Sunday, May 23, 2010

What if 25% of the Cars were plug in...How much power is needed?

Last week Toyota announced a partnership with Tesla motors backed by $50M in investments. Tesla is the manufacturer of the trendy $100K all electric plug in sports car and has a model for us all in the works, the Model S. Toyota wants the technology and I can just imagine a Tesla/Prius in every garage. Gov. Schwarzenegger hailed the joint venture as the future and asked us all to imagine CA with more plug ins.

“What we are witnessing today is an historic example of California’s transition to a cleaner, greener and more prosperous future. We challenged auto companies to innovate, and both Tesla and Toyota stepped up in a big way, not only creating vehicles that reduce emissions and appeal to consumers but also boosting economic growth,” said Governor Schwarzenegger.

How will all these plug ins be powered? Everyone seems to think that electricity comes from a plug in the wall. Power has to come from somewhere.  How will we make a green lifecycle from source to vehicle?  Wind turbines? Coal? Gas? Solar? Nuclear? 

Lets break it down.

136,000,000 registered passenger vehicles in 2007. Lets say 25% of the cars suddenly become plug ins. Therefore: 34,000,000 vehicles.

16.8 KW = 56miles charged per hour per the Tesla website.

Assume 12,000 miles per year driven we have 214 hrs of charge at 16.8 KW or 3600 KW-Hrs per car.

with 34M cars we have 1.2 x 10^11 KW-Hrs
A new nuclear power plant generates 13 billion kilowatt-hours (kWh) or 1.3 x 10^10 (assuming 1600MWe and 92% availability).

So the final answer is: 9.4 new nuclear plants would be required to keep all those vehicles charged.  One plant charges 3.6M vehicles. There were 16,153,952 new vehicles (cars trucks and SUVs) sold in 2007.

Conclusion: We need one new 1600MWe plant a year if 25% of the new cars are all electric using the numbers and 2007 sales rates above.

Electric vehicles are great, we just need to remember that the power source is part of the equation and that conservation and alternative energy will not be enough to account for future energy demands.

3 billion barrels of gasoline were refined in 2006 out of 5.5 billion barrels of crude oil.   1.6 x10^9 gallons or 3.8 x 10^7 barrels of gasoline would be removed per year if 25% of new cars were all electric.  Using the ratio of gas to oil equates to  7 x 10^7 barrels of crude oil saved per year (2006 refining and 2007 car sales and 30mpg).

Numbers and calculations are for illustrative purposes.  I am hoping for credit for error carried forward--ECF.

Good points raised from readers comments:
1. The number of cars calculation I used omits trucks and SUVs reducing the overall number of cars.  
2. What about reduced electricity demand off peak at night?  Good question.  I did not take that into account, however smartgrid technology and offpeak charging will mitigate the effects of EV.  There is also talk of VTG or vehicle to grid where the electric vehicle could actually supply power during peak or the most expensive time of day and then charge during off peak or cheaper times of day.


1 comment:

  1. what is the peak off-peak differential of the current generation capacity?