Unleaded 88, explained

Why it matters: That's significantly cheaper than the average Richmond-area price of regular fuel (Unleaded 87) which sat at $3.61 a gallon yesterday, per AAA.

• Which had us wondering: What exactly is Unleaded 88 and why is Sheetz the only major retailer trying to sell it?

The big picture: The only difference between Unleaded 88 and regular fuel is the ethanol content.

• 88 is 15% ethanol, whereas regular and most other grades are 10%.

And it's fine to use in most cars.

• The fuel comes with a standard line of advice that it can be used in vehicles manufactured after 2001 that accept regular fuel.

Of note: It's slightly less fuel efficient than regular, per the Columbus Dispatch.

Yes, but: Daniel Ciolkosz, a professor of agriculture and biological engineering at Penn State, told the newspaper that any difference in fuel efficiency is likely negligible given we're only talking about a 5% difference in ethanol content.

The bottom line: It's probably worth buying in cases where it's at least 5% cheaper than regular, per Ciolkosz.