Since 1982, the electricity sector in Hong Kong, which accounts for more than half of the total energy consumption, has undergone two major changes in terms of the type of fuels used for power generation. In 1982, it switched from oil to coal generation. In 1994, nuclear power was introduced; and in 1996, natural gas was imported for power generation. Given the dominance of electricity in the energy economy, these changes led to drastic modifications in the fuel mix and the geographical sources of energy supply for Hong Kong. This study analyses the rationale behind the above changes in fuel selection, the impact on the fuel mix and the geographical sources of energy supply, the security of energy supply, and the cost of power.