How Electric are Cars Going to Get?

By Vikram Rao, Executive Director, Research Triangle Energy Consortium

With Electric vehicles are at in interesting inflection point. Car makers are finally getting serious about traversing the main hurdle: battery cost. When the Nissan Leaf first emerged, and for that matter also the Chevy Volt hybrid, lithium cells cost over $450 per kWh (kilowatt hour). As a rule of thumb, each mile driven uses 0.25 kWh. A hundred mile range will require 25 kWh in principle. But it is impractical to drain down to zero and a useful figure is likely 80 or 85%. In other words, 100 mile range likely needs a battery pack with about 30 kWh.

Many of us have posited the notion that cost had to drop below $200, preferably $150 for any sort of widespread use. At $150 per kWh, a 30 kWh battery would cost about $5500, accounting also for the ancillary costs for the pack beyond that of the cells. That is a reasonable fraction of a selling price of $25,000, a useful target for an economy 5 seating car. An all-electric car has no internal combustion engine, no transmission, possibly no differential (if 4 motors are used), all of which reduces cost. But a 100 mile range may not sell broadly (witness the muted enthusiasm for the current Nissan Leaf). At 200 miles, we are talking the battery pack costing $11,000. That probably takes the pre-rebate price up to $36,000. Is that too pricey for most?

A Prius type of hybrid has many of the good features of EV’s: regenerative braking, engine stops when stationary, electric drive for start and low speed, where IC engines are less efficient, to name the principal features. All of these combined will typically add 40% or so to the gas mileage in city driving. I mention city driving for two reasons: one is that it shows off the hybrids the most and two because the all-electrics such as the Leaf are impractical for distance driving at this time. These cost 2 to 4K more than the base model. 200 mile range all-electrics eventually ought to cost about 6K more (after realizing gains on lower cost mechanicals).

Tesla is making things interesting. Their luxury Model S is priced not much more than regular luxury models. The 60 kWh battery is about to be replaced with a 70 kWh pack. They flirted with a 40 kWh pack and it never really left the blocks because of perceived customer reaction. It shows in buying behavior as shown in the 2015 statistics for large luxury cars. It seems that the same luxury for about the same price with zero tailpipe emissions makes it an easy decision.

The buying habits of this cohort may not comport with those of economy car buyers. So the $36K (before rebates) crossover may not have the same reaction. GM is betting on the forthcoming Bolt (great name by the way, reflective of the fast start possible with electric drive). Priced at $37,500, it will have 200 mile range (which, with a 60 kWh battery, is consistent with our computation above and so is believable) and seat 5. It will have plenty of pep: 200 HP (150 kW) and 206 foot pounds of torque. With the heavy batteries on the bottom of the cabin compartment, the center of gravity is in the middle and low. So in addition to being peppy it ought to handle well. GM can do this because they claim to be getting the batteries for $145 per kWh and much as Tesla has claimed, expect that to drop to $100 by 2020. These prices ought to translate to Nissan as well. So expect a bigger battery Leaf model.

Low gasoline prices, likely for a couple of years, affects some of the decisions. But it comes down to this: a hybrid five seat vehicle can deliver 45 mpg in the city. An all-electric will give about 105 to 110 mpg (computed on the basis of a gallon of gasoline containing 34 kWh of energy). It will cost more but maintenance will be much less, and so on. And there is the environmental benefit. Provided the big guns go forward with their intent the consumer will have choice.


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