The Higer STEED XL will be on Guernsey's roads for the next couple of weeks.
The zero emission bus has been described as ‘Island-Ready’ by manufacturers Harris Group.
It is the same length as the current fleet, at 8.9 metres, but 2cm wider, at 2.32 metres.
The electric vehicle is supposed to be able to cover 186 miles. CT Plus has previously said the average Guernsey bus runs for 100 miles a day.
The Higer STEED XL has capacity for 48 people, with up to 26 seats.
It is the fourth electric bus to be trialled on the island since January last year, and the second this month.
For the next couple of weeks Harris Group and CT Plus will see how the bus handles the island's bus routes and consumes energy.
CT Plus Director Kevin Hart says this is the first in-service trial.
"We know it fits, but by putting passengers on it and the weight, we can see if it will really do what it says on the tin.
Are we really going to get the mileage?
If the States of Guernsey are going to invest a lot of money into electric vehicles we need to make sure the product is right for Guernsey."

The Yutong E9 tested February 2023, the Sigma 8 tested August 2023 and the Enviro100EV tested 9 April 2024.
Niall Roberts from Harris Group says Guernsey is the ideal testing ground for new bus technology.
"The island offers the stop-start of a busy Town setting with also the hills and longer reaches of a rural environment, ideal for the intelligent power saving technology from Harris Group that adapts to the conditions.
Added to that, with a full charge possible in less than two hours the Higer STEED XL is a bus that spend its day on the road - not waiting at the depot."
Electric buses were introduced to Jersey's fleet in December 2023.

The Red Arrows pull out of performing over Guernsey
Guernsey's Ladies' Pool reopens after pollution incident
Passengers at Guernsey Airport told to expect some flight disruption
Guernsey flights impacted by UK air traffic control issue
Engine fault sees private jet diverted to Guernsey Airport
Travel issues ahead of Channel Islands Pride
WATCH: Car 'sails' from Guernsey to Sark
Guernsey donates to Nepali disaster relief effort