Final answer:
True, using ethanol-enhanced gasoline can result in reduced fuel economy due to the lower energy density of ethanol compared to conventional gasoline.
Step-by-step explanation:
Using ethanol-enhanced or reformulated gasoline can result in reduced fuel economy. This is due to the fact that ethanol has a lower energy density compared to conventional gasoline. Most gasoline in the U.S. is blended with ethanol in various concentrations such as E10 (10% ethanol), E15 (15% ethanol), or E85 (up to 85% ethanol). Not all vehicles are equipped to handle the higher concentrations of ethanol without experiencing lower energy performance. Flex-fuel vehicles, designed to run on high-ethanol blends, do expect a decrease in miles per gallon (MPG).
While ethanol reduces dependency on oil and has a high octane rating that increases combustion efficiency, it still contributes to lower fuel economy because of its chemical structure. Ethanol molecules contain an oxygen atom, which reduces both the energy density and carbon mass per fuel mass when compared to gasoline. Despite its ability to reduce carbon emissions somewhat, its higher volatility can lead to increased evaporative emissions, which are harmful to the environment.
Moreover, the use of ethanol as an alternative fuel has broader implications. The feedstocks for ethanol, such as corn and sugarcane, demand considerable agricultural resources. The competition for land between fuel and food production can drive up food prices and affect food supply. In addition, the growth of crops for ethanol production has contributed to deforestation in some regions, raising concerns about sustainable land use.
Some alternatives to ethanol, such as methyl t-butyl ether (MTBE), have been shown to cause environmental concerns like groundwater contamination. As a result, there has been an increase in the use of more eco-friendly octane enhancers like ethanol. Though ethanol-blended fuels are more environmentally conscious in terms of reducing pollutants like lead and benzene, one of the trade-offs is the reduced fuel economy in vehicles.