Petroleum refining produces approximately 13% of US industrial greenhouse gas emissions and approximately 3% of all US emissions. While the US is seeking to reduce its reliance on fossil fuels rapidly, some demand will remain for petroleum refinery products in the coming decades. For the US to meet its current climate target of net-zero emissions economy-wide by 2050, petroleum use must significantly decline and refineries must transform to reduce their substantial emissions.

New analysis from World Resources Institute finds that using current and novel technologies—such as fuel switching to clean hydrogen; the electrification of heat; and carbon capture, utilization and storage—can deeply decarbonize refineries, delivering climate benefits and improving local air quality as the US transitions away from fossil fuels in the coming decades.

Refinery emissions—GHGs such as carbon dioxide, methane, and nitrous oxide—can be divided into three categories: stationary combustion, process, and miscellaneous. Stationary combustion emissions come from burning fossil fuels in combustion units to generate heat for on-site processes such as distilling crude oil, creating steam, and cracking hydrocarbons. Stationary combustion results in approximately 63% of the refining industry’s total emissions.

Process emissions are produced by chemical reactions inherent in the refining process. The two most notable sources of process emissions are fluid catalytic crackers (FCCs) and steam methane reformers (SMRs); these units require high temperatures and generate emissions originating from the chemical reactions they induce. The account for about 31% of total emissions.

The remaining 6% generally are derived from gas flaring, catalytic reforming, electricity production, landfills, methane leaks, and sulfur recovery. The WRI report does not examine mitigation pathways for these.

The working paper “Technological Pathways for Decarbonizing Petroleum Refining” shows how, in the long-term, refineries could shift to processing renewable feedstocks to produce low-carbon fuels for aviation, shipping and trucking—the toughest-to-abate transportation sectors.

Key findings include:

• Even with ambitious decarbonization policies and growing electric vehicle penetration, demand will remain for transportation fuels and petrochemicals in the coming decades. The refineries that make these products must decarbonize to meet US climate goals.

• Decarbonizing refineries has the potential to reduce nearly 3% of U.S. greenhouse gas emissions and improve local air quality. That potential stems from reducing emissions from on-site heat generation and refining processes.

• The refining sector can meet its annual heat demands while cutting emissions by switching from fossil fuels to low- and zero-carbon hydrogen fuel and/or through electrification of low-to-medium-grade heating. Process emissions can be abated through carbon capture and storage technology.

• Most of the technological options are available today at various levels of development, and innovation and deployment will expand their usage.

• Immediate access to carbon dioxide and hydrogen uniquely situates refineries to produce low-carbon and carbon-negative fuels today through existing approaches such as Fischer-Tropsch synthesis.

• In the long term, refineries could switch from processing crude oil for conventional fuel to renewable feedstocks for synthetic fuels, primarily for aviation and trucking. This could reduce fuel carbon intensities by up to 80%.