ADB President Mr Haruhiko Kuroda said the new target, up from US$1 billion invested in 2008, will take effect from 2013.

It represents only a fraction of Asia's clean energy needs, but is expected to draw additional resources from the private sector, carbon markets and others, he said.

'These investments will assist our developing member countries in building energy efficient and low-carbon economies for a prosperous and environmentally sustainable future,' Mr Kuroda told reporters.

Among the Manila-based lender's clean energy investments are power transmission improvement for Azerbaijan, wind power projects in China and India, hydro power developments in Bhutan, China and Vietnam, and expansion of energy-efficient mass transit systems in several Asian cities. -- AP