As oil prices continue to rise, the U.S. Department of Energy (DOE) has started looking for alternative fuels which would cost less, have lower emissions, and decrease our dependence on the Middle East’s oil reserves. One option that has become more feasible is the use of liquefied natural gas (LNG) to fuel vehicles. Natural gas is an extremely clean burning resource that has become cost-competitive with other fossil fuels. Natural gas is best stored and transported as a compressed or liquefied gas.
LNG is beneficial because is comparable to diesel or gasoline in energy content per gallon. LNG is a more compact way to store gas that can be used in distribution lines, as compressed natural gas, or in LNG vehicles.
Currently there are only a few large-scale plants in the United States. Large-scale liquefiers cost between $2 billion and $3 billion, and they require hundreds to thousands of acres. Typically these plants require a large amount of natural gas to be fed into the plant. A portion of that gas is used to fuel the process. The overhead costs of such plants can be expensive as they require a significant number of personnel and energy to run the process.
Such plants consist of numerous liquefaction “trains” that allow them to process a substantial amount of LNG per day (upward of 150,000 gallons).
Large-scale liquefaction plant.
The INL Natural Gas Products Team has designed small-scale LNG plants capable of producing a desired output of up to 30,000 gallons of LNG per day. These plants are small enough to fit into a cargo container. And can be built to code for most locations. INL small-scale liquefiers cost between $2 million and $3 million to manufacture. They have a very low overhead. The plants are designed to use little or no LNG in the process and they are equipped with an integrated “stand alone” mode.
The unit built with Pacific Gas and Electric (PG&E) produces around 10,000 gallons of LNG a day and it located on a 1/2-acre lot less than 1 mile from old town Sacramento. INL is currently working with the Southwest Transportation Association (STA) and Harris Ranch in the San Joaquin Valley. The INL group has designed a small-scale LNG liquefier capable of producing around 30,000 gallons of LNG a day. The INL/PG&E liquefier and the San Joaquin Valley liquefier are examples of the INL group’s innovative and creative designs for a liquefaction plant.
INL/PG&E small-scale liquefaction plant in Sacramento.
The INL/PG&E liquefier is small enough to fit into a cargo hold. It is capable of extracting CO 2 and H 2 O during the liquefaction process.
The process is extremely efficient. The power for the liquefaction process comes from the energy created as the gas is expanded from a high pressure to a lower one.
This station comes equipped with a storage tank and a fueling station so that the LNG product can be used, stored or shipped from one location.