Energy Transfer recently commissioned its 100th automated butane blending site in Utah and its 101st in Arizona, continuing a successful run of implementing industry-leading technology across the nation to the benefit of consumers.

One of Energy Transfer’s 101 automated butane blending sites.

Energy Transfer now blends butane into gasoline at 101 automated butane injection sites in 33 states, with several more sites on deck. Blending typically occurs at terminals before being loaded onto trucks, and at times is injected directly into our pipelines. Our automated butane blending system continuously monitors gasoline flows, creates additional gasoline through blending, and ensures all gasoline meets specific state and federal parameters.

Why does this matter? Each fall, gasoline prices dip during the colder months due to differences in gasoline blending – specifically due to increasing the amount of butane in the mix to adjust for seasonal weather changes. Vapor pressure is the pressure at which a liquid and its vapor are at equilibrium at a given temperature. As temperature increases, vapor pressure also increases, and vice versa.

Butane has the highest vapor pressure of the usual components in gasoline blending. This means that during the summer, the butane level in gasoline must be low in order to meet the appropriate state and federal specifications for vapor pressure – and in colder months, it must be increased to meet those same specifications.

A close-up view of some of the equipment found at each of Energy Transfer’s automated butane injection sites.

And because butane (one of the natural gas liquids moved through the Mariner East pipeline system and processed at the Marcus Hook Terminal) is less expensive than other blending components used in gasoline, fall and winter gas blends cost less to produce than summer blends with less butane. Butane is also abundant, which increases overall gasoline supply during the cold-weather months and further reduces prices for consumers at the pump.

Butane blending is a win-win for consumers, and Energy Transfer is proud to play a key and growing role in the process across the United States.