Hampering Hydroelectricity?

Only 30.5% of sub-Saharan Africa has access to electricity (Cole et al. 2014). Electricity is an essential ingredient for developing an economy, but it is also important for this energy to be cheap to produce and come from an environmentally friendly, renewable source. So what energy source ticks all these boxes? Hydroelectric power!

Hydroelectric power (HEP) is generated by using turbines built into dam infrastructure to capture the kinetic energy of river flow and convert it into electrical energy. It’s a clean and affordable method of producing electricity, and its uptake and expansion would be a welcome shift in countries such as South Africa which is so reliant on coal for energy that it now has one of the highest carbon footprints worldwide (Mukheibir 2007).

HEP generation is currently concentrated in sub-Saharan Africa on the main rivers: the Nile, the Congo and the Zambezi. Many sub-Saharan African countries are highly dependent on this energy source, with some – including Mozambique, Zambia, Uganda and the DRC – deriving over 90% of their energy from HEP (Blackshear et al. 2011, Sharife 2009). HEP is a valuable tool for sustainable development as well as for alleviating poverty, and it’s estimated that Africa has only exploited 9% of its HEP potential (Cole et al. 2014).

So surely current HEP infrastructure power should be expanded – what could possibly go wrong?

Well, actually, a lot.

Hydroelectricity generation relies on a plentiful supply of water in the rivers, but climate change threatens the success of HEP schemes across Africa due to shifting rainfall patterns and rising temperatures. The increase of drought frequency and intensity due to climate change will lower water levels which will in turn reduce the capacity of hydroelectric plants.

However, these environmental considerations have not been taken into account when locating existing and planned African dams. For example, a dam is being planned on the border between Burundi, Congo and Rwanda on their common border regardless of all three countries having experienced power shortages from plummeting river levels (Cole et al. 2014).

Already, droughts in the past decade have forced power rationing in a number of sub-Sahara African countries: the Kenyan drought in 1998-2000 caused HEP production to fall by 25% (Karekezi et al 2009), lack of rainfall in 1998 in Ghana reduced hydropower production by 40%, and Tanzania had to impose electricity rationing after droughts in both 2006 and 2011 (Cole et al 2014). As climate change continues, this is only expected to worsen over time (Blackshear et al 2011).

A 10-20% decline in rainfall is predicted in some regions which will completely dry up the rivers in Botswana and Tunisia (Sharife 2009). On the Zambezi River, even though precipitation is predicted to increase during the rainy season, the dry season is expected to get even drier, resulting in the annual flow levels of Victoria Falls to decrease by 10-35%. If water levels fall by 35%, power production will drop by 21% making HEP production here uneconomic (Harrison and Whittington 2002).

The location of the Zambezi River in East Africa

Zambia is one of the most recent victims of electricity shortages. The Kariba Dam along the Zambezi River is one of the world’s largest hydroelectric dams and in the past has provided Zambia with such abundant cheap energy that as well as achieving political stability, its economy has been growing at over 5% every year through the copper mining industry (which requires vast quantities of water). However due to climate changes in the region, between 1960 and 2003 temperatures have increased by 1.3°C, rainfall has dropped by 2.3% every decade, and the rainy season has shortened (New York Times 2016). Consequently, recent droughts have led to a 25% decrease in HEP generation capacity (Reuters 2015). Due to Zambia’s extremely high reliance on the Kariba Dam for its energy requirements, power shortages are now frequent, rolling blackouts have been introduced, and copper mines are being threatened with 30% less power (Kozacek 2015). As a result, Zambia has been forced to reach out to the IMF for assistance.

The Kariba Dam

But what about the periods of increased precipitation that are predicted to occur in the wet season and in certain years on the Zambezi River? Surely this is an advantage of these environmental changes? Unfortunately not – although more rainfall can be a huge benefit by increasing the capacity of HEP generation, unexpected flooding can be destructive to hydroelectric infrastructure due to the vast quantities of sediment, vegetation, and even logs that accumulate and block the dam, decreasing its efficiency and requiring infrastructure repairs (Mukheibir 2007).

Nevertheless, the exploitation of hydroelectricity should not be ruled out as a source of electricity in Africa. If hydroelectric power is to be expanded to serve rising energy demands across the continent, it is essential that HEP generation coexists alongside other renewable energy sources, such as biomass, because diversifying the energy mix will reduce the vulnerability of economic development to hydrological changes (World Bank 2013). Furthermore, effective water management methods should be put in place at the water basins used for HEP generation to ensure that all water is used efficiently in order to maximise capacity (Yamba et al 2011).

Lastly, if the goal of expanding HEP generation is to increase the capacity of energy available for development across Africa, it is vital that this energy is equitably distributed. For example, even though Mozambique currently produces enough electricity to power the whole country, they export much of this energy, leaving only 9% of Mozambicans with access to electricity. Small scale farmers, rural communities and the poor members of the population have been excluded from the ‘luxury’ of electricity (Sharife 2009). At present, this 91% don’t have to worry about climate change; power cuts are irrelevant if you never had any electricity to begin with.