‘The numbers don’t look satisfactory,’ says environment official
Hybrid electric double-decker buses actually guzzle more fuel than conventional buses because of Hong Kong’s hilly roads and hot weather, according to preliminary results from an ongoing trial.
Environmental Protection Department officials admitted the six hybrid buses, trialled over a year, were “not as efficient as they thought”. They pointed to heavy use of air conditioning systems, which accounted for up to 40 per cent of the energy used in the summer.
Although fuel performance was better in winter, the buses still used 3.4 per cent more fuel on average than regular buses.
“The numbers don’t look satisfactory right now,” assistant director for air policy Mok Wai-chuen told the legislature’s environmental affairs panel on Wednesday.
“Because buses in Hong Kong use a lot of energy in air conditioning, the benefits of the hybrid mode are not maximised. We are allowing [the manufacturer] time to improve designs … and will come back to report on this later.”
The government spent HK$33 million helping the three franchised bus companies acquire the six hybrids in a bid to explore less polluting vehicle options. The two-year trial began in November 2014.
Lawmaker Tony Tse Wai-chuen questioned why none of the obvious issues were identified before the start of the trial and feared the experiment would end up being “futile”.
Separately, the department announced the start of its latest review of the city’s air quality objectives. These objectives were last tweaked in 2014.
It set up a working group to conduct the review and look into control measures “for other lesser air pollution sources” such as aviation emissions and volatile organic compounds, a major component of ozone.
The latest official data shows ambient concentrations of PM10, PM2.5, nitrogen dioxide and sulphur dioxide dropping 21, 24, 13 and 31 per cent respectively from 2011 to 2015.
Roadside concentrations fell 26, 21, 19 and 33 per cent in the same period respectively. But harmful ozone pollution at both general and roadside stations is still on the rise.
The Clean Air Network urged the government to set the new objectives according to the World Health Organisation’s most stringent air quality guidelines, as several of the current objectives only met its interim targets, which it said did not provide adequate protection to public health.
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Source URL: http://www.scmp.com/news/hong-kong/health-environment/article/1932126/hong-kongs-hybrid-electric-buses-found-use-more