At the request of MPCA senior managers, technical staff reviewed literature to compare WTE plants and on five criteria:

• per ton • Effect on rates • Costs at existing facilities • Greenhouse-gas emissions • Air other than GHG emissions

This matrix summarizes the finding of MPCA staff:

Landfill with recovery of gas for Mass Burn Waste to Energy Notes and Comments energy (LFGE) (WTE)

Key • Based on existing U.S. large MSW • Based on existing U.S. large mass burn assumptions landfills with LFGE, no thermal energy WTE plants behind models sales • 18% efficiency since is hardwired into and consensus • LFGE is internal models available data • WARM assumes dry tomb • Ferrous recovery from ash, but not front-end separation 0.2 to 1.05 MMBTU/ton 8.9 to 9.7 MMBTU/ton • Total electricity production Energy would be less than 2%, if production in • Reason WTE plants have so much hypothetical 1.5 million millions of BTU • Uncertainties: Need model that can be more energy available per ton of MSW tons/year extra were per MSW ton adjusted for higher or lower LFG (almost an order of magnitude) is redirected from LF to WTE capture efficiency due to ability to use both fossil and • Under MN RES law all LF and biogenic content WTE electricity is currently • Uncertainties: Need model that can be classified as renewable adjusted for higher or lower LFG though 45% of WTE is from capture efficiency fossil-derived

w-sw8-02a • Assuming that the approximate 1.5 million tons of MSW that is landfilled annually is combusted in WTE, this would account for approximately 1.6% of Minnesota’s total electric generation

GHG avoided per MSW ton, at 75% GHG avoided per MSW ton, for WTE • Two runs, one based on Greenhouse efficient with LFGE: 0.7 MTC02E selling electricity only: 0.8 MTC02E (100 yr Peter C’s calculation using gases per MSW (100 year calculation) or 2.8 MTCO2E method) or 3.2 MTCO2E (WARM tool) “100 year carbon” (detailed ton, life cycle, (WARM tool) as Option 1 in his 12/14/09 from generator Sensitive to: rate of avoided grid-based memo) and another on using to disposal Uncertainties: (1) rate of LFG production emissions from on-site electricity the WARM model, version 10 point in situ in the landfill (2) LFG capture production, actual thermal efficiency • Small difference in GHG efficiency (3) rate of avoided grid-based compared to assumptions in WARM, emissions avoided per MSW emissions from on-site electricity percentage of fossil vs biogenic waste in ton, compared to landfill production (4) landfill oxidation rate. waste burned without any gas recovery; LFGE has slight edge if 100 yr LFG capture efficiency is not known method is used, WTE has because operating landfills take no slight edge if WARM is used continuous measurements of methane and would have larger emissions from the uncovered portions, advantage when plants have openings through cover for wellheads, and higher efficiency fissures. Models of • But difference in GHG after closure are also based on emissions would be less than unvalidated assumptions, e.g., assume no 1/1000th of annual MN GHG moisture will enter a dry tomb landfill and emissions, for 1.5 million restart after 30-yr tons MSW switched from postclosure period has finished. one method to the other • It is important to reduce uncertainties around LFG capture efficiency, the proper timeline to use, and carbon sequestration.

w-sw8-02a • Based on Municipal Solid Parameter Units Landfill Parameter Units Waste to Waste Decision Support Tool Life cycle air Gas to Energy (MSW DST); the estimated emissions per Energy Energy MMBtu/Ton -8.9 emissions are based on Life MSW ton, Energy MMBtu/Ton -0.2 Consumption Cycle Environmental Aspects assuming that Consumption Total lb./ton -0.94 of Total lb./ton -0.04 Particulate the electricity Management Alternatives for Particulate Nitrogen lb./ton -1 generated the Minnesota Pollution Nitrogen lb./ton 1 Oxides offsets the Oxides Sulfur Oxides lb./ton -5 Control Agency, (RTI Minnesota mix Sulfur Oxides lb./ton -1 Carbon lb./ton 0 International 6/30/08. of electric Carbon lb./ton 1 Monoxide • The study does not assess the generation. Monoxide Hydrocarbons lb./ton -0.5 spatial or temporal variation Hydrocarbons lb./ton 0.06 (non CH4) of local concentrations of (non CH4) Lead (Air) lb./ton 0 pollutants emitted, the Lead (Air) lb./ton 0 Ammonia (Air) lb./ton 0 human health or Ammonia (Air) lb./ton 0 Methane (CH4) lb./ton -2 environmental impacts from Methane (CH4) lb./ton 15 Hydrochloric lb./ton 0.34 exposure to the emitted Hydrochloric lb./ton 0.01 Acid pollutants. A more holistic life Acid cycle assessment could Criteria and toxic air pollutant data from include a more complete list Criteria and toxic air pollutant data quality waste to energy facilities are very high of air (GHG, criteria and toxic) from landfills are generally low with very quality, the result of more than ten years and pollutants, low quality data available for important of continuous (for O2, CO, SO2, and NOx) identification of impacts and pollutants such dioxins/furans and and frequent (for particulate, fine weighting of those impacts. mercury. Data are generally from a small particulate, hydrogen chloride, number of facilities monitored for short dioxins/furans, lead, cadmium and periods of time. At this time the EPA is mercury) monitoring. developing the procedures for monitoring landfill fugitive air emissions. There are no accepted methods to continuously monitor these emissions.

SCORE: Minnesota “centroid” counties SCORE: Minnesota “centroid” counties While WTE has an edge here, it Effect of this relying entirely on landfills have a 34% relying on some degree of WTE have a can be difficult to compare disposal average recycling rate for 2008 47% average recycling rate for 2008, or recycling rates across states and

w-sw8-02a method on 13% higher than centroid counties that nations. California’s rate tends to local source- use no WTE at all. Statewide the be artificially high compared to separated advantage to WTE is narrower, probably 4- Minnesota because non-MSW recycling rates 6%. wastes are counted there.

U.S.: Consultants hired by the WTE industry report average 4% higher recycling rates in the 94 U.S. urban areas with WTE, compared to the national average.

EU: Eurostat figures for 2007 MSW recycling rates in the : The average MSW recycling rate at the 8 high- WTE countries was 47% and the MSW recycling rate for the 19 low-WTE countries was 21%. (“low WTE” means nations that directed less than 20% of their MSW to WTE, 20% being the average WTE rate in the EU for 2007) Price needed $30-40/ton, including financial assurance $40-60/ton if bonds are paid off; costs can Ultimate cost of burying per MSW ton set-aside. Lower price is for large exceed $100 per ton for small WTE paying biologically or chemically reactive at gate to commercial LFs, higher price for small debt service. waste is unknown at this time. break even, if publicly operated LFs. run as merchant facility without subsidies

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