PGE/REWE 2015

Sessions Speakers Exhibitors Products Press Releases Show Specials Floor Plan

Extending Renewable Electricity Generation for Decades at Closed Landfill Sites with Gas below 30% methane (Room G107)

Conventional engines and turbines have problems combusting landfill gas that is below 30-40% methane. At this point, the traditional choice is to decommission the generation equipment and waste the gas through flaring. As the closed landfill gas methane decreases to below 20%, destroying the landfill methane becomes more difficult. This is a real issue, as landfills will continue to emit methane for 50-60 years after closure. But the methane content of these gases are too low to be used by traditional equipment. Attero, one of the largest producers of biogas in the Netherlands, had this problem at its Schinnen landfill. The landfill gas to electricity project, commissioned in 1995, started with three 825 kW engines. After the landfill closed, the gas methane content decreased to where the engines struggled to operate. Attero actively managed the landfill gas collection to optimize the gas quality by separating the bad producing wells from the high quality ones. This extended the operation life of the engines by a few more years. Eventually, the engines had to be decommissioned, as they could not run on such low-quality gases. By 2012, only one reciprocating engine would still run at 50% power for about 3 days per week. The landfill gas was flared for the rest of the week. Attero decided to look for alternatives to reduce its flaring. It decided to replace the struggling reciprocating engine with an Ener-Core 250 kW oxidizer powerstation. The advantages of this oxidizer powerstation were the ability to operate on gas that is as low as 5% methane, so Attero can continue generating power from its closed landfills, for many decades. The powerstation operates with very low NOx exhaust emission of below 1 ppmv. The project was commissioned in 2014 and is operating continuously. Attero and Ener-Core, Inc. (manufacturer of the 250 kW oxidizer powerstation) will present the design of the project, integration details of the project and operations data.