Re-Tasking Spent Hybrid Vehicle Batteries as Peak Load Shavers Gregory D Carlson Energy and Earth Resources Jackson School of Geosciences University of Texas at Austin

Gregory D Carlson20 November 2007University of Texas at Austin Demand (MW) Marginal Cost ($/MW) Motivation to Store Power In PJM, the Brattle Group determined that reducing the peak demand by 0.9% dropped the market price of power 5-8%.

Gregory D Carlson20 November 2007University of Texas at Austin Power Storage Grid Pumped Hydro Compressed Air Magnetic Storage BatteriesHydrogen Thermal Storage

Gregory D Carlson20 November 2007University of Texas at Austin Storage – Efficiency Source:

Gregory D Carlson20 November 2007University of Texas at Austin Storage – Costs Source:

Gregory D Carlson20 November 2007University of Texas at Austin Hybrid Vehicle Batteries - Prius Chemical Composition - NiMH Capacity – 6.5 Ah, V (1.95kWh) Size cubic feet Weight – 99lbs Modules - 28 Useable Life – cycles in vehicle usage (translates to 6-12 years) Cost – Almost free since they are being discarded

Gregory D Carlson20 November 2007University of Texas at Austin Pros/Cons of Hybrid NiMH Pros  Cheap  Point of Use  High number (failure is probabilistic)  Small size (relatively)  No additional land requirement Cons  No clear vendor  Not very efficient (50-70%)

Gregory D Carlson20 November 2007University of Texas at Austin PHEV – HEV – EV Projections Over 600,000 hyrbids in US right now Hybrid market share is increasing EV/PHEV battery size versus HEV  EV and PHEV battery packs will be similar chemical composition initially, but much larger Next Gen Batteries – Li-Ion vs NiMH  Li-Ion have higher energy density, but lower life expectancy – may not be good for this application

Gregory D Carlson20 November 2007University of Texas at Austin References “Quantifying Demand Response Benefits in PJM,” Brattle, “Potential for DR, EE, and Onsite RE to Meet Texas’ Growing Need,” ACEEE