The timber industry in Ghana comprised about 134 wood-processing firms in 1996 (S-B. Atakora, 1999). It is the fourth foreign exchange earner in the country after gold, cocoa and tourism, and a heavy user of both electricity and heat. The industry has been constantly troubled with power outages due to power rationing in the entire country, especially in the dry season that lasts for almost a quarter of the year.

Meanwhile, this industry generates significant amounts of waste, which represent between 55 and 70 per cent of the total log input. This waste is in the form of sawdust, edgings, off-cuts and slabs which are suitable for power generation. It is estimated that about 3.7 million m3 of lumber was processed in 2001. This generated between 2.0 and 2.6 million m3 of wood waste of which only a fraction was used inefficiently in boilers to heat the kilns.

There are large quantities of sawdust currently causing nuisance in practically all the wood-processing areas of Ghana. The sawdust could be used to provide the energy needed in local industries, especially those located in periurban and rural areas where the energy crunch is felt most severely. Figure 16.1 shows a “mountain” of sawdust produced just over a single weekend operation in one of the medium­sized sawmills in the district of Kumasi. Most of this sawdust is disposed off mainly through open burning or dumping in pits at the sawmills. Besides posing great environmental hazards to the sawmills and the neighborhood, this implies the loss of significant biomass resources that could be used for energy purposes.

In 1998, the Kumasi Institute of Technology and Environment (KITE) conducted a prefeasibility study to look into opportunities of cogeneration using wood waste in Kumasi. The prefeasibility study established that:

• Cogeneration using residues of the wood-processing industry is feasible and has a great potential for meeting some of the energy requirements of the country.

• The resource availability is enough to sustain cogeneration plants in the larger sawmills where continuous supply is assured.

• Kumasi is an ideal location for siting biomass cogeneration plants considering that about 60 per cent of wood-processing firms in Ghana are located here.

• Electricity tariffs in Ghana are at a level that makes cogeneration very competitive.

The above revelations led to the full feasibility study of a project, undertaken in 2001 by Econergy International Corporation (EIC) of USA in collaboration with KITE, under the auspices of the US Department of Energy. The feasibility study proposed a combined heat and power (CHP) plant with an installed capacity of 3.6MWe/9.3MW, h using steam turbine technology to be sited at the cluster of sawmills (Kaase) in Kumasi. The plant is projected to have an annual wood waste requirement of about 80000 m3. The CHP plant is to meet the power and heat requirements of the main sawmill, which is also the provider of the bulk of the wood waste (about 70 per cent), and a nearby brewery. This project is now possible as the Government of Ghana has liberalized the energy sector for independent power pro­duction (IPP). In addition, the project is perceived to have a good potential within the emerging CDM market.