Hydropower: Just Another Brick In The Wall

KF - Writer

In a world where fossil fuels are finally revealing their ugly hands, green alternatives have risen like a Biblical prophet. Full of truth and light and generic good things, the likes of hydroelectric, wind and solar are a rope thrown as the boat goes over the waterfall. We have taken to them slowly and in recent years enthusiasm is gathering momentum. Political movements advocating greener deals now place heavy importance on renewable power generation and a sharp steer away from coal and oil.

Now, Hydroelectric power (HEP) plays a major part in global electricity generation, already] contributing 20% of the world’s electricity. It has dominated electricity supply in developed countries such as Switzerland, Canada, Norway and the Pacific Northwest regions of the US, living very much in the public eye and heralded as the mark of forward thinking, responsible nations. HEP has taken less of a public spotlight in developing countries, however that’s not to say it isn’t playing an equally huge role. HEP already supplies a whole 1/3 of electricity needs across developing nations. More impressively, this is being achieved while exploiting less than 10% of its full potential. This makes HEP an untapped goldmine in terms of energy generation. In fact, in many places, HEP generation is only set to increase. Total capacity in China is expected to reach 350GW of pure hydropower and 70GW of pumped storage as early as 2020.

There are many upsides to HEP besides its potential for energy generation. Generally speaking, HEP plants don’t have the conflicting public image of nuclear or wind power but seem blessed with a saintly reputation for being efficient and durable. HEP generation can be very small scale, from domestic Pico-hydro generators running from small streams producing less than 5kw, to the grandeur of the iconic Hoover and Three Gorges Dams. Industrial plants themselves can be very large, scalable from 10KW to 22.5 GW (Three Gorges, China) which allows for large scale job creation and economies of scale which make for very efficient the operational costs.

HEP comes in 3 main forms. The first being the conventional form of a dam blocking the pathway of a river, creating a reservoir of water stored behind the dam wall. This design can give way to a multitude of other uses such as water supply, flood control, agricultural irrigation and recreation. The list of possibilities is lengthy and exciting. A lesser known systems is known as ‘run of the river’, where water flows through a turbine system and straight back into its river course. There is no reservoir and therefore can be little to no water storage, making power generation more variable and less dependable than the conventional dam.

The third method is almost a category in its own right: pumped storage. This is currently one of the only viable ways of storing energy, acting as a sort of natural battery. The system depends on a gradient such as a steep hill: at the top of the hill is a conventional dam creating a reservoir of stored water. At the bottom of the hill is a second reservoir. During times of high demand (which for the UK is roughly 5-7pm when everyone comes home from work and switches on their kettles, TVs and washing machines) the water is released from the top dam, flowing through the turbine and converting gravitational potential energy into kinetic energy to power the turbines. This water is collected in the bottom reservoir until there is a demand trough (say 3 in the morning when the lights are off and most people are snoring) and then the water is pumped back up to the top reservoir to start the process all over again.

Sounds like a pretty perfect system, right? Energy storage, on demand generation, huge untapped potential and no fossil fuels! Not quite. Although the reputation of hydropower has remained shockingly unscathed for decades, it is not necessarily the wonder kid it seems to be.
HEP has a variable output- the amount of water and therefore power available depends on annual rainfall and snowfall which also changes seasonally, so it isn’t as reliable as fossil fuels’ constant production. The initial capital costs can be staggering, China’s Three Gorges Dam is estimated to have cost around $24 billion, although there is controversy surrounding the true figure (which may be double this). This also exemplifies the extremely long timescales in construction of mega-sized projects, as construction began in 1995 but the last section was not completed until 2015. Does this make HEP a realistic alternative for our very immediate energy concerns?

Perhaps most importantly, the construction and operation of dams can have devastating environmental impacts. Incredible quantities of cement are required to construct the initial dam and the cement production process is a huge contributor of GHG emissions, being solely responsible for around 8% of the whole world's carbon dioxide (CO2) emissions. Once built, dams form a physical barrier, blocking migratory and breeding pathways for fish and mammals such as dolphins. This can lead to a complete species extinction, as was the case for the Baiji (aka the Chinese River Dolphin) which is considered to be the first dolphin species driven to extinction almost entirely by human action (or more pointedly by the construction of the Three Gorges Dam).

The physical dam itself causes numerous complicated problems wherever it is placed, however in order to maximize efficiency of the HEP plant, there are only select locations where dams are viable. These locations are areas with relatively steep valley sides, preferably a steep gradient and nonpermeable underlying rock (you don’t want your reservoir draining into the ground). This means that when a suitable location is found it often takes priority over existing infrastructure, wildlife or even the people that reside there. Displacement of human settlement is a huge problem with HEP.
In 1943, the United States Army Corps of Engineers was asked to solve a historic problem with flooding in the Missouri River basin. ​Eventually the Pick-Sloane plan was developed which called for the creation of multiple dams along the Missouri River and its tributaries. Not only would these dams stop the flooding problem, but they would provide HEP and recreation opportunities. A win-win all around. ​The creation of these dams would naturally require large land areas to be surrendered and flooded as reservoirs to be used for water storage and recreation. ​ Much of this land was unused or agricultural land and American farmers were offered compensation to relocate as well as promised that any remaining farms in the arid upper basin would have priority over the irrigation water provided by the dam.

It seemed like a reasonably fair deal for industrious American citizens… but what about those who weren’t technically citizens? The Missouri river basin also happened to be home to 10 major Native American groups. They too were affected by the flooding, however would not benefit from the same agreement. Instead, the dams were built with little (if any) consideration for the tribal land rights of the Native American community. Instead, over 200,000 acres of land across 2 Native American reservations was flooded​ and the Native American land lost 90% of its timber and 75% of its wildlife. The majority of the area’s fertile cropland was in the reservoir taking area​, meaning both farming and hunting were now severely diminished for the community. The more urban American areas to the south east received most of the economic and social benefits, while the Native American population was forcibly relocated without adequate compensation​. To this day, the affected Native American population and their descendants are still seeking adequate compensation for the developments first proposed in 1943.

Surely, we have learnt from our mistakes and decided to prioritize our people and wildlife over placement of HEP dams? Sadly, that is not the case as the Three Gorges Dam forced the relocation of a record 1.3 million people and flooded 13 cities, 140 towns, 1,350 villages (International Rivers, 2008). It led to a decline in the quality of river water and almost every species found along the river was negatively impacted by the dam whether through a reduction of population or of general population fitness.

Currently indigenous groups all across the Amazon are fighting the Brazilian government for the right to their ancestral land, which the right-wing President Bolsonaro is threatening to be handed to logging, mining and HEP projects. One can see how he is eager to boost the economy of the country through large scale projects such as these, however there is no telling exactly what extent of industrial land-take could be on the cards.

Bureau of Reclamation (2019). Pick Sloan Missouri Basin Program. [online] Bureau of Reclamation. Available at: https://www.usbr.gov/projects/index.php?id=380

David C. Campbell (1984) The Pick-Sloan Program: A Case of Bureaucratic Economic Power, Journal of Economic Issues, 18:2, 449-456, DOI: 10.1080/00213624.1984.11504244​


International Rivers (2008). Three Gorges Dam: The Cost of Power. Berkeley.
Lawson, M. (1994). Dammed Indians: The Pick-Sloan Plan and the Missouri River Sioux, 1944-1980. Norman: University of Oklahoma Press.​

Lawson, M. (2009). Dammed Indians Revisited: The Continuing History of the Pick-Sloan Plan and the Missouri River Sioux. Pierre, S.D: South Dakota State Historical Society Press.

MacCully, P. (1996). Silenced rivers.
Rodgers, L. (2018). The massive CO2 emitter you may not know about. [online] BBC News. Available at: https://www.bbc.co.uk/news/science-environment-46455844
Wines, M. (2011). China Admits Problems With Three Gorges Dam. The New York Times. [online] Available at: https://www.nytimes.com/2011/05/20/world/asia/20gorges.html

Photo by Jacek Dylag on Unsplash
Photo by Milada Vigerova on Unsplash


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