Synthesizing Clean Transportation Fuels from CO₂ Will at Least Quintuple the Demand for Non-carbogenic Electricity in the United States

Abstract

We review alternatives that have been proposed to mitigate greenhouse gas (GHG) emissions from vehicles by comparing alternatives for displacing the current suite of transportation fuels to more GHG-sparing fuels and, to a lesser extent, powertrains. Two topical approaches, biofuels and electrofuels, appear to be less effective than direct electrification of the fleet. By biofuel, we mean a fuel derived from sustainably sourced biomass or waste carbon streams. By electrofuel, we mean a fuel derived from a carbon source in which most of the stored energy stems from an electrochemical conversion. For any direct electrification (e.g., battery-powered vehicle) or indirect electrification (e.g., electrofuel) technology to significantly reduce the overall emissions of carbon dioxide and criteria pollutants from the transportation sector, the grid would need to be modernized and decarbonized.

Reducing Economy-Wide Greenhouse Gas Emissions with Electrofuels and Biofuels as the Grid Decarbonizes

“…First, despite e-fuels' potential, they cost more to produce than fossil fuels. 2,7,65,66 Biofuels also face challenges in cost-competitiveness. 67−69 Therefore, research and development support, financial incentives, and policy interventions for these fuel types should be considered as pathways to reduce biofuel and e-fuel costs.…”

“…Furthermore, the technical and commercial immaturity of e-fuels and the fact that they are energy-intensive to produce have raised questions about their role in decarbonization. 2,3,6,7 Various authors have explored different decarbonization pathways to reduce emissions in different sectors of the economy. Some studies of decarbonizing transportation suggest the deployment of a portfolio of carbon-neutral synthetic fuel technologies including e-fuels to help evaluate pathways for decarbonization, economies of scale, and learning by doing.…”

“…3,6,8−14 Others emphasize reducing the growth of energy consumption in hard-to-electrify transportation modes to ease the shift to full decarbonization. 2,15,16 Finally, some encourage a focus on fleet electrification and the need for grid decarbonization. 2,17−19 These existing analyses highlight the need for a collective approach to decarbonization.…”

Editorial: The motivations for and the value proposition of sustainable aviation fuels

“…The syngas can then be converted to hydrocarbons using the FT process or to alcohols to be used in an alcohol-to-jet process (Schmidt, Weindorf, Roth, Batteiger, & Riegel, 2016). However, the supply of these fuels is dependent on a significant ramp up in production and availability of low cost, low carbon renewable energy (Holladay, Male, Rousseau, & Weber, 2020;Male et al) to achieve the targeted very low fuel carbon intensities. These e-fuels, outside of those that might be produced via FT conversion of syngas, are not yet being evaluated as part of the ASTM qualification process.…”

Special Issue of Energy & Fuels Honoring Michael T. Klein

“…Yang et al 30 Economics of the Choice of Energy and Fuels. Holladay et al 31 compare the economics, environmental footprint, and timing of approaches that promise to decrease greenhouse gas emissions generated during the operation of the U.S. fleet of ground transportation vehicles.…”