Propane is a hydrocarbon compound widely used as a fuel for heating, cooking, and transportation. It is easily converted into a liquid under moderate pressure, allowing it to be stored and transported efficiently as liquefied petroleum gas (LPG). The classification of propane as a resource—renewable or nonrenewable—is determined by the origins of the raw materials from which it is produced.
Where Propane Comes From
The majority of commercially available propane is a co-product generated during the processing of other energy streams. Propane is primarily sourced during the extraction and purification of raw natural gas, accounting for roughly 60% of the total supply. The remaining 40% is recovered as a byproduct during the refining of crude oil into gasoline, diesel, and other petroleum products.
When natural gas is extracted, it contains a mixture of hydrocarbons, including methane, ethane, butane, and propane, known as Natural Gas Liquids (NGLs). These heavier NGLs must be separated from the main methane stream to meet pipeline specifications. This separation often involves cryogenic expansion, a low-temperature process that cools the gas stream, causing propane and other NGLs to condense into a liquid.
The liquid mixture of NGLs is then transported to a fractionation plant, where propane is isolated from the other hydrocarbons. This separation relies on the different boiling points of each component. Because its production is directly tied to the rates of natural gas and crude oil extraction, propane’s availability fluctuates with the global production of these two primary resources.
Why Propane is Nonrenewable
Propane is classified as nonrenewable because its source materials, natural gas and crude oil, are fossil fuels. Fossil fuels are organic compounds created over millions of years from the buried remains of ancient marine organisms and plant matter. Geological forces, specifically immense pressure and heat, converted this organic material into the hydrocarbon deposits we use today.
The timescale required for this transformation is measured in millions of years, far exceeding the pace of human consumption. A resource is deemed nonrenewable when it cannot be naturally replaced quickly enough to keep up with the rate of use. Since the geological conditions necessary to form new deposits cannot be replicated on a practical human timeframe, the propane derived from them is inherently finite.
Every gallon of propane used represents a permanent depletion of the Earth’s limited supply of fossil hydrocarbon reserves. Traditional propane cannot be considered a sustainable long-term energy source due to the fixed nature of its geological origins.
The Difference Between Propane and Biopropane
While traditional propane is nonrenewable, a chemically identical alternative exists: biopropane, also known as renewable propane. Biopropane has the exact same molecular structure (C₃H₈) as traditional propane, meaning it can be used in existing storage tanks and appliances without modifications. The fundamental difference lies entirely in the source material used for its creation.
Biopropane Production
Biopropane is produced from renewable feedstocks, including plant and vegetable oils, animal fats, and used cooking oils. The production process involves treating these renewable oils with hydrogen in a refinery setting, often called hydrotreating. This converts the fats and oils into hydrocarbon chains, yielding renewable diesel fuel and biopropane as a co-product.
Because the source materials are biomass that can be regrown or wastes that regenerate quickly, biopropane is considered a renewable resource. The carbon released when biopropane is burned is largely balanced by the carbon absorbed by the plants during their growth cycle, creating a much smaller net environmental impact. This alternative allows consumers to continue using the propane molecule while transitioning away from a nonrenewable fossil fuel source.