V2G: Vehicle to Grid Power

1. V2G: Vehicle to Grid Power Seth Insley CH 407H

2. Concept • Cars use large amounts of power • Far more than other power uses • 750 GW electric vs 12 TW from cars • Must generate or store it themselves • Unused most of the time • Average use only 1 hour per day • Fuel cell, hybrid and battery cars generate power as electricity • Why not hook them up to the power grid?

3. Conventional View

4. V2G View

5. Examples • Use the battery in plug-in hybrid/battery cars to buy cheap power at night and sell during the day • Use hybrid/fuel cell car to generate peak power • Use either to provide ‘spinning’ reserve or regulation services

6. Benefits • Better utilize existing generation capacity • Will need to build fewer new electric plants • Allow better load balancing by diversifying the electric grid • Reduce transport load on grid by distributing generation • Increase grid reliability • Provide income to car owners • Offset or reduce the cost of the car

7. Considerations • How will vehicles be connected to the grid? • How will this effect drivers? • Is this a cost effective way to generate power?

8. Infrastructure • Requires physical connection between car and grid • Only useful when parked • Could hook up at home • Could be incorporated into public charging stations or parking lots • Should be simple to set up, automatically handling payment, etc • Just plug it in • May also desire fuel connection: • Natural gas or hydrogen

9. Driver Experience • Primary Consideration: Will this affect range? • Allow owner to easily limit extent of discharge/fuel use • Will it be easy to set up? • Will it be sufficiently profitable to make it worth the effort? • The car owner should not have to worry about this • Only sell power when profitable

10. Economics • Not worthwhile unless it returns sufficient amounts of money after expenses incurred • Cost of fuel/ electricity • Maintenance costs for • Battery • Fuel cell • Engine • Effort required by owner

11. Economic Advantages • Very low capital costs • Car already bought • Adding grid capabilities relatively cheap • Even so, costs roughly $60/kw • Compared to $1000/kw for traditional generators • Due to lower efficiencies, reliability • Has freedom to buy/sell only when profitable • Much more responsive than traditional generators

12. Economic Disadvantages • Poor Efficiency • Smaller/cheaper generators are less efficient • Need more fuel to generate same power • Requires relatively expensive fuels • Gasoline or hydrogen or natural gas vs coal • Cannot buy fuel in bulk

13. Economic Conclusions • Not suitable for baseline power generation • Cost of power to high vs. conventional generators • ~5¢/kwH vs >10¢/kwH • Unique Advantages not used • Suitable for • Peak power generation • Spinning Reserves • Power Regulation • Economic analysis depend heavily on exact assumptions

14. Cost of generation • Cost per kwh • Batteries (charged at base rate) • Lead acid $.23 • NiCad $.32 • NiMH $.45 • Hybrid generating w/ gasoline $.20 • Fuel Cell w/ H2 $.09-$.38

15. Peak Generation • Used when electricity needs are much higher than baseline • During daytime, hot/cold weather, etc. • Considerably more expensive than baseline • Often Generated by natural gas • Low capital, high incremental expense • ~200 hours a year where > 50¢ kwh

16. Economics of Peak Gen • Not to slightly profitable for batteries • Depends on current power markets • Can be fairly profitable for fuel cells • ~1k / year • Less so for hybrids • ~.5k / year

17. Spinning Reserve • Generators ready to provide power in ~10 min • Used to preserve grid stability if generators go down, load is too high • Sold on contract basis • Ex. 1 Kw for a day • Payment even if not used • Extra payment if used

18. Spinning Economics • Profitable for all vehicle types • Batteries $10-$700 • Fuel cell, hybrid generating: ~$2000

19. Power Regulation • Used to keep frequency stable at 60 Hz • Must be able to respond instantly • 2 kinds • Regulation up – generating power • Regulation down – absorbing power

20. Regulation Economics • Batteries are ideal for this purpose • Up/down corresponds to discharge/charge • Has minimal effect on total charge • ~3k for lead acid • ~2k for NiMH • Actual degradation hard to determine • Not profitable for other types

21. Market Size • All numbers for CA electric market • ~300k battery vehicles for regulation • 76k – 273k vehicles for spinning reserve • ~ 734k vehicles at max for peak • .5% – 5% of total light vehicle count • Additional uses are likely in a saturated market • More reliability, renewable

22. Conclusion • V2G is a promising concept • Provides a cheaper way to provide many grid services • Needs more detailed study • Not hard to implement simply • May play an important role in the future power grid

23. Sources • V2G research group at U of DE. “V2G: Vehicle To Grid Power” http://www.udel.edu/V2G/ • Kempton, et. al. “Vehicle-to-Grid Power” http://www.udel.edu/V2G/V2G-Cal-2001.pdf • Kempton, Letendre. “Electric Vehicles as a new Source of Power for Electric Utilities” http://www.udel.edu/V2G/Kempton-Letendre-97.pdf