Fuel ethers are high-octane, efficient petrol components, which can immediately enable CO2 reductions from petrol vehicles via improved fuel efficiency. They also reduce emissions of harmful air pollutants from passenger cars.
In the case of MTBE, typical emission reductions are:
- Carbon dioxide (CO2): Replacing directly blended ethanol with ETBE can save 4 million tons per year of CO2 emissions
- Carbon monoxide (CO): Emissions are reduced on average by at least the same percentage as MTBE content in petrol.
- Unburned hydrocarbons (HCs): For each 1 or 2 % of MTBE, there is a 1 % reduction in total HC emissions.
- Particulate Matter (PM): It is estimated that each 1 % of MTBE results in a 2 to 3 % PM emission reduction.
- Volatile organic compounds: Fuel ethers can save more than 50,000 tonnes per year of VOC emissions compared with other blending components.
- Ozone: MTBE generates about half the ozone compared with isooctane /alkylates and one-tenth that of aromatics.
- Benzene: For each 1 % of MTBE there is an equivalent percentage reduction in benzene emission, both evaporative and exhaust. As benzene is a class 1 carcinogen such a replacement is important.
In addition to air quality benefits, fuel ethers offer an effective substitute for lead, a toxic compound that has been phased out in most parts of the world. It can also effectively substitute other harmful components including metal organic components (MMT), aniline and derivatives.
Further reading: Fuel Ethers Benefits and Uses