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University of California Santa Cruz Electrical Engineering Department

University of California Santa Cruz Electrical Engineering Department. Energy Storage and Hydrogen Economy Ali Shakouri. Edited by Mona Zebarjadi for EE80j, Summer 2009. EE80J-180J; 21 May 2009. Electricity Usage Pattern. Energy Usage in a typical household.

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University of California Santa Cruz Electrical Engineering Department

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  1. University of California Santa CruzElectrical Engineering Department Energy Storage and Hydrogen Economy Ali Shakouri Edited by Mona Zebarjadi for EE80j, Summer 2009 EE80J-180J; 21 May 2009

  2. Electricity Usage Pattern

  3. Energy Usage in a typical household • Electricity Usage ~15 kWh/day (54 MJ/day) power ~ 625W • Storage: • Water: 78,717 liter (a cube whose side measures at 4.3 m) at 100 meter (70% conversion efficiency) • Flywheel: 2138kg, 4m radius, 600rpm (80% conversion efficiency) • Compressed Air: 3600 liter (0.03 MJ/liter, 50% conversion efficiency) • Hot Water Usage ~25-35MJ • 150-200 liter water heated from 15C up to 55C • Burn 4-5kg of wood in 50% efficient wood stove.

  4. Energy Storage Options

  5. Compressed air energy storage • Air is compressed and stored under ground • Huntorf, Germany 1978, hold pressures up to 100bar (2kWh/m3) • Alabama (1991) 70bar energy density 0.54kWh/m3

  6. Battery • Primary batteries • Zinc-Carbon • Alkaline • Secondary (rechargeable) batteries • Lead-Acid • Nickel-Cadmium • Vanadium

  7. Battery Characteristics • Battery capacity: Amount of charge that it holds (amp-hours) I xt • Discharge rate: number of hours over which the battery discharges • A battery rated at 100 A·h will deliver 5 A over a 20 hour period at room temperature. However, if it is instead discharged at 50 A, it will run out of charge before the 2 hours theoretically. . Practically, when discharging at low rate, the battery's energy is delivered more efficiently than at higher discharge rates

  8. Discharge Characteristics

  9. Battery Characteristics Cycle life • State of charge (SOC): percentage of storage capacity still available in the battery • Battery cycle: cycle of discharge and recharge from a given SOC down to a lower state of charge and back to the original state of charge

  10. Battery Characteristics Figure 1: Cycle life of nickel-metal-hydride batteries under different operating conditions. (Zhang, 1998) NiMH performs best at DC and analog loads and has lower cycle life with digital a load. Figure 2: Cycle life of lithium-ion at varying discharge levels. (Choi et al., 2002) Like a mechanical device, the wear-and-tear of a battery increases with higher loads

  11. Lead Acid Battery www.daviddarling.info

  12. Battery Discharging Pb+PbO2+2H2SO4→ 2 PbSO4 + 2 H2O Pb PbO2 H2SO4

  13. Battery Charging Pb+PbO2+2H2SO4← 2 PbSO4 + 2 H2O

  14. Vanadium flow Battery • Advantages: • Rechargeable • it can offer almost unlimited capacity simply by using larger and larger storage tanks, • it can be left completely discharged for long periods with no ill effects, • it can be recharged simply by replacing the electrolyte if no power source is available to charge it, and if the electrolytes are accidentally mixed the battery suffers no permanent damage. • Disadvantages • a relatively poor energy-to-volume ratio, 87 liter 1kWh (compare to 1liter gasoline which has 9.3kWh) • the system complexity in comparison with standard storage batteries • Shortage of vanadium supply

  15. Fuel Cells H2 + O2® H2O + electrical energy

  16. Energy Storage Options Combustion Engine Specific Power (W/kg) Specific Energy (Wh/kg)

  17. Basic Research Needs for the Hydrogen Economy June 24, 2004 DOE Nano Summit Washington, D.C. Presented by: Mildred Dresselhaus Massachusetts Institute of Technology millie@mgm.mit.edu 617-253-6864

  18. Hydrogen: A National Initiative in 2003 • “Tonight I'm proposing $1.2 billion in research funding so that America can lead the world in developing clean, hydrogen-powered automobiles… With a new national commitment, our scientists and engineers will overcome obstacles to taking these cars from laboratory to showroom, so that the first car driven by a child born today could be powered by hydrogen, and pollution-free.” • President Bush, State-of the-Union Address, January 28, 2003 M. S. Dresselhaus, MIT

  19. solar wind hydro automotive fuel cells consumer electronics H2 H2O H2 nuclear/solar thermochemical cycles stationary electricity/heat generation fossil fuel reforming Bio- and bioinspired $3000/kW 4.4 MJ/L (Gas, 10,000 psi) 8.4 MJ/L (Liquid H2) production 9M tons/yr $30/kW (Internal Combustion Engine) 150 M tons/yr (light cars and trucks in 2040) 9.70MJ/L (2015 FreedomCAR Target) The Hydrogen Economy gas or hydride storage use in fuel cells storage M. S. Dresselhaus, MIT

  20. Hydrogen issues 1 –H2 is not dense even liquid H2 is 10 times less dense than gasoline H2 vs Gasoline • 3 xmore energy per gram (or per lb) • 3 x less energy per gallon (or per liter) 2- H2 liquid is dangerous to store; expands by a factor of a thousand if warmed 3-There is virtually no hydrogen gas in the environment 3.1.If we use methane to create H2, we also create Co2 3.2.A Hydrogen production plant would get its power from somewhere else. Hydrogen is not a source of energy. It is only a means for transporting energy. 4-Hydrogen production (electrolysis) 70% efficient, Best efficiency from a fuel cell 60%>>Overall 70x60~ 40% 5-It is not yet competitive with the fossil fuel economy in cost, performance, or reliability - The most optimistic estimates put the hydrogen economy decades away

  21. Hydrogen Production Panel Panel Chairs: Tom Mallouk (Penn State), Laurie Mets (U of Chicago) • Current status: • Steam-reforming of oil and natural gas produces 9M tons H2/yr • We will need 150M tons/yr for transportation • Requires CO2 sequestration. • Alternative sources and technologies: • Coal: • Cheap, lower H2 yield/C, more contaminants • Research and Development needed for process development, • gas separations, catalysis, impurity removal. • Solar: • Widely distributed carbon-neutral; low energy density. • Photovoltaic/electrolysis current standard – 15% efficient • Requires 0.3% of land area to serve transportation. • Nuclear: Abundant; carbon-neutral; long development cycle. M. S. Dresselhaus, MIT

  22. Hydrogen Storage Panel Panel Chairs: Kathy Taylor (GM, Retired) and Puru Jena (Virginia Commonwealth U) • Current Technology for automotive applications • Tanks for gaseous or liquid hydrogen storage. • Progress demonstrated in solid state storage materials. • System Requirements • Compact, light-weight, affordable storage. • No current storage system or material meets all targets. • IDEAL SOLID STATE STORAGE MATERIAL • High gravimetric and volumetric density • Fast kinetics • Favorable thermodynamics • Reversible and recyclable • Safe, material integrity • Cost effective • Minimal lattice expansion • Absence of embrittlement M. S. Dresselhaus, MIT

  23. Priority Research Areas in Hydrogen Storage Metal Hydrides and Complex Hydrides Degradation, thermophysical properties, effects of surfaces, processing, dopants, and catalysts in improving kinetics, nanostructured composites Nanoscale/Novel Materials Finite size, shape, and curvature effects on electronic states, thermodynamics, and bonding, heterogeneous compositions and structures, catalyzed dissociation and interior storage phase Theory and Modeling Model systems for benchmarking against calculations at all length scales, integrating disparate time & length scales, first principles methods applicable to condensed phases Neutron Imaging of Hydrogen NaBH4 + 2 H2O 4 H2 + NaBO2 Cup-Stacked Carbon Nanofiber H Adsorption in Nanotube Array M. S. Dresselhaus, MIT

  24. Types of Fuel Cells Phosphoric Acid FC (PAFC), 250 kW United Technologies Alkaline Fuel Cell (AFC), Space Shuttle 12 kW United Technologies Low-Temp High Temp Proton Exchange Membrane (PEM) 50 kW, Ballard Solid Oxide FC (SOFC) 100 kW Siemens- Westinghouse Molten Carbonate FC (MCFC) 250 kW FuelCell Energy,

  25. Hydrogen refueling station, Chino, CA Photo: NREL Fuel Cell Vehicle Learning Demonstration Project Underway; 3 Years into 5 Year Demo • Objectives • Validate H2 FC Vehicles and Infrastructure in Parallel • Identify Current Status and Evolution of the Technology Keith WipkeNational Renewable Energy Laboratory

  26. Vehicle Status: All of First Generation Vehicles Deployed, 2nd Generation Initial Introduction in Fall 2007 77 Keith WipkeNational Renewable Energy Laboratory

  27. Fuel Cells and Novel Fuel Cell Materials Panel Panel Chairs: Frank DiSalvo (Cornell), Tom Zawodzinski(Case Western Reserve) Current status: Limits to performance are materials, which have not changed much in 15 years. 2H2 + O2 2H2O + electrical power + heat • Challenges: • Membranes • Operation in lower humidity, more strength, • durability and higher ionic conductivity. • Cathodes • Materials with lower overpotential and resistance to impurities. • Low temperature operation needs cheaper (non- Pt) materials. • Tolerance to impurities: S, hydrocarbons, Cl. • Anodes • Tolerance to impurities: CO, S, Cl. • Cheaper (non or low Pt) catalysts. • Reformers • Need low temperature and inexpensive reformer catalysts. M. S. Dresselhaus, MIT

  28. Messages • Enormous gap between present state-of-the-art capabilities and requirements that will allow hydrogen to be competitive with today’s energy technologies • production: 9M tons  150M tons (vehicles) • storage: 4.4 MJ/L (10K psi gas) 9.70 MJ/L • fuel cells: $3000/kW $30/kW (gasoline engine) • Enormous R&D efforts will be required • Simple improvements of today’s technologies will not meet requirements • Technical barriers can be overcome only with high risk/high payoff basic research • Research is highly interdisciplinary, requiring chemistry, materials science, physics, biology, engineering, nanoscience, computational science • Basic and applied research should couple seamlessly http://www.sc.doe.gov/bes/ hydrogen.pdf M. S. Dresselhaus, MIT

  29. Some Useful References Basic Research Needs for the Hydrogen Economy (DOE/BES)http://www.sc.doe.gov/bes/hydrogen.pdf Basic Research Needs to Assure a Secure Energy Future (DOE/BES) http://www.sc.doe.gov/bes/besac/Basic_Research_Needs_To_Assure_A_Secure_Energy_Future_FEB2003.pdf Powering the Future - Materials Science for the Energy Platforms of the 21st Century: The Case of Hydrogen (MIT lecture notes) http://web.mit.edu/mrschapter/www/IAP/iap_2004.html Hydrogen Programs (DOE/EERE) http://www.eere.energy.gov/hydrogenandfuelcells/ National Hydrogen Energy Roadmap (DOE/EERE)http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/national_h2_roadmap.pdf FreedomCAR Plan (DOE/EERE) http://www.eere.energy.gov/vehiclesandfuels/ Fuel Cell Overview (Smithsonian Institution) http://fuelcells.si.edu/basics.htm The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs (National Research Council Report, 2004) http://www.nap.edu/books/0309091632/html/ M. S. Dresselhaus, MIT

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