Presentation on theme: "1 The Potential of Hydrogen in a Climate-Constrained Future Tom Kreutz Princeton Environmental Institute Princeton University Presented at the 2005 AAAS."— Presentation transcript:
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 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 The Carbon Mitigation Initiative (CMI) at Princeton University,
3 Brief sketch of the hydrogen landscape Overview of our work on production of low- carbon H 2 and electricity from fossil fuels (primarily coal) A potential role for centralized H 2 production in an emerging H 2 economy Outline of Talk
4 Drivers for the H 2 Economy H 2 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 H 2 Economy Efficiency losses during production Safety Cost: - distribution - storage (at both large and small scales) - utilization - safety Storage
6 H 2 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 H 2 is a package deal
7 The Case for Hydrogen - Climate Change 1.Most of the century's fossil fuel carbon must be captured. 2.About half of fossil carbon, today, is distributed to small users – buildings, vehicles, small factories. 3.The costs of retrieval, once dispersed, will be prohibitive. 4.An all-electric economy is unlikely. 5.An electricity-plus-hydrogen economy is perhaps a more likely alternative. 6.Hydrogen from fossil fuels is likely to be cheaper than hydrogen from renewable or nuclear energy for a long time.
8 Brief sketch of the hydrogen landscape Overview of our work on production of carbon-free H 2 and electricity from fossil fuels (primarily coal) A potential role for centralized H 2 production in an emerging H 2 economy Outline of Talk
9 Motivation for Studying Coal (vs. Gas) Plentiful. Resource ~ 500 years (vs. gas/oil: ~100 years). Inexpensive (low volatility) $/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 H 2 production systems (both conventional and membrane-based)
12 “Commercially Ready” Coal IGCC with CO 2 Capture CO 2 venting: 390 MW 1200 $/kW e, LHV = 43.0%, 4.6 ¢/kWh CCS: 362 MW 1500 $/kW e, LHV = 34.9%, 6.2 ¢/kWh
13 An example of such a plant...
14 Our Reality...
15 Economics of Coal IGCC with CO 2 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 H 2 Production: Add H 2 Purification/Separation Replace syngas expander with PSA and purge gas compressor. Reduce the size of the gas turbine.
18 H 2 Production from Coal with CCS 1070 MW th H 2 LHV (771 tonne/day) + 39 MW e electricity, efficiency LHV =60.9%, H 2 cost=1.04 $/kg
19 Disaggregated Cost of H 2 from Coal with CCS Typical cost is ~1 $/kg (note: 1 kg H 2 ~ 1 gallon gasoline)
20 The carbon tax needed to induce CCS in H 2 production from coal is significantly lower than that for electric power Economics of H 2 from Coal with Carbon Storage
21 H 2 Production from Coal with CCS Incremental cost for CO 2 capture is less for hydrogen than electricity because much of the equipment is already needed for a H 2 plant.
22 Where Might that H 2 be Used? Displacing traditional H 2 from NG (1% of global primary energy). At 200 $/tonne C, H 2 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 + CO 2 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, CO 2 storage cost, etc.
24 Membrane System Results Summary No matter how hard we work, the cost of coal-based H 2 with CCS is ~1 $/kg!
25 Hydrogen in the Transportation Sector
26 Production Cost of H 2 (Scale=1 GW th HHV)
27 Add CO 2 Transport and Geologic Storage...
28 Add H 2 Storage and Distribution Pipelines...
29 Add H 2 Refueling Stations...
30 Add the Incremental Vehicle Cost... Switching to H 2 as a transportation fuel is expensive! The cost of H 2 production is only a small piece of the whole.
31 Brief sketch of the hydrogen landscape Overview of our work on production of low- carbon H 2 and electricity from fossil fuels Is there a role for centralized H 2 production in an emerging H 2 economy? Outline of Talk
33 H 2 DEMAND DENSITY (kg/d/km 2 ): YEAR 1: 25% OF NEW Light Duty Vehicles = H 2 FCVs Blue shows good locations for refueling station
34 H 2 DEMAND DENSITY (kg/d/km 2 ): YEAR 5: 25% OF NEW LDVs = H 2 fueled
35 H 2 DEMAND DENSITY (kg/d/km 2 ): YEAR 10: 25% OF NEW LDVs = H 2 fueled
36 H 2 DEMAND DENSITY (kg/d/km 2 ): YEAR 15: 25% OF NEW LDVs = H 2 fueled
37 What is this Curve? Time Consumption
38 The “Elephant-in-the-Snake” Problem “Le Petit Prince”, Antoine de Saint Exupéry or “How does Ohio swallow a 1 GW th H 2 plant?”
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)
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 H 2 Economy Primary drivers for a U.S. H 2 economy: 1) secure energy supply, 2) improved air quality, 3) reduced greenhouse gas emissions. H 2 via distributed SMR provides only one of these (#2). Will a H 2 economy emerge in this scenario? H 2 from coal IGCC+CCS satisfies all three drivers. Yes, large scale, dedicated H 2 plants from coal with CCS are economically problematic in the transition. However, “slipstream H 2 ” from coal IGCC+CCS is not.
42 Coal IGCC+CCS Coal IGCC + CCS is a hydrogen plant!
43 “Slipstream Hydrogen” System Design H 2 production “piggybacks” off of coal IGCC+CCS: - H 2 is economical (marginal production cost ~0.8 $/kg) and has a stable price relative to natural gas-based H 2. -H 2 flow rate is flexible (only PSA, compression and storage change to match increasing demand). Assume medium-sized refueling stations (1 tonne/day H 2 ) 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 CO 2 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 H 2 is available to those demand centers for industry and transportation. The H 2 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 -Slipstream H 2 from coal IGCC+CCS is competitive with distributed SMR. Preliminary Results
47 Preliminary Results - At low demand (< tonne/day), trucked H 2 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 Year data:CincinnatiColumbusOhio Population (million people) Light Duty Vehicles (million) LDV gasoline (10^6 gal/day, at 20.1 mpg) LDV H 2 use (tonne/day, at 60 mpge) LDV H 2 requirement (MW th HHV H 2 ) HPQ plants needed for all H Electric capacity (GW e ) EPQ / (total electric demand)6%7%1% EPQ plants needed for all power (Coal for H 2 ) / (coal for electricity)10% 11% H 2 from EPQ+X% (tonne/day H 2 )48 55 Fraction of total H 2 from "extra" coal (i.e. HHV = 33.9% 37.7%) 48% Electricity and H 2 Plants with CCSEPQHPQ Coal input (MW th, HHV) Power output (MW e )36239 H 2 output (tonne/day)-771 Efficiency (%, HHV)34.9%68.4% Product cost (¢/kWh, $/kg H 2 ) How does this play out in Ohio?
51 Slipstream H 2 Upshot Slipstream H 2 with compressed H 2 truck delivery is an economical (~2 $/kg, delivered), flexible source of low- carbon H 2 from indigenous coal. This H 2 can be used by fleets of (and commuters with) H 2 ICVs (and later, FCEVs). It requires nearby IGCC+CCS, and associated high carbon prices. Since the former is an oft-cited outcome of a serious climate management regime, a H 2 economy for transportation seems to me much more likely than before because it aggressively addresses climate change.