Introduction to Propane
Propane, also known as liquified petroleum gas (LPG), is a three-carbon alkane gas (C3H8). Stored under high pressure in a cylindrical tank, propane converts into a colorless, odorless liquid. As pressure is released, the liquid propane vaporizes and becomes a gas which can then be used for combustion. The smell commonly associated with propane is actually an added odorant, ethyl mercaptan, to help users to detect leaks. Propane has a high octane rating and excellent ignition properties for spark-ignited internal combustion engines. It is non-toxic and therefore presents no threat to soil, surface water, or groundwater.
Propane is produced as a by-product of natural gas processing and crude oil refining. It accounts for about 2% of the energy used in the United States. Uses include home and water heating, cooking and refrigerating food, clothes drying, powering farm and industrial equipment, and drying corn. Rural areas that do not have natural gas service commonly rely on propane. The chemical industry uses propane as a raw material for making plastics and other compounds. Less than 2% of U.S. propane consumption is used for transportation fuel.
Propane as an alternative fuel
Propane is considered an alternative fuel under the Energy Policy Act of 1992. This designation is a reflection if its relatively clean-burning properties, high energy density, and wide spread domestic availability. Because propane is transformed into a gaseous state before it is burned in an internal combustion engine, the engine is able to run more efficiently in low-speed, light-throttle conditions. The introduction of Liquid Propane Injection engines are a new development in propane energy and promise an even higher fuel efficiency than current propane use systems.
Propane in Alaska
Propane is already a common fuel used in rural Alaska, used primarily for cooking. The Alaska Natural Gas Development Authority (ANGDA) is now assessing the feasibility of using propane in river communities across the state for electricity, as well as for space and water heating. They are using Tanana as a demonstration community to determine the feasibility of converting existing appliances, testing small co-generation systems, and converting heavy equipment and vehicles to run on propane.
The Yukon-Kuskokwim Propane Demonstration Project feasibility study is designed to asses greatly expand use of propane in rural Alaska. This pilot project subsidizes propane costs to reflect the cost ANGDA anticipates, assuming a natural gas pipeline is constructed and a propane extracted at the Yukon River crossing. The study includes assessing the challenges associated with transporting propane by existing barge companies and using propane for electricity and space heating. Two 1000-gallon propane tanks have been delivered to Tanana as part of the project; however, there are some concerns with Coast Guard regulations regarding propane transport on navigable waterways. A major factor missing from the cost analysis at this time is the cost of mass produced 1000 gallon tanks, as no supplier for these tanks could be identified.
While the cost of propane including delivery is not a major expense for rural Alaskans in the small volumes currently used, larger quantities do not demonstrate an economic benefit when used for space heating or power generation. Nonetheless, there are some benefits to propane over diesel fuels, primarily in terms of environmental concerns, both the elimination of spills and the reduction in emissions.
ANGDA’s preliminary estimates suggest that communities could save money by using propane instead of other fossil fuels if the natural gas pipeline is built. The Tanana project is designed as an initial test site to get a better sense of conversion costs and economic viability of the fuel.
Links, Resources, and Documents
U.S. Department of Energy: A comprehensive source to propane use and distribution, as well as other alternative and advanced fuels.
Propane: The Wikipedia article on propane.
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