Technologies
Fuels
Cleaner fuels refer to the use of cleaner burning diesel or other fuels such as natural gas or propane.
Cleaner Marine Fuel
Houston and Mexican Ports
Switching to a lower sulfur fuel demonstrates significant SOx and PM reductions.
- Ultra-Low Sulfur Diesel (ULSD)
- Biodiesel/Renewable Diesel
- Emulsified Diesel
- Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG)
- Liquefied Petroleum Gas (LPG) or Propane
Ultra-Low Sulfur Diesel (ULSD)
Switching to fuels that contain lower levels of sulfur reduces PM and enhances the effectiveness of retrofit technologies. Emissions reductions from ultra-low sulfur diesel (ULSD) alone will vary depending on the application, level of sulfur reduction, and other fuel characteristics, such as cetane number and aromatics. ULSD is required beginning:
- 2007 for highway use
- 2010 for non-road use
- 2012 for locomotive and marine use
For More Information:
Biodiesel/Renewable Diesel
Biodiesel and renewable fuels can be manufactured from new and used vegetable oils and animal fats. Biodiesel is safe, biodegradable, and reduces air pollutants such as PM, CO, HC and air toxics. However, NOx emissions increase with the concentration of biodiesel in the fuel. Some biodiesel produces more NOx than others, and some additives have shown promise in mitigating those increases.
Blends of 20% biodiesel with 80% petroleum diesel (B20) can be used in unmodified diesel engines.
Biodiesel can be used in its pure form (B100), but may require certain engine modifications to avoid maintenance and performance problems. Pure blends of biodiesel may not be suitable for cold climates.
For more information:
- Biodiesel: Technical Highlights (PDF) (3 pp, 90K, EPA-420-F-10-009, February 2010, About PDF)
- List of Registered Biodiesel Fuels
- Biodiesel Emissions Analysis
Emulsified Diesel
Emulsified diesel is a blended mixture of diesel fuel, water, and other additives that lowers combustion temperatures and reduces emissions of PM as well as NOx. The additives also prevent water from contacting the engine.
Emulsified diesel can be used in any new or existing diesel engine, but the addition of water reduces the energy content of the fuel, so some reduction in power and fuel economy can be expected. Over time the water can settle out of the emulsified fuel and may cause performance problems.
Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG)
Natural gas is an inherently cleaner burning fuel that is ubiquitous in the US and can be produced domestically. Compressed natural gas (CNG) consists mainly of methane (CH4) and is drawn from gas wells or in conjunction with crude oil production. Liquefied natural gas (LNG) is compressed natural gas that is cooled to -260F degrees.
When paired with catalysts or filters, CNG and LNG emissions are comparable to diesels outfitted with diesel particulate filters (DPFs). Natural gas replacements may require changes to fueling infrastructure and maintenance facilities. CNG and LNG are currently used to power yard tractors, forklifts and loaders.
Liquefied Petroleum Gas (LPG) or Propane
Liquefied petroleum gas (LPG or propane) is a byproduct of natural gas processing and petroleum refining and is primarily produced domestically. LPG requires a dedicated engine. LPG forklifts and loaders are common applications.