Methane Capture and Use: Current Practices vs. Future Possibilities

Methane Capture and Use: Current Practices Today’s primary use of capture Methane from a landfill or digester is Electrical Power Generation by internal combustion engine (turbine or reciprocating) typical installation consist of the following major components: Gas compression equipment for gas field extraction and compression to 2-3 psig Internal Combustion Engine is usually a reciprocating engine that manufactured for numerous other commercial applications with some enhancements to run on landfill or digester gas. Engine is coupled to synchronous generator. Electrical power controlled and connected to the grid via common electrical switchgear with some additional controls for load control. Electrical substation consisting of station transformer (stepping up to utility distribution voltage and well as utility tie breaker (at distribution voltage.

Methane Capture and Use: Current Practices Why is electrical power generation the preferred choice? Financially feasible in most areas of the country. Proven technology that is relatively simple with a system that is comprised of common everyday components. Operation fits in well with day to day operation of a landfill. Low risk compared to alternatives Other common current practices: Direct fired heating examples: leachate evaporation, asphalt plant, space heating Steam production for various commercial and industrial processes.

Methane Capture and Use: Current Practices Current state of landfill methane to energy development Market is mature; almost all large landfills have projects or are committed to projects. Most opportunities today involve landfills with 1000 SCFM or less of gas. In cases where there is REC market and or high electrical energy cost smaller power plants once thought to be unfeasible are now feasible. Changing landscape of the energy market opens new possibilities for methane use.

Methane Capture and Use: Future Possibilities Conversion of LFG to pipe line quality gas Different technologies used: membrane separation process pressure swing adsorption absorption process using a liquid solvent Benefits Delivery of renewable energy to anyone within the natural gas transmission and distribution network. Eliminates some emissions issues associated with conventional combustion and power generations. Extraction and isolation H2S is possible with pressure swing adsorption. Extraction of CO2 for commercial sale

Methane Capture and Use: Future Possibilities Conversion of LFG to pipe line quality gas Challenges: High capital cost for equipment Financial Feasibility is limited to large scale projects Very limited number current operating applications; technology still developing Location has to be in close proximity to natural gas pipeline Uncertainity natural gas market High parasitic for conversion and compression CO2 is only suitable for industrial application not food market due impurities and stigma associated with LFG

Methane Capture and Use: Future Possibilities Conversion of LFG to CNG for use in vehicular applications Technologies similar to LFG to pipeline quality with additional compression equipment and storage Benefits More commercial vehicles available with CNG option A small landfill with 250 SCFM of 50% could displace over a 1000 gallons of # 2 diesel fuel. Cleaner fuel for commercial vehicles. Extraction and isolation H2S is possible with pressure swing adsorption. Extraction of CO2 for commercial sale

Methane Capture and Use: Future Possibilities Conversion of LFG to CNG for use in vehicular applications Challenges: High capital cost for equipment Financial Feasibility is limited to large scale projects No current commercial operating applications; technology still very early in developing Storage Vehicles available. Regulatory issues exist in many states High parasitic for conversion and compression CO2 is only suitable for industrial application not food market due impurities and stigma associated with LFG

Methane Capture and Use: Future Possibilities Combine Heat and Power Technologies are similar to straight power generation with heat recovery for heating and cooling. Benefits With net metering small CHP projects 500 kW or less make very good financial sense. Inexpensive energy source for electricity, heating and cooling for industrial or commercial real estate development in close proximity to a landfill. Total thermal efficiency approaching 85% are possible. Small scale possibilities Challenges Net metering Electrical interconnect. Island operation Location must have loads (electrical and heat) in close proximity of landfill.

Methane Capture and Use: Future Possibilities Other Possibilities Conversion to methanol or ethanol Fuel Cells Hydrogen Production