Authors: H. Mielke, C.R. Donnelly, K. Bhan, all Hatch and K. Koffi, Volta River Authority
Hydropower Africa, July 29, 2009
Abstract
The Akosombo Hydroelectric Power station provides more than half the electric power for all of Ghana. Over the last decade there has been an increasing demand for energy as a result of rapid electrification and industrial growth. However, in 1988, after about 25 years of service, a decline in efficiency and a general need for refurbishment of the generating units became apparent, placing increasing stress on the facility. For this reason, the Volta River Authority (VRA), which is the management authority of the power stations on the Volta River, engaged Hatch (formerly Acres International) to study more eco-efficient, cost-effective strategies to improve the station's generation efficiency in order to meet the increasing demands for clean reliable power.
This paper describes the refurbishment process followed at the Akosombo Hydroelectric Power Station. The process involved the use of state of the art numerical analyses and model testing including a unique and innovative contracting strategy that encouraged creativity in establishing cost effective rehabilitation approaches that would maximize future energy production. This included various methods including a unique and innovative use of a splitter vane mounted in the elbows of the unit draft tubes.
The results of the project were outstanding, the refurbishment resulted in an increase in the generating capacity of the plant by 108 MW (almost a 12% increase) and an unprecedented increase in the efficiency of the generating units thereby providing additional cost effective clean and renewable energy from the power plant that will continue to support economic growth in the region.
