zion

Bui And The Tale Of Three Hydro Dams

GHANA can now boast of three hydroelectric power dams with the completion and inauguration of the Bui Dam Hydroelectric Power project located on the Black Volta, a boundary river between Bole in the Northern Region and wenchi in the Brong Ahafo Region.

With its turbines turning, Bui becomes the third hydro-power plant to be developed in Ghana after the Akosombo and Kpong projects. 

This means, three regions of the country can boast of hydro-power dams. These are the Northern and Brong Ahafo regions for Bui and the Eastern Region for Akosombo and the Kpong dams. 

Size of dams and capacity 

The Akosombo Dam remains the largest of the three, covering an area of 8,502 square kilometres and has an installed capacity of 1,020 MW of power. 

The Volta Lake created by the dam is the largest reservoir by surface area in the world, and the fourth largest by water volume. Its northernmost point is close to the town of Yapei and its southernmost at the Akosombo Dam, 520 kilometres downstream from Yapei. 

Ghana's famed Akosombo Dam holds back both the White Volta and the Black Volta which formerly converged where the middle of the reservoir now lies, to form the single Volta River. 

It takes approximately 36 hours to travel round the vast expanse of the Volta Lake, which has been created by the dam. The Akosombo Dam is 2,200 ft long,  440ft high and 1,400ft wide at the base and holds a water volume of 148 kms  (32.6 x 1012 gallons). 

The Kpong hydro-electric project, which represents the third stage in the development of the Volta River, commonly known as the Volta River Project, is the third largest dam in Ghana, with a total installed capacity of about 160 MW. 

Nonetheless, if all four units at Kpong are running, there is a rise in tail water elevation, which limits the output of the generation to about 148 MW. 

The combined Akosombo/Kpong system has an installed capacity of 1,180 MW, while the Kpong head pond has minimal storage capacity and is therefore operated in tandem with Akosombo, as a run-of-the-river plant to optimise water use from the Volta Lake. 

The joint firm energy output from the Akosombo/Kpong hydroelectric. Development is about 4,800 Gigawatt hours (GWh).Meanwhile, the Long-Term Average (LTA) capability of the two plants is about 6,100 GWh. 

Ghana's second largest dam, the Bui Dam, which was commissioned in December 2013, is the largest Chinese- funded project in Ghana and the largest foreign investment in Ghana, since the construction of the Akosombo 

Hydroelectric Power Project in the early 1960s, according to Baah. 

The main dam's structural volume is 1,000,000 m3 (35,314,667 cu ft), while its full capacity is 12,570,000,000 m3 (10,190,665 acre-It), Its active capacity is 7,720,000,000 m3 (6,258,706 acre-It) and minimum level: 288 km2 (111 sq miles). With a surface area of 444 km2 (171 sq miles) at maximum level and 167 m (548 ft) at minimum level, the Bui Dam has a normal elevation of 183 m (600 ft). 

Its reservoir also measures 40 km (25 miles in average length and has a maximum water depth of 88 m (289 ft). 

Construction of the Bui Dam is to increase power supply to meet the growing consumer and industrial demand and is expected to generate 400 megawatts of electricity power. 

Construction of the dam 

Originally conceived by geologist Albert Ernest Kitson in 1915, construction of the Akosombo Dam by an Italian consortium, Imbroglio, began in 1961 after plans were finally drawn in the 1940s, and was completed in 1965. 

The first stage of construction of the Akosornbo hydro dam began in 1961 when the Volta River Authority (VRA) was established, and work started on the Akosombo dam and power station. 

Whereas by September 1965, the first power was flowing from Akosombo, marking an important step in the economic development of the newly formed Republic of Ghana, the Kpong generating station was completed in 1982.

 

Although the actual construction of the Bui Dam began in 2008 and was completed in 2013, it took over 50 years of conceptualisation, drawing of plan, negotiations and scouting for funding before the dream could be actualised. 

After a long-term preparation for the Bui Hydro-electric Project in 2007, through international bidding, the employer, the Ministry of Energy, successfully brought in the Chinese governmental aid funds to Africa, and as a world-class construction contractor, Sino hydro Corporation Limited was contracted to build it. 

With the total contracted sum of about US$790 million and the duration of 1,640 days, the project was contracted in international popular EPC (Engineering - Procuring - Constructing) mode. 

Financial implications 

The Akosombo Dam project was estimated at over GH¢552 million ($258 million, £230 million). This sum was to cover the cost of the dam and power installation (at Ajena), the opening up and equipping of the bauxite mines and a complete plant for producing aluminum, the Volta Aluminum Smelting plant (VALCO). 

On the other hand, the Bui Dam project was estimated at US$622 million. It was jointly funded by the Government of Ghana counterpart funding of US$60 million and a concessional loan of US$263.5 million, as well as a buyers credit of US$298.5 million from the Chinese Exim-Bank. 

These loans are expected to be repaid in part by the supply of cocoa at the current market prices. Consistent with the Chinese practice of linking their aid to Chinese construction services, the Bui project was undertaken by the Sino hydro Corporation - a state-owned Chinese  construction firm. 

Socioeconomic benefit and employment 

The Akosombo and Kpong dams provide electricity for much of the country, as well as for export to Togo, Benin, and nearby countries, to earn foreign exchange value. 

Lake Volta is also important for transportation, providing a waterway for both ferries and cargo watercraft. Given good management, Lake Volta is the location of a vast population of fish and large fisheries. The lake also attracts tourism, and tourists visit the island of Dodi.· 

Establishment of the Volta River Authority (VRA), to manage the two dams, has also created permanent jobs for hundreds of Ghanaians all over the country. 

In 2008, officials of Sinohydro indicated that at its peak, the Bui Dam project was expected to employ about 3000 workers. 

The construction and management of the project has already provided about 1,500 positions, while more than 6,000 people have worked at the Bui site since the commencement of the project. 

The Bui hydropower plant is also expected to increase the installed electricity generation capacity in Ghana by 22 per cent up from 1,920 MW in 2008 to 2,360 MW. Furthermore, like all hydropower plants, the project avoids greenhouse gas emissions that would have occurred if thermal power plants had been built instead. 

An additional expected benefit is the irrigation of high-yield crops on 30;000 hectares of fertile land in an "Economic Free Zone." 

Challenges and impact 

In spite of the immense benefits the construction of the three hydroelectric dams has brought to Ghana, sight cannot be lost on the challenges and negative impacts they have had on several Ghanaians. As a result of the formation of the Volta Lake, about 78,000 people were relocated to new towns and villages, along with 200,000 animals belonging to them, while about 120 buildings were destroyed. 

 

Also, the presence of aquatic weeds along the lake and within the tributaries has resulted in even greater detriment to local human health, as the weeds provide the necessary habitat for black-fly, mosquitoes and snails, which are the vectors of waterborne illnesses such as bilharzia, river blindness and malaria. These diseases have increased remarkably, since the construction of the dam. 

Additionally, the loss of land experienced by the 78,000 people relocated meant the loss of their primary economic activities from fishing and agriculture, loss of their homes, loss of their family grave sites, loss of community stability, and the eventual loss of important social values among others. 

Impacts as a result of the Bui dam project can be classified into two - social and environmental. Socially, building of the dam required the forced relocation of 1,216 people, of which only 217 had been resettled as of June 2010. In theory, all affected people were expected to be moved to a new locality called Bui City. 

However, as of 2010, the city did not exist and there was not even a schedule for its construction. Instead, the first 217 relocated people were moved to a temporary settlement called Gyama Resettlement Township. Fisherfolk were also resettled on dry land, losing their livelihoods. 

The environmental impact was mainly the inundation of parts (21 per cent) 9f the Bui National Park, home to the only two populations of black hippopotamus in Ghana, whose population is estimated at between 250 and 350. 

But the then Manager of the Bui National Park, Mr Christian Atsu Fumey- Nassah, is quoted as having said on Space FM in Sunyani on August 29,2007, "We have adequate measures for hippo habitats which would be flooded, but would in the long run be moved upstream”, adding, "the issue of trans locating the hippos, which wouldn't pose much of a problem, would be addressed later."

Source: Daily Graphic