During October 2024, the premium of Non-TET propane over TET propane in Mont Belvieu went completely nuts, averaging a level far outside the norm, peaking several days at record levels. This is not simply some arcane NGL differential that makes little difference to propane markets. It is a key aspect of the propane export market, since the largest volume of physical propane exported is sourced from locations priced at the average Non-TET price (the price in Enterprise storage caverns), while the TET price index (the price in Energy Transfer storage) is typically used for hedging of source barrels for propane export cargos.
This decades-old vestige of propane markets is rarely a problem. As shown in the left graph below, for the past eleven years, TET has averaged 0.28 c/gal (about one-third of a cent) above Non-TET, and the differential is quite stable. The annual average has never been above +0.2 c/gal or below -0.7 c/gal.
