A bright future

Tanzania has one of the fastest growing economies in Africa. The need for affordable, sustainable and clean electricity to meet increasing demands is as pressing as ever. According to a recent article by Baraka Kichonge, published in the Journal of Renewable Energy, although Tanzania is gifted with huge hydropower potential which is estimated at approximately 38,000MW, only a small portion has been exploited to date; thermal generation still dominates fulfilling the country’s electricity demands.

Kichonge explains that “in pursuing her quest to attain a middle-income economy as envisioned in its Development Vision 2025, Tanzania faces huge tasks of meeting energy needs due to the high expectations in growth to fuel the economy, and at the same time minimise environmental challenges”. However, despite the abundant hydropower potential available in the country, “past decades have witnessed the actual electricity sector fall short of the required level of reliability”.

Tanzanian water resource management and governance is divided into nine hydrological water basins. Seven of these are transboundary. Kichonge describes Tanzania as a water rich country that is endowed with lakes, rivers and water basins; a third of its water resources are located in the highland areas of the country with precipitation in excess of 1000mm.

According to the report: “These water resources if sustainably exploited and managed would provide a bright future in terms of hydropower generation and also revenue from economic activities such as tourism and irrigation.”

Historically, hydropower generation in Tanzania dates back to the colonial era when most of the operational small hydropower plants were installed through the efforts of missionaries. Today more than 190,000GWH/yr could be generated through utilisation of potential large and medium scale resources mainly located on the rift valley escarpments in the west, south west and north east areas of the country.

Drivers for change

One of the main drivers for hydropower development would be its role in reducing greenhouse gas emissions. Tanzanian GHG emissions, specifically CO2 from fossil fuels, are described as having grown at a phenomenal rate since 1971.

However, climate change is an important factor when considering hydropower potential in Tanzania, and its effects are already being felt. Observed rainfall over Tanzania, as described by several sources, “depicts statistically considerable annual decreasing trends of up to 17% over the past decade”.

In 2015 Tanzanian hydropower generation was estimated at 6296GWh or 33.5% of total electricity generation, according to data from the International Energy Agency. This was opposed to 1628GWh or 95% in 1990. Kichonge explains that during the period 1990-2015 hydropower generation tended to rise and fall irregularly, exhibiting varying water availability due to phases of above or below average rainfall. The share of hydropower in total electricity generation has declined over this period, reflecting the higher growth of alternative forms of electricity resources. Indeed, “less availability of hydropower reveals huge impact on the environment including GHG emissions”.

Kichonge reiterates: “Notwithstanding efforts to mitigate climate change effects, reduced precipitation and increased evaporation are anticipated to increase in future and therefore water security problems in water-stressed areas of Southern Africa will be increased. Subsequently, authorised and unlawful water abstractions from rivers and reservoirs are expected to increase, limiting water availability for electricity generation”.

Hydropower still remains an important renewable energy option for Tanzania and the country has identified and proposed 23 hydropower schemes, totalling 4765GW of capacity as future power development options. Some of these are described as being in the planning phase or implementation stages. The largest scheme is the Stiegler’s Gorge hydropower project in the Rufiji River basin. Still in initial stages of implementation it is expected to have an installed capacity of 1048MW in Phase I and 1048MW in Phase II.

In addition, small hydropower continues to play an important role in rural electrification. The potential for schemes less than 10MW is estimated at 315MW, with only 8% of this currently being exploited. As a large proportion of these schemes are located in remote rural settings where the national grid does not spread, most of these will remain suited to supplying power to rural areas. Most of the promising small hydro schemes are located close to the main lakes such as Nyasa, Tanganyika and Victoria.

In conclusion, Kichonge concludes that Tanzania is a country with huge water resources potential, which possesses sufficient and suitable characteristics to develop and maintain sustainable hydropower generation from a small to large scale. As hydropower is the country’s main clean domestic energy resource option, he believes “there are substantial benefits to promote its development to ensure a more sustainable growth pathway in electricity generation”.

Reference

The Status and Future Prospects of Hydropower for Sustainable Water and Energy Development in Tanzania by Baraka Kichonge, Mechanical Engineering Department, Arusha Technical College, Tanzania. Journal of Renewable Energy Volume 2018, Article ID 6570358, https://doi.org/10.1155/2018/6570358