Houston — Sales of plug-in electric vehicles in the US were down in the third quarter compared with Q3 2018, and the slowing economy may bring year-over-year growth in this sector of the US power market to a halt by the end of the year, postponing the load benefits many have been expecting.

Sales in the US plug-in vehicle market in Q3 2019 were down roughly 20% compared with Q3 2018, but year-to-date sales for 2019 were slightly ahead of sales through the third quarter in 2018.

Sales in Q4 last year soared, helping the EV industry in the US reach a record of just over 361,000 plug-in electric vehicles sold. Industry analysts have been questioning whether plug-in sales can realistically reach a range of 345,000 to 350,000 this year.

A slowing economy and low availability of new, pure electric vehicle models have already begun to affect 2019 sales, according to a market analyst, and could slow sales through the end of the year.

Strong 2018 sales, particularly late in the year, were largely on the back of the Tesla Model 3 release.

"The new model rollouts since have been scant, and that has also put some downward pressure on US growth," said Zane McDonald, senior transportation technology analyst at S&P Global Platts Analytics.

"Of the 35 major US auto brands, 14 do not offer any PEV options, and 12 only offer one PEV option," McDonald said Tuesday. "This results in many consumers walking into a US auto dealership and having little to no choice in electrified model lines."

Though 2019 sales seem somewhat stalled, estimates are that US light-duty EV sales could breach 1 million per year in 2025. "By 2025, Platts Analytics anticipates light-duty electric vehicles will account for over 13 TWh/year of incremental load," said McDonald.

EARLY 2019 SALES HAVE HELPED

In Q3 2019, sales of plug-in vehicles totaled 87,363, according to data provided by the industry publication Inside EVs. In Q3 2018, comparable sales totaled 110,483, meaning Q3 2019 saw a sales decline of more than 23,000 plug-ins.

Sales of Tesla's Model 3 totaled 44,000 in Q3 2019, or roughly 50% of all plug-ins sold, according to an estimate by Inside EVs. This compares with about 56,000 Model 3s sold in Q3 2018.

Toyota had the second most actively sold plug-in car in the third quarter. It sold 7,100 Prius Primes, giving it an 8.1% market share.

The year-to-date sales through the end of the third quarter of 2019, according to Inside EVs, totaled 236,067, which compared with the nine-month total in 2018 of 234,745.

Sales in the early months of 2019 into June were greater than sales in those same months in 2018. The third-quarter decline was the turning point.

CHEVY'S PLUG-IN SALES ARE MIXED

On October 8, a strike against General Motors entered its fourth week, with over 50,000 workers on the picket lines.

The GM strike has a specific electric vehicle component to it, as the Detroit-based auto manufacturer indicated late last year and earlier this year that it intends to dedicate more resources to PEVs that will require fewer parts, workers and time to build.

Analysts have noted that parts suppliers are also bound to feel the impact of a shift to EVs, as, for example, suppliers of conventional powertrains will be at risk if they can't convert operations to supply battery-car components.

GM's recent sales of EVs, however, have been mixed. In Q3 2019, Chevrolet sold 4,830 Bolt EVs compared to 3,949 in Q3 2018.

In late November 2018, Chevrolet announced it would eventually discontinue production of its plug-in hybrid Volt. In Q3 2019, Chevy sold just 874 Volts compared to 5,429 in Q3 2018.

A SLUMPING PERCENTAGE

According to data compiled by S&P Global Platts Analytics, sales of plug-in electric vehicles as a percentage of total light-duty vehicle sales have never risen above 3%.

Sales reached 3% of total light-duty sales in September 2018 for the first time and reached that mark again in November and December of 2018.

The figure, though, has been idling between the 1.4% and 2.4% per month range since January 2019.

In August 2019, according to Platts Analytics, light-duty vehicle sales in the US totaled 1.64 million, while plug-in electric vehicle sales totaled 26,472, or 1.6% of the total.

-- Jeffrey Ryser, jeffrey.ryser@spglobal.com

-- Edited by Zac Aiuppa, newsdesk@spglobal.com