Citing concerns over the possibility of gasoline shortages due to the impact of Hurricane Harvey on Texas oil and gas production, Louisiana has requested a waiver of national fuel requirements aimed at curbing air pollution.
Vivian Aucoin, the environmental scientist manager with the Louisiana Department of Environmental Quality’s air planning division (LDEQ) explained that the Clean Air Act requires the sale of certain gasoline blends during the summer months, from June 1-Sept. 15, to help lower ozone levels in non-attainment areas.
Because there is the possibility of a shortage of the summer blend due to the downed refineries in the Houston area, LDEQ submitted a waiver request to the U.S. Environmental Protection Agency on Monday. “I think they’re gonna act on this pretty quickly,” Aucoin said, adding Florida is already experiencing some shortages.
Summer versus winter gasoline blends
What is the difference between the two gasoline blends? It comes down to the Reid Vapor Pressure (RVP) of the fuel. The RVP is a measure of how quickly the fuel evaporates at a given temperature. The more volatile the gasoline, meaning having a higher RVP, the easier it evaporates.
So what does this mean? Wintertime-blend fuel has to have a higher RVP rate because the fuel must be able to evaporate at low temperatures for the engine to operate properly, especially when the engine is cold. If the RVP is too low, the vehicle will be hard to start and if you get the motor running, it will sound rough.
Conversely, summertime-blend fuel has a lower RVP reading so it will evaporate slowly when the temperature is high. By decreasing the volatility of gasoline during the summer months, this decreases harmful gas emissions that contribute to unhealthy ozone and smog levels. A little-known advantage to using a lower RVP gasoline in the summer is that it prevents vapor-lock on hot days, particularly in older cars.
The bottom line? Getting the waiver will allow the sale of wintertime-blend about two weeks earlier than usual, not really that big a deal right now. The Environmental Protection Agency (EPA) gave the same kind of waiver to Texas on Friday.
Waivers were granted by EPA Administrator Pruitt, in coordination with the U.S. Secretary of Energy Rick Perry, at the request of Texas Commission on Environmental Quality Executive Director Richard Hyde and Texas Governor Greg Abbott.
