Peter Owu *
ineteen ninety-four was a challenging year for the Volta River Authority (VRA), currently Ghana's sole power producing utility. In June, the Authority began curtailing its domestic load from 6pm to 10pm daily. Barely two months later, on August 4, the curtailment program was extended to 24 hours a day. Then, on September 11, the utility declared force majeure, and cut off electricity supply to the Volta Aluminum Company's aluminum smelter in Tema, which alone consumes 45% of the energy produced by VRA from its two major hydro-electric plants at Akosombo and Kpong.
These events had serious consequences. Although the domestic load curtailment program did not include the industrial and mining sectors, it was still economically and psychologically disruptive. The decision to cut off power supply to the aluminum smelter led to a legal dispute which brought the VRA to court for the first time in its 33-year history. For an organization that had built a solid reputation of professionalism and efficiency in its operations, these were major concerns.
Low Rainfall Affects Power
The reasons for Ghana's energy troubles are not hard to find. VRA generates most of its electricity from two hydro-electric plants on the Volta River. Although hydro plants are less expensive to operate than thermal ones, they depend on a critical supply of water. This is a major disadvantage in a region which is characterized by wide variations between very wet or extremely dry periods. For example, records of annual inflows to the Volta Lake, the reservoir created by the Akosombo dam, show a ten-fold variation. This irregularity can cause fluctuations in energy output, since the capability of the generating system depends on the level of water in the reservoir. Fortunately, Lake Volta has a storage capacity that enables it to contain almost twice the system's average annual run-off volume. This had helped to regulate output fluctuations to a large extent.
Since 1982, however, rainfall in the Volta Lake basin has fallen below average, resulting in low reservoir levels. In 1994, the lake elevation fell to 239.50 feet, 8.50 feet below the minimum operating level (MOL) of 248 feet. The system's power generating capacity has been adversely affected as a result.
To make matters worse, domestic load demand has grown enormously in recent times. Since the beginning of 1985, when Ghana's Economic Recovery Programme (ERP) was launched, domestic demand has grown at an average of 13-15% per annum. This is in contrast to an average annual growth rate of 2% for the period prior to the ERP. VRA's system, as it currently exists, can no longer reliably meet the demands of the utility's customers.
The obvious solution is to add new generation facilities to the system. This has been one of VRA's major preoccupations for some time. As far back as 1975, a generation expansion study was conducted by the Authority's consultants, Acres International of Ontario, Canada. By this time, the utility had commissioned six generating units at Akosombo, four by 1968 and two by 1972, yielding a total installed capacity of 912 MW. The 1975 study recommended the development of the Kpong hydroelectric project downstream from Akosombo on the Volta River. Kpong's four generating units, with a total capacity of 160 MW, was subsequently constructed and commissioned in 1981.
Following the prolonged and severe drought which Ghana experienced in the early 1980s, VRA commissioned Acres to conduct a new generation and transmission planning study. The purpose of this study was to provide VRA with a comprehensive masterplan for the orderly and economic expansion of generation facilities.
New Facilities Planned
The resulting Ghana Generation Planning Study published in 1985 identified combustion turbines as the most attractive option. In 1992, a Thermal Plant Feasibility Study recommended the construction of about 400 MW of new generating facilities by 1997. Based on further analysis and as a result of discussions with the World Bank, the project was scaled down to a 300 MW Combined Cycle Plant made up of two 100 MW Combustion Turbines to be commissioned in early 1997, and one 100 MW Steam Turbine with associated Heat Recovery Steam Generators to be commissioned by the end of 1997.
The thermal plant forms the initial phase of an optimized long-term generation expansion plan to ensure that VRA's power supply obligations can be reliably met. To be located at a sea coast site near Aboadze, near the western seaport of Takoradi, the plant will burn Light Crude Oil (LCO) or a blend of LCO and Residual Fuel Oil (RFO), as well as natural gas. The fuel oil will be supplied through a dedicated marine tanker unloading facility and connecting pipeline. Power from the thermal plant will be fed into the existing 161 kV system through 500 km of single- and double-circuit transmission lines.
The project, which is estimated to cost over US$400 million, is being funded by the International Development Association, European Investment Bank, Commonwealth Development Corporation, Kuwait Fund for Arab Economic Development, Arab Bank for Economic Development in Africa, African Development Bank, Caisse Francaise de Developpement, and the VRA. The Authority is financing the local cost component of the project, amounting to the equivalent of US $64.8 million and interest during construction of about US$33 million.
In addition to the Takoradi project, VRA is encouraging arrangements for the establishment of an independent power producing unit to be owned by the Ghana National Petroleum Corporation (GNPC). The facility, to be fueled by gas from the Tano gas fields, will be located on a barge in the Effasu Lagoon in Ghana's Western Region. It is projected that the first phase, which will provide 130 MW of electricity, will be completed in the second quarter of 1996.
The Authority is also exploring other potential sites for hydro-power. These include Bui on the White Volta and Awisam and Hemang on the Pra River. With the potential of providing up to 300 MW of power, Bui appears to be the most promising. However, the project will require more exhaustive studies before it can be implemented.
Undoubtedly, the years ahead will continue to be challenging ones for the VRA. Apart from seeking to meet the demand for power which is likely to rise as Ghana's economy grows, the utility has also began to respond to the global shift towards market-oriented restructuring in the electricity industry. VRA's management is implementing strategies and measures in response to both present and anticipated challenges. With a good record in handling similar challenges in the past, VRA gives many observers good reason to believe that the utility will be able to ensure a reliable supply of electricity to meet both the present and future demand of its customers.
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* Peter Owu is a freelance journalist and ATF correspondent in Ghana.