Electric cars may not be so green in Hong Kong

The conventional wisdom that electric cars are better for the environment than gasoline-powered cars might not apply in Hong Kong.

Amid government efforts to encourage electric vehicles, a report was released in April claiming that battery-powered cars emit 20% more carbon dioxide in the city than gasoline vehicles do.

Sanford C. Bernstein, a U.S. research company, compared a sedan from leading U.S. electric-car manufacturer Tesla Motors and a popular gasoline-powered model from Germany's BMW, by considering the impact of "indirect" emissions during the process of power generation.
   
The study highlighted Hong Kong's heavy reliance on coal power. It concluded that the aggregate amount of CO2 resulting from the power generation needed to drive an electric car for 150,000km, and from car battery manufacturing, could exceed what is emitted by a gasoline-powered vehicle, even when the latter includes emissions resulting from the process of refining oil.
   
The promotion of electric cars is a key part of the government's efforts to curb the territory's severe air pollution. It has introduced tax exemptions for the registration of new electric vehicles, helping boost the number of such vehicles on Hong Kong roads from fewer than 100 in 2010 to some 4,500 in January. Tesla accounted for 70% of those cars.
   
 Neil Beveridge, a Hong Kong-based analyst at Bernstein, says in the report that "electric vehicles are increasing rather than reducing pollution, with taxpayers effectively being asked to subsidize this."
   
It does not say Tesla and other electric cars emit carbon dioxide on the road. Tesla says that according to its own analysis, emissions per kilometer from its cars are no more than half of what gasoline cars emit, even after adding indirect emissions. A customer who was visiting a Tesla dealership on Hong Kong Island was also puzzled, saying electric cars can definitely reduce carbon emissions on the streets.
   
Coal power accounts for over half of the total electricity in Hong Kong, but the government aims to significantly increase the use of natural gas, as well as renewable energy sources, by 2020. Reduced reliance on coal could enhance the contribution of electric cars to the environment.
   
The government plans to revise its current measures to promote electric cars by next March. The Bernstein report could prompt the government to explain the impact that Hong Kong's power mix has on the effort.