GTI has released a site-specific engineering design titled “Low-Carbon Renewable Natural Gas (RNG) from Wood Wastes”. GTI led a team of engineers and scientists to produce a blueprint for converting an existing biomass facility into an RNG production site, using the wood waste feedstock and some of the existing infrastructure. A biomass power plant in Stockton, California, was the host site for the engineering design effort.

New RNG production facilities using the commercial technologies outlined in the analysis could reduce criteria pollutants by approximately 99% compared to existing operational biomass power plants and produce a very low carbon fuel in the base case and below zero in the case including carbon sequestration technologies.

The RNG product with very low carbon intensity could be used for carbon emission reductions in the transportation, industrial, commercial, and residential energy sectors. According to the analysis, California has the potential to produce tens of billions of cubic feet of RNG per year from the wastes that are now being used for biomass-based electricity.

The gasification technology provides an additional option for addressing the woody biomass waste in California while providing a clean renewable energy source that can further help the state meet its greenhouse gas objectives.

The Gasification-powered RNG Process. Source: GTI.

The study quantifies the large greenhouse gas (GHG) benefits achieved by RNG produced from wood wastes from a product standpoint, as well as from the reduced potential for forest fires and open burning of agricultural wastes in the San Joaquin Valley and other areas in California by cleanly processing forest, urban and agricultural wastes.

The engineering design was performed by GTI, Black & Veatch, Andritz, and Haldor Topsoe. These companies are world experts in gasification, gas clean-up, and conversion technologies. The LCA was performed by Argonne National Laboratory, the developer of the GREET model.

GTI has a history of research, analysis, and expertise in the technological issues involved in the expanded production and use of RNG. Recent projects include reports for policymakers and the public about the potential of RNG, the development of analytical equipment for determining levels of specific contaminants from various sources of RNG, and technology for the use of RNG as a transportation fuel.

The engineering design study, funded by California Air Resources Board (ARB), PG&E, SoCalGas, Northwest Natural and SMUD, was conducted to better understand the value, benefits, and cost of utilizing wood wastes to reduce greenhouse gas (GHG) emissions.

Open burning of agricultural wastes and devastating forest fires in California severely degrade air quality in the state. Reducing black carbon—a potent climate change pollutant—and other conventional air pollutants that can lead to breathing disorders is high on our priority list.

We can produce RNG with a carbon footprint that is near zero or even negative, depending on the equipment configuration of the wood waste-to-RNG production facility. In the base configuration in our study, one plant could displace approximately 170,000 tons of CO2 vehicle emissions each year, which is roughly equal to offsetting the emissions from 400 million vehicle miles

—Vann Bush, GTI Vice President, Technology Development and Commercialization