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GNA - Promise + Challenges of RNG as a Vehicle Fuel
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GNA - Promise + Challenges of RNG as a Vehicle Fuel


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Great overview of RNG looking at entire U.S. and resources and opportunities.

Great overview of RNG looking at entire U.S. and resources and opportunities.

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  • 1. US DOE Clean Cities Waste-to-Wheels: Building for Success Erik Neandross Gladstein Neandross and Associates Promise and Challenge of Renewable Natural Gas as a Vehicle Fuel Clean Cities / 1 Gladstein Neandross and Associates December 1, 2010 Natural Gas as a Vehicle Fuel
  • 2. Biogas: Medium Btu, Methane-Rich Gas Generally Produced by Anaerobic Digestion Biomethane: Pipeline quality natural gas produced by purifying biogas  LandfillsLandfills  Animal waste  Wastewater  Food waste  Industrial waste sources Clean Cities / 2
  • 3. Biogas Produced in Landfills = Landfill Gas (LFG) • US EPA Landfill Methane Outreach Program (LMOP) tracks landfill gas to energy (LFGE) • ~1754 “active” landfills in US: ~1040 candidate LFGE sites• ~1754 active landfills in US: ~1040 candidate LFGE sites • Operational LFGE sites are well dispersed geographically • Rule of thumb: one ton landfilled MSW generate 200 SCF LFG per year • Recovered LFG is typically ~50% methane (500-600 BTU/SCF) G t t t it ti l dfill• Greatest opportunity: active landfills close to markets with > 2 million tons in place in place • Majority projects in US produce electricity (72%) • A handful of transportation projects are operational or under construction Clean Cities / 3 Operating LFGE Projects (Oct 2010)
  • 4. Biogas Produced in Wastewater Treatment (WWT) Plants = Digester Gas • USEPA/USDOE Combined Heat & Power (CHP) partnership tracks WWT projects th t di t t d l t i it it h tithat use digester gas to produce electricity or onsite heating • 16,000 wastewater treatment (WWT) plants in US • Like landfills, WWT sites tend to be near population centers Rules of thumb: 100 gal of wastewater generate 1 SCF of digester gas per day;• Rules of thumb: 100 gal of wastewater generate 1 SCF of digester gas per day; 100 gal of wastewater generated per person/day • Recovered WWTP digester gas is typically 60+% methane (550-600 BTU/SCF) • 544 WWTPs > 5 million gallons/day have digesters • 76 of those use digester gas for onsite and/or offsite energy needs • WWTP digesters can co-digest wastes from other sources: e.g., food waste, industrial waste, etc. • One project uses recovered gas for transportation (Flint) Clean Cities / 4
  • 5. Biogas Produced from Animal Waste = Digester Gas • USEPA/USDA/USDOE AgSTAR program tracks energy projects at commercial livestock farms • 7000+ large-scale dairy, poultry, beef and swine farms in US • Many states have potential sites (dairy in Midwest, Northeast and West; swine in South and Northeast, poultry in South and Midwest) • Rule of Thumb: 1 lb of manure generate 1 SCF of digester gas per dayg g p y • Digester gas is typically 55-65% methane (600 BTU/SCF) • As of Nov. 2010, AgSTAR estimates 160 it h di t i l160 sites have digesters in place • Most use recovered gas to generate electricity; several inject gas to pipeline • One project currently uses recoveredOne project currently uses recovered gas for transportation (Hillarides); another is under development with Clean Cities support Operating Anaerobic Digester Projects (Nov 2010) Clean Cities / 5
  • 6. From “Waste” to Wheels, Biogas Must Be Upgraded to Renewable Natural Gas NATURAL GAS PIPELINE PipelineFOOD WASTE Adapted from K. Sorchek, Xebec,Inc. Biogas USA, Oct. 2010. R bl N t l G (RNG) Bi th Clean Cities / 6 Renewable Natural Gas (RNG) = Biomethane
  • 7. Upgrading Biogas to RNG Adds Complexity and Cost Biogas Requires More Purification than Natural Gas from Most Fossil Sources Parameter Unit EU LFG EU AD- Biogas NA NG NNA NG Pipeline NG in US Source (Persson 2006) (Segeler 1965)  All gas requires purification  Biogas purification reduces H2S, oxygen, Source (Persson 2006) (Segeler 1965) LHV: avg. range Btu/ft3 406 584 1081 835–1336 1145 627–1717 1049 945–1121 CH4: avg. range vol % 45 36–65 63 53–70 51.5 84.7–98.8 77.0 22.8–98.0 89.4 72.8–95.2 reduces H2S, oxygen, CO2, N2 and various contaminants  Biogas purification on smaller scale (thus CO2: avg. range vol % 40 15–50 47 30–47 0.55 0–6.0 4.1 0–29.0 0.7 0–2.0 N2: avg. range vol % 15 5–40 0.2 – 4.03 0–29.4 1.7 0–12.1 2.9 0–17.1 O : avg 1 0 0 06 0 1 0 0 smaller scale (thus more costly) than fossil NG  Combustion engines ( hi l ) d ’ O2: avg. range vol % 1 0–5 0 – 0.06 0–0.4 0.1 0–1.4 0.0 0–0.4 H2S: avg. range ppmv <100 0–100 <1000 0-10000 100 0–3100 400 0–5200 – NH3 ppm 5 <100 – – – (vehicles, gensets) don’t need pipeline grade NG, but do need >90% CH4 & siloxane removal Clean Cities / 7
  • 8. Lack of Vehicles and Infrastructure Have Constrained Market Penetration Potential markets for RNG – Like fossil natural gas, nearby fleets seeking price stability (long-term fixed price contracts) • Refuse trucks (garbage, recycling ande use uc s (ga bage, ecyc g a d transfer trucks) • Milk trucks • Other local users (taxi, municipal )vehicles, etc.) – LNG production plant for more regional fleet use G tiliti di t t t ( i– Gas utilities, distant customers (via pipeline injection) RNG projects often can produce more Clean Cities / 8 p j p fuel than available fleets can consume
  • 9. Yet as a Vehicle Fuel, RNG Has Significant Benefits RNG Has Significant Carbon Benefits Beyond Conventional NG  Depends on reference case (flaring versus venting)  Flaring is good, reducing impact of carbon by factor of 8  Energy recovery is better (renewable energy qualifies for state Renewable Portfolio Standards) Clean Cities / 9 Renewable Portfolio Standards)  RNG is better still, reducing greenhouse gases by 75-90%, or more.
  • 10. Biomethane Potential  1998 DOE Study: “Biogas For Transportation Use: A 1998 Perspective,”  In the U.S., feasible to capture and use about 1.25 quadrillion BtuIn the U.S., feasible to capture and use about 1.25 quadrillion Btu from landfills, animal waste and sewage alone  This is equivalent to 6 percent of all natural gas used in the U.S.  If all used in transportation it would displace 10 billion If all used in transportation, it would displace 10 billion gallons of gasoline per year.  Potential for cellulosic biomethane is almost unlimited E ( i ll S d ) i l di h Europe (especially Sweden) is leading the way:  Sweden’s goal: to displace all natural gas use with biomethane and all diesel with renewable fuels, including biomethane  European studies conclude that cellulosic biomethane production is far more energy efficient and less costly than any other cellulosic energy - today Clean Cities / 10