This is an interesting study that performs a Life Cycle Analysis of hybrid and electric vehicles, taking into account the cleanliness of the grid in the 50 US states, and also the embodied energy and emissions in the manufacturing process of various vehicles. The authors rightly conclude that the benefits of electric vehicles are dependent on the source of electricity they use to charge.
A couple of things the study does not appear to address are the time of day when cars are charged (many grid locations have higher CO2 emissions during peak loads) , and the presence of any distributed energy generation at the charging location. I am an advocate of marrying electric vehicles with grid-tied pv at the charging location, I think this accomplishes the cleanest charging possible, and also trumps the economics of charging from standard grid-power (not to mention filling up at the gas pump.) It also seems that as more aggressive RPS targets continue to kick in across the nation, the sources of grid electricity will be generally emitting less carbon over the coming years.
Here at Power Trip Energy, we have just ordered a Toyota RAV4 EV, which will replace the bulk of the driving we are currently doing in a 23 year old Toyota pick-up truck and a 21 year old Chevy Astro van. Although this vehicle is smaller than those other two, with the back seat down and a folding ladder in the back we will be able to use this vehicle for site evaluations and other light duty work on single story buildings within 50 miles, which describes about 75% of our projects.
We have 4 kw of grid-tied pv, currently generating about 75% of our electricity here at the Power Trip Energy shop, and we will more than double that generating capacity by the end of the year. This will cover the additional electrical consumption we anticipate from our own electric vehicle and from the other EV drivers who are using our free public charging station to recharge. As we are now seeing more occasions when there are two EVs here simultaneously, we will be adding a second charging station when we add the additional pv.
While we are moving forward with what we perceive to be the cleanest smartest energy generation and usage realistically feasible, we look forward to reading the studies of more researchers. We also look forward to installing pv systems and EV service equipment for you.