One of last month’s blogs was centered on the impact a heat wave was having on the electrical grid. In this edition, let’s look at the potential impact of electric cars. A typical gallon of gasoline theoretically has the electrical equivalent of ~36.6 kW hours of electricity. A typical gasoline engine is 20% efficient in converting that energy to motion and an electric car is approximately 75% efficient in doing the same task.
As gasoline powered vehicles are being replaced by electric powered versions, some quantity of energy that had been delivered to the previous vehicle as gasoline will now need to be delivered to the new one via the electric grid. If we crunch the numbers ((36.6*.2)/.75) we get ~9.76 kWh that needs to be delivered by the electric grid to replace each gallon of gasoline.Let’s assume that the gas and electric vehicles are being used in a typical commuting day plus a few errands for a round trip of 45 miles. We also will assume that the average gasoline powered vehicle gets 20 miles per gallon. So we get (45/20) or 2 ¼ gallons of gasoline for the old vehicle which translates to ~ 22 kWh of electricity for the new one. Reading the specs for a typical in-home electric vehicle charging station we find that they use a ~220V / 30A outlet which delivers 6.6 kW per hour if it is cranked to the fastest charging rate. As we see, it would take ~3 hours and 20 minutes to charge at that rate. Now the math might have been a bit rough but it’s probably in the right ballpark as we have seen electric car specs. mentioning ~100 mile range and ~6 hour charges.
In closing, let’s imagine another heat wave. The electric grid is already under strain. The evening commute finishes. Stoves and air conditioners are turned on and now, a whole bunch of electric cars get plugged in so that they can be ready for morning. The smart grid might be able to shift some demand around to mitigate some of the peak demand but not likely all of it. The grid in the USA might be much better than many places but, unless something significant happens in infrastructure improvement, more blackouts and power events are likely. If this does in fact happen, it is likely that sales of power protection products will increase in response. The VDC demand side reports for the 2010 Power Protection Product markets are publishing this week and we are heavily into the research on the supply side. Look to this space for future updates on how suppliers feel about this.