1. What do you think the power from a wind turbine looks like over the course of a month?

3. What do you think the power from a solar panel looks like over the course of a day?

5. There is a need to store energy if your supply isn’t constant

6. Grid Energy Storage What is the maximum power capacity needed here?

7. Grid Energy Storage What is unrealistic about this example?

8. Total Grid Energy Storage: >250 GW  Most is pumped hydro

9. Pumped hydro storage: (Example --- Luddington, Michigan)

10. New Taum Sauk Reservoir

11. Pumped hydro storage: ~ 70-85% efficient  First used in 1890’s in Italy and Switzerland  ~22 GW of power storage in the US  Largest is in Bath County, VA  3 GW

13. Batteries: 50 to >90% efficient 1917 English gasoline engine with 16 batteries that could supply 4.5 amps at 32 V for 7.5 hours

14. Batteries:

16.  Lead-Acid Battery

17. Traditional Batteries: Expensive, high maintenance, and limited lifetimes, but can supply large power for short amounts of time  Many new compositions are being explored (lithium iron phosphate, sodium-sulfur, vanadium, etc.)  A system in Puerto Rico has a capacity of 20 MW for 15 minutes (5 MWhr)  A system in a remote area of Fairbanks (Alaska) provides 27 MW for 15 minutes (6.75 MWhr)

18. Experimental: Liquid Metal Batteries

19.  Initially Magnesium/Anitmony; now Lead/Antimony  Operates at 350-430°C (cooler than previous alloys)  Energy storage efficiency of 70% (down to 60% after 10 yrs)  Cost is $500/kWhr (needs to get down to ~$100/kWhr)

20. Experimental: Liquid Metal Batteries  Liquid is mobile (so more efficient)

21.  Many computer systems are hooked to UPCs (uninterruptible power supplies)

22. Compressed Air Energy Storage (CAES): Usually <60% efficiency  McIntosh, Alabama  27 efficiency http://www.powersouth.com/mcintosh_power_plant/compre ssed_air_energy

23. Where is energy lost?

25. Compressed Air: New technology involving adiabatic storage and retrieve (heat is retained with high insulation)  German ADELE plant in development (2015?)  Will operate at ~70% efficiency But then need a way to store heat (as hot oil, up to 300°C, or as molten salt, up to 600°C)

26. Compressed Air Energy Storage: Good geologic locations are salt layers and aquifers Why?

27. Compressed Air Energy Storage: Good geologic locations are salt layers and aquifers Why? How could you make a salt cavern?

28. Flywheels: Small, but fast retrieval of power Beacon Power has a 20 MW flywheel energy storage plant in Stephentown, NY

29. Flywheels: Beacon Power has a 20 MW flywheel energy storage plant in Stephentown, NY What happens if it gets too big?

30. Size vs. Retrieval Time:

34. Total Grid Energy Storage: >250 GW

36. Hydrogen Storage: Energy can be converted into hydrogen by: 1)Steam reformation of hydrocarbons 2)Water electrolysis

37. Hydrogen Storage: Energy can be converted into hydrogen by: 1)Steam reformation of hydrocarbons (~65%-75% efficient) Steam reacts with hydrocarbons (usually methane) to release hydrogen gas Ex/ 2-step process starting with methane: A)CH 4 + H 2 O  CO + 3H 2 (“methanation”) B)CO + H 2 O  CO 2 + 3H 2 (“water-gas shift”)

38. Hydrogen Storage: Energy can be converted into hydrogen by: 2) Water electrolysis (~30-45% efficient): The decomposition of water (H 2 O) into oxygen gas (O 2 ) and hydrogen gas (H 2 ) by passing an electric current through the water.

39. Water electrolysis

40. Hydrogen Fuel Cells: The released hydrogen can then be compressed, transported and used for hydrogen fuel cell technology

41. Hydrogen Fuel Cells: In a hydrogen fuel cell, the reverse of hydrolysis happens  The hydrogen and oxygen combine to make water, driving an electric current

42. Hydrogen Fuel Cell Cars: Target availability = 2015 Honda Clarity can now be leased in California for $600/mo  Production costs have dropped from $1M/car to about $120K/car

43. Electric Cars: Thomas Edison and a Detroit electric car, 1913

44. Electric Cars: Nissan Leaf – best selling electric car  55,000 sold by March, 2013

45. Electric Cars: Tesla (Roadster - $110,00) and Model S Sedan ($57,000). Soon, the Bluestar (~$30,000) http://www.youtube.com/watch?v=oLiLGTqzfBU

46. 98% of Evs use Lithium-ion batteries  Expensive, but high energy density

47. Tesla ESS (energy storage system) uses 6831 lithium cells

48. 87% of Hybrid Cars use NiMH (Nickel-Metal Hydride)  Half the energy density and cost  The Prius uses a battery back of 168 NiMH cells that are 1.2 V each

49. Salar de Uyuni (Andes Mountains, Bolivia), salt polygons:

50. Salar de Uyuni, mirror-like quality

52. Salar de Uyuni: Harvesting Salt

53. Salar de Uyuni, brine beneath salt crust

54. Lithium plant at Salar de Uyuni

55. Lithium plant at Atacama Salt Flats (Chile)

56. Hydrogen Fuel Cell vs. Electric Cars: EVs more efficient

57. It is still not clear which technology for cars will dominate: Hydrogen Fuel Cells vs. Electric Cars (Each has plenty of pros and cons)