Hong Kong bus companies driving toward carbon neutrality

Electric buses are appearing on Hong Kong's streets starting in 2022,  transforming the city’s image of traffic clogged up with old double deckers that belch out pollution. These buses use environmentally friendly new energy as fuel, which can reduce emissions better than diesel buses.

Citybus will put Hong Kong’s first hydrogen bus into road commissioning this month, and it will soon come into the market. 

“We plan to test the performance of diesel, electric, and hydrogen buses by deploying five buses of each type on the same route in the second half of this year. ” said Lee Ka-ming, Citybus's Head Engineering Manager.

“Based on the results, we will decide on the proportion of hydrogen and electric buses in our plans. We prefer to use data comparisons to support our decisions on which buses to choose,"Lee said.

At present, there are 21 KMB routes serving the public with electric buses, accounting for about 56 electric buses.

“Double-decked electric buses have been in service since 2023, and their performance has been very satisfactory. Since a bus can operate for 18 years, we will continue to monitor its performance and prepare to cope with any possible difficulties,” said Kenny Kan, Head of KMB's corporate communications and public affairs department. “KMB expects to replace diesel buses with fully electric ones by 2040,” he added. 

According to local think tank, Civic Exchange, Hong Kong's transportation sector accounts for the second largest share of total Greenhouse gas sessions, emitting 18.7%. Commercial vehicles such as buses only account for 20% of the total number of vehicles in Hong Kong but contribute over 90% of nitrogen oxide (NO) emissions, a significant contributor to roadside air pollution.

“Compared with diesel buses, new energy buses do not produce harmful emissions, thus directly reducing the use of non-renewable energy such as fossil fuels and the emission of GHG,” Kan added, “We can effectively alleviate air pollution and that has considerable benefits for the sustainable development of Hong Kong's environment.”

Despite the smooth operation and numerous advantages of new energy buses in Hong Kong, there are limitations to the technology and a regulatory framework.

 “The characteristics of Hong Kong's bus routes with many slopes and stops will result in higher power consumption for buses carrying bulky batteries,” said the Assistant Corporate Communications Manager of Citybus, John Yu.

Compared with electric buses, hydrogen buses have low battery weight and low loss of energy, so they can easily cope with the routes in Hong Kong. However, the supply of hydrogen is a problem.

Shao Minhua, head professor of  Department of Chemical and Biological Engineering at the Hong Kong University of Science and Technology, says Hong Kong's hydrogen energy mainly relies on imports, and the local hydrogen energy industry is small.

Most hydrogen production in Hong Kong is gray hydrogen from fossil fuels. "If we can't guarantee hydrogen purity when we use it, the process of producing hydrogen may produce more pollutants than the original vehicle," said Tom Wu, Project Director at Greenpeace.

The introduction of new energy buses has resulted in higher costs for the bus companies, KMB and Citybus hope the government will provide subsidies to help them realize the new energy transformation.

“The existing road traffic laws do not consider the emergence of hydrogen buses, thus imposing restrictions on their usage,” said John Yu, City’s bus Assistant Corporate Communications Manager, “We could  only plan for hydrogen buses to run within Kowloon because the tunnel regulations prohibit vehicles carrying inflammable and explosive substances from crossing the tunnel."

“After our repeated verification, the risk factor of hydrogen buses is almost zero despite carrying hydrogen. We hope the policy can change to allow hydrogen buses to pass through tunnels soon.” Yau said.

"We have installed hydrogen concentration detectors in our buses for real-time notification of whether there is a hydrogen leak, as well as at least four automatically activated fire extinguishers," he added.“We plan to collaborate with Towngas on the upcoming second hydrogen filling station to maximize the utilization of available hydrogen and enhance the energy supply,” 

On the future of hydrogen energy, Prof. Shao says Hong Kong should cooperate with mainland cities or even directly produce energy instead of relying on imported energy or extracting hydroxide from natural gas.

"We can produce hydrogen in the South China Sea and deliver it to Hong Kong to become a storage center for green hydrogen, which will also make us a centre for hydrogen trading," Shao said.

Bus companies must focus on technological development policy assistance and effectively promote new energy buses to achieve the carbon neutrality goal. “Collaboration from various policy aspects is necessary to overcome regulatory limitations,” said Yu.

"As the new energy market gets bigger and bigger, we believe that the policy cooperation will also get better," Yu added.