Energy demand in Southeast Asia countries could triple by 2050 and the region could become net importer of natural gas and coal before that if the region do not develop alternative sources of energy, a study by the region's energy sector body found. For the 10-nation group Association of Southeast Asian Nations (ASEAN), diversification of energy sources would be crucial, not only due to efforts to cut emissions, but also to meet rising energy demand, Nuki Agya Utama, executive director of ASEAN Centre for Energy (ACE) said on Thursday.