Some riders of TheBus will begin today to help the city determine if switching to electric buses makes sense.

The expanded testing of emissions-free public transportation will also reach the neighbor islands.

One 40-foot white bus that features TheBus logo along with images of blue snake-like electrical plugs and the slogan “Testing Tomorrow’s Technology” will be tested on routes throughout Oahu.

The bus made by China-based BYD Motors Inc. also will be tried out later this year on Maui and Kauai.

Testing the BYD bus follows a city test in February of another electric bus made by California-based Proterra Inc., which also sent its bus to Maui for a trial and later this month is sending the bus to Kauai. And then in the fall, both the Proterra and BYD buses are slated to help shuttle passengers between Daniel K. Inouye International Airport terminals and rental car facilities in a test for the state Department of Transportation.

Both companies showed off their buses mainly to state officials Wednesday at ‘Iolani Palace next to the state Capitol.

Gov. David Ige, who participated in the event, said the demonstration projects are key to helping Hawaii reduce its dependence on fossil fuels and meeting a goal of achieving 100 percent renewable energy production by 2045.

“This is an ambitious and worthy goal,” Ige said.

Each county also has committed to making their vehicle fleets 100 percent electric by 2035, which will involve not only buses but also public works and emergency vehicles.

Jon Nouchi, deputy director of the city Department of Transportation Services, said the Proterra bus test in February was positive.

“Our passengers responded favorably,” he said. “They like the quiet ride. In general our operators really enjoy operating them. No one really had anything negative to say.”

The city, which has 544 buses, ran the Proterra bus on about 20 routes, including one between Ala Moana and Haleiwa passing over the H-2 freeway. Nouchi said the bus did fine, making two Ala Moana-Haleiwa round trips on a charge.

Range is a big consideration for deploying electric buses. Nouchi said buses on city routes run from two to 18 hours straight, with most going 10 to 12 hours. Proterra’s bus can go at least 250 miles on one charge. Some models can go further, and quick charging also is possible.

“We think there’s a great opportunity here in the islands,” said Matt Horton, Proterra’s chief commercial officer.

Bobby Hill, vice president of U.S. sales for BYD, said municipal bus operators can start to save money with electric buses after as little as three or four years.

Electric buses cost more than diesel buses — roughly $700,000 to $800,000 compared with $500,000 to $600,000 for diesel or diesel-hybrid buses — but maintenance and fuel costs are lower.

Proterra claims an owner can save $450,000 over 10 years when factoring the cost of a new bus, maintenance and fuel.

Proterra has reported selling about 550 buses to municipalities and other users in 30 states, including an order last month for 10 buses from the San Mateo County Transit District in California.

BYD, which has a U.S. manufacturing plant, has reported selling almost 40,000 buses worldwide, including an order last month for three buses from the Capital Area Transit System in Baton Rouge, La.