Energy matters: Electric cars, range anxiety, plug-in hybrids


Is it time to get an electric car (EV)? Aren’t EVs with a large “range” expensive? Can you afford one with enough range to get where you need to go in Maine? Will you be stranded in the middle of nowhere without a charging station? And then, how long does it take to charge?

To address the range anxieties, consider a plug-in hybrid.

We won’t go into finances here except to note that there are currently rebates from Efficiency Maine and tax credits from the federal government designed to help with EV affordability, and the plug-in hybrid qualifies.

Electric car range is improving every year. Typical all-electric models can now go between 200 and 300 miles on a charge. Most of the average person’s driving keeps them near home and the best option for charging is in their own driveway or garage. That means that most of the time, range anxiety should not be an issue. The problem is what to do when going on a long trip. Location of charging stations, time spent charging, and cost to charge are all issues.

While battery storage, charging station infrastructure, and charging speeds are all going to improve rapidly over the next several years according to the experts, these questions raise legitimate concerns at present. The plug-in hybrid addresses these issues to a good degree.

We’ve recently had the good fortune to test the performance of a plug-in hybrid all-wheel-drive Toyota RAV-4. The plug-in differs from a regular hybrid in that it can run purely on electricity for a certain range. When the batteries drop to a certain level of charge, the gasoline engine kicks in and the car works like a regular hybrid vehicle.

The RAV4 batteries, when fully charged, allow you to travel around 45 miles before using any gasoline. If you stay near home it’s possible to not use any gasoline at all for weeks at a time. Only when you take longer trips will you use gas. The rating for pure hybrid mode, which would apply, say, on a cross country trip, is 45 mpg.

Over about five weeks we have driven the car just over 1900 miles, taking several trips beyond the 45 mile range. Over that distance we have used a total of 21 gallons of gas – which might mean we’ve gone over 90 miles per gallon – but of course we need to consider electrical usage.

Without actually metering it, based on how many miles we have traveled on just electricity, we estimate that we have used a total of 320 kWh. It takes 16 kWh to fully charge the car for the 45 mile range. That comes out to 2.8 miles per kWh or about 5.4 cents per mile. Calculating the total energy cost so far we paid about $62 in gas (at $2.95 per gallon) and $48 in electricity (at $0.15 per kWh) for a total of $110 to go 1900 miles.

So how does it compare to a gasoline car? There are a number of comparable small SUVs (Jeep Renegade, Honda CR-V, Chevy Equinox.) One of these will typically get between 25 and 30 mpg. So how much energy would it use? At 27 mpg, over 1900 miles it would use 70 gallons of gas, which would total about $206, or almost twice that of the plug-in.

You might also want to compare greenhouse gas (GHG) emissions from the plug-in and the all-combustion car.

Burning one gallon of gas produces around 10kg (22 pounds) of CO2. Here in Maine, generating a kWh of electricity will produce anywhere between 50 and 500g of CO2 (The number varies hugely depending on your energy source). We will use the average for New England, which is about 340 g per kWh.

Putting these numbers together, over 1900 miles we produced about 320kg of CO2, while the gasoline car would have produced around 700kg—more than twice as much.

A significant disadvantage of the hybrid car over the all-electric vehicle is lifetime maintenance costs – higher in the hybrid due to its internal combustion engine. The electric vehicle has far fewer moving parts and far fewer expected repairs.

A friend who works for Efficiency Maine, the quasi-governmental office that handles state energy incentive programs, turned us on to a sweet chart at Carboncounter.com https://www.carboncounter.com/#!/explore – It charts greenhouse gas emissions against lifetime vehicle costs for a whole lot of vehicle types and engine configurations, so you can see how standard gas models compare with these new breeds. Quite fascinating.

Electrification of our transportation sector is inevitable, but there are still issues that are difficult to transcend. In the meantime, we will treat our range anxiety with the plug-in hybrid—and have fun doing so! Did we mention that it goes from zero to 60 in a smooth six seconds??

Paul Stancioff, PhD., is a professor of Physics at the University of Maine Farmington who studies energy economics on the side. He can be reached at [email protected] Cynthia Stancioff is a nature-lover who likes to re-word things. Previous columns can be found at https://paulandcynthiaenergymatters.blogspot.com/.

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