Where you live is an important factor:
As vehicles powered by electricity make up a larger percentage of the nation's fleet over the next generation, demand for electricity could surge. That extra power has to come from somewhere — and right now, nearly two-thirds of electricity generated in Michigan comes from burning fossil fuels.
This is a subject that comes up *every single time* I get into a debate with climate change deniers, when discussing zero-emissions electric vehicles. But unlike many of their other arguments, there is more than just a grain of truth in their position. When you tap power from the grid, it makes a direct connection with "how" that grid generates its power. If we choose to ignore that, we're no better than those who ignore all the costs associated with other forms of industrial pollution. Before we proceed, here's a related personal anecdote:
A few months ago, during a Board of Aldermen's meeting (I was sitting in the audience, because I lost that race), the Town Manager presented to the Board an opportunity to have an EV charging station installed somewhere in the town, helped by a big chunk of money from Duke Energy. To make a long story less long, this is part of a lawsuit settlement Duke agreed to pay, and the clock was ticking on the application for a grant. Being the brave and intrepid (that's sarcasm) body they are, the Board instructed the Town Manager to determine if there would be *any* costs to the Town associated with this charging station.
After the meeting, I met with the Town Manager and told him I would see what I could find out. The next day, I stumbled across this Town of Cary report on its charging stations, which I forwarded to Ben. Here's some info on one of Cary's stations:
On average, there were approximately 20 charging sessions per month, with an average of three charging sessions occurring per month that were public or non-fleet and 17 sessions that were the town fleet vehicle. Over the two year reporting period, a total of 3,354 kWh of electricity was consumed (approx. $254.93), averaging a round 134 kWh per month (approx. $10.20). The average energy consumed was 7.76 kWh per session overall, 7.62 kWh per session for public charging sessions and 7.16 for fleet charging sessions.
Okay, so: costs for charging each vehicle are negligible, but since "zero" cost was the target our esteemed local officials had set, our Town did not pursue an EV charging station. This time...
Back to the national geographical assessment of climate impact per vehicle:
To calculate the damage from gas-burning cars, they weighed the car's Environmental Protection Agency fuel economy ratings (city miles per gallon for urban counties, highway MPG for rural areas, average wind patterns, and number of environmental damages to health, infrastructure and crops. Together that data gave them the aggregate emissions of driving a certain gas car one mile in a given U.S. county.
To find the impact from electric vehicles, the researchers used the car's fuel-efficiency equivalent (kilowatt-hours per mile) to measure how much power it took from the grid. They also had information about the emission patterns from nearly 1,500 power plants throughout the country.
From that they could get an estimate of the draw from the grid when an EV owner plugs in, showing the environmental impact at the power source.
The Union of Concerned Scientists in 2015 published a two-year study that looked at emissions from production, operation and disposal of electric and gasoline vehicles. Among the findings: battery-electric cars generate half the emissions of an average comparable gasoline car, even after factoring in pollution from battery manufacturing.
Yet UCS acknowledges that the net benefit varies depending on the energy sources of a region's grid.
One thing that both of these studies agree on: Self-charging hybrids are currently at the top of the "clean and efficient" scale. Keep in mind, Solar charging stations for plug-in hybrids and all-electric vehicles were not factored into these equations, something that will (hopefully) become more common. But for now, where you live *must* be calculated into your decision before you take the step to go EV. I know a lot of folks will find this distasteful, but this factor could actually promote more renewable energy generation.