Five years after the first mass-market electric car hit the market, cars with plugs haven't lived up to the most optimistic projections for their adoption.
They are at least pacing the rate of hybrid cars over their first five years, but numerous factors have challenged what advocates see as an obvious evolution.
Many of those challenges reside in the automakers themselves, many of which still largely view plug-in electric cars as a necessary regulatory evil rather than a new product category.
Green Car Reports was recently quizzed by an auto-industry analysis firm about its views on the next five years of plug-in cars.
After a conversation, we decided to expand that discussion into a full-blown article.
What follows is our assessment of the six most important trends (some admittedly closer to predictions) that will govern the electric-car segment between now and 2020.
2016 Tesla Model X with 2011 Tesla Roadster Sport, photographed by owner Bonnie NormanEnlarge Photo
(1) Everything gets more range
The Tesla Model 3 was described years ago as a 200-mile electric car to sell for $35,000, but the date for actual launch remains murky at best. Tesla has said it'll start production at the end of next year; analysts remain skeptical.
The 2017 Chevrolet Bolt EV, on the other hand, will be rated at 200 miles and cost $37,500--and GM will ensure that it goes into production by the end of this year.
That will force Nissan, BMW, Volkswagen, and others to keep pace, adding 200-mile capability to their mass-market battery-electric vehicles.
2017 Chevrolet Bolt EVEnlarge Photo
Within three years, we expect 150 to 200 miles to become the new normal for all-electric cars priced at $30,000 to $45,000, perhaps lower.
Similarly, we now have a raft of new (and mostly low-volume) plug-in hybrids with ranges of 15 to 24 miles.
At the moment, they're largely to tick the Chinese-market box that lets them qualify for all the incentives given to New Energy Vehicles--even if they're never, ever plugged in.
But the 2016 Chevy Volt has a real 53-mile range, which means nine of every 10 trips will be entirely on grid power.
Ranges of 40 to 60 miles are likely to become the benchmark for future generations of plug-in hybrids.
And those ranges have been most specifically telegraphed by BMW's Power eDrive system.
BMW 5-Series Gran Turismo Power eDrive prototypeEnlarge Photo
(2) Mild hybrids will be supplanted by 48-Volt enhanced start-stop systems
With significant advances made in 48-Volt enhanced start-stop systems from a variety of suppliers, the era of the high-voltage mild hybrid has likely come to a close.
They were first launched by Honda minimalist 1999 Insight; it built a few million mild hybrids with motors of 10 to 20 kilowatts (13 to 27 horsepower). The challenge is the expense of a high-voltage battery pack and associated power electronics.
GM followed the mild-hybrid path as well, with two (not very successful) generations of its eAssist (nee Belt-Alternator-Starter) system--but conventional gasoline powertrains kept duplicating their fuel-economy figures at much lower cost.
So we expect that GM may join a number of European and North American makers in adopting cheaper 48-Volt enhanced "microhybrid" systems on a wide variety of models by 2020.
Lithium-ion cell and battery pack assembly for Nissan Leaf electric car in Sunderland, U.K., plantEnlarge Photo
(3) Lithium-ion chemistries will stay with us
While advanced battery chemistries and huge advances in energy storage density are alluring, slow, steady, incremental improvements in all facets of lithium-ion cells will power electric cars for at least the next 10 years.
Cell chemistries, anode and cathode materials, higher-yield fabrication processes, and economies of scale will all combine to continue the reduction in cost-performance that averages 6 to 8 percent a year.
And better-than-predicted improvements since 2010 have already brought large-format cells to a price of $145 per kilowatt-hour (if you believe repeated statements from GM's product chief Mark Reuss) when the 2017 Bolt EV launches late this year.
Change comes slowly. Note that Toyota still uses the nickel-metal-hydride battery packs it launched in its first hybrid 20 years ago.