fuel economy

After much waiting, our new Nissan Leaf is finally here. I picked it up this afternoon. It’s definitely a new kind of car — not only is it fully electric, but in many respects it seems a bit like a computer on wheels. It goes faster than any computer, though. Driving on Oak Ridge Turnpike, I noticed that I was going too fast — my guess is that since there’s no engine noise, I wasn’t getting the auditory feedback that I’m accustomed to.

One thing that will take some getting used to is the fact that many of the major controls of the vehicle seem to be closely related to the controls for the radio — it’s all about communication, I guess.

The dashboard display behind the steering wheel includes the speed and the odometer reading (just like a gas-powered car), some interesting symbols that measure current power utilization — how hard the car is either using power or regenerating the battery while decelerating or braking, a display that looks like a gas gauge but indicates how much charge is left — measured in miles remaining on the battery, and a temperature gauge that shows the temperature of the battery. I don’t yet know what we are supposed to do if the battery starts getting “too hot.” There’s a coolant reservoir under the hood, but I still don’t know where the coolant circulates and what part of the car it cools (maybe it cools the battery — or maybe it’s part of the HVAC system).

There’s a touch screen with a complicated collection of displays — far more than in our Toyota Prius. I think that it’s probably best to ignore this touch screen while driving, as the Google navigation maps, energy use details, radio station displays, heating/cooling details, etc., could be very distracting. The touchscreen display is where I saw a readout indicating that the car was getting 3 miles per kilowatt-hour, on average.

Both the car and the plug-in charger are programmable devices that can be told when to charge the car (I don’t know which device takes priority if they have different programming), so the battery is scheduled to get recharged in the middle of the night, when baseload electricity generating facilities (nuclear power plants, plus some coal-fired plants) typically crank out more electricity than the grid needs. At this time, Oak Ridge residential customers pay the same price for that off-peak power as we do for peak power during the day, so we’re not saving any money by charging at night, but over the next few years that’s expected to change. TVA recently started charging the city a dual rate that has both a monthly usage (kilowatt hours) component and a peak demand component (based on the hour each month that the city had the highest usage). Over the next several years, they’ll introduce peak and off-peak rates, and the city will begin to pass differential rates on to consumers — encouraging us to shift the timing of some of our electric use. Until then, I guess we’re practicing for that future — and our car and our charger will be sending data to Department of Energy researchers to help them understand and model how electric cars will interact with the electricity grid and the transportation system in future years.