Twelve years ago, a Chinese state-owned company signed an agreement with the government of Cambodia to undertake a monumental feat of engineering: the Sambor Dam, the largest hydroelectric dam on the Lower Mekong Basin. The 2,600MW behemoth, double the size of any other dam planned or constructed on the Lower Mekong, would stretch for 18km, trailing an 82km-long reservoir behind it.
The company ultimately dropped the plan in 2011 in the wake of protests from local villagers who didn’t want to see 100km of their river, home to their fisheries and livelihood, disappear. “If the river is blocked by the dam, it will be difficult for us to catch fish,” a resident of Thmey village told the South China Morning Post at the time.
But the potential effect on villagers’ livelihoods is just part of the story. There are also concerns about the dam breaking and flooding their homes, which recently happened in Laos, killing at least 35, with hundreds missing, and making over 6,000 homeless across two countries. There’s the issue of villagers being relocated in order to build the dam, which happened to hundreds of residents near the Lower Sesan II dam in Cambodia. Then there’s the possibility that the dam will cause floods and droughts incongruous with the natural flow of the Mekong.
“Even if we get compensation, we will have to use the money to feed our families and pay for their electricity,” another resident of Thmey village told the Morning Post in 2011. “It is better to use our own money than other people’s money.”
But the idea of the dam didn’t die, and in 2014 the government of Cambodia signed a memorandum of understanding with an independent nonprofit conservation organisation in California, the Natural Heritage Institute (NHI), to get a real idea of the potential impacts of the proposed Sambor Dam as well as alternatives. The institute spent the next three years studying the potential effects at the Sambor site and looking at ten possible alternative dams and no-dam options. It reported its results in the Sambor Hydropower Dam Alternatives Assessment.
It turns out the villagers were right to worry – and for many more reasons than they’d realised. The report concluded that the original Sambor Dam “could literally kill the Mekong River by creating a complete barrier to migratory fish and sediment that replenishes the Mekong Delta and nourishes the food chain of the Tonle Sap Great Lake.”
“If you put on a pair of your very best hiking boots and you start at sun-up at one end of that dam and hike pretty vigorously to the other side of the dam, it’d be sundown by the time you get there,” Gregory Thomas, executive director of the NHI, told Southeast Asia Globe. “That’s just the structure of the dam. So it would block off the entire river, disconnect the entire river.”
An environmental catastrophe
According to the report, over 60 million people depend on the Mekong River for their livelihood and food security – 1.3 million in Cambodia alone – so killing it would endanger lives in catastrophic fashion. The river is home to the most productive fishery in the world and is the second most biodiverse, with roughly 1,200 species.
The Sambor reach, site of the proposed dam, has the largest annual migration of fish on the planet, and the dam was designed to lie directly between their spawning grounds and the nursery habitats. Normally there are ways that fish can migrate through hydroelectric dams, but because of this dam’s sheer size, essentially no fish or larvae would make it through – and “mortality is likely to be near 100%”, according to the report.
“The biggest issue isn’t an individual dam or a handful of dams as it is the entirety of the system that’s slowly moving ahead”
Courtney Weatherby, Stimson Centre
This would be a massive loss for the economy as well. According to the NHI study, fish catch in Cambodia brings in an estimated $2.76 billion a year, or 12.8% of the GDP. The Sambor reach alone lands between 2.5 million and 3.8 million tonnes of fish annually, and 40 to 70% of that catch are migratory fish.
Besides exterminating fish, the dam could kill the physical river by trapping sediments and their accompanying nutrients. Sediments are essential to maintaining the river structure and diversity of habitats for different species, says the report, and their depletion would be particularly detrimental to the Mekong Delta in neighbouring Vietnam. The nutrients feed fisheries in the Vietnamese delta as well as the Tonlé Sap lake.
Analysts told Southeast Asia Globe that looking at this one dam – which likely will never be built as originally planned – is a red herring.
“The biggest issue isn’t an individual dam or a handful of dams as it is the entirety of the system that’s slowly moving ahead,” said Courtney Weatherby, a research analyst with the Stimson Centre’s Southeast Asia program. “That’s really where you get the death-by-a-thousand-cuts issue.”
The demand for power
The NHI assessment had come up with one dam alternative that in theory could be viable. If all went according to plan, it would pass 95% of the sediment, fish and larvae, and potentially allow Irrawaddy dolphins to move up and down the river as well. The Sambor alternative requires 7,000 people to be relocated, as opposed to the original dam’s 19,000, while producing a substantial amount of power, at 1,236MW.
The reason it’s viable in theory is that the mitigation efforts the NHI team came up with have never been done before – and never with the volume of fish that this dam would encounter.
“[The alternative dam is] a lot more expensive to build than the original Sambor,” said the NHI’s Thomas. “And unless they include all of the mitigation measures and unless they work perfectly, this would also be quite devastating to the yield of the fishery.”
Thomas added: “We ended up concluding that there’s still too high of a risk factor, even with the most fully mitigated design possible.”
With all of these risks to land and people, why would anybody go ahead with building hydroelectric dams? Does Cambodia need electricity that badly?
In fact, it does.
“Cambodia’s demand for power supply is currently growing at 20% a year, so that is astonishingly high,” said Thomas. “And the reason for that is that they are moving rapidly to complete their rural electrification programme… So that’s 20% year on year because of demand, and we estimate that to continue for seven more years.”
According to Thomas, the Lower Sesan II dam that just came live late last year has basically made Cambodia self-sufficient for power. But given its expected growth rate, the country clearly needs additional power sources. One direction Cambodia and the rest of the region is heading is coal.
With all their risks, hydroelectric dams are another avenue, and they have worked well for neighbouring countries, especially Laos, which is able to export the majority of its electricity to the much more power-dependant Thailand.
But dams are also extremely time consuming and costly to build. No hydrodam would likely get started in Cambodia until 2020 – and then it would not be ready to generate power, after getting financing and approvals in place, until roughly 2030, according to Thomas. By then, Cambodia’s power demands will have already grown exponentially.
Unfortunately for Cambodia, its landscape is not built for hydrodams like those of its neighbours to the north.
“By the time the river gets to Cambodia, it’s very flat,” explained Weatherby. “All of the large dams in China and even some of them in Laos are built in gorges and valleys, so you’re able to put the dam in one spot and flood the valley and have a natural reservoir.”
“I think the government of Vietnam, who are conversing about this at the high levels, share our view of the impermissibility of anything as destructive as the large Sambor”
Gregory Thomas, National Heritage Institute
The flat terrain is why the original Sambor Dam was designed to be so large, said Weatherby: “It’s not located there because it’s an ideal spot for a dam; it’s located there because it’s one of the few spots where you’re able to build some sort of large wall like that to create this huge lake behind it.” Once the dam’s size was decided, the company would decide how many turbines it could fit in that space, she added, surmising that that’s how it decided on 2600MW.
It’s true, Cambodia doesn’t actually need 2600MW, according to the NHI assessment, which said the original goal was to sell the excess electricity to Vietnam. But there’s now a question of whether there will still be a market.
Thailand is currently revising its master power development plan and is debating how much power it wants to buy from its neighbours, if any, because of its maturing solar market. Weatherby also pointed out that “Thai planners have often over-anticipated demand, and so what they’ve ended up doing is paying for projects that they had built in Laos where they’re not using the electricity.”
Vietnam is the only other viable customer, and it too is debating how much it wants to rely on others for energy. “So for them, it’s more of an energy security thing than it is the cost and energy mix thing,” Weatherby added.
Vietnam would also naturally not be interested in something that would be as destructive as the original Sambor Dam to its Mekong Delta.
“I think the government of Vietnam, who are conversing about this at the high levels, share our view of the impermissibility of anything as destructive as the large Sambor,” said Thomas. “Even the fully mitigated alternative would be of great concern to them… Vietnam is a large investor in Cambodia, after all. It is a downstream member of the MRC [Mekong River Commission]… It would be very difficult, I think, for Cambodia to defy strongly asserted dictates of Vietnam.”
Floating solar
One innovation involving floating solar photovoltaic panels could be the answer.
“We were the first one to launch the market in the world,” said Harold Meurisse, managing director for the Southeast Asia operations of the French company Ciel & Terre, which developed the technology in 2011. “We started with 1.3MW. When we started, people said we were crazy to go on a lake, and we had to convince the full industry to do it. And we see more and more projects of 200MW, 400MW, under development now.”
He added: “Solar energy is very cheap now, very cheap, but we use a lot of land to develop solar energy… Like for Myanmar or Cambodia, you need that space for agricultural purposes… [A hydrodam] lake is often never used, or only by very small fish farmers and only on a very small part of the surface. So if you use this space, you pay nothing for the land – and you’ve saved the land as well.”
Floating solar panels are exactly what they sound like: solar panels that have been attached to floats on a body of water, like a lake or reservoir.
Photovoltaic power and hydroelectric dams work together like teammates. In the daytime, the solar panels generate energy and hydro takes over in the nighttime or on cloudy days. During the dry season, when hydro doesn’t function at full capacity, solar picks up the slack – which is particularly needed then because it is also the hottest season, when air conditioners are used more. The panels also prevent the water from evaporating.
Once placed on a hydroelectric dam reservoir, solar panels do not need separate storage for their electricity because the energy that’s generated from them can be fed immediately into the dam’s system and thus into the grid.
For these reasons and more, Natural Heritage Institute recommended in its assessment that Cambodia place 400MW of floating solar panels on the Lower Sesan II dam as the alternative to building a new dam, doubling its energy output. Individual panels can be added incrementally and quickly so funding can be done over time to add panels as demand increases – as long as the transmission lines are able to handle the additional load.
“There’s no real limit to how much could be deployed,” said Thomas. “The problem is that in order to make it economic, it has to be deployed at a scale that neither the solar nor the hydro would suffer curtailments during portions of the year. That means it needs to be scaled to the next increment of demand that needs to be fed in the power system. That’s the key.”
Meurisse cautioned that adding floating solar to a hydroelectric dam requires intensive knowledge of both grid and dam management: “We must be responsible because the market is growing faster than the regulation. So that means if you’re not responsible, you could potentially face some activities like the one you had in Laos… So you need to be very careful about protecting the dam activity and account for all of the parameters.”
Besides the technical, there are human hurdles to floating solar. The government and dam stakeholders need to be on board. The tariff agreement would have to be renegotiated to provide a higher return on investment. In the case of the LSII dam, Thomas said that it wouldn’t need to be much higher to be economically viable (a difference of 0.6 cents/kw): “The important information is that would still be cheaper than any other alternative for the next increment of power for the system in Cambodia.”
Utilities also have to be amenable to the scheme because the electricity that is generated from solar power uses their grid, explained Thomas: “We need to satisfy EDC [Electricité du Cambodge, Cambodia’s utility] that this would not cause grid destabilisation problems for them.”
The private sector has already started to push the EDC in the solar direction. Over a dozen companies in Cambodia see solar as a viable investment. Third party companies have started installing solar panels on the roofs of businesses, maintaining and operating the panels, and selling the electricity to businesses at a lower rate than the EDC. In response, the EDC recently announced a new tariff for those types of projects.
“EDC has an asset there,” said Bridget McIntosh of the nonprofit EnergyLab. “They paid for [the distribution infrastructure] assuming they were going to sell a certain amount of electricity. So what they’re saying is, ‘OK, put solar on your roof, but please also pay us a fixed demand charge per month to pay back the cost of our infrastructure and we’ll still sell you electricity.’”
So the businesses effectively have two electricity suppliers – the EDC and the company that installed the solar panels – and they buy electricity from one at night and one during the day, both at a lower rate. (EDC has yet to create such a tariff for households.)
Large private-sector companies have also started putting floating solar panels on their reservoirs, with several projects completed or underway in Cambodia, according to McIntosh, who explained: “It’s inevitable as the economics are now marching it forward.”
China, the world’s largest producer of PV components, has a flooded domestic market, said Weatherby, “so there is a likelihood that many of those Chinese investors will start looking abroad now or in the next year into solar investments in a way that they hadn’t been before. There’s a reasonable chance that China will explode suddenly onto the scene as a big investor in solar in the next few years.”
The dam that collapsed in Laos in July was a fraction of the size of the original Sambor Dam or the proposed Sambor alternative, and yet it was able to swiftly destroy the lives of thousands and cause millions of dollars in damage, which will be felt for years to come. Besides the horrific destruction that a dam in the Sambor corridor would naturally bring, one shudders to think of the catastrophe that would ensue should that dam fail.
With solar power promising a path to Cambodia’s energy self-sufficiency, Thomas said, the prospect of building new hydropower dams is unconscionable.
“If Cambodia had no other option, then one could imagine that despite the huge economic consequences, they’d go ahead with this,” he said. “But what our report shows is that they do have other options. They do have better options.”
The Irrawaddy dolphin
There are only 92 Irrawaddy dolphins left that call the Mekong River their home. These freshwater mammals inhabit a small portion of the river, a 190km stretch between Kampi, Cambodia, and the Khone waterfalls on the Cambodia-Laos border.
Within this tiny population are four subgroups with strong social bonds and deep pools that each group frequents. The locations of the original Sambor Dam and its alternative are directly on top of some of these core pools. The dolphins also use specific channels to move up and down the river, and any dam would block their passage along these routes.
Unsustainable fishing practices like gillnet and dynamite fishing had brought the dolphin population to a record low of 80 as recently as 2015, but enforcement of conservation laws is credited for their uptick. 2017 was the first year that saw more births than deaths since the data has been tracked, according to the World Wildlife Foundation.
Tourists can take boat tours departing from Kampi to see the dolphins.
