BANGKOK, May 11 (Reuters) – Laos has submitted plans to build a new hydropower dam on the Mekong River, with construction expected to start later this year, the Mekong River Commission (MRC) said on Monday. The Sanakham hydropower plant, with an estimated cost of $2.073 billion, will be developed by Datang Sanakham Hydropower company, a subsidiary of China’s Datang International Power Generation Co. Ltd., MRC said.