Fossil fuels are most thought of in terms of the energy services they provide: petroleum-derived fuels in transportation, natural gas for heating, and coal for electricity generation. But fossil fuels are consumed—but not combusted—when used as construction materials, chemical feedstocks, and many other non-energy products. About eight percent of fossil fuels used worldwide are for non-energy (non-combustion) purposes.
The consumption of fossil fuels for non-energy purposes has more than doubled since 1990 due to rising supply and demand.1 The production of oil and natural gas has expanded, driven in part by a large increase in the United States enabled by the boom in hydraulic fracturing (fracking). Demand has increased for end use products such as plastics, pharmaceuticals, and chemicals.
Non-energy uses of petroleum (oil) include:
— Asphalt: This extremely viscous product binds materials such as crushed stone and gravel to pave surface roads, parking lots, and airports.
— Petrochemical feedstocks: These are chemicals made from petroleum that form the building blocks for a wide range of products such as plastics, detergents, pharmaceuticals, fertilizers, textiles, and synthetic rubber.
–Petroleum coke (petcoke): This carbon-rich solid material is a byproduct of the refining process of crude oil that is used in producing steel, aluminum, and chemicals.
–Lubricants: These products are made from refined crude oil and used to reduce friction, wear, and heat between moving surfaces in machinery, vehicles, and industrial equipment.
–Special naphthas: This group of petroleum-derived products consists of highly refined, light hydrocarbons that are used primarily to produce paint thinners, cleaners, or solvents.
–Hydrocarbon gas liquids (HGLs). This group of hydrocarbons includes ethane, propane, butane, and a class of chemicals known as olefins that include ethylene and propylene. HGLs are derived from the processing of oil and natural gas, and they are used as fuels and for non-energy applications. Liquefied petroleum gases (LPGs) are a subset of HGLs, primarily consisting of propane and butane, which are liquefied for storage and transportation. LPGs are used primarily as fuels for heating and cooking, but also in the production of plastics, synthetic rubber, aerosol propellants, refrigerants, solvents, blowing agents, and fertilizers.
Non-energy uses of natural gas include:
— Olefins: This class of chemicals includes ethylene, propylene, and butadiene which are the raw materials for most plastics, as well as synthetic rubber, detergents, coatings, adhesives, and carpet fibers.
–Ammonia: Natural gas is the primary source to produce hydrogen via a process known as steam methane reforming (SMR). The hydrogen is then used in the synthesis of ammonia, a process that makes ammonia fertilizer widely available. Ammonia is also used to manufacture pharmaceuticals, plastics, textiles, explosives, and other chemicals.
–Methanol: In addition to hydrogen, the SMR process yields carbon monoxide and carbon dioxide that are then used to produce methanol, an important chemical feedstock.
Non-energy uses of coal include:
–Coke in steel manufacturing: Coke is produced in a process called coking or coal carbonization, which involves heating specific types of coal (coking coal or metallurgical coal) in the absence of air in a coking oven. Coke is a key input to steel manufacturing where it provides the carbon required to convert iron ore into molten iron.
–Chemicals: Coal can be gasified or liquified to yield feedstocks that are used to manufacture ammonia, methanol, and many other important chemicals.
Discussion of carbon dioxide emissions is centered on fossil fuel combustion and land use change. But carbon dioxide emissions from the non-energy use of fossil fuels are an important and growing source of emissions.2 For example, the use of natural gas and coal in the production of hydrogen via steam reforming or gasification is a major source of carbon dioxide emissions. CO₂ is released as a byproduct during the conversion pathways that produce ammonia, methanol, and other chemicals. Carbon dioxide is released when coke, derived from coal, is used as a reducing agent in blast furnaces to convert coke, derived from coal, is used as a reducing agent in blast furnaces to convert iron ore into molten iron. Products such as solvents, lubricants, and asphalt release carbon dioxide slowly over time via oxidation and degradation. Carbon dioxide is released from the combustion of plastics in waste-to-energy facilities. These non-energy pathways of carbon dioxide emissions are drawing specific scrutiny in the development of policies and technologies to mitigate climate change.
1 United Nations, “Energy Statistics Database,” accessed December 29, 2024, https://unstats.un.org/unsd/energystats/data/
2 Zanon-Zotin, Marianne, Luiz Bernardo Baptista, Rebecca Draeger, Pedro R. R. Rochedo, Alexandre Szklo, and Roberto Schaeffer. “Unaddressed Non-Energy Use in the Chemical Industry Can Undermine Fossil Fuels Phase-Out.” Nature Communications 15, no. 1 (September 14, 2024): 8050. https://doi.org/10.1038/s41467-024-52434-y.