Clean energy from a landfill? No, it’s not a science experiment. With biogas, it’s reality.
Biogas is an energy-rich gas produced when organic matter decomposes. The raw materials that produce biogas include municipal waste, agricultural waste, manure, plant material, sewage, compost and food waste. The gas primarily forms in agricultural settings, landfills and sewage systems.
Biogas is typically composed of 40 to 60% methane, the same compound found in natural gas, with carbon dioxide making up the remainder of the mix. It can be burned directly as a fuel or treated to remove the CO2 and other gases for use just like natural gas.
The biogas that forms in farms, landfills and other waste treatment facilities must be gathered and transported before it builds up to unsafe levels. Polyethylene pipe, like HDPE, is an excellent material for this task. HDPE is strong, flexible, leak-proof and won’t corrode or rust in corrosive environments like landfills and farms.
Economics of biogas production
Biogas and its main component methane represent an untapped resource that is present in many common locations such as farms, ranches, municipal wastewater plants and landfills. But unlike other renewable energy sources, biogas can be brought to market at a much lower cost than other renewables such as geothermal (where cost include pipe infrastructure, heat exchangers and drilling), solar (manufacturing cost of solar panels, installation) and wind farms (extreme manufacturing costs, transport and hook up to the power grid from remote locations), especially when the gas collected is used on site, such as to generate electricity in factories and ranches.
Landfills
When landfill material starts to decay, it emits methane. An array of pipes at the surface of the landfill collects the landfill gas and transports it to a treatment facility where carbon dioxide, water vapor and hydrogen sulfide are removed. The clean gas can then be used to generate electricity or sold as a substitute for natural gas.
According to the U.S. Energy Information Administration (EIA), “In the United States, regulations under the Clean Air Act require municipal solid waste landfills of a certain size to install and operate a landfill gas collection and control system.”
The EIA estimates that in 2019 about 257 billion cubic feet of landfill gas was collected at 336 U.S. landfills and burned to generate about 10.5 billion kilowatt hours of electricity, or about 0.3% of total U.S. utility-scale electricity generation in 2019.
Wastewater treatment
Although much less popular than landfills, many municipalities are exploiting wastewater treatment plants for further biogas extraction. In fact, the biogas produced in the anaerobic decomposition process can be used to heat the digesters as part of the process for further efficiency. The remaining gas can be marketed. Other possible sources include sewage treatment plants and industrial facilities. The EIA estimates that in 2019, 65 of these types of waste treatment facilities in the United States produced a total of about 1 billion kilowatthours of electricity.
Ranches and farms
Although currently the least-used source of the biogas feedstock discussed here, farms and ranches have the greatest potential for producing biogas. Similar to the wastewater treatment process, anaerobic digesters are used to produce biogas from manure and used bedding material such as hay and straw. Biogas produced from this process can result in a self-sufficient, closed-loop system where the product is used to heat water and buildings and used as fuel for electricity generation. EIA estimates that in 2019, 25 large dairies and livestock operations in the United States produced a total of about 224 million kWh (or 0.2 billion kWh) of electricity from biogas.
United Poly Systems Earth-Line™ Suite
United Poly System’s Earth-Line™ suite represents the company’s commitment to sustainable material and a sustainable future and is ideal for many renewables-related pipeline applications. Products in the Earth-Line suite include Thermal-Line for geothermal applications, Wind-Line for wind farm infrastructure and Bio-Line™ for methane capture and transmission.
In corrosive landfill environments, wastewater treatment facilities and on farms and ranches, Bio-Line is ideal for the capture and transmission of biogas in both the gas recovery system and leachate treatment system.