Modern plug-in electric cars first became available in the U.S. in December 2010, when the Nissan Leaf and the first-generation Chevrolet Volt went on sale.

Shortly after that, in his 2011 State of the Union address, President Barack Obama set the goal of putting 1 million such cars on U.S. roads by 2015.

Regrettably, that goal was not reached.

DON'T MISS: Plug-in electric car sales for Oct: steady before Bolt EV, Prius Prime arrival

In fact, U.S. electric-car sales have only just gotten halfway there.

Combined U.S. sales of battery-electric cars and plug-in hybrids surpassed 500,000 units as of September, according to the U.S. Department of Energy.

Specifically, sales since December 2010 reached 512,137 units in September.

2017 Chevrolet Bolt EV

2017 Chevrolet Bolt EV

Sales of 16,069 plug-in cars in that month helped push total sales past the 500,000-unit mark.

We noted that October sales continued at roughly the same pace as September, at least among vehicles for which sales were reported.

The pace of sales will likely increase with the introduction of two highly anticipated plug-in cars.

ALSO SEE: Energy Secretary Confirms: U.S. Will Fall Short Of Obama Goal Of 1 Million Electric Cars By 2015 (Jan 2015)

Those are the 238-mile Chevrolet Bolt EV electric car and the Toyota Prius Prime plug-in hybrid, both 2017 models.

Their arrival will likely boost sales next year, and could go a long way toward meeting a revised goal for plug-in electric car sales.

Acknowledging slower-than-expected sales, U.S. Energy Secretary Ernest Moniz said earlier this year that the country might not achieve 1 million electric-car sales until after 2020.

2017 Toyota Prius Prime Premium

2017 Toyota Prius Prime Premium

With its 238-mile range and $37,495 base price (before any Federal, state, or local incentives), the Bolt EV in particular could be a major factor in achieving that goal.

It will be joined at some point by the Tesla Model 3, which will have a range of 215 miles and a base price of $35,000 before incentives.

A new second-generation Nissan Leaf, which is expected to offer a range of 200 or more miles for its top-line version, is also expected to be unveiled next year.

MORE: Tesla says it will build 500K cars a year by end of 2018; can it?

But the Tesla Model 3 is the affordable electric car that may have generated the most buzz, both in media and among electric-car and technology fans.

The Model 3 has already generated more than 400,000 reservations, so consumer interest in the smaller Tesla sedan is certainly piqued.

However, the Model 3 likely won't hit U.S. roads in large volumes until well after the Bolt EV goes on sale.

Tesla Model 3

Tesla Model 3

Tesla has said it plans to start production at the end of 2017, and that it will prioritize West Coast deliveries before moving on to other regions.

But Tesla has missed all of its car-launch deadlines so far, and hasn't even shown the Model 3 in production-ready form.

Still, it seems safe to say that the rate of plug-in car sales should accelerate notably in 2017 and 2018 with the new arrivals.

The question then becomes simply how long it takes to hit Obama's goal of 1 million such vehicles on U.S. roads.


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