Even with effective implementation of energy efficiency and energy saving initiatives it is expected that in the long run Hong Kong will require additional power generation capacity. Constraints on the provision of new power generation facilities in Hong Kong are likely to include air quality controls (see Paragraph 5.4.4.7 - Assimilative Capacity of Air) and difficulties in identifying new sites due to competing land uses and environmental constraints (see Paragraphs 3.2.2.1 - 3.2.2.7 - Land Use and Land Supply). The land supply constraint is expected to be the more severe of the two, since air quality issues are of less concern for the cleaner fuels and technologies proposed for Hong Kong's new power stations than they would be for stations using older and less efficient technologies. A case for maintaining at least a proportion of local electrical power generation within Hong Kong can be made based on security of supply considerations.

An alternative to providing additional generation capacity within Hong Kong is to purchase electricity from generators in the Mainland. It should be cheaper to generate electricity in the Mainland due to lower costs there, but this would need to be balanced against concerns about the potential for detrimental effects on regional air quality that may result from a proliferation of coal-fired power plants in Guangdong Province operating to lower emission standards than would be required of plants in Hong Kong. Hong Kong would need to work with the relevant parties in Mainland China to develop ways to avoid this problem, to encourage implementation of cleaner technologies in the Mainland, and diminish these problems of sourcing additional electricity for Hong Kong from the Mainland. Sufficient transmission network capacity would be required between the Mainland and Hong Kong and within Hong Kong, but this should not present any major obstacles in the medium to long-term.