Ghana: Bui Dam Comes Alive - Ghana Energy Problems Now Over

Ghana's enthusiastic quest to become the West African energy powerhouse has seen a major boost following the commissioning of the 400 megawatts (MW) Bui Hydroelectric Dam in the Tain District of the Brong Ahafo Region.

The project, which cost over $622 million, is funded with a concessional loan of $263.5 million and a buyer's credit of US$298.5 million from the government of the People's Republic of China and the Exim Bank respectively, with the Government of Ghana contributing $60 million.

The commissioning comes off, following the completion of the third and final generating unit of the Bui Hydroelectric Project. The first unit of the Project, which provided about 133 megawatts of power, was inaugurated in May, to augment energy supply in the country.

After dry and wet tests, which were to verify proper, complete and satisfactory erection of the entire sub systems were successfully carried out, the three generating units, which have the capacity to generate 133MW each, were commissioned in May, July and November 2013.

The substantial completion of the Project now, provides Ghana with additional 400MW (20% increment) of installed capacity, with average annual generation of 1000GWh.

Meanwhile, other associated and non-power works on the Project including the Bui City will continue till the second quarter of 2014, when all works on the Project would be completed. The city is expected to have resorts, hotels, water sports facilities and diverse other recreational centres for both domestic and international tourists.

Ghana is on course to achieve the targeted power generation capacity of 5000 megawatts by 2016, the President John Dramani Mahama, said at the commissioning of the final phase Bui Dam.

Mr. Mahama, who was joined by the former President John Agyekum Kufuor , Chinese Ambassador to Ghana, Ministers of State, senior officials of the Sinohydro Corporation Limited, chiefs and people of the area to commission the power facility, noted that; "the project comes at the time when the Ghanaian economy is growing at 7-8% of gross domestic product (GDP). So, the demand for energy in the country is therefore increasing".

The Chief Executive Officer of the Bui Power Authority, Jabesh Amissah-Arthur said the Bui City project, the luxury aspect of the just-completed 400 megawatts dam, could be realized if private investors come onboard.

Geologist discovered the dam

The Bui hydro-electric dam had first been envisaged in 1925 by the British-Australian geologist and naturalist Albert Ernest Kitson when he visited the Bui Gorge.

The dam had been on the drawing board since the 1960s, when Ghana's largest dam, the Akosombo Dam, was built further downstream on the Volta River. By 1978 planning for the Bui Dam was advanced with support from Australia and the World Bank.

However, four military coups stalled the plans. At the time Ghana began to be plagued by energy rationing, which has persisted since then. In 1992, the project was revived and a first feasibility study was conducted by the French firm, Coyne et Bellier.

The three-turbine Dam is nestled in a gorge separating the Bono Ahafo Region from the Northern Region of Ghana. Ghana entered into an engineering procurement and construction turnkey project contract for the implementation of the project in April 2007, with Sinohydro Corporation Limited, a major Chinese dam construction firm, as the contractor.

The role of the employer was subsequently assigned to the Bui Power Authority (BPA) to manage and supervise the project, with the assistance of an engineering consultant, Coyne et Bellier.

On August 24, 2007, the sod was cut for the commencement of the project, which has been divided into two phases.

Dam design

The Bui Dam is a gravity roller-compacted concrete-type with a height of 108 m above foundation and 90 m above the riverbed. The crest of the dam is 492 m long and sits at an elevation of 185 m above sea level (ASL).

The main dam's structural volume is 1,000,000 m3. Southwest of the dam two saddle (or auxiliary) dams maintain pool levels and prevent spillage into other areas of the basin. The first and closest to the main dam is Saddle Dam 1. It is 500 m southwest of the main dam and is a rock-fill embankment dam.

The dam rises 37 m above ground level and has a crest length of 300 m.1 km southwest of the main dam is Saddle Dam 2. This dam is a zoned earth-fill type with a height of 7 m ASL and a crest length of 580 m (1,903 ft). Both saddle dams have a crest elevation of 187 m (614 ft) ASL.

The reservoir that the main and saddle dams create will have a maximum capacity of 12,570,000,000 m3 of which 7,720,000,000 m3 is useful for power generation and irrigation.

The reservoir's maximum operating level is 185 m ASL and the minimum 167 m ASL. At the maximum level, the reservoir will have a surface area of 440 km2 (170 sq mi) while at the minimum it will be 288 km2.

The reservoir's volume at minimum level is 6,600,000,000 m3 .The average length of the reservoir will be 40 km (25 mi) with an average depth of 29 m (95 ft) and a maximum 88 m (289 ft).

Just downstream of the dam on the left bank is the dam's powerhouse. The intake at the reservoir will feed water through three penstocks to the three separate 133 MW Francis turbine-generators.

Each turbine-generator has a step-up transformer to increase the voltage to transmission level. A fourth unit, with a penstock on the spillway, will provide four megawatts for station service and black start power, and will provide minimum flow to maintain river levels if the main units should be shut down.

The power station will have an installed capacity of 400 MW and an estimated average annual generation of 980 GWh.

The power station's switchyard is located 300 m (984 ft) downstream. Four 161 kV transmission lines connect the substation to the Ghana grid.

The dam's spillway near the right bank consists of five radial gates, each 15 m wide. The spillway sits at an elevation of 169 m (554 ft) and has a maximum discharge of 10,450 m3/s which correlates to a 1-in-10,000 year flood. The dam's outlet works consist of a single outlet on the right bank converted from one of the diversion tunnels.

Development of dam

Phase one comprises detailed field investigations and preparatory works needed for the construction of the main works, while phase two included the construction of the main dam, the power-house, the spillway and transmission lines.

Impoundment of the dam which commenced in June 2011 continued this year - 2013 with the completion expected mid this year. Presently the water level is over 169.61 metres above sea level.

The Powerhouse Overhead Bridge Crane with a maximum lifting capacity of 360 tonnes was installed and successfully tested in May 2012. At this time, the crane is being used for the erection of the generating units.

The erection of the Turbine-Generator components (turbine runner, wicket gates, turbine shaft, head cover, servomotors, generator stator, generator rotor and others) are about 15%, 55%, and 85% complete for Units 1, 2, and 3 respectively.

The overall progress of the transmission lines is completed while four electricity transmission lines are constructed to aid in the evacuation of power from the Bui Generating Plant to the national grid.

These four lines send the power produced from the Plant to the four Ghana Grid Company Limited (GridCo) substations in Sawla, Techiman, Kintampo, and Sunyani all in Northern and Brong Ahafo regions for distribution to consumers.

The development of the hydro-power scheme on the Black Volta River at the Bui Gorge becomes the third largest hydro-power dam after Akosombo and Kpong hydro-power dams in the West African country.

The Bui Hydroelectric Project, which is commissioned, was designed primarily for hydro-power generation. It, however, also includes the development of an irrigation scheme for agricultural development, and it also presents an opportunity for enhanced eco-tourism and fisheries.

It also includes a Resettlement and Community Support Program, the Chief Executive Officer of the Bui Power Authority, Jabesh Amissah-Arthu said.

Compensation

The Lands Valuation Division of the Lands Commission, acting on behalf of the Government of Ghana and with the assistance of the Bui Power Authority (BPA) has completed the payment of the first batch of crop compensation to persons whose economy trees and crops have been affected by the ongoing Bui Hydroelectric construction work.

According to Amissah Arthur, the economy trees and crops for which payment is currently being made were those located at either the current construction site, the resettlement sites or within the area to be inundated by the Bui reservoir.

The beneficiaries for this batch of compensation payments, about 580 people, have since received a total of $1 million.

"The next batch of compensation payments which is also being processed cover the economic trees and crops also affected by the construction of transmission lines and substations as part of the Project," Arthur said.

Work has been completed on all 170 housing units in the Resettlement Part B Township where the three remaining communities comprising Bui, Bator-Akanyakrom, and Dokokyina are to be resettled, Arthur revealed.

While 29 households, comprising 156 people out of a total of 36 households (165 people) from Dokokyina have been resettled amicable.

He disclosed that "Livelihood enhancement programme to restore lost economic activities and improving living standards in project affected communities is underway".

Under the programme, the Authority gives US$100 to each person in a household. This will continue for a year.

"In addition, the Authority will build fish ponds for the settlers. They can also fish in the downstream of the dam," Arthur said.

Water supply systems (bore holes) are in place. The construction of a 6-unit classroom block for primary school has been completed.

Works on the community centre are 75% completed, while construction of internal roads is underway. All these facilities will be connected to electricity with help of the Authority.

To add up, construction of 24 replacement housing units to replace the temporary houses provided earlier for four communities such as Brewohodi, Lucene, Agbegikuro and Dam Site is underway.

Benefits

The project which commissioned today will increase the installed Ghana's electricity generation capacity which stands at 2,000MW, with a demand of 1,500MW.

Together with three thermal power plants (Aboadze, Asugli and Tema Thermal 1 Power Plant) will contribute to alleviate power shortages that are common in Ghana.

It will also reinforce the Transmission Network in the three northern regions comprising Northern, Upper East and Upper West regions.

Furthermore, like all any hydro-power 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 over 30,000 hectares of fertile land in an "Economic Free Zone".

"As the country moves to develop its oil and gas resources, the government is keen not to push agriculture to the backstage but to continue to improve inputs for sustainable agricultural growth, food availability for the people of Ghana," the Minister of Energy and Petroleum, Emmanuel Armah-Kofi said.

He said the government was therefore taking advantage of the reservoir to be created by the Bui Hydropower Project to promote the irrigation over 30,000 hectares of land.

The proposed land area is located about 32km of the Dam site.

Crops which will be cultivated on the area include but not limited to maize, sorghum, yam, cassava, soya bean, pepper, cashew, sugar cane, cabbage, and vegetables.

An agronomist, Philip Abayori explained: "The Bui area has large tracts of fertile and irrigable land second only to the Afram Plains in the Eastern part of Ghana and it is the intention of government to utilize the land to augment efforts at opening Northern Ghana for economic growth and development".

He was quick to reveal that the Bui area had been declared an Economic Free Zone to enjoy the same benefits granted to companies under the Ghana Free Zone Board's regime.

All these are geared towards the creation of thousands of employment opportunities in the area, according to the CEO, Amissah-Arthur.

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