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Options. Energy Future: Options (An SE’s Sample Of Topics). Options for sources “Reduced Carbon” fossil fuel Renewables Nuclear Options for energy transport systems Hydrogen Options for efficiencies Distributed generation Spinning reserve Options for policies. Energy Future: Options.
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Energy Future: Options(An SE’s Sample Of Topics) • Options for sources • “Reduced Carbon” fossil fuel • Renewables • Nuclear • Options for energy transport systems • Hydrogen • Options for efficiencies • Distributed generation • Spinning reserve • Options for policies
Energy Future: Options • Topics: • The importance of Natural Gas • A solar future • Nuclear?
Carbon Intensity of Energy Mix M. I. Hoffert et. al., Nature, 1998, 395, 881 Source: Nathan Lewis
LNG • Worldwide proven reserves of Natural Gas: 5500 T ft3 • 1999 – 84 T ft3 total, worldwide production • U.S. production of liquefied natural gas (LNG) has plateaued. • New U.S. electric power plants are largely natural gas • Prediction: by 2020, 25% of the world’s energy will be natural gas • Consumption: • 1997 LNG – 4 T ft3 • 1999 LNG – 5.4 T ft3 shipped • 2010 LNG – U.S. will go from .5 T ft3 to 2.2 T ft3 Source: Arabicnews.com, 12/19/2003
LNG http://www.kryopak.com/LNGships.html LNG requires a heavy infrastructure for cooling and transportation. This is currently capacity limited. http://www.energy.ca.gov/lng/
Coal Gasification And Sequestering • Great Plains Coal Gasification Plant (North Dakota) • From coal to the equivalent of natural gas • Sequester carbon dioxide into oil fields to assist in pumping • Oil field operator pays for Carbon Dioxide http://www.dakotagas.com/
Renewable Energy Potential Recall that the world needs 20 TW of carbon-free energy by 2050. Source: Turkenburg, Utrecht University
Solar Energy Potential • Facts: • Theoretical: 1.2x105 TW solar energy potential (1.76 x105 TW striking Earth; 0.30 Global mean albedo) • 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 Source: Nathan Lewis
Solar Thermal Energy Potential • 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) Source: Nathan Lewis
PV Land Area Requirements For U. S. Energy Independence • Facts: • 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 • Conclusions: • 3.3 TW /(2x102 W/m2 x 10% Efficiency) = 1.6x1011 m2 • Requires 1.6x1011 m2/ 9.1x1012 m2 = 1.7% of Land Source: Nathan Lewis
PV Land Area Requirements 3 TW 20 TW Source: Nathan Lewis
It takes .16% of the Earth’s surface to generate the Carbon Free energy needed in 2050 • 1.2x105 TW of solar energy potential globally • Generating 20 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.) Source: Nathan Lewis
A “Notional” Distribution Of PV “Farms” To Achieve 20 TW of Carbon Free Energy in 2050 6 Boxes at 3.3 TW Each Source: Nathan Lewis
How Much Energy Can Be Produced On The Roofs of Houses? • 7x107 detached single family homes in U.S. • ≈2000 sq ft/roof = 44ft x 44 ft = 13 m x 13 m = 180 m2/home or … 1.2x1010 m2 total roof area • This can (only) supply 0.25 TW, or ≈1/10th of 2000 U.S. Primary Energy Consumption • … but this could provide local space heating, surge (daytime) capacity. Source: Nathan Lewis
crystalline Si amorphous Si nano TiO2 CIS/CIGS CdTe Efficiency of Photovoltaic Devices 25 20 15 Efficiency (%) 10 5 2000 1980 1990 1970 1950 1960 Year Source: Nathan Lewis Margolis and Kammen, Science 285, 690 (1999)
Status Of Solar Photovoltaics • Current efficiencies of PV modules: • 6-9% on amorphous Silicon; 13-19% for crystaline Silicon • Performance efficiency improvement of 2X is anticipated • Increase in PV shipments (50MW in 1991; 280 MW in 2000) • Continuous reduction in investment costs up front • Rate of decline is 20%/year • Current cost is $5/Watt; target is $1/Watt (5X) • Payback time will be reduced from 3-9 years to 1-2 years • Electricity production cost prediction: • $.30 to $2.50/kWh would be reduced to $.05 - $.25/kWh • Over 500,000 Solar Home Systems have been installed in the last 10 years Source: Turkenburg, Utrecht University
Nuclear As An Option? • Nuclear plants do not scale well. • Typically most effective at 1 GWatt • To produce 10 TW of power … • 10000 new plants over the next 50 years • One every other day, somewhere in the world • Nuclear remains an option • Fusion power remains as a “great hope”
Energy Future: Options • Topics: • Hydrogen • Fuel Cells
Hydrogen • Widely produced in today’s world economy • Steam-methane reformer (SMR) process • Just now, beginning to successfully scale down (e.g. to be used at “gas stations” in future (100,000 places in U.S,). Source: NAE Article, The Bridge, “Microgeneration Technology”, 2003
Electrolysis • Hydrogen can also be made from solar power on electrolysis of water • A liquid, transportable form can be produced (methanol; (good catalysts exist to do this from CO2 )). This ends up as carbon neutral or CO. • At bulk power costs of $.03/W electrolysis of water can compete with compressed or liquid H2 (transported) • Could produce small quantities of H2 to fuel cars, even at the level of a residence
Hydrogen, Again • Fuel cells using Proton Exchange Membrane have made enormous progress, but are still expensive. • Hydrogen storage in carbon fiber strengthened aluminum tanks. • Hydride systems and carbon from solar power on electrolysis of water • A liquid, transportable form can be produced (methanol; (good catalysts exist to do this from CO2). This ends up as carbon neutral. • Hydrides appear to be promising as means of storing hydrogen gas
Is there Carbon in Hydrogen? • If used in a fuel cell, Hydrogen still produces Carbon (Dioxide) because of how it was manufactured: • 145 grams/mile if it comes from natural gas • 436 grams/mile if it comes from grid electricity • But, for context: • 374 grams/mile if it came from gasoline (no fuel cell) • 370 grams/mile if natural gas had been used directly (no fuel cell). • 177 grams/mile through hybrid vehicles (no fuel cell; with natural gas) Source: Wald, New York Times, 11/12/2003
Fuel Cell Technology Source: CETC
Fuel Cell Power Generation Is Emerging Source: Ballard
Energy Future: Options • Topics: • Distributed Power Generation • Spinning capacity
Microgeneration Technology(Distributed Generation) • 7% of the world’s energy is generated on a distributed basis • In some countries this is up to 50% • Generate power close to the load • 10 – 1000 kW (traditional power plants are 100 – 1000 MW) • Internal Combustion, Turbine, Stirling Cycle (with efficiencies approaching 40%), Solid-oxide fuel cells (over 40% efficiency), Wind Turbines, PV • Modular (support incremental additions of capacity) • Low(er) capital cost • Waste heat can be captured and used locally via Combined Heat and Power (CHP) systems • Storage technology is also moving forward to deal with localized capacity (e.g. zinc-air fuel cell). Source: NAE Article, The Bridge, “Microgeneration Technology”, 2003
Spinning Reserves From Responsive Loads • How to avoid significant “reserves” in power generation? • Control both generation and load: • Historically only generation was controlled • Network technology enables control of load (through management of numerous small resources) Source: Oak Ridge Research Report, March 2003.
Spinning Reserve From Responsive Loads(Smart Energy) Carrier ComfortChoice themostats provide significant monitoring capability - Hourly data - No. of minutes of compressor/heater operation - No. of starts - Average temperature - Hour end temperature trend - Event data - Accurate signal receipt and control action time stamp
Conservation • Hybrid Vehicles • Space heating • Water heating • Co-generation
Energy Future: Options(Policies) • Topics: • Taxes • Forced Standards • Research and Development
Energy Future: The EE Role • Electricity is the future • Most energy sources will come via electricity • Systems will have to be significantly more efficient, smarter: • More distribution • More connectivity (communication) • More intelligence • More information • More integration • More transparency • The entire energy infrastructure will have to be changed within 50-100 years Electrical Engineers will play a critical role in making this transition effective
Conclusions (Mine) • There is an “energy problem” (a “carbon problem”), an unsustainable dependence on fossil fuel • Market forces and innovation will play a major role, but are not responsive enough to deal with mass scale, current low costs of energy, and long time constants • The economic impact of a forced shift from fossil fuels is unacceptable • Policy shifts and long term investment are needed • Natural Gas to Solar is the most visible path to sustainability, today • Major, near term investment in Natural Gas infrastructure is needed • Cost of a major solar power infrastructure is daunting, but we should organize ourselves for this eventuality • Hydrogen can/will become an important transport system (start with methane derived hydrogen and move toward renewable resource driven hydrogen) • Known efficiencies can produce near term gains. E.g., Distributed power (with co-generation of heat), “smart power”, hybrids • Substantial investment in renewable energy research is justifiable • Sufficient research is needed to achieve attractive economies of scale