How Solar Could Save The Mekong


A simple feasibility analysis shows the Mekong River in Cambodia would benefit from floating solar plants coupled with storage, rather than more hydro.

Cambodia’s Great Lake, the Tonle Sap and Vietnam’s Mekong Delta are suffering harmful impacts from the suppression of the Mekong River’s annual flood pulse – a consequence of the operation of hydroelectric dams far upstream in Yunnan, China, and on tributaries of the Mekong in Laos and Vietnam. Many more dams are planned. If they are built, Cambodia will see the end of the reverse flow that supports the enormously fecund flood pulse at the Tonle Sap. Subsequently, in the dry season, Vietnam will be starved of the fresh water that supports its delta ecosystem and food security.

This brief proposes an alternative approach: A floating solar power system on the Tonle Sap, built on a scale that will satisfy Cambodia’s power needs at lower cost.

Can the sun on the Great Lake Project save the Mekong and Vietnam?

The answer is ‘yes!’ and the feasibility analysis in this report seeks to prove that a 25-year program for a 28 GW floating solar project with 4-hours battery storage will meet Cambodia’s projected energy needs to 2045 at the cost of US$31 billion.

The high cost of electricity in Cambodia

Cambodia is the least developed and most energy-thirsty country in Southeast Asia. The price of electricity in Cambodia is the highest[1] in the region, ranging from $0.15 to $0.18 per kWh. In some rural areas, the price reaches $0.50 to $1.00 per kWh.[2]  By comparison, the price in Thailand ranges from $0.105 to $0.143 per kWh, and in Vietnam from $0.072 to $0.126 per kWh.

Hydroelectricity in Cambodia is not cheap

Cambodia’s 2030 energy plan includes several new coal and gas fired power plants plus two giant hydroelectric projects—the run-of-river Stung Treng[3] (980 MW) and Sambor[4] (2,600 MW) power plants on the Mekong mainstream. These two hydroelectric projects face strong objection both from local communities and from Vietnam.

The International Rivers organization reports that: “The Sambor Dam would be a tragic and costly mistake for Cambodia. Cambodia’s fisheries safeguard the food security of millions of subsistence fishers and contribute over 15% to the country’s Gross Domestic Product (GDP).”


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