China Southern Grid electricity imports could adversely affect cost and supply

I read with concern your editorial ("Energy plan can be made to work", May 7) where you asserted that "there is only a small difference in reliability of the output of CSG (China Southern Grid) and Hong Kong's two power companies".

You rightly pointed out that the supply reliability for Shenzhen and Guangzhou in 2012 was 99.98 per cent and 99.97 per cent respectively, but might have overlooked the meaning behind these figures. At 99.98 per cent, Shenzhen's power interruption is 1.1 hours and Guangzhou 1.8 hours.

In Hong Kong, our reliability is much higher at over 99.999 per cent. Power interruption on Hong Kong Island is less than one minute and in Kowloon and the New Territories less than two minutes. Such a minute-vs-hour comparison cannot be considered "a small difference".

Hong Kong is a densely populated vertical city with extensive mass transportation. Reliability cannot be compromised. You also suggested that "our electricity bills can be kept in check" if energy is produced in Guangdong, but this may only be wishful thinking.

Macau imports more than 90 per cent of its power from CSG. The price of the imported power increased by 27 per cent from 2008 to 2013. Macau's current domestic tariff is HK$1.31 per unit, or 30 per cent higher than ours.

As far as the environment is concerned, importing power is bound to increase emissions in Guangdong, contrary to your suggestion that pollution from power plants can be "reined in", because the marginal fuel to meet the added demand from Hong Kong will most likely be coal.