Currently, all aviation propulsion systems depend on fossil-based fuels – sometimes called Jet A or kerosene, derived from petroleum. Alternative fuels from other source stock can be used in a blend of up to 50% with traditional jet fuel to help reduce emissions and dependence on fossil-based fuels. Some alternative fuels include the following sources:
- Natural Gas
The International Air Transport Association (IATA) has two classifications for biofuel: First Generation biofuels are produced from sugars, starches, oils or fats of agricultural products using conventional technologies. These fuels have traditionally been developed on the same land used for food production and/or water. According to IATA, most First Generation biofuels do not meet all specifications for aviation fuel. Second Generation biojet fuels are made from sustainable sources that are not widely used, including forest, industry and agricultural residue (e.g. sawdust, black liquor from the paper industry and corn stover), and municipal waste. Or, those biofuels made out of non-food biomass sources such as algae, switch grass, jatropha, babassu and halophytes.
Bypass ratio refers to how much air goes through a jet engine’s core versus how much air goes around the core. The higher the bypass ratio, the more fuel efficient the engine is. Pratt & Whitney’s GTF engines have a bypass ratio of 12:1, meaning, 12 parts air are pushed by the fan blades around the core for every 1 part flowing through the core. The prior generation engine, the V2500, has a bypass ratio of 4.5:1 to 5.4:1 (based on the model).
Carbon Dioxide (CO2) is a colorless, odorless gas that is exhaled by animals and engines and “inhaled” by plants.
Carbon Dioxide (CO2) is emitted in a variety of human and natural ways. According the U.S. Environmental Protection Agency, human activities have increased CO2 concentrations in the atmosphere.
A change in climate that can be identified through statistical testing and measurement of its properties. It must persist for an extended period, typically decades or longer. Climate change may be due to natural internal processes, external forces, and human-induced activity.
A process that converts coal into electricity, hydrogen or other energy products through gasification. Gasification is a thermo-chemical process used to break down coal into its basic chemical components. The gasifier is typically exposed to steam and controlled amounts of air or oxygen under high temperatures or pressures. Some industry experts predict that coal gasification will be a viable part of clean coal technology plants.
In terms of aircraft engine maintenance, “washing” is literally cleaning the dirt off an engine’s airfoils, which can improve fuel efficiency by approximately 1 percent. Legacy technologies use harsh detergents or abrasives. Pratt & Whitney's EcoPower® engine wash service uses a closed-loop system with pure, atomized water to wash aircraft engines, which avoids potential contaminant runoff.
The Fischer-Tropsch (F-T) process was discovered by Franz Fischer and Hans Tropsch and used to make fuels during World War II. Liquid fuel is produced through a Fischer-Tropsch reaction that converts a mixture of hydrogen and carbon monoxide - derived from coal, methane or biomass - into liquid fuels. According to the U.S. Department of Defense (DOD), F-T fuels reduce the number of different fuels required and their environmental impact because they burn cleaner than other liquid fuels. The U.S. Department of Energy advocates F-T fuels because they have a high energy content, and powering capabilities, comparable to traditional jet fuel. They also do not require technology redesign or component development.
Geared Turbofan technology is a result of more than 20 years of development at Pratt & Whitney.The unique gear system allows the engine’s fan and low-pressure compressor and turbine to operate at their optimal speeds, resulting in greater fuel efficiency, reduced emissions and up to a 75% smaller noise footprint. The fan blades in the front of the engine operate approximately 1/3 the speed of the turbine. Pratt & Whitney has the only operational and proven geared turbofan engine in the world.
Geothermal energy is heat from the Earth. Geothermal resources can come from shallow ground, and hot water and rock found beneath the Earth's surface. Resources can also be found in high temperatures of molten rock (or magma).
Greenhouses gases (GHGs) are generally considered gases that trap heat in the atmosphere. GHGs that enter the atmosphere because of human activity include Carbon Dioxide (CO2), Methane (CH4), Nitrous Oxide (N2O), Fluorinated Gases and ozone depleting substances (e.g. CFCs, HCFCs and halons).
The Leadership in Energy and Environmental Design (LEED®) Green Building rating system was first published in 1999 by the U.S. Green Building Council. It helps professionals across the U.S. improve the quality of the country's buildings and their impact on the environment.
A material that has the potential to adversely impact the health or safety of individuals exposed to it, or has an adverse impact on the environment during the life-cycle of a product containing the material.
Nitrogen oxide (NOx) is the generic term for a group of colorless and odorless highly reactive gases. They contribute to smog formation and are regulated by the U.S. Environmental Protection Agency.
Pratt & Whitney is working with the aerospace industry to develop and approve jet fuels made from sustainable sources, to be used as a blend of up to 50% with traditional jet fuel, with a pathway toward 100% drop-in alternative fuels in the future.
R.E.A.C.H. (Registration, Evaluation and Authorization of Chemicals) is a European Union regulation that requires businesses to show the chemicals it uses are safe (on an annual basis) by providing environmental testing and safety information for all substances manufactured or imported, in quantities of one metric ton or more, in the EU.
Pratt & Whitney's Technology for Advanced Low Oxides of Nitrogen (TALON) low-emissions combustor is designed to reduce nitrogen oxide (NOx) emissions. In partnership with NASA, Pratt & Whitney developed the TALON family of combustors that reduce NOx, unburned hydrocarbons (UHC) and carbon monoxide (CO), which are regulated pollutants that impact local air quality, and in the case of NOx, can also impact climate change.