energy

Global Energy Perspective : Global Energy Perspective Present Primary Power Mix Future Constraints Imposed by Sustainability Theoretical and Practical Energy Potential of Various Renewables Challenges to Exploit Renewables Economically on the Needed Scale Nathan S. Lewis, California Institute of Technology Division of Chemistry and Chemical Engineering Pasadena, CA 91125 http://nsl.caltech.edu


Mean Global Energy Consumption, 1998 : Mean Global Energy Consumption, 1998 Gas Hydro Renew Total: 12.8 TW U.S.: 3.3 TW (99 Quads)


Energy From Renewables, 1998 : Energy From Renewables, 1998 Elec Heat EtOH Wind Sol PV SolTh LowT Sol Hydro Geoth Marine TW Biomass 5E-5 1E-1 2E-3 1E-4 1.6E-3 3E-1 1E-2 7E-5


Today: Production Cost of Electricity : (in the U.S. in 2002) 1-4 ¢ 2.3-5.0 ¢ 6-8 ¢ 5-7 ¢ Today: Production Cost of Electricity 6-7 ¢ 25-50 ¢ Cost, ¢/kW-hr


Energy Costs : Energy Costs Brazil Europe $0.05/kW-hr www.undp.org/seed/eap/activities/wea


Energy Reserves and Resources : Energy Reserves and Resources Reserves/(1998 Consumption/yr) Resource Base/(1998 Consumption/yr) Oil 40-78 51-151 Gas 68-176 207-590 Coal 224 2160 Rsv=Reserves Res=Resources


Conclusions : Abundant, Inexpensive Resource Base of Fossil Fuels Renewables will not play a large role in primary power generation unless/until: –technological/cost breakthroughs are achieved, or –unpriced externalities are introduced (e.g., environmentally -driven carbon taxes) Conclusions


Energy and Sustainability : 'It’s hard to make predictions, especially about the future' M. I. Hoffert et. al., Nature, 1998, 395, 881, 'Energy Implications of Future Atmospheric Stabilization of CO2 Content adapted from IPCC 92 Report: Leggett, J. et. al. in Climate Change, The Supplementary Report to the Scientific IPCC Assessment, 69-95, Cambridge Univ. Press, 1992 Energy and Sustainability


Slide9 : Population Growth to 10 - 11 Billion People in 2050 Per Capita GDP Growth at 1.6% yr-1 Energy consumption per Unit of GDP declines at 1.0% yr -1


Slide10 : 1990: 12 TW 2050: 28 TW Total Primary Power vs Year


Slide11 : M. I. Hoffert et. al., Nature, 1998, 395, 881 Carbon Intensity of Energy Mix


Slide12 : CO2Emissions for vs CO2(atm) Data from Vostok Ice Core


Slide13 : Observations of Climate Change Evaporation andamp; rainfall are increasing; More of the rainfall is occurring in downpours Corals are bleaching Glaciers are retreating Sea ice is shrinking Sea level is rising Wildfires are increasing Storm andamp; flood damages are much larger


Slide14 :


Slide15 : Greenland Ice Sheet Coral Bleaching


Slide16 : Projected Carbon-Free Primary Power


Slide17 : 'These results underscore the pitfalls of 'wait and see'.' Without policy incentives to overcome socioeconomic inertia, development of needed technologies will likely not occur soon enough to allow capitalization on a 10-30 TW scale by 2050 'Researching, developing, and commercializing carbon-free primary power technologies capable of 10-30 TW by the mid-21st century could require efforts, perhaps international, pursued with the urgency of the Manhattan Project or the Apollo Space Program.' Hoffert et al.’s Conclusions


Slide18 : If we need such large amounts of carbon-free power, then: current pricing is not the driver for year 2050 primary energy supply Hence, Examine energy potential of various forms of renewable energy Examine technologies and costs of various renewables Examine impact on secondary power infrastructure and energy utilization Lewis’ Conclusions


Slide19 : Nuclear (fission and fusion) 10 TW = 10,000 new 1 GW reactors i.e., a new reactor every other day for the next 50 years 2.3 million tonnes proven reserves; 1 TW-hr requires 22 tonnes of U Hence at 10 TW provides 1 year of energy Terrestrial resource base provides 10 years of energy Would need to mine U from seawater (700 x terrestrial resource base) Carbon sequestration Renewables Sources of Carbon-Free Power


Slide20 : Carbon Sequestration


Slide21 : 130 Gt total U.S. sequestration potential Global emissions 6 Gt/yr in 2002 Test sequestration projects 2002-2004 CO2 Burial: Saline Reservoirs Study Areas One Formation Studied Two Formations Studied Power Plants (dot size proportional to 1996 carbon emissions) DOE Vision andamp; Goal: 1 Gt storage by 2025, 4 Gt by 2050 Near sources (power plants, refineries, coal fields) Distribute only H2 or electricity Must not leak


Slide22 : Hydroelectric Geothermal Ocean/Tides Wind Biomass Solar Potential of Renewable Energy


Slide23 : Globally Gross theoretical potential 4.6 TW Technically feasible potential 1.5 TW Economically feasible potential 0.9 TW Installed capacity in 1997 0.6 TW Production in 1997 0.3 TW and#x8;(can get to 80% capacity in some cases) Source: WEA 2000 Hydroelectric Energy Potential


Geothermal Energy : Geothermal Energy Hydrothermal systems Hot dry rock (igneous systems) Normal geothermal heat (200 C at 10 km depth) 1.3 GW capacity in 1985


Geothermal Energy Potential : Geothermal Energy Potential


Geothermal Energy Potential : Geothermal Energy Potential Mean terrestrial geothermal flux at earth’s surface 0.057 W/m2 Total continental geothermal energy potential 11.6 TW Oceanic geothermal energy potential 30 TW Wells 'run out of steam' in 5 years Power from a good geothermal well (pair) 5 MW Power from typical Saudi oil well 500 MW Needs drilling technology breakthrough (from exponential $/m to linear $/m) to become economical)


Ocean Energy Potential : Ocean Energy Potential


Slide28 : Electric Potential of Wind http://www.nrel.gov/wind/potential.html In 1999, U.S consumed 3.45 trillion kW-hr of Electricity = 0.39 TW


Slide29 : Significant potential in US Great Plains, inner Mongolia and northwest China U.S.: Use 6% of land suitable for wind energy development; practical electrical generation potential of ≈0.5 TW Globally: Theoretical: 27% of earth’s land surface is class 3 (250-300 W/m2 at 50 m) or greater If use entire area, electricity generation potential of 50 TW Practical: 2 TW electrical generation potential (4% utilization of ≥class 3 land area) Off-shore potential is larger but must be close to grid to be interesting; (no installation andgt; 20 km offshore now) Electric Potential of Wind


Slide30 : Relatively mature technology, not much impacted by chemical sciences Intermittent source; storage system could assist in converting to baseload power Distribution system not now suitable for balancing sources vs end use demand sites Inherently produces electricity, not heat; perhaps cheapest stored using compressed air ($0.01 kW-hr) Electric Potential of Wind


Slide31 : Global: Top Down Requires Large Areas Because Inefficient (0.3%) 3 TW requires ≈ 600 million hectares = 6x1012 m2 20 TW requires ≈ 4x1013 m2 Total land area of earth: 1.3x1014 m2 Hence requires 4/13 = 31% of total land area Biomass Energy Potential


Slide32 : Land with Crop Production Potential, 1990: 2.45x1013 m2 Cultivated Land, 1990: 0.897 x1013 m2 Additional Land needed to support 9 billion people in 2050: 0.416x1013 m2 Remaining land available for biomass energy: 1.28x1013 m2 At 8.5-15 oven dry tonnes/hectare/year and 20 GJ higher heating value per dry tonne, energy potential is 7-12 TW Perhaps 5-7 TW by 2050 through biomass (recall: $1.5-4/GJ) Possible/likely that this is water resource limited Challenges for chemists: cellulose to ethanol; ethanol fuel cells Biomass Energy Potential Global: Bottom Up


Slide33 : Theoretical: 1.2x105 TW solar energy potential (1.76 x105 TW striking Earth; 0.30 Global mean albedo) Energy in 1 hr of sunlight  14 TW for a year Practical: ≈ 600 TW solar energy potential (50 TW - 1500 TW depending on land fraction etc.; WEA 2000) Onshore electricity generation potential of ≈60 TW (10% conversion efficiency): Photosynthesis: 90 TW Solar Energy Potential


Slide34 : Roughly equal global energy use in each major sector: transportation, residential, transformation, industrial World market: 1.6 TW space heating; 0.3 TW hot water; 1.3 TW process heat (solar crop drying: ≈ 0.05 TW) Temporal mismatch between source and demand requires storage (DS) yields high heat production costs: ($0.03-$0.20)/kW-hr High-T solar thermal: currently lowest cost solar electric source ($0.12-0.18/kW-hr); potential to be competitive with fossil energy in long term, but needs large areas in sunbelt Solar-to-electric efficiency 18-20% (research in thermochemical fuels: hydrogen, syn gas, metals) Solar Thermal, 2001


Slide35 : 1.2x105 TW of solar energy potential globally Generating 2x101 TW with 10% efficient solar farms requires 2x102/1.2x105 = 0.16% of Globe = 8x1011 m2 (i.e., 8.8 % of U.S.A) Generating 1.2x101 TW (1998 Global Primary Power) requires 1.2x102/1.2x105= 0.10% of Globe = 5x1011 m2 (i.e., 5.5% of U.S.A.) Solar Land Area Requirements


Slide36 : Solar Land Area Requirements 3 TW


Slide37 : Solar Land Area Requirements 6 Boxes at 3.3 TW Each


Slide38 : U.S. Land Area: 9.1x1012 m2 (incl. Alaska) Average Insolation: 200 W/m2 2000 U.S. Primary Power Consumption: 99 Quads=3.3 TW 1999 U.S. Electricity Consumption = 0.4 TW Hence: 3.3x1012 W/(2x102 W/m2 x 10% Efficiency) = 1.6x1011 m2 Requires 1.6x1011 m2/ 9.1x1012 m2 = 1.7% of Land Solar Land Area Requirements


Slide39 : 7x107 detached single family homes in U.S. ≈2000 sq ft/roof = 44ft x 44 ft = 13 m x 13 m = 180 m2/home = 1.2x1010 m2 total roof area Hence can (only) supply 0.25 TW, or ≈1/10th of 2000 U.S. Primary Energy Consumption U.S. Single Family Housing Roof Area


Slide40 : Light Fuel Electricity Photosynthesis Fuels Electricity Photovoltaics sc e M Energy Conversion Strategies Semiconductor/Liquid Junctions


Slide41 : Production is Currently Capacity Limited (100 MW mean power output manufactured in 2001) but, subsidized industry (Japan biggest market) High Growth but, off of a small base (0.01% of 1%) Cost-favorable/competitive in off-grid installations but, cost structures up-front vs amortization of grid-lines disfavorable Demands a systems solution: Electricity, heat, storage Solar Electricity, 2001


Efficiency of Photovoltaic Devices : 1950 1960 1970 1980 1990 2000 5 10 15 20 25 Efficiency (%) Year Efficiency of Photovoltaic Devices


Cost/Efficiency of Photovoltaic Technology : Cost/Efficiency of Photovoltaic Technology Costs are modules per peak W; installed is $5-10/W; $0.35-$1.5/kW-hr


Cost vs. Efficiency Tradeoff : Cost vs. Efficiency Tradeoff Efficiency µ t1/2 Long d High t High Cost d Long d Low t Lower Cost d t decreases as grain size (and cost) decreases Large Grain Single Crystals Small Grain And/or Polycrystalline Solids


Cost vs. Efficiency Tradeoff : Cost vs. Efficiency Tradeoff Efficiency µ t1/2 Long d High t High Cost d Long d Low t Lower Cost d t decreases as material (and cost) decreases Ordered Crystalline Solids Disordered Organic Films


Slide46 : SOLAR ELECTRICITY GENERATION Develop Disruptive Solar Technology: 'Solar Paint' Grain Boundary Passivation Interpenetrating Networks while Minimizing Recombination Losses Challenges for the Chemical Sciences Increase t Lower d


Cost/Efficiency of Photovoltaic Technology : Cost/Efficiency of Photovoltaic Technology Costs are modules per peak W; installed is $5-10/W; $0.35-$1.5/kW-hr


The Need to Produce Fuel : The Need to Produce Fuel 'Power Park Concept' Fuel Production Distribution Storage


Slide49 : Photovoltaic + Electrolyzer System


Slide50 : O2 A H2 e- cathode anode Fuel Cell vs Photoelectrolysis Cell H2 anode cathode O2 Fuel Cell MEA Photoelectrolysis Cell MEA membrane membrane MOx MSx e- H+ H+


Photoelectrochemical Cell : Photoelectrochemical Cell metal e - e - O2 H2O H2 H2O e - h + Light is Converted to Electrical+Chemical Energy Liquid Solid SrTiO3 KTaO3 TiO2 SnO2 Fe2O3


Slide52 : By essentially all measures, H2 is an inferior transportation fuel relative to liquid hydrocarbons So, why? Local air quality: 90% of the benefits can be obtained from clean diesel without a gross change in distribution and end-use infrastructure; no compelling need for H2 Large scale CO2 sequestration: Must distribute either electrons or protons; compels H2 be the distributed fuel-based energy carrier Renewable (sustainable) power: no compelling need for H2 to end user, e.g.: CO2+ H2 CH3OH DME other liquids Hydrogen vs Hydrocarbons


Slide53 : Need for Additional Primary Energy is Apparent Case for Significant (Daunting?) Carbon-Free Energy Seems Plausible Scientific/Technological Challenges Provide Disruptive Solar Technology: Cheap Solar Fuel Inexpensive conversion systems, effective storage systems Provide the New Chemistry to Support an Evolving Mix in Fuels for Primary and Secondary Energy Policy Challenges Will there be the needed commitment? Is Failure an Option? Summary


Global Energy Consumption : Global Energy Consumption


Slide55 : Carbon Intensity vs GDP


Matching Supply and Demand : Matching Supply and Demand Oil (liquid) Gas (gas) Coal (solid) Transportation Home/Light Industry Manufacturing Conv to e- Pump it around Move to user Currently end use well-matched to physical properties of resources


Matching Supply and Demand : Matching Supply and Demand Oil (liquid) Gas (gas) Coal (solid) Transportation Home/Light Industry Manufacturing Conv to e- Pump it around Move to user If deplete oil (or national security issue for oil), then liquify gas,coal


Matching Supply and Demand : Matching Supply and Demand Oil (liquid) Gas (gas) Coal (solid) Transportation Home/Light Industry Manufacturing Conv to e- Pump it around Move to user If carbon constraint to 550 ppm and sequestration works -CO2


Matching Supply and Demand : Matching Supply and Demand Oil (liquid) Gas (gas) Coal (solid) Transportation Home/Light Industry Manufacturing Conv to e- Pump it around Move to user as H2 If carbon constraint to andlt;550 ppm and sequestration works -CO2 -CO2


Matching Supply and Demand : Matching Supply and Demand Oil (liquid) Gas (gas) Coal (solid) Transportation Home/Light Industry Manufacturing Pump it around If carbon constraint to 550 ppm and sequestration does not work Nuclear Solar ? ?


Slide61 : Quotes from PCAST, DOE, NAS The principles are known, but the technology is not Will our efforts be too little, too late? Solar in 1 hour andgt; Fossil in one year 1 hour $$$ gasoline andgt; solar Randamp;D in 6 years Will we show the commitment to do this? Is failure an option?


US Energy Flow -1999Net Primary Resource Consumption 102 Exajoules : US Energy Flow -1999 Net Primary Resource Consumption 102 Exajoules


Slide63 : Tropospheric Circulation Cross Section


Primary vs. Secondary Power : Primary vs. Secondary Power Hybrid Gasoline/Electric Hybrid Direct Methanol Fuel Cell/Electric Hydrogen Fuel Cell/Electric? Wind, Solar, Nuclear; Bio. CH4 to CH3OH 'Disruptive' Solar CO2 CH3OH + (1/2) O2 H2O H2 + (1/2) O2 Transportation Power Primary Power


Slide65 : Challenges for the Chemical Sciences CHEMICAL TRANSFORMATIONS Methane Activation to Methanol: CH4 + (1/2)O2 = CH3OH Direct Methanol Fuel Cell: CH3OH + H2O = CO2 + 6H+ + 6e- CO2 (Photo)reduction to Methanol: CO2 + 6H+ +6e- = CH3OH H2/O2 Fuel Cell: H2 = 2H+ + 2e-; O2 + 4 H+ + 4e- = 2H2O (Photo)chemical Water Splitting: 2H+ + 2e- = H2; 2H2O = O2 + 4H+ + 4e- Improved Oxygen Cathode; O2 + 4H+ + 4e- = 2H2O


Slide66 :