E15 is a commercially available fuel blend designed to increase the renewable content of transportation fuels while remaining compatible with most standard combustion engines. The 15 percent ethanol content raises the octane rating but slightly lowers the volumetric energy density compared to pure gasoline. Regulatory bodies often restrict its use in older vehicles or small off-road engines due to the potential for material degradation and higher combustion temperatures.
Heard on the job
The station down the highway just added pumps for E15 to meet the new blending mandate.
Insider tip
At retail stations, E15 is frequently marketed as Unleaded 88 to highlight its octane rating rather than its ethanol content.
Also heard as
- Unleaded 88