Hong Kong will need to import renewable energy from the mainland if the city expands its use of sustainable power, the Council for Sustainable Development said.
The council's report said it was possible to meet 2 per cent of the city's power requirements from renewable sources by 2012.
The figure is higher than the government's earlier stated 1 per cent target, which the report also gave as an alternative.
But achieving a higher percentage of sustainable-energy use would mean giving over huge amounts of land for wind farms or solar panels, it said. Otherwise, the target could only be met by importing renewable energy from the mainland.
Meeting the 1 per cent requirement would require 100 wind turbines of 2mW each installed on 4,000 hectares, it said.
The council also drew attention to the need to determine the public's willingness to pay for renewable energy, which can cost several times more than power from conventional sources, such as coal-fired plants.