Hawaii has now surpassed a milestone, having logged its 10,000th registered electric vehicle some time last month, according to the latest monthly energy trends report.

In September, the number of passenger EVs in the state reached 10,003, up 2,205 vehicles, or 28.3% higher than the same month a year ago, and 98 more, than August.

That 10,003 figure, however, is still less than 1% of the total number of registered passenger vehicles in the state, which totaled 1,083,258 in September.

The number of passenger hybrid vehicles in the state last month was 25,049, representing 2.3% of total passenger vehicles. The number was 0.1% less than the some month last year, and 0.04% less than in August.

“The role EVs play in the future of ground transportation and our state’s ambitious energy goals is widely recognized,” said Greg Gaug, senior vice president of investments and analytics at Ulupono Initiative, in a news release. “However, EVs still represent less than 1% of all passenger vehicles in the state. Increasing adoption will only accelerate and expand the benefits that EVs bring to our communities, including reducing our fossil fuel dependence and providing cleaner air for our keiki to enjoy.”

Of the 10,003 total, the majority of passenger EVs are in Honolulu County, which registered 7,989, followed by Maui County, at 1,136, Hawaii County at 562 and Kauai County at 316, according to the state energy office.

The Drive Electric Hawaii Coalition, which is made up of eight public, private and nonprofit organizations, says that as EVs become more mainstream, costs are increasingly comparable to internal combustion engine cars. The increasing number and longevity of EVs also means more can return to the market as secondhand cars at a more affordable price.

The coalition is heralding the “clean transportation” milestone by partnering with companies across the state to offer free and discounted car washes for EVs.

On Thursday, The Car Parlor is offering free car washes for EVs all day.

From Thursday through Nov. 10, The Car Parlor and other participating car washes are offering a $10 car wash special for EV drivers across the state through a downloadable coupon at driveelectrichi.com. The offer is only valid for vehicles equipped with a government-issued “Electric Vehicle” license plate.

Participating locations include:

>> The Car Parlor, 1111 Kapiolani Blvd.

>> McKinley Car Wash, 1139 Kapiolani Blvd.

>> Hilo Express Car Wash, 1089 Kilauea Ave. in Hilo

>> Kona Express Car Wash, 75-5570 Kuakini Highway in Kailua-Kona

>> Wash It Hawaii, 1203 Keawe St., Lahaina