Greenhouse Gas Emission Reductions for Seven On-Farm Dairy Manure-based Anaerobic Digestion Systems - Final Results

摘要

Greenhouse gas (GHG) emission reduction calculations were performed following four different accounting methodologies for seven New York State on-farm dairy manure-based anaerobic digesters. The four methodologies followed were: Climate Action Registry (CAR), EPA Climate Leaders (EPA), Regional Greenhouse Gas Initiative (RGGI), and Chicago Climate Exchange (CCX). The Power Profiler tool was used to assess the GHG implications of the farms' reduced use of traditional fossil fuel-based electricity usage, which was offset with renewable bio-methane derived electricity. Digester performance was analyzed for seven digesters following the Association of State Energy Research and Technology Transfer Institutions protocol, "A Protocol for Quantifying and Reporting the Performance of Anaerobic Digestion Systems for Livestock Manures". One full year's worth of digester performance data, including biogas production, quality, composition and utilization, has been collected and analyzed for these seven AD systems. Results from the monitoring study were used in this paper to quantify CH_4 and carbon dioxide (CO_2) emission reductions on a TCO_2e basis (metric tonnes of CO_2 equivalents), for seven farms. The comparison of GHG emission reductions for these sevenfarms was performed to assess the ability of each digester system to mitigate GHG emissions based on traditional practices. The comparison of these four methodologies was performed to assess the differences in each methodology and the effects of these differing emission reduction calculations on carbon trading revenues for each farm. This paper presents results of GHG reductions based on the following reduction calculation methodologies: CAR, RGGI, CCX and EPA Climate Leaders, as well as avoided emissions from reduced fossil-fuel generated electricity estimated by Power Profiler. The average emission reduction estimate for all seven farms was 2,369 TCO_2e/year, and the average displaced GHG emissions estimated by Power Profiler was 335 TCO_2e/year. These reductions are equivalent to removing over 3,400 passenger cars from the road each year, which equates to approximately one car removed from the road for every two cows worth of manure digested.