The wrong climate for big dams

Africa is the least electrified place in the world. An estimated 550 million Africans have no access to electricity. Nearly half of African countries have a power crisis. Solving this huge problem is made more difficult by widespread poverty, and because most Africans live far from the grid, greatly adding to the cost of bringing electricity to them.

Under these challenging conditions, there are no second chances for electrifying Africa: It must be done right the first time. Yet many of the continent's energy planners are pinning their hopes for African electrification on something as ephemeral as the rain, by pushing for a grid of large hydro dams across the continent. The World Bank has joined the fray, with its latest World Development Report calling for a major hydropower rollout for the continent. This model is well-suited for facilitating industrialisation and exploitation of natural resources, but not for reducing Africa’s energy poverty.

Putting aside the appropriateness of this plan for meeting basic needs, this vision fails to take into account the unpredictable nature of Africa’s rivers, a situation that will be made worse by a changing climate. New African dams are being built with no examination of how climate change will impact them. Many existing dams are already suffering from drought-caused power shortages. Climate change is expected to dramatically alter the hydrology of African rivers, creating both worse droughts and more dangerous floods (the latter causing safety concerns for poorly maintained or operated dams). At the same time, many African nations face huge water-security problems. In this climate, the proposed frenzy of African dam building could be literally disastrous.

The oft-repeated sound-bite that only 5-8 per cent of the continent's hydro potential has been tapped is an incomplete message at best. The other side of the coin is that Africa is already dangerously hydro-dependent.[1] Meanwhile, Africa has not developed even a tiny fraction of a percent of its available solar, wind, geothermal, or biomass power. While large dams have done little to bridge the ‘electricity divide’ which has left so many Africans in the dark, renewable energy projects can be scaled to meet the needs of the smallest African village to its biggest urban areas. At a time when global warming threatens to make Africa’s rivers even less reliable for large hydro projects, and their waters more precious for other uses, governments and donors should be looking to diversify the energy mix.

RISKY RIVERS

Past hydrological records, upon which dozens of new large dams are being planned, has little bearing on future hydrology. The economic impacts of hydro-vulnerability will be felt both in the costs of power cuts on industrial output, and the cost of wasted investments in non-performing dams.

The economic risks of unviable dams will compound the risk already being taken by so many African nations: That of over-dependency on hydropower to supply electricity. Already, the majority of sub-Saharan states get most of their electricity from rivers. (At least two nations have begun to reverse this dependency: Tanzania, which is now developing its gas fields, and Kenya, which has become an African leader in geothermal power.) The question of who bears the costly risks of nonperforming dams has yet to be debated, but thus far, private developers appear to be mostly shielded from such risk.

The other climate risk is that many large dams seriously harm downstream riverine communities and ecosystems, which is likely to make climate adaptation that much harder for the many millions of Africans who depend directly on rivers and lakes for their livelihoods, food and water supply. Like the fairy tale that warns of ‘killing the goose that lays the golden egg,’ African dam planners are putting at risk irreplaceable ‘golden egg’ resources such as clean, abundant water supply, agriculturally important sediments that replenish floodplains, riverine forests and fisheries.

Currently, according to the UN Environment Programme (UNEP), 14 African nations are considered water-stressed or water-scarce, and an estimated 11 countries will join them in the next 25 years. Under such conditions, free-flowing, healthy rivers will become an even more valued resource than they are today.

Some dam planners agree that African hydroelectric schemes may be plagued by variable rainfall patterns, but believe that they can ‘play the odds’ and just build more dams, across a wider region, and connect them all with transmission systems that would allow power to be traded to places where drought has crippled the power supply. Yet it’s hard to sell electricity from empty reservoirs.

Climate scientists predict truly alarming changes to various African waterways. UK government researcher Sir Nicholas Stern recently predicts that a 3-6 degree Celsius increase in temperature in the next few years will result in a 30 per cent to 50 per cent reduction in water availability in Southern Africa. Scientists have discovered evidence that droughts in West Africa lasted centuries in the past.[2] Their 2009 study suggests global warming could create conditions that favour extreme droughts across much of Western Africa, home to Africa’s biggest reservoir (Akosombo’s Lake Volta), among others.

East Africa has been drying since the mid-1980s, a trend that is already shaving percentage points off GDP for the region’s states. A new report, ‘Large Scale Hydropower, Renewable Energy and Adaptation to Climate Change’ by AFREPREN states, ‘Kenya’s GDP is equivalent to US$ 29.5 Billion; the estimated loss during the aforementioned drought-induced power crisis was about 1.45% of GDP. This translates to US$442 million lost which could have been used to install 295 MW of new renewable power capacity.’

Most of the Nile Basin states get more than 70 per cent of their electricity from hydro. The Intergovernmental Panel on Climate Change notes that there has already been ‘a reduction in runoff of 20% between 1972 and 1987’ in the Nile, and ‘significant interruptions in hydropower generation as a result of severe droughts.’ Even though some parts of Africa are expected to receive more rain, that increase is expected to be overwhelmed by an increase in temperature across the continent, which will lead to higher evaporation rates.

A 2006 study by climate experts at the University of Cape Town revealed that even a small decrease in Africa’s rainfall could drastically reduce river flows, affecting a quarter of the continent. For example, a 10 per cent reduction in rain over the Johannesburg area could lead to a 70 per cent drop in the Orange River's levels. In parts of northern Africa, river water levels would drop more than 50 per cent. ‘It's like erasing large sections of the rivers from the map,'' said Maarten de Wit, who headed up the study.

MISSING THE BOAT

Numerous African hydro projects have been put forth with little or no regard to whether they are the best option for meeting citizens’ energy needs. Electricity from large hydropower will not reach the majority of Africans, who live far from the power grid and to whom expanding the grid would be prohibitively expensive. Large hydro projects increase a nation’s electricity supply in big increments, an inefficient way to address the gradual increases in market demands typical of African economies.

Big, centralised hydro dams also spur the development of costly long-distance regional electricity grids. The recipients and beneficiaries of the electrons flowing over long distances are not generally Africa's unelectrified majority but urban centres and large, often foreign-owned industries. Such projects are not the most practical way to improve access for new customers, especially not for the rural areas most in need of electrification. Wider distribution of modern energy services could bring enormous benefits for health, education and livelihoods to the majority of Africa’s rural population involved in such activities as small-scale agriculture, but for now the priority is clearly on industrial expansion and mega-projects.

The example of DR Congo is instructive. In a country of 66 million people, only 6 per cent have access to electricity, despite two large dams on the Congo River. The national power utility, SNEL, serves just over 400,000 customers, but almost half of the electricity is consumed by just 20 large clients. The Congolese government has set a highly aggressive target to provide 60 per cent access to electricity by 2025. But given population growth projections, this would require an estimated 400,000 new connections every year. Rising rehabilitation costs for the two dams (both in disrepair) and momentum to develop future large dams are draining investments which could achieve the domestic electrification target. Investments in decentralised power supply projects, including small- and medium-scale hydro across the country, could more evenly reach the population.

LEADING BY BAD EXAMPLE

Ethiopia is fast becoming Africa’s poster child for bad-dam development. Not only is the Ethiopian economy on track to become a ‘hydrological hostage’ due to its almost total reliance on high-risk hydropower (85 per cent now, jumping to 95 per cent with its current slate of dams). Its master energy plan calls for US$3 billion in new investments, most in new big dams.

Ethiopia’s Gibe III Dam, now being built on the Omo River, is the most poorly planned major hydropower project being built on the continent today. The government has cut corners in its preparation, increasing its risks of economic and technical failure, and has done next to nothing to reduce the project's massive ecological and social footprint. The dam will change forever the Lower Omo River Valley, homeland of half a million farmers, herders and fishermen.

The dam will affect ecosystems and disrupt communities all the way to the world's largest desert lake, Turkana, downstream in Kenya. An oasis of biodiversity in a harsh desert, Lake Turkana, a World Heritage site, supports more than a quarter of a million Kenyans and rich animal life. The Omo River accounts for 80-90 per cent of the lake's inflow. That will be curtailed by half as the dam fills, and reduced thereafter by evaporation from the massive reservoir. The project is also expected to lead to large diversions of water from the river for huge agribusiness operations. Lake Turkana may not survive this onslaught.

Such outcomes should have been predicted in project analysis, but Ethiopia started construction before proper studies were done. Ethiopian government officials told the BBC that proper environmental studies were simply ‘luxurious preconditions.’

Currently, some four million Kenyans depend on food aid in the current drought. Ethiopia has had five major droughts since 1980. In 2003, Ethiopia’s power supply was held hostage by severe drought, forcing sudden and severe power cuts that lasted six months, and costing US$200 million in annual productivity. A drought-crippled Gibe III would bring a sea of red ink to Ethiopia and lead to blackouts and economic consequences for regional governments that buy its electricity.

ENERGY INSURANCE

African nations have many better alternatives to big, destructive dams. A few examples:

GEOTHERMAL: Tapping hot water reserves underground is an excellent option for much of East Africa and other nations. Achim Steiner, UN Under-Secretary General and UNEP Executive Director, says, ‘There are least 4,000MW of geothermal electricity ready for harvesting along the Rift. It is time to take this technology off the back burner in order to power livelihoods, fuel development and reduce dependence on polluting and unpredictable fossil fuels.’ UN figures show that Africa has tapped less than 0.6 percent of its geothermal. Kenya is the exception, with 10% of its electricity now coming from geothermal.

SOLAR: Africa’s potential is nearly limitless. To give just one example, a study co-sponsored by my organization shows that Mozambique’s huge and virtually unexploited solar potential is about 1.49 million GWh – thousands of times more than the country’s current annual energy demand. And this power is distributed evenly across the country. Exploiting this energy would benefit the more than 80% of Mozambique’s population that is now off-grid.

ENERGY EFFICIENCY: There is huge potential for reducing energy use. For example, South Africa, the main client for the bulk of the electricity from the planned Mphanda Nkuwa Dam in Mozambique, could quickly save 3-5 times the amount of Mozambique’s entire electricity consumption. Energy savings can be found even in low-use countries. In fact, putting efficiency measures in place now for growing economies means there will be more to share with those currently without access to electricity, and saves money to invest in other pressing needs. ‘Developing countries, which will account for 80 per cent of global energy demand growth up to 2020, could cut their demand by more than half using existing technologies to improve energy efficiency, according to McKinsey Global Institute. Efficiency is the cheapest energy source of all.

WIND: Wind potential is also high in many parts of Africa, and is finally beginning to be developed (new large projects are underway in Kenya and Egypt, for example).

CO-GEN: The production of electricity from steam, heat, or other energy sources as a by-product of another industrial process is well-suited to many African nations. AFRPREN estimates that Africa could get 20% of its electricity from co-gen. Mauritius now gets almost half of its electricity from co-gen plants using mostly sugar cane waste.

Diversifying Africa's energy sector would help its climate-adaptation efforts in key ways: It would de-emphasise reliance on erratic rainfall for electricity, reduce conflict over water resources, and protect river-based ecosystems and the many benefits they bring. And it would share the wealth with the half a billion Africans now living in the dark.

CASE STUDY: HOW DAMS AFFECT WATER SUPPLY

Most rural Africans are directly dependent on surface water – rivers, wetlands, springs and lakes – for their water supply. Today, 20 African countries experience severe water scarcity and another 12 will be added in the next 25 years. As the climate changes, free-flowing, healthy rivers will become an even more valued resource than they are today. Dams are expected to affect water quality and quantity for millions of downstream users. A few ways that dams harm water supply include:

By trapping river-borne nutrients, dams can lead to the growth of toxic algaes. Massive algal blooms in reservoirs in the ex-USSR, South Africa[3], and California have rendered reservoirs unfit to drink. Four hydro dams in California have nearly killed off the fisheries of the Klamath River, and made the river unsafe for drinking or swimming. Water stored for months or even years behind a major dam may become lethal to most life in the reservoir and in the river for many kilometres below the dam. Reservoirs that also receive treated effluents from upstream towns and cities are more apt to have this problem.

Dams also lead to riverbed deepening for tens or even hundreds of kilometers below the reservoir. Riverbed deepening can lower the groundwater table along a river, threatening vegetation and local wells in the floodplain and requiring crop irrigation in places where there was previously no need.

Tropical reservoirs are particularly prone to colonization by aquatic plants. In addition to causing other problems, mats of floating plants can lower reservoir levels. Losses of water from evaporation and transpiration in weed-covered reservoirs can be up to 6 times higher than those from evaporation in open waters.

Because they greatly increase the surface area of water exposed to the sun, dams can increase the evaporation of huge amounts of water. About 170 cubic kilometres of water evaporates from the world's reservoirs every year, more than 7 percent of the total amount of freshwater consumed by all human activities. The annual average of 11.2 cubic kilometres of water evaporated from Nasser Reservoir behind the High Aswan Dam is around 10 percent of the water stored in the reservoir and is roughly equal to the total withdrawals of water for residential and commercial use throughout Africa. The proposed Epupa Dam reservoir would have evaporated more water than the city of Windhoek uses in a year.

Rising salinity (which ruins the land for farming) is another water-scarcity risk from large reservoirs. The massive amounts of evaporation from the reservoirs behind Hoover and the other dams on the Colorado — one third of the river's flow is evaporated from reservoirs — is one of the reasons why that river's salinity has risen to damaging and costly levels. High salt concentrations are poisonous to aquatic organisms and corrode pipes and machinery.

Dams change the timing, amount and chemical composition of a river's flow, leading to dramatic changes to groundwater-storing floodplains and wetlands. Such changes can also lead to the destruction of forests, which among other things help regulate the local climate. The forest on the floodplain of Kenya's Tana River appears to be dying out as it loses its ability to regenerate because of the reduction in high floods due to a series of dams upstream. The Lower Zambezi has lost much of its rich floodplain and wetlands due to upstream dams, with wide-ranging effects throughout the ecosystem.

BROUGHT TO YOU BY PAMBAZUKA NEWS

* Lori Pottinger has for 16 years worked on the Africa campaigns for International Rivers. Terri Hathaway contributed to this article.
* This article is part of a special issue on water and water privatisation in Africa produced as a joint initiative of the Transnational Institute, Ritimo and Pambazuka News. This special issue is being published in English and in French.
* Please send comments to editor[at]pambazuka[dot]org or comment online at Pambazuka News.

NOTES

[1] A map of Africa’s hydrodependency, see http://www.internationalrivers.org/en/node/5808
[2] ‘West African Droughts are the Norm, not an Anomaly,’ http://www.nsf.gov/news/news_summ.jsp?cntn_id=114583
[3] For more on algae in SA reservoirs: The incidence of in South African waterbodies: http://www.csir.co.za/news/2009/06/predict_algal.html)