Natural gas as a renewable fuel

Amazingly, natural gas can be produced from a variety of sources – including a pile of garbage. Some would say that makes natural gas a renewable fuel.

When organic material decomposes without a lot of oxygen present, nature makes methane. If you can capture and process that methane, you can make natural gas. Biomethane and biogas are the terms used for the energy that is developed from the breakdown of organic material in the absence of oxygen from sources such as sewage, municipal solid waste, and farm waste.

Producing natural gas for vehicles at the Altamont Landfill

Biogas is the mixture of methane and other gases produced from the deomcomposition of organic materials. It is produced naturally in landfills and from the processing of animal waste, sewage, and crop waste.

Biomethane is the fuel that is produced by purifying the biogas.

And unlike fossil fuels, which are considered a finite resource, the natural gas produced from these sources is not.

Turning these sources into fuel is not easy. It is technically challenging and expensive, but there are many efforts underway both here in the United States and around the world to create fuel from these sources.

Environmental benefits

There are also some tremendous environmental benefits.

For example, there are 519 landfills in 44 states that are recovering energy from landfill gas, according to the Environmental Protection Agency’s Landfill Methane Outreach Program. The energy that’s captured is used in a variety of applications –including energy for power plants, manufacturing facilities, homes.

According to the federal agency, landfills are the second largest human-made source of methane, which is 20 times more potent by weight that CO2. These landfill gases were either or vented or are often burned off or flared to reduce the emissions going into the atmosphere. The EPA has reported that all together these projects have captured 82 billion cubic feet of landfill gas.

And this has the added benefit of being a clean energy resource that reduces the country’s reliance on fossil fuels.

How do they do it?

The landfill gas is extracted using a series of wells and a blower/flare system. This system directs the collected gas to a central point where it can be processed and treated, including the potential to produce pipeline–quality gas that may be used directly or processed into an alternative vehicle fuel.

For a complete description, click here to see the EPA’s pictures and graphs on how it’s done.

Powering vehicles

In California, Waste Management’s Altamont Landfill near Livermore is producing natural gas that is being used to power its refuse trucks. It is one of a handful of projects exploring the possibilities of using landfill gas to produce either compressed natural gas as a vehicle fuel for light and medium duty vehicles or liquefied natural gas as a vehicle fuel for heavy duty trucks, such as refuse vehicles.

The Altamont project, which includes the world’s largest landfill natural gas plant, opened in November 2009, following almost 10 years of research. By July 2010, the plant was producing 1.7 million gallons of fuel. When the facility is at full capacity, it will produce 13,000 gallons of liquefied natural gas per day, which will be enough fuel to power 300 heavy-duty refuse trucks serving 20 California communities.

And because these trucks will not be using diesel fuel, the project is expected to reduce greenhouse gas emissions by 30,000 tons a year.

Waste Management and the Lined Group have partnered together to operate this $15. million facility, which collects, purifies and liquefies landfill gas using technology developed by the Gas Technology Institute.

The goal is to develop an efficient and low capital plant that can economically produce fuel on a small scale. The project is both technologically and economically challenging, but it has made significant progress in advancing the technology so that it could be implemented at other locations. Projects such as this are often done in conjunction with government support, since this helps reduce the risks and enables the acceleration of technology and market development. The Livermore project received support from four California agencies.

For another example, see the profile of Prometheus Energy’s work with Bowerman Landfill, which is located just five miles from the Orange County (California) Transit Authority. The two organizations have formed a partnership where the landfill will produce liquefied natural gas that is used to power the county’s transit system.

Learn more about other biomethane projects from these videos