Technology assessment of Animal Manure to Power (MtoP) and a potential wind-biogas synergy

1. Technology assessment of Animal Manure to Power (MtoP)and a potential wind-biogas synergy Kyle Meisterling Carnegie Mellon University kmeister@cmu.edu June, 2005 Carnegie Mellon University, Electricity Industry Center

2. Anaerobic Digestion 100 kW electricity Heat 700 Cows Biogas Digester Heating Manure: ~14,000 gal/day Manure Storage Digester: 35° C, 20-day HRT Carnegie Mellon University, Electricity Industry Center

3. Animal production Dairy freestall barn Manure storage Meisterling, 2003 http://www.epa.gov/agriculture/ag101/pork.html Carnegie Mellon University, Electricity Industry Center

4. The task • How much energy from manure? • How much does it cost? • Will renewable energy policies drive MtoP adoption? • Investigate wind + MtoP synergy Carnegie Mellon University, Electricity Industry Center

5. Manure to power potential Carnegie Mellon University, Electricity Industry Center

6. Not all manure is recoverable Carnegie Mellon University, Electricity Industry Center

7. Anaerobic Digestion (AD):Capital Cost Dots = U.S. digesters; circles with triangles = German digesters (Kottner, 2004). Cost in 2004 dollars. Compiled by author Carnegie Mellon University, Electricity Industry Center

8. solids accumulation in digester may reduce energy output CF = 0.9 DR = 10% AD: Cost of electricity Carnegie Mellon University, Electricity Industry Center

9. Will renewable obligations (RPS) drive MtoP installation?... Power potential from manure: Carnegie Mellon University, Electricity Industry Center

10. (Note log plot) …or, will wind dominate? Carnegie Mellon University, Electricity Industry Center

11. Production tax credit? Many digesters are built with grants that cover 25-50% of capital costs (state & federal) • 100 kW digester costs ~ $400,000 • Production credit ~ 2 ¢ / kWh • discount rate = 10% Over 10-year period: • Revenue = $110,000 • Comparable to 25% grant Carnegie Mellon University, Electricity Industry Center

12. Energy policy impacts • RPS probably won’t drive adoption • Unless biomass mandate (e.g. Xcel Energy) • As confidence in digester reliability grows, production credit will be important • Might also drive co-digestion: nutrient management plans will key Carnegie Mellon University, Electricity Industry Center

13. Synergy Store biogas when the wind is blowing, burn gas in generator when no wind + Carnegie Mellon University, Electricity Industry Center

14. Wind Simulation • 1 MW wind turbine NW Iowa • Baseline: 100 kW digester plant • Constraints: • Storage volume (65,000 ft3, 2 psig) • Minimum gas volume in storage • Minimum gas volume at end of period Carnegie Mellon University, Electricity Industry Center

15. Results: Wind Simulation • Summer: 160 kW continuous power (75% increase) • Spring: 250 kW (175% increase) • Cost: ~8 ¢ / kWh vs. baseline of 6 ¢ Wind data from NCDC, NOAA Carnegie Mellon University, Electricity Industry Center

16. Wind simulation:Power from digester Carnegie Mellon University, Electricity Industry Center

17. 160 kW continuous power Wind simulation:Year-long run Carnegie Mellon University, Electricity Industry Center

18. Synergy: Sensitivity tostorage volume Carnegie Mellon University, Electricity Industry Center

19. In conclusion • Potential electric power from manure ~1% of current consumption • Cost of electricity is competitive on large farms (< ½ of potential from all farms) • Production incentive at 2 ¢/kWh will likely provide incentive, particularly for utility owned MtoP generation • Odor mitigation will continue to be major driver Carnegie Mellon University, Electricity Industry Center