The Altamont Landfill and Resource Recovery Facility is home to the world’s largest landfill gas to liquefied natural gas plant. Here, Karen Stern of Waste Management Inc. gives us an insight into the past, present and future of this operation...
by Karen Stern
The Altamont Landfill and Resource Recovery Facility, located near the city of Livermore in northern California, is at the forefront of green energy production from landfill gas. In November 2009, the landfill’s owner, Waste Management Inc., commissioned the world’s largest landfill gas (LFG) to liquefied natural gas (LNG) plant. Producing an estimated 13,000 gallons (59000 litres) of LNG a day, the plant provides enough fuel to power 300 of Waste Management’s nearly 500 LNG vehicles in California. The benefits to Waste Management, the communities it serves and the state of California are significant.
Harnessing the energy of LNG to power its growing fleet of biofuel vehicles reduces Waste Management’s dependence on foreign fossil fuel and introduces a domestic green energy source to the fuel market. An estimated four million gallons (18 million litres) of Altamont biofuel is produced annually, reducing CO2 emissions by an estimated 30,000 tons (27,000 tonnes) per year. Altamont biofuel has the lowest carbon density of any fuel available today – about 85% lower than either gasoline or diesel according to the California Air Resources Board. The carbon footprint of a solid waste collection vehicle running on Altamont LNG is even less than that of a plug-in electric vehicle. It is the ultimate closed-loop fuel; gas from waste is fueling MSW collection vehicles.
LNG plant background
In April 2008, Waste Management – North America’s largest waste management company, and Linde North America – part of The Linde Group, a leading global gases and engineering company – announced a joint venture to build an LNG facility at Altamont. The $15.5 million project received grant assistance from the California Integrated Waste Management Board, the California Air Resources Board, the California Energy Commission and the South Coast Air Quality Management District.
Conversion process
Through an elaborate network of wells and a vacuum extraction system, landfill gas with about 50% methane is fed into a gas purification system. This multi-step process, including compression, chilling, absorption and membranes, removes impurities from the gas stream. These include sulphur, carbon dioxide, nitrogen and alcohols. The purified stream is then fed into a natural gas liquefier where the gas stream is cooled to below the natural gas boiling point of -260°F (-167°C) to produce liquefied natural gas (LNG).
The cooling process occurs as a mixture of refrigerants flows through one pass of an aluminum heat exchanger and cools the natural gas into a liquid, which then flows through a different pass in the heat exchanger. As the gas is cooled the refrigerant mixture is warmed. The refrigerants are cooled down again, essentially by compressing and expanding them, and are recycled through the heat exchanger. The LNG is piped to a storage tank that could be compared to a giant thermos bottle to keep it at liquid temperatures. Currently a tanker transfers the LNG to Waste Management fueling stations in eight California communities.
The plant consumes approximately 2150 standard cubic feet per minute (scfm) throughout a 24-hour period to produce 13,000 gallons of LNG a day. Based on the volume of existing organic waste in place since 1980, the Altamont is expected to produce on average more than 10,000 gallons a day of ultra low-carbon LNG for the next 25 years.
The US Department of Energy Clean Cities Coalition – East Bay Chapter, awarded its East Bay Clean Cities 2009 Clean Air Champion Award to Waste Management for its ‘commitment to petroleum fuel displacement as evidenced most recently by the construction of the LNG facility’.
Greenhouse gas emissions
California is the vanguard of greenhouse gas emissions controls in the USA. Its Global Warming Solution Act of 2006 requires the development of regulations and market mechanisms to ultimately reduce greenhouse gas emissions by 25% by 2020.
The Altamont Landfill not only ensures the capture of landfill gas, it is repurposing it to a green energy. Waste Management employs the most sophisticated Tunable Diode Laser (TDL) technology to measure the landfill’s capture rate of methane gas. The Altamont’s capture rate is in excess of 93% – among the highest in the industry. The industry standard is generally recognized as a 75% capture rate for landfill methane gas.
Any landfill gas not consumed by the LNG plant is used to power two gas turbines and two Duetz internal combustion engines. Together, the plants generate enough energy to power nearly 8000 homes. The Altamont has been home to a landfill gas to energy plant since 1989. Waste Management operates 115 LFG to energy plants and is in the process of building more plants within its network of 277 landfills in the United States.
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The US Environmental Protection Agency Landfill Methane Outreach Program awarded the Altamont Landfill a 2009 Project of the Year Award for its creative reuse of landfill gas for renewable energy in January 2010.
The future for landfill LNG
Waste Management along with its partner Linde North America is already exploring landfill sites for future LNG plants. It expects to break ground in southern California within the next two years. With the successful completion of the prototype plant at the Altamont, Waste Management has made an important step toward fuel independence, reducing the emissions of its fleet and further harnessing the power of landfill gas.
While recognizing the trend towards banning organic materials in landfills, Waste Management is mining the waste that is already in place to provide a green fuel alternative for the foreseeable future.
Karen Stern is a communications specialist for Waste Management Inc.
e-mail: kstern2@wm.com
