Cambodia’s energy conundrum: what are the alternatives to the Sambor Dam?

Photo of construction of the Lower Sesan 2 Dam, taken by Socheata Sim and used courtesy of the Mekong Commons Flickr account under a creative commons license.

This is the second in a short series featuring voices from emerging experts in Cambodia on the water-energy-food nexus and resource management in the Mekong region.

Cambodia’s demand for power is currently growing at 20% a year, and experts estimate that double digit growth will continue for seven more years. While alternatives like solar are increasingly attracting attention, this energy deficit has driven discussion about the proposed Sambor dam on the mainstream of Mekong river in Kratie and other tributaries. Fortunately, EDC general director Keo Rattanak has recently announced that Cambodia will prioritize renewable energy development rather than hydropower, and estimates that it will expand to 12% of the energy mix by 2020 and rise to 20% over the next three years. It now seems like the Sambor Dam and hydropower more broadly are becoming less prioritized because there are other options available that will not have the same impacts and risks.

While the recent drought has caused concerns over hydropower’s reliability and enforced a drive to diversify the energy supply, Sambor has a long history: it was first proposed in the 1950s, but the project has been controversial because of the huge negative impacts on fish population and sediment resource, tourism and people livelihood. As a result, it has changed hands on multiple occasions.

In 2013, the Cambodian government hired the US-based Natural Heritage Institute (NHI) to review options for the project. NHI reviewed ten possible alternative design options, including a no-dam option, and concluded Sambor was among the worst proposed place for hydropower because of its large size and position as the lowermost hydropower dam on Mekong mainstream.

The Cambodian Government had previously hoped that the Sambor Dam could act as a major potential source of hydroelectricity in Cambodia. However, the recent unprecedented drought and drop of capacity factor raise questions in drought years about the benefits of hydropower, and the projected impacts for Cambodia and Vietnam make it important to seriously consider alternatives. The main problems from Sambor are the negative impacts on fish population and the serious implications for food security for the region. Sambor would block fish migration from the Tonle Sap—the largest freshwater fisheries nursery in the world— to spawning grounds in the upper reaches of the Mekong river and its tributaries. The Cambodian Fisheries Administration reports that they will see a 16% to 30% drop in fishery yields if the dam is built; other experts estimate a higher loss because 40% to 70 % of Mekong fish are migratory. NHI estimates a total forecasted loss in fish harvest of between 550,000 to 880,000 tons, or a 26% to 42% decrease in total fish capture. Such a loss would decimate the income of tens thousands of subsistence and commercial fishers.

The proposed dam would also affect the movement of sediment and nutrients that flow downstream and are key inputs for agriculture in the Mekong Delta and floodplain. The NHI study estimates that the dam would capture 95% of the sediment flows to the delta. These effects are so severe because of geology: the flat floodplain on which the dam would be built does not allow for the discharge of sediment. Carl Middleton, former Mekong Program Coordinator at International Rivers, noted that the Cambodian landscape is not build for hydro dams like those of its neighbors to the north because of its flatness.

The dam would also affect national economic development. It is close to tourist attractions, such as the only habitat for the endangered Irrawaddy Dolphin estimated by WWF. It also would require the relocation of about 19,000 people. The Mekong River Commission’s 2010 Strategic Environmental Assessment placed the number of affected villagers’ livelihoods even higher.

Finding and investing in alternatives to Sambor and other hydropower dams is more than possible. The NHI study proposed specific alternatives including a floating solar array on the Lower Se San 2 reservoir. This is being explored as one of the no dam options, and the floating array technology has attracted attention as a way of increasing reservoir efficiency because the floating solar panels deflect heat and reduce evaporation. Cambodian land and weather are high potential for solar energy, with an average of slightly over 5 kWh/m2 per day and technical potential of 8100 MW of installed capacity.

Recently, Singapore-based renewables company Cleantech Solar conducted a trial in Cambodia with a 9.8 MW solar installation that includes 2.8 MW of floating PV. It sells power to Cambodian cement manufacturer Chip Mong Insee Cement Corporation (CMIC). Cleantech Solar said floating solar can cut down the economic losses,  as  water cools down the temperature of panels, boosts its efficiency, and limits long –term degradation from the heat. In addition, solar panels can also reduce water loss through evaporation. Riccardo Puliti, Senior Director for Energy and Extractives at the World Bank, said “floating solar technology has huge advantages for countries where land is at a premium or where electricity grids are weak.”

Cambodia also has potential for wind power: Duguet estimated that Cambodia could generate up to 500MW of wind power. Currently, energy in Cambodia is largely produced from coal-fired plants, hydropower dams, and some pilot solar farms.

The Ministry of Mines and Energy estimates that the country will see a 16.1% increase in the supply of electricity in 2019, reaching a total demand of 2,870 MW. NHI’s analysis of alternatives would seek to maximize power production while minimizing environment impact at the same time. WWF has also highlighted that it is possible to design a power system that is low carbon and low impact which would produce reliable and affordable electricity to meet Cambodia’s power demand. Wind and solar energy were 2/3 of all new global power generation capacity in 2018, partly because greater investment in wind and solar can reduce negative impacts on rivers, environment, fish population and human resolution. Equally important, the costs for wind and solar energy sources have dropped dramatically and are now approaching US$0.05/kWh, a price which is comparable to the low end of fossil fuel cost range and the average costs of hydropower.

The significant negative impacts that could result from dam construction and the severe electricity shortage due to drought in recent years is driving Cambodian policymakers to consider renewable energy alternatives.  Further investment in renewable energies would complement the existing power generation sources in the country and help avoid harm to natural resources, the environment, and Cambodia’s people.

Seanghak Khin works with Caritas Switzerland in Cambodia, where she works on Water Governance and Water Sanitation and Hygiene (WASH). She was previously the Program Coordinator on Innovation and Research program at Center for Sustainable Water. She holds a master’s degree in Water Engineering and Management in Asian Institute of Technology (AIT), Thailand and a bachelor’s degree in Hydrology and Water Resource Engineering in Institute of Technology of Cambodia (ITC), Cambodia. 

Piseth Kim is the Project Manager at the Community Assessment Capacity Building Lab (CACB) and Project SAART. He was previously the Program Coordinator at Center for Sustainable Water (CSW). Piseth has a water resources and environmental engineering educational background in Cambodia and Indonesia, and has been working in Cambodia water sector since 2015.

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