The Future of Biogas
- Jan 7, 2014 8:30 pm GMT
- 6300 views
By Rodger Schwecke
It is time to consider the future of biogas.
Biogas is a mixture of methane and carbon dioxide produced when organic material decomposes. This renewable energy resource can be used to produce on-site heat and electricity, conditioned for injection into the natural gas delivery infrastructure or consumed as a transport fuel.
Since 2006, Southern California Gas has actively implemented a research, development and demonstration program and also fostered commercial programs to increase the use of renewable natural gas. Early work focused on studying feedstocks and setting guidelines for purifying biogas to pipeline quality. Looking ahead, SoCalGas is working to develop algae as an energy crop and is exploring the use of solar thermochemical processes to create renewable natural gas. We have a full-scale commercial demonstration of biogas cleanup technology already in operation at a wastewater treatment facility in Escondido, Calif.
SoCalGas is also active in aiding regulatory and policy efforts to advance biogas. We are currently working with other stakeholders in a California Public Utilities Commission proceeding to develop statewide standards and protocols for the cleanup of biogas so it can be injected into a common carrier pipeline. To help stimulate the development of a robust renewable natural gas, we have a proposal before the commission to provide gas cleanup services to biogas producers.
Today, renewable natural gas can be produced from larger biogas sources such as wastewater facilities and landfills at prices competitive with other renewable resources. Advances in gas cleanup and conversion technology such as digesters and gasifiers will expand the amount of feedstock that can be economically converted.
Biogas is considered to be a renewable resource because its production-and-use cycle is continuous, and it generates no net carbon dioxide. Organic material grows, is converted and used and then regrows in a continually repeating cycle. From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released when the material is ultimately converted to energy.
When carbon dioxide and other minor constituents are removed, the product is a purified pipeline-quality natural gas that is almost 100 percent methane. This biomethane is interchangeable with any other natural gas, but it is a zero-carbon resource. Coupling this zero-carbon profile with the ultra-low “conventional” emissions of natural gas makes renewable natural gas a nearly perfect fuel. It is storable, it boasts a high energy density that is almost emission-free, and it is easily transported over existing infrastructure to serve any natural gas application.
Biogas is plentiful and is available from sources such as landfills, wastewater treatment facilities, and animal and agricultural waste. If fully utilized, the yield from existing organic waste streams could satisfy about 20 percent of current natural gas use. Biogas feedstock may also soon be farmed economically. Work is already underway to develop low-cost dedicated energy crops such as algae and other plant species that can be grown on marginal land to serve as a source of biogas production. Future energy crops could make the potential availability virtually unlimited.
The mix of future uses for renewable natural gas will depend upon how markets for renewable resources develop. Because of the high price of oil and limited options for renewable transportation fuel, it’s likely that transportation uses will be key demand drivers. Renewable natural gas is a low-cost option for zero-carbon transportation
fuel, and the sector will potentially consume the majority of renewable natural gas produced.
Ultimately, technology and market advances will help determine the future of renewable natural gas, but its success also depends on a level playing field in energy policy. For the United States to fully realize the economic and environmental potential of renewable gas, it is imperative that public policymakers recognize the benefits of renewable natural gas.
Rodger R. Schwecke is vice president of customer solutions for Southern California Gas.