Coupling Carbonless Electricity and Hydrogen Transportation

Transcription

1 Coupling Carbonless Electricity and Hydrogen Transportation 9 July 2003 Gene Berry & Alan Lamont (berry6@llnl.gov) Energy and Environment Directorate Lawrence Livermore National Laboratory Livermore, CA 1

2 Present Challenges and Future History: global energy use may quadruple over 50 years according to Shell s sustained growth scenario Today: Near-term concerns merit moving toward hydrogen zero tail-pipe emissions national security: universal availability economic security: vehicles, fuel, and utilities are critical industries economic integration of renewable intensive & decentralized transportation and utility sectors QuickTime and a TIFF (PackBits) decompressor are needed to see this picture. 20 TW Tomorrow: Energy carriers will be hydrogen and electricity food,land, and water will limit biomass atmosphere will limit carbon emissions security will limit economic oil and gas 2

3 2000 U.S. Energy Flow is 104 EJ/yr (3.3 TW) but Electricity is only 3.6 Trillion kwh (0.4 TW) (30% eff.) 3

4 Energy/economic security has been a critical challenge each recession in the last 3 decades - costing trillions - has been associated with oil price shocks Petroleum Prices Oil Price (1992 $/Barrel) $60 $50 $40 $30 $20 $10 $ GDP Growth Annual Change in U.S. Gross Domestic Product Source: EIA 1995,1996 4

5 U.S. highway oil consumption is projected to grow from twice to three times domestic oil production by 2020 QuickTime and a TIFF (PackBits) decompressor are needed to see this picture. Source: EIA 1995,1996 5

6 Myriad (future) replacements for oil can be envisioned Gas Primary Energy Renewable Nuclear Fusion Fossil Processed Energy Electricity Heat Material Air Water Natural Gas Biomass Waste Fuels Hydrogen Oxygen Ammonia Methane Water Compressed Cryo Compressed Liquid Recover Gas LH 2 Electrolyze LO 2 Heat LNG Ammonia Water Solid Warm: FeTiH 2, LaN 5 H 6 Fuel Cell Plastic Ceramic Alkaline Molten Combustion Engine Turbine Motor Electric Auxiliary Flywheel Supercap Transportation Automibile Bus Truck Train Ship Airplane PEM FC SO FC Gas Turbine Hot:MgH 2, TiH 2 Fullerene 6

7 H 2 is just one of many potential synthetic fuels but also the majority component and production precursor for them all QuickTime and a TIFF (PackBits) decompressor are needed to see this picture. 7

8 H 2 is uniquely capable of dynamically linking carbonless electricity and transportation through electrolysis of H 2 O Nuclear Wind Photovoltaic Hydroelectric Electrolytic Hydrogen Station Electrolytic Home Refueling Fuel Cell Vehicles 8

9 Distinct from fossil fuels, H 2 is not an energy source, H 2 instead carries energy from primary sources Electric demand Aircraft demand Cars and trucks demand H 2 Utilization (transportation fuel) Long term storage (liquid H2) Short term storage (compressed H2) H 2 Storage (gaseous & cryogenic liquid) Liquefier Compressor H2 flows Electricity flows Electrolyzer 1 Electrolyzer 2 H 2 Production (electrolysis) Distribution (market) nodes Flywheel Electricity Generation (regeneration by fuel cell) Fossil generator Natural gas Nuclear Wind Photovoltaic Fuel cell Primary Energy (fossil or non-fossil) 9

10 Strategic advantages of H 2 as an energy carrier Clean non-toxic, made from (and returns to) H 2 O Carbonless Universal Zero emissions (e.g. greenhouse gases) Feasible for all transportation modes (air, land,sea) Versatile H 2 can carry energy from any source (electricity) Synergistic Transitional Dynamic integration of electricity & transportation Smooth, scalable, flexible infrastructure evolution Ultimate H 2 is simple, pure, light, efficient, final 10

11 H 2 production fundamentally requires decomposing H 2 O into H 2 and O 2 by myriad methods but all use thermal, electric, or chemical energy Primary Energy Nuclear Fusion Fission Secondary Energy Thermal Production of H 2 (& O 2 ) Thermochemical Steam Decomposition Cycles Steam Electrolysis Solar Hydropower Wind Electric Water Electrolysis Photovoltaic Photoelectrolysis Biomass Fossil Chemical Steam Reforming 11

12 Direct thermal decomposition of H 2 O is hampered by the thermodynamic equilibria of steam. T > 2500 K is needed but H 2 and O 2 also decompose at these high temperatures 12

13 Multi-step thermochemical H 2 O decomposition reduces peak temperatures, but also lowers Carnot efficiency GA claims HTGR S-I cycles can achieve ~42% (50% HHV) 13

14 + Electrolytic H 2 production technologies are fundamentally distinguished by choice of ion (OH -, H +, O 2- ) to be conducted across the electrolyte Anode Cathode Anode Cathode Anode Cathode e - e - e H 2 O + O 2 H 2 O 2 H 2 O (g) + H 2 O 2 H 2 H 2 O (l) H 2 O (g) OH - H + O 2- Alkaline Polymer Electrolyte Membrane Solid Oxide 14

15 Conventional alkaline (KOH) electrolysis theoretically requires 1.23 Volts but 1.48 V (83%)to be thermoneutral and ~1.9 V (65% or 50 kwh/kg H 2 ) at high current density 15

16 Electrolysis thermodynamics mean high water (steam) temperatures and pressures reduces theoretical voltage - if both heat and electricity are available QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. 16

17 On an equal energy basis H 2 is the lightest - but also the least compact fuel magnifying storage vessel mass, volume and cost 17

18 Vessel walls, insulation, and LH 2 thermal expansion limit volumetric efficiency of high density H 2 storage (all volumes shown store 5 kg H 2 or energy equivalent) 5 gallons Gasoline 20 L 3600 psi CH 4 (300 K) 0.3 m CH 4 Volume = 65 L 6 15% Ullage 2.5 cm cryogenic insulation 5 kg LH 2 (20 K) LH 2 Volume = 75 L 11 L 35 L 2.5 cm cryogenic insulation 3600 psi H 2 (80 K) H 2 gas Volume = 93 L 8 L 39 L 3600 psi H 2 (300 K) H 2 gas Volume = 290 L 20 L 5000 psi H 2 (300 K) H 2 gas Volume = 220 L 25 L 10,000 psi H 2 (300 K) H 2 gas Volume =130 L 32 L Vessel Wall Volume 18

19 H 2 will cost more than fossil fuels as long as the energy to produce & store H 2 costs more than fossil fuels Polymer Electrolysis Alkaline Electrolysis Polymer Electrolysis Alkaline Electrolysis Liquid Hydrogen (Truck) Steam Electrolysis Polymer Electrolysis Alkaline Electrolysis Ammonia Reforming Methanol Reforming Liquid Hydrogen (Truck) Figure 8. Cost Breakdown of 7 Hydrogen Pathways for Stations, Fleets, and Homes (broken down by cost element ) Individual Car (30 miles/day) Fleet (10 cars/day) Small Station (60 cars/day) $1.50/gallon of gasoline (energy equivalent) Station Overhead ($2.40/car) Electricity($0.05/kwh) Steam Electrolysis Polymer Electrolysis Alkaline Electrolysis Ammonia Reforming Methanol Reforming Steam Reforming Liquid Hydrogen (Truck) Full Station (300 cars/day) Fuel/Feedstock (Natural Gas, Methanol, Ammonia, Water) Interest (20% except for individual vehicle case) Operation and Maintenance Capital Investment (Prod. Equip yr. life) (Storage Equip yr. life) Delivered Hydrogen Cost ($/kg Hydrogen) 19

20 The expense and volume of H 2 can (only) be overcome by high efficiency ( mpg or km/l) vehicles using only ~ 5 kg of H 2 for mile ( km) range Electric drive motor: 80 kw maximum power Body and frame - C d = 0.2; 1100 kg (empty wt) Cross-sectional area: 2.0 m 2 Regenerative braking 35km/L energy equivalent (0-60 mph < 10 sec.) mph i0- PRIMARY ENERGY CONVERSION: 30 kw fuel cell HYDROGEN STORAGE: 5 kg/400 mile range Compressed H 2 (5,000-10,000 psi) Cryogenic (Insulated) Pressure Vessel (20-80K) PEAK POWER (2 kwh) Advanced Batteries or Ultracapacitors or Metal hydride sponge <100 psi, < 100C Liquid hydrogen tank (50 psi, 20-28K) Advanced Flywheel 20

21 BMW has prototyped 5 generations of LH 2 cars A fleet of 15 dual-fuel vehicles have been road tested > 100,000 km 300 km LH 2 range km gasoline range 21

22 A robotic LH 2 refueling station has been demonstrated 22

23 LH 2 storage is lightweight and routine for spacecraft but Liquefaction is energy intensive (10 kwh/kg LH 2 or 30%) LH 2 requires heat transfer below 1 W to remain cold (~1 week) 23

24 Covalent H 2 compounds are more compact than LH 2 but are hazardous (NH 3 ) or use carbon (CH 4 ). Ionic & metallic hydrides are either heavy or release H 2 only when very hot 10,000 psi H 2 gas on prototype automobiles 24

25 U.S. automakers have developed concept/prototype cars in the past 2-3 years. Each stores 5-10 ksi compressed H 2 4 kg H 5000 psi Fuel-cell Battery Hybrid mpg mile range 25

26 GM s prototype chassis height is 6-12 inches to capture platform independent manufacturing economics but only stores kg H 2 in 5-10 ksi tanks ( mpg) QuickTime and a TIFF (PackBits) decompressor are needed to see this picture. 26

27 Nonlinear H 2 gas density vs.. pressure is the fundamental property characteristic of gaseous H 2 limiting storage capacity to ~10 kg H 2 in 250 L (66 gal) vessels 27

28 Cooling from 300 K to 80 K or to LH 2 (20 K) reduces H 2 volume dramatically but energy intensity rises at cryogenic temperatures H 2 density (kg/m3) kwh/kg 2.50 kwh/kg 350 atm 250 atm 500 atm 700 atm 1000 atm 2000 atm kwh/kg Temperature, K Volume (liters) occupied by 5 kg of H2 28

29 Cryogenic compatible pressure vessels compromise between LH 2 (20 K) and high pressure H 2 (300 K) storage High pressure eliminates the H 2 boiloff of LH 2 (low-pressure) tanks More compact and/or lower pressure than conventional (300 K) vessels Can be refueled flexibly 300 K H 2 (urban) or Cryogenic (80 K) H 2 & LH 2 (highway) 29

30 The theoretical instantaneous maximum energy release from an H 2 vessel rupture is dramatically lower for cryogenic H 2 and independent of pressure above atm K Maximum energy release from adiabatic expansion (kwh per kg H 2 ) K 80 K Hydrogen storage pressure (atmospheres) 30

31 2000 U.S. carbon (dioxide) emissions from energy consumption 1547* MtC 31

32 Future deep greenhouse gas cuts must come from electricity and transportation Transportation (23%) and electricity (44%) will account for 2/3 of all US energy-related carbon Pie Chart#2 emissions All Other Energy Autos Freight Trucks Aircraft Marine Pipelines, Others Electricity EIA 2020 projection, adjusted for full PNGV passenger vehicle implementation 32

33 Complete integration of non-fossil electricity with transportation will require H 2 use beyond automobiles Carbonless Electric Grid Transportation e - e - e - (L)H 2 H 2 Electrolysis H 2 O Hydrogen Storage 33

34 LLNL has constructed an equilibrium network model integrating hourly demand patterns with generation of hydrogen transportation fuel and electricity This system has _ 120,000 inequality constraints _ 25,000 equality constraints Nine capacities must be determined Each hour allocations must be made for _ Five generators _ Two electrolyzers _ Withdrawals from long and short-term storage _ Purchases of H2 by the storage devices Electric demand H2 flows Electricity flows Distribution (market) nodes Fossil generator Long term storage (liquid H2) Liquefier Electrolyzer 1 Aircraft demand Electrolyzer 2 Flywheel Compressor Cars and trucks demand Short term storage (compressed H2) Fuel cell Natural gas Nuclear Wind Photovoltaic 34

35 Carbonless electricity and H 2 transportation markets modeled using simultaneous equilibrium optimization Hourly Electricity and Transportation Demands Fuel Cell Vehicle Refueling Patterns Short and Long Term Hydrogen Storage Hourly Variations in Electrolytic Hydrogen Production Electricity for both Grid use and Hydrogen Production Hourly Electric Generation from a mix of Technologies Solar, Wind, Hydro Resource Patterns and Availability 35

36 Hypothesis: Coupling carbonless electricity sources with hydrogen fuel production can reduce the cost of deep carbon reductions Electricity Supply Variations Large carbon reductions in the electric sector will require significant amounts of intermittent electricity sources (solar and wind) Hydrogen Fuel: Flexible Load and Energy Storage Electrolytic hydrogen production would be a very large and flexible load Utility hydrogen storage could also serve as transportation fuel storage Shared Functions Reduce Overall Cost Hydrogen and electric infrastructure would serve both electricity and transportation sectors Decentralized production of electricity and hydrogen can ease transmission and distribution requirements Carbonless Electricity and Transportation Would Eliminate 2/3 of US CO 2 Emissions 36

37 Typical electric demand variations exhibit clear hourly, daily, weekly, and seasonal patterns Power Nov Feb May August Nov 37

38 Wind energy supply patterns show great variability over daily, weekly and seasonal periods Power Nov Feb May August Nov 38

39 Typical solar supply patterns show marked seasonal variability, but predictable daily patterns Power Nov Feb May August Nov 39

40 Modelling Electricity Production Patterns: Baseload Nuclear Balanced by Fossil Generation emissions 1.0 and total system Power Generati on (T W) Nuclear Fossil PV Hours from Wind st art Fuel ofcell Elect ric Load S2h:1/0; 0;0/f0.9n0. 1w0st20 segment Load (T W) 40

41 Modelling electricity production patterns: Baseload nuclear, wind/fossil hybrid Power Generation (TW) Load (TW) Hours from start of segment Nuclear PV Fossil Wind Fuel Cell Electric Load S2h:1:0;0;0/f0.5n0.1w1st

42 Modelling Electricity Production Patterns: Wind/Fossil/Solar Power Generation (TW) Hours from start of segment Nuclear PV Fossil Wind Fuel Cell Electric Load S2h:1/0;0;0/f0.1n0.1w1st Load (TW) 42

43 Modelling Electricity Production Patterns: Nuclear/Solar/Wind and H2 Fuel for cars Power Generation (TW) Hours from start of Nuclear PV Fossil segment Wind Fuel Cel Electric Load S2h:1:0;0;0/f0n0.1w1st Load (TW) 43

44 Projected patterns (10 days) of electricity demand supplied by fossil & non-fossil sources (with H 2 fuel produced from excess electricity) Power Generation (TW) Power Generation (TW) Hours from start of segment Nuclear Fossil PV Wind Fuel Cell Electric Load Hours from start of segment Nuclear PV Fossil Wind Fuel Cell Electric Load S2h:1:0;0;0/f0n0.1w1st Load (TW) S2h:1/0;0;0/f0.9n0.1w0st20 Load (TW) Natural Gas (CH 4 ) & Nuclear/Hydro Solar Wind Nuclear/Hydro H 2 electrolysis Night-time fuel cell 44

45 Carbonless electricity combined with H 2 transportation can replace CH 4 but could need 1/3 more energy for LH 2, electrolysis, and utility fuel cell operations Power Load Generation (TW) (TW) Hours from start of segment S2h:1/0;0;0/f0.9n0.1w0st20 Nuclear Fossil PV Wind Fuel Cell Electric Load Efficiency of fossil to non-fossil transition Power Generation Load (TW) (TW) Hours from start of segment Nuclear PV Fossil Wind Fuel Cell Electric Load S2h:1:0;0;0/f0n0.1w1st10 Wind not used Photovoltaic not used Photovoltaic Natural gas fueled electric generation Natural gas fueled transportation Wind Delivered Energy (TWh/yr) Nuclear Electricity 500 Liquefaction Losses 400 Compression Losses 300 Fuel Cell Losses Electrolysis Losses Carbon Emissions (mmtc/yr) 45

46 Efficiency will determine the economics of H 2 because the H 2 infrastructure (e.g. fuel cells) will cost less than the energy it carries H2 Related Opr Costs 700 H2 Liquefaction Capacity 600 LH2 Storage Compressed H2 Storage Compression Capacity 500 Peak Electrolyzer Natural Gas Transportation Fuel Baseload Electrolyzer Wind Solar Photovoltaic 400 Annual Fuel and Electricity Cost 300 (B$) 200 Natural Gas Generation Nuclear Fuel Cell Capacity 100 Gas Capacity Carbon Emissions (mmtc/yr) 46

47 Cost and emissions for a variety of carbon reduction paths: timing of H2 vehicle intro appears flexible 700 System cost (B$/yr) a a t t The transportation served by H2 is indicated as: None: normal symbol, no letter 50% cars: half sized symbol, no letter 100% cars: letter "c" 100% cars and trucks: letter "t" 100% cars, trucks, aircraft: letter "a" 450 c t 400 c t 350 c c c Carbon emissions (mmtonnes/yr) 900 GW gas 500 GW gas 350 GW gas 250 GW gas 100 GW gas 0 GW gas Slope of $500/tonne C emissions reduction 47

48 Aggressive efficiency and economic assumptions were used (both for fossil and non-fossil) Electricity Sources Capital Cost Fuel/Power Cost Efficiency Gas Combined Cycle $600/kW 1.9 c/kwh 56% Nuclear $2000/kW small - Hydroelectric $2000/kW small - Wind $655/kW small - Solar Thermal (12hr) $2500/kW small - Photovoltaic $1100/kW small - Hydrogen Infrastructure Electrolysis(Steam) $500/kW small 92% Utility fuel cells $200/kW small 50% CH 2 storage $6/kWh H 2 $100/kW 91% LH 2 storage $.30/kWh LH 2 $500/kW 75% Hydrogen Vehicles ~80 mpg hydrogen passenger vehicles ($500 extra) with 400-mile range EIA efficiencies for trucks. LH 2 aircraft were EIA x 1.1 Note: 4% Real Discount Rate, yr life for capital equipment. Conventional electricity costs drawn from EPRI, GRI, EIAI. Hydrogenand renewable electricity costs from DOE rnewable energy characterizations(1998).. 48

49 Technological prerequisites for widespread implementation of H 2 as an energy carrier Energy efficient design, integration, and operation of H 2 and electricity infrastructure ( just in time liquefaction, flexibly fueled hydrogen onboard storage) km/l or mpg H 2 (fuel-cell) light-duty vehicles Efficient (80-90%) electrochemistry for both forward & reverse reactions (H 2 fuel cells and H 2 O electrolysis) Non-fossil $ /kWh 49

50 Potential improvements to be examined Electrolysis and fuel cells close-coupled for heat and O 2 integration where needed. Peak and Baseload electrolyzers and Fuel Cells Potential synergies with hydrogen for chemical industry (NH 3 ) Biomass and Natural gas for seasonal leveling, with minimal carbon sequestration burden 50

51 1.5 TW (13 Trillion kwh/yr yr) ) U.S. circa 2050 Carbonless Electricity and Transportation Scenario shows decarbonize the grid first Electricity Sources Capacity (TW) Capacity Factor Trillion kwh/yr Nuclear Hydroelectric Wind Photovoltaic total H 2 Transportation Miles/year kg H 2 /yr 400 million autos (100 mpg) 15k 60 billion 2.0 (3.2) 2 million trucks (15 mpg) 150k 20 billion 0.66 (1.1) 400 million flights (60 seat mpg) 6k 40 billion (LH 2 ) 1.33 (2.7) 120 billion 4 (7) total Direct Electricity use 400 million kwh/yr per person 6 CO 2 Displaced 6 trillion kwh of displaced coal generation (66% efficient) is 1 GtC or 6 trillion kwh of displaced natural gas generation (66% Efficient) is 0.5 GtC 7 trillion kwh of electricity creates 4 trillion kwh of H 2 offsetting only 0.25 GtC of oil 51

52 Only 30 years of economic/technological change have altered the H 2 economy concept dramatically How robust are our conceptions for the next 100 years? H 2 pipelines (large) were cheaper than power lines Electric growth was thought to be 8x by 2000 (2x actual) H 2 mostly for stationary uses Automotive viewed as possible not mentioned - energy security greenhouse gases photovoltaics wind compressed H 2 on cars Electricity was $0.02/kWh Gas was $0.50/GJ 52

53 The H 2 transition will take years, but is the essential element pivotal to universal and enduring solution of global challenges Clean Air, Water, Transportation Energy and Economic Security Stabilizing Greenhouse Gases Sustainable Development 53