TY - JOUR TI - Global change and conservation triage on National Wildlife Refuges AU - Johnson, Fred A. AU - Eaton, Mitchell J. AU - McMahon, Gerard AU - Nilius, Raye AU - Bryant, Michael R. AU - Case, David J. AU - Martin, Julien AU - Wood, Nathan J. AU - Taylor, Laura T2 - ECOLOGY AND SOCIETY AB - Johnson, F. A., M. J. Eaton, G. McMahon, R. Nilius, M. R. Bryant, D. J. Case, J. Martin, N. J. Wood, and L. Taylor. 2015. Global change and conservation triage on National Wildlife Refuges. Ecology and Society 20(4):14. https://doi.org/10.5751/ES-07986-200414 DA - 2015/// PY - 2015/// DO - 10.5751/es-07986-200414 VL - 20 IS - 4 SP - SN - 1708-3087 KW - adaptive management KW - allocation KW - decision analysis KW - ecosystem valuation KW - global change KW - National Wildlife Refuge KW - objectives KW - policy KW - portfolio analysis KW - reserve design KW - stakeholders ER - TY - JOUR TI - A techno-economic assessment of offshore wind coupled to offshore compressed air energy storage AU - Li, B. H. AU - DeCarolis, J. F. T2 - Applied Energy AB - A critical challenge associated with renewable energy is managing its variable and intermittent output. Offshore compressed air energy storage (OCAES) is a carbon-free storage technology that can used to support renewable energy generation in marine environments. This paper provides the first economic characterization of OCAES performance when coupled to an offshore wind farm by employing a mixed integer programming model. The model seeks the minimum levelized cost of electricity by optimizing the grid-tied cable capacity and OCAES component sizes across a range of specified cable capacity factors. OCAES can be used to increase the capacity factor of the grid-tied transmission cable, but the resultant levelized cost of electricity strongly depends on the OCAES cost assumptions. Compared to using a land-based gas turbine as backup, OCAES is significantly more expensive, even when the price of carbon exceeds 1000 $/tC. DA - 2015/// PY - 2015/// DO - 10.1016/j.apenergy.2015.05.111 VL - 155 SP - 315-322 ER - TY - JOUR TI - Characterization of Uncertainty in Estimation of Methane Collection from Select US Landfills AU - Wang, Xiaoming AU - Nagpure, Ajay S. AU - DeCarolis, Joseph F. AU - Barlaz, Morton A. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Methane is a potent greenhouse gas generated from the anaerobic decomposition of waste in landfills. If captured, methane can be beneficially used to generate electricity. To inventory emissions and assist the landfill industry with energy recovery projects, the U.S. EPA developed the Landfill Gas Emissions Model (LandGEM) that includes two key parameters: the first-order decay rate (k) and methane production potential (L0). By using data from 11 U.S. landfills, Monte Carlo simulations were performed to quantify the effect of uncertainty in gas collection efficiency and municipal solid waste fraction on optimal k values and collectable methane. A dual-phase model and associated parameters were also developed to evaluate its performance relative to a single-phase model (SPM) similar to LandGEM. The SPM is shown to give lower error in estimating methane collection, with site-specific best-fit k values. Most of the optimal k values are notably greater than the U.S. EPA's default of 0.04 yr(-1), which implies that the gas generation decreases more rapidly than predicted at the current default. We translated the uncertainty in collectable methane into uncertainty in engine requirements and potential economic losses to demonstrate the practical significance to landfill operators. The results indicate that landfill operators could overpay for engine capacity by $30,000-780,000 based on overestimates of collectable methane. DA - 2015/2/3/ PY - 2015/2/3/ DO - 10.1021/es505268x VL - 49 IS - 3 SP - 1545-1551 SN - 1520-5851 ER - TY - JOUR TI - Analysis of material recovery facilities for use in life-cycle assessment AU - Pressley, Phillip N. AU - Levis, James W. AU - Damgaard, Anders AU - Barlaz, Morton A. AU - DeCarolis, Joseph F. T2 - WASTE MANAGEMENT AB - Insights derived from life-cycle assessment of solid waste management strategies depend critically on assumptions, data, and modeling at the unit process level. Based on new primary data, a process model was developed to estimate the cost and energy use associated with material recovery facilities (MRFs), which are responsible for sorting recyclables into saleable streams and as such represent a key piece of recycling infrastructure. The model includes four modules, each with a different process flow, for separation of single-stream, dual-stream, pre-sorted recyclables, and mixed-waste. Each MRF type has a distinct combination of equipment and default input waste composition. Model results for total amortized costs from each MRF type ranged from $19.8 to $24.9 per Mg (1Mg=1 metric ton) of waste input. Electricity use ranged from 4.7 to 7.8kWh per Mg of waste input. In a single-stream MRF, equipment required for glass separation consumes 28% of total facility electricity consumption, while all other pieces of material recovery equipment consume less than 10% of total electricity. The dual-stream and mixed-waste MRFs have similar electricity consumption to a single-stream MRF. Glass separation contributes a much larger fraction of electricity consumption in a pre-sorted MRF, due to lower overall facility electricity consumption. Parametric analysis revealed that reducing separation efficiency for each piece of equipment by 25% altered total facility electricity consumption by less than 4% in each case. When model results were compared with actual data for an existing single-stream MRF, the model estimated the facility's electricity consumption within 2%. The results from this study can be integrated into LCAs of solid waste management with system boundaries that extend from the curb through final disposal. DA - 2015/1// PY - 2015/1// DO - 10.1016/j.wasman.2014.09.012 VL - 35 SP - 307-317 SN - 0956-053X KW - Recycling KW - Material recovery facility KW - Life-cycle assessment KW - Municipal solid waste ER -