Tuesday, December 13, 2011

Economic feasibility of hydrogen enrichment for reducing NOx emissions from landfill gas power generation alternatives: A comparison of the levelized cost of electricity with present strategies

Abstract: Based on recent research showing that hydrogen enrichment can lower NOx emissions from landfill gas combustion below future NOx emission control standards imposed by both federal and California state regulations, an investigation was performed to compare the levelized cost of electricity of this technology with other options. In this cost study, a lean-burn reciprocating engine with no after-treatment was the baseline case to compare six other landfill gas-to-energy projects. These cases include a lean burn engine with selective catalytic reduction after treatment, a lean-burn microturbine, and four variations on an ultra-lean-burn engine utilizing hydrogen enrichment with each case using a different method of hydrogen production. Only hydrogen enrichment with an in-stream autothermal fuel reformer was shown to be potentially cost-competitive with current strategies for reaching the NOx reduction target in IC engines.

► Levelized cost of electricity for hydrogen enriched combustion was compared.
► Various ultra-lean-burn engines and microturbines with hydrogen were analyzed.
► Combustion with an autothermal fuel reformer was potentially cost-competitive.
According to a full free version of the paper currently available at:

In this study, a landfill gas-to-energy pathway is considered cost competitive if the levelized cost of electricity is within 15 percent of the lean burn with SCR pathway, the most commonly used pathway.... The levelized cost of electricity for the lean burn with SCR pathway is $109/MWhe, which sets the maximum LCOE that is cost competitive at $126/MWhe.
Total capital costs ... are dominated by generator equipment and any supplementary equipment needed for individual fuel pathways. The miscellaneous costs are driven by the contingency cost (15% of total equipment costs), inspection, shipping, and project management. Both the electrolyzer and steam reformer contributed a large capital cost, almost matching the cost of the generator making these cases less cost-competitive options.

Scenarios requiring the purchase of fuel or electricity where shown to yield a levelized cost of electricity between 45% and 100% higher than those not requiring fuel purchase. Hydrogen enrichment via autothermal reformation was shown to have a levelized cost of electricity 10% and 14% higher than the commercially available microturbine and lean burn SCR options respectively, making it potentially cost-competitive with both LFGTE projects.

... If the hydrogen production equipment cost only half as much (12% decrease in overall capital cost), the LCOE would decrease by about $10/MWh, which is not enough for this scenario to become cost-competitive by itself. However, if a low-cost source of natural gas were available, the 12% decrease in overall capital cost combined with a cheaper source of natural gas, could make this option cost-competitive.
by Kurt Kornbluth, Jason Greenwood, Eddie Jordan, Zach McCaffrey and Paul A. Erickson; all of the University of California, Davis, Department of Mechanical and Aerospace Engineering, One Shields Avenue, Davis, California 95616, United States; Tel.: +530 752 5360; fax: +530 752 4158
Energy Policy via Elsevier Science Direct www.ScienceDirect.com
In Press, Corrected Proof; Available online 7 December 2011
Keywords: Hydrogen combustion; Landfill gas; Levelized cost of electricity

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