The world is going clean at almost the same pace at which crude oil dominated the world in the mid-19th century. The last few decades have seen a tremendous increase in clean energy use to provide grid and off-grid electricity. By the beginning of 2020, 32.6 percent of the world’s energy came from renewable sources, compared to 29.6 in 2000. This significant increase shows the conscious efforts the world is making to reduce global warming and its attendant adverse effects.
The case is not entirely different in Nigeria. However, adopting clean energy solutions in Nigeria stems from an urgent need to provide electricity to the 80 million mostly rural dwellers. Therefore, identifying and deploying decentralised solutions for such regions is gaining ground, focusing on using available clean energy sources.
The Abandoned Puzzle Piece
Nigeria has an abundance of natural, clean energy sources, notably solar and hydro. Recent trends focus on harnessing solar power for off-grid electrification in rural, peri-urban, and urban areas. In less than a decade, the Rural Electrification Agency has overseen the installation of over 99,450 off-grid connections. This figure does not account for all the mini-grid and solar home system installations done by private individuals.
Figure 1. Hydropower constitutes only one percent of total energy consumption in Nigeria
Source: US Energy Information Administration.
While making progress in solar, the Off-Grid Industry seems to have dropped the ball on developing small hydropower (SHP) plants for electrification, despite the potential to bridge the electricity gap through embedded generation and decentralised supply. Nigeria ranks ninth in hydropower potential in Africa, with a combined capacity to generate over 2,000 megawatts (MW) of electricity across the country. SHP is also feasible to generate sufficient power for heavy loads, which would be more feasible for industrial and manufacturing clusters countrywide.
Read Also: Again, Lagos mulls generating own electricity
Small Hydro Perception
Conventional hydropower arrangement is large-scale, encompassing thousands of acres and producing hundreds of megawatts of electricity from a single plant. These large-scale projects are usually associated with prohibitive costs, long project development time, and significant environmental and social complexities. These conditions are not always the case with SHP. SHP projects usually provide capacities of 0.1 to 10 MW of electricity. They may not require a dam, or they can leverage already existing ones. The reduced requirements reduce the costs and complexities of planning, development, construction, and environmental impact; hence, they are relatively cheap. SHP’s are further classified based on their capacities :
Table 1: Classifications of Hydropower Plants
The power output of SHP for any location depends on the head (slanted elevation), flowrate measured across the year, geological features of the location, including topography, suitable and available turbines, and civil engineering work. Furthermore, the water used to generate power is available for other uses, especially in agricultural and industrial areas for irrigation and processing. The available energy capacity from SHP is predictable, unlike intermittent sources such as wind and solar. Therefore, it can serve to produce baseload power. Furthermore, SHP technology is long-lasting and requires only little maintenance. Systems can last for 50 years or more without the need for significant changes.
On the flip side, SHP projects are mainly site-specific; hence, developers cannot replicate data and design from one site in other sites. SHP projects are data-intensive, given that it takes at least one to two years to gather reliable data to determine output. Due to the volume of water and fixed head per site, maximum power is usually limited for a site, making expansion difficult. However, developers can expand through cascading plants. Seasonal changes also affect water levels, which affect the power generation of plants. Seasonal changes also affect water levels, which affect power generation.
Nigeria’s Potentials
In Nigeria, the major rivers and their tributaries, including Niger, Benue, Kano, and Cross River, provide the hydropower potential. These major rivers branch into smaller ones, many of which are around hills and mountains with high slopes, predominantly in Bauchi, Jos, and Taraba states. Nigeria has over 278 of such small rivers with a total capacity of 734 MW identified as SHP potential sites for further exploration. The National Electricity Supply Company (NESCO) has developed some SHP schemes amounting to 19MW around Jos Plateau. UNIDO has also developed a 400kW plant in Kankara Tea Community, Sardauna LGA, and Taraba State, which became operational in 2014.
Potentials-in-Waiting: The Darkness Continues
The potential for small Hydropower (SHP) in Nigeria is grossly underexploited. There are 17 already existing hydro dams recognised by the Federal Government. These facilities have dams constructed and can cumulatively provide an estimated 19MW of electricity to the surrounding communities. If developed, the hydropower plants can operate based on the embedded generation model, where they are connected directly to the nearest distribution network.
Apart from these 17 existing small hydro projects, the federal government owns three already existing small hydropower projects: Goronyo Dam, Ikare Gorge Dam, and Oyan Dam. The government abandoned the 6MW power plant construction in Ikare Gorge Dam, Iseyin, Oyo State in 1982. A recent 2020 documentary shows that the two turbines and generators, and other components, are still in crates and deteriorating. The Oyan River Dam 9MW power plant was completed by 1986 but was not grid-connected.
These power plants were intended to serve the surrounding rural communities, but these are still without electricity today. Such negligence amounts to wasted years of data collection and survey for these sites, favourable heads, flowrates, and other surrounding topographical conditions. These towns are far behind in terms of development and exposure owing to the lack of electricity.
To be Continued
The following article will present lessons learned from existing studies about small hydropower in Nigeria and how they can be applied. A few of these lessons include the need to create awareness, build capacity and prioritise productivity. Selected innovations that make the SHP even more feasible for the Nigerian economy and landscape will also be discussed. These are already in use in other parts of the worlds, including Germany, India, South Africa and the United States of America.
