The Potential of Hydrogen in a Climate-Constrained Future Tom Kreutz

1. The Potential of Hydrogen in a Climate-Constrained Future Tom Kreutz Princeton Environmental Institute Princeton University Presented at the 2005 AAAS Annual Meeting, Symposium: “Sustainability - Energy for a Future without Carbon Emissions” 19 February 2005, Washington, DC

2. The Carbon Mitigation Initiative (CMI)at Princeton University, 2001-2010  CMI Project Areas: - Carbon capture (Kreutz, Larson, Socolow, Williams) - Carbon storage (Celia, Scherer) - Carbon science (Pacala, Sarmiento, GFDL) - Carbon policy (Bradford, Oppenheimer) Integration (Socolow, Pacala) Funding: 15.1$ from BP, 5 M$ from Ford

3. Outline of Talk Brief sketch of the hydrogen landscape Overview of our work on production of low-carbon H2 and electricity from fossil fuels (primarily coal) A potential role for centralized H2 production in an emerging H2 economy

4. Drivers for the H2 Economy • H2 is abundant and can be utilized relatively and cleanly (via combustion, electrochemistry) • Energy security • Air pollution • Climate change • Common clean chemical energy carrier from: • - renewables, • - fossil fuels, • - nuclear power, • - fusion, etc.

5. Difficulties with the H2 Economy • Efficiency losses during production • Safety • Cost: • - distribution • - storage (at both large and small scales) • - utilization • - safety • Storage

6. H2 Issues • Zealotry • Safety • Straw men • Poorly designed systems • Pie in the sky • Different goals, time scales • Response to climate change • Oil prices, politics of nuclear power • Other ways to solve the problems • H2 is a package deal

7. The Case for Hydrogen -Climate Change • Most of the century's fossil fuel carbon must be captured. • About half of fossil carbon, today, is distributed to small users – buildings, vehicles, small factories. • The costs of retrieval, once dispersed, will be prohibitive. • An all-electric economy is unlikely. • An electricity-plus-hydrogen economy is perhaps a more likely alternative. • Hydrogen from fossil fuels is likely to be cheaper than hydrogen from renewable or nuclear energy for a long time.

8. Outline of Talk Brief sketch of the hydrogen landscape Overview of our work on production of carbon-free H2 and electricity from fossil fuels (primarily coal) A potential role for centralized H2 production in an emerging H2 economy

9. Motivation for Studying Coal (vs. Gas) • Plentiful. Resource ~ 500 years (vs. gas/oil: ~100 years). • Inexpensive (low volatility). 1-1.5 $/GJ HHV (vs. gas at 2.5+ $/GJ). • Ubiquitous. Wide geographic distribution (vs. middle east). • Carbon intensive. • Potentially clean. Gasification, esp. with CCS, produces few gaseous emissions and a chemically stable, vitreous ash. • Ripe for innovation. • Globally significant. For example: China: extensive coal resources; little oil and gas. Potential for huge emissions of both criteria pollutants and greenhouse gases.

10. Annual U.S. Carbon Emissions (2002) • Let’s focus for a moment on the power market...

11. Process Modeling • Heat and mass balances (around each system component) calculated using: • Aspen Plus (commercial software), and • GS (“Gas-Steam”, Politecnico di Milano) • Membrane reactor performance calculated via custom Fortran and Matlab codes • Component capital cost estimates taken from the literature, esp. EPRI reports on IGCC • Benchmarking/calibration: • Economics of IGCC with carbon capture studied by numerous groups • Used as a point of reference for performance and economics of our system • Many capital-intensive components are common between IGCC electricity and H2 production systems (both conventional and membrane-based)

12. “Commercially Ready” Coal IGCC with CO2 Capture • CO2 venting: 390 MWe @ 1200 $/kWe, LHV = 43.0%, 4.6 ¢/kWh • CCS: 362 MWe @ 1500 $/kWe, LHV = 34.9%, 6.2 ¢/kWh

13. An example of such a plant...

14. Our Reality...

15. Economics of Coal IGCC with CO2 Capture and Storage (CCS) • Coal IGCC+CCS becomes competitive with new coal plants at ~100 $/tC

16. Coal IGCC+CCS • Coal IGCC + CCS is a hydrogen plant!

17. H2 Production: Add H2 Purification/Separation • • Replace syngas expander with PSA and purge gas compressor. • Reduce the size of the gas turbine.

18. H2 Production from Coal with CCS • 1070 MWth H2 LHV (771 tonne/day) + 39 MWe electricity, efficiency LHV=60.9%, H2 cost=1.04 $/kg

19. Disaggregated Cost of H2 from Coal with CCS • Typical cost is ~1 $/kg (note: 1 kg H2 ~ 1 gallon gasoline)

20. Economics of H2 from Coal with Carbon Storage • The carbon tax needed to induce CCS in H2 production from coal is significantly lower than that for electric power

21. H2 Production from Coal with CCS • Incremental cost for CO2 capture is less for hydrogen than electricity because much of the equipment is already needed for a H2 plant.

22. Where Might that H2 be Used? • Displacing traditional H2 from NG (1% of global primary energy). • At 200 $/tonne C, H2 for industrial boilers, furnaces, and kilns becomes competitive with gas at 4 $/GJ.

23. System Parameter Variations System Performance: • gasifier/system pressure • syngas cooling via quench vs. syngas coolers - hydrogen recovery factor (HRF) • hydrogen purity • sulfur capture vs. sulfur + CO2 co-sequestration - membrane reactor configuration - membrane reactor operating temperature - hydrogen backpressure - raffinate turbine technology (blade cooling vs. uncooled) System Economics (Sensitivity Analysis): • membrane reactor cost (and type) • co-product electricity value, capacity factor, capital charge rate, fuel cost, CO2 storage cost, etc.

24. Membrane System Results Summary • No matter how hard we work, the cost of coal-based H2 with CCS is ~1 $/kg!

25. Hydrogen in the Transportation Sector

26. Production Cost of H2 (Scale=1 GWth HHV)

27. Add CO2 Transport and Geologic Storage...

28. Add H2 Storage and Distribution Pipelines...

29. Add H2 Refueling Stations...

30. Add the Incremental Vehicle Cost... • Switching to H2 as a transportation fuel is expensive! • The cost of H2 production is only a small piece of the whole.

31. Outline of Talk Brief sketch of the hydrogen landscape Overview of our work on production of low-carbon H2 and electricity from fossil fuels Is there a role for centralized H2 production in an emerging H2 economy?

33. H2 DEMAND DENSITY (kg/d/km2): YEAR 1: 25% OF NEW Light Duty Vehicles = H2 FCVs Blue shows good locations for refueling station

34. H2 DEMAND DENSITY (kg/d/km2): YEAR 5: 25% OF NEW LDVs = H2 fueled

35. H2 DEMAND DENSITY (kg/d/km2): YEAR 10: 25% OF NEW LDVs = H2 fueled

36. H2 DEMAND DENSITY (kg/d/km2): YEAR 15: 25% OF NEW LDVs = H2 fueled

37. What is this Curve? Consumption Time

38. The “Elephant-in-the-Snake” Problem or“How does Ohio swallow a 1 GWth H2 plant?” “Le Petit Prince”, Antoine de Saint Exupéry

39. 2004 NRC Report: The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs • Among the “major messages” of the report: • “The (50 year) transition to a hydrogen fuel system will be best accomplished through distributed production of hydrogen, because distributed generation avoids many of the substantial infrastructure barriers faced by centralized generation.” (pp. 117) • “It seems likely that, in the next 10 to 30 years, hydrogen produced in a distributed rather than centralized facilities will dominate.” (pp. 120)

40. 2004 NRC Report: Consensus Slides • Distributed production of hydrogen by SMR is likely transition strategy • Potential role for natural gas conversion to supply hydrogen both in transition (small, distributed) and long term (large, centralized generators) • Focus DOE program on development of mass-produced hydrogen appliances for fueling stations (SMR and POX/ATR) • Downsize effort on centralized generation

41. Likelihood of a H2 Economy • Primary drivers for a U.S. H2 economy: • 1) secure energy supply, • 2) improved air quality, • 3) reduced greenhouse gas emissions. • H2 via distributed SMR provides only one of these (#2). • Will a H2 economy emerge in this scenario? • H2 from coal IGCC+CCS satisfies all three drivers. • Yes, large scale, dedicated H2 plants from coal with CCS are economically problematic in the transition. • However, “slipstream H2” from coal IGCC+CCS is not.

42. Coal IGCC+CCS • Coal IGCC + CCS is a hydrogen plant!

43. “Slipstream Hydrogen” System Design • H2 production “piggybacks” off of coal IGCC+CCS: • - H2 is economical (marginal production cost ~0.8 $/kg) and has a stable price relative to natural gas-based H2. • H2 flow rate is flexible (only PSA, compression and storage change to match increasing demand). • Assume medium-sized refueling stations (1 tonne/day H2) for commercial/government fleet vehicles • Begin with a handful of plants, and increase to many over time.

44. An Alternative Scenario • The U.S. gets serious about climate change in the next quarter century (before fusion, large-scale renewables). • The cost of CO2 emissions becomes high enough to force significant reductions in the power sector (~100 $/tC). • CCS is shown to be a safe and economical strategy. • All new coal power plants are IGCC+CCS, built near demand centers (cities). • Arbitrary quantities of low-carbon H2 is available to those demand centers for industry and transportation. • The H2 economy builds from this base.

45. Scenarios Investigated • Temporal: early “fleet phase” through “commuter phase” • Geographic: two limiting cases (Ohio case study): • - “city gate” plant  Cincinnati, 24 driving miles • “distant plant”  Columbus, 106 driving miles (91 rural)

46. Preliminary Results • Slipstream H2 from coal IGCC+CCS is competitive with distributed SMR.

47. Preliminary Results • - At low demand (< 20-50 tonne/day), trucked H2 from CGCC+CCS is lowest cost option; pipelines thereafter.

48. NRC Report Results • Our work agrees with theirs.

49. Preliminary Results • Don’t upsize the gasification train! Displace or replace power instead.

50. How does this play out in Ohio?