, fossil NG-based DME produced in large-scale DME plants or from NG-based methanol shows GHG emissions at the similar level as petroleum diesel does.