Police officers in the northern emirate are doing their part to help the environment by going green with eco-friendly patrol vehicles.

So far, nine fuel-guzzling 4x4 patrol vehicles have been converted to run on either natural gas or petrol. The move is the first step in a project with Emirates Transport that will eventually lead to 30 eco-friendly vehicles patrolling Ajman's roads.

"These vehicles work on both natural gas and petrol. In case of running out of [natural] gas we can press a button to use petrol,” said the force's Capt Essa Al Hosani.

He noted there was no difference in speed or performance between the fuel sources, but hybrids were cheaper to operate.

"The car can travel a distance of 140 kilometres [on natural gas], which costs just Dh20, and it doesn't consume too much gas because we only use them inside the emirate. But to avoid the interruption of gas, we monitor the odometer and if the car has travelled about 120km we provide it with more gas.”

Converting each vehicle costs about Dh6,000, Capt Al Hosani said. However, a lack of filling stations that could supply the fuel meant plans to convert more vehicles was moving ahead slowly.

Natural gas is only available at a handful of Adnoc stations and from the Sharjah Electricity and Water Authority. Both are working on ways to increase supply to Ajman.

The Ministry of the Interior has recommended that more police forces use hybrid vehicles, but so far only Ajman and Abu Dhabi do, Capt Al Hosani said.

He encouraged all governmental institutions to convert their vehicles to hybrids to be kinder to the environment.

Rasha Al Shamsi, manager at Emirates Transport's Ajman branch, said the amount of vehicles using natural gas was expected to grow in the UAE.

"About four years ago we had provided a number of vehicles running on natural gas at certain agencies in Abu Dhabi, but we had started with Ajman police this year,” she said.

"We found a positive effect on the environment in terms of emissions and saving fuel cost, whereas petrol's price is high. For this reason we found the alternative in natural gas.”

Emirates Transport plans to convert its entire 10,000-vehicle fleet to hybrids, but the project will take several years, Ms Al Shamsi said.

Rachel Bartz, of the Dubai Carbon Centre of Excellence, said natural gas was a more environmentally friendly fuel source.

"Natural gas has a higher octane than petrol. In essence, it mixes better in the air and burns more completely. This means fewer carbon deposits, leading to fewer oil changes. It actually has approximately 15 per cent lower carbon emissions than petrol.”