The United Nations has initiated a project to promote cogeneration investment in seven eastern and southern African countries. While all of these countries already have some cogeneration capacity – mostly in the sugar industry – the scope for more, and more efficient, plant is very large. Stephen Karekezi and Waeni Kithyoma report.
by Stephen Karekezi & Waeni Kithyoma
While cogeneration has for the last 40 years been a reality in a number of agro-industries in Africa, most of the cogeneration plants are inefficient – operating with low-pressure boilers generating low volumes of power – and have very limited sales to the grid. The ‘Cogen for Africa’ initiative (see box on the next page) is designed to promote wider use of efficient cogeneration options and stimulate well over US$300 million investment in the region’s cogeneration industry in the medium to long term. It will also provide policy support to expand sales to the national grids of the seven participating countries.
POTENTIAL FOR CHP IN THE POWER SECTOR IN EAST AND SOUTHERN AFRICA
Most African countries have lower levels of electricity consumption per capita (see Figure 1) than other developing regions. However, it is expected that with economic development and population growth, the demand for electricity in Africa will continue to increase. This demand would therefore need to be met with an increase in generating capacity.
Sugar cane in Kenya being transported to a factory. ‘Cogen for Africa’ aims to get biomass-based CHP on the road for east and southern Africa
Hydro power currently supplies a significant portion of the electricity generated in east and southern Africa. However, the share of high-cost oil-fired power generation is growing, primarily due to the unreliability of hydro power. For example, a serious drought in eastern Africa in 2005/2006 reduced power production from hydro dams in Kenya, Uganda, Tanzania and Ethiopia by up to 50% in some cases, forcing utilities in these countries to turn to power from very high-cost oil-fired emergency power producers.
Cogeneration in agro-based industries can provide an important option for improving security of power supply as well as guarding against reliance on expensive oil-fired power generation. Based on available AFREPREN/FWD research findings, there is significant cogeneration potential in a large number of agro-industries in east and southern Africa, including – but not limited to – sugar, pulp and paper, wood processing, coffee, maize, rice, sisal and palm oil.
Sugar is produced in many of these countries. It is a major agricultural export for Ethiopia, Madagascar, Malawi, Mozambique, Swaziland, Zambia and Zimbabwe. The potential for electricity generation from bagasse is high, since cogeneration equipment is almost always an integral component of sugar factory design. An estimate of cogeneration potential for the sugar industry is provided in Table 1.
The following sections briefly review the status of the power sector and the prospects for cogeneration in the ‘Cogen for Africa’ target countries of Kenya, Uganda, Tanzania, Sudan, Malawi, Ethiopia and Swaziland.
Kenya currently has a total installed capacity of 1143 MW, consisting of hydro power 58.26%), oil-fired (30.53%), geothermal (11.19%) and wind (0.03%).
Figure 1. Electricity consumption per capita by region of the world (2001). Source: World Bank, 2003
Cogeneration (albeit of the low-pressure boiler, inefficient type) is already used in the western part of Kenya where sugar factories use bagasse as a primary fuel. Currently, seven sugar factories in western Kenya produce an average of 1.8 million tonnes of bagasse per annum, 60% of which is used as boiler fuel for steam generation, with electricity being generated from surplus steam. The remaining 40% of bagasse is simply discarded, usually at a cost. Only one sugar company (Mumias Sugar Company) is self-sufficient in electricity supply using its cogeneration system, with a small surplus capacity of 2.5 MW for export to the national grid. The remaining sugar companies, because of the old equipment used for energy generation, are net importers of electricity. Generally, the boilers in these sugar factories are inefficient, supplying low-pressure steam of 20-30 bars.
In Uganda, most of the electricity is generated by hydro power stations, with just over 300 MW of total installed capacity. As mentioned earlier, prolonged drought recently resulted in a drop of the water level in Lake Victoria (the main source of water for the country’s major hydro power dams) by about 2 metres, which reduced the effective generation capacity in the two hydro power plants (Kiira and Nalubale) by up to 50%. This led to extensive power rationing and daytime load-shedding, as well as commissioning of very high-cost oil-fired power plants.
Table 1. cogeneration potential in the sugar industry in selected African countries
Uganda’s sugar industry offers potential for generating excess power from the residues produced by the factories that, if tapped, could help fulfil the country’s electricity needs and partially replace the emergency and other thermal power plants that are planned to be built. Three sugar factories produce an average of 130,000 tonnes of sugar annually. These factories produce electricity from cogeneration to meet most of their internal factory demand using low-pressure boiler systems.
Tanzania’s installed capacity is currently about 863 MW, with annual energy generation of about 2770 GWh. Hydro power stations supply about half of the installed capacity, with the remainder being generated from thermal power plants, natural gas and an insignificant amount from coal and biomass. There are also some imports from Uganda and Zambia. Again due to drought and the resultant power shortfall, Tanzania is now experiencing load-shedding of up to 12 hours a day. High-cost oil- and natural-gas-fired emergency plants are now being considered.
Cogeneration could provide a near-term competitive alternative and improve the reliability of the country’s power system in the long term. Low-pressure boiler cogeneration has been exploited in the sugar industry, wattle-processing industry, and sawmills in Tanzania. There are plans to expand the cogeneration capacity in the sugar industry, as well as facilitate the sale of excess power to the grid.
Malawi’s Electricity Supply Industry (ESI) generates power for the grid mainly using hydro and thermal (largely diesel-fired) systems. The commercial electricity supply industry is dominated by a publicly owned and vertically integrated power utility, the Electricity Supply Corporation of Malawi (ESCOM) Ltd. ESCOM’s total installed capacity was estimated at 306 MW. Of this, approximately (93%) is generated using hydro power and the remaining (7%) is from thermal plants. As with other countries of the region, drought continues to impede the Malawi power generation industry.
A sugar cane factory in Kenya. There is significant potential for cogeneration in east and southern Africa, especially for the region’s sugar industry
Currently there are two sugar factories in the country, with a combined annual production of bagasse of 60,000 tonnes. Almost all of the bagasse generated in these factories goes to cogeneration systems for the factories’ own use. There are plans to implement more efficient cogeneration systems in these factories to cover their energy requirements and sell excess power to the grid.
The Ethiopian Power Sector is dominated by the vertically integrated utility, the Ethiopian Electric Power Corporation (EEPCo). EEPCo maintains two different power supply systems, namely, the inter-connected system (ICS) and the self-contained system (SCS). Inter-connected systems are mainly supplied from hydro power plants, with some use of thermal (diesel) sources. Self-contained systems consist of mini-hydro power plants and a number of isolated diesel-generating units widely spread all over the country. In the past, Ethiopia has faced serious drought-related hydro power crises. Cogeneration can provide an important option for increasing the security of the country’s power generation sub-sector.
Bagasse-based energy cogeneration for export to the national grid is not practised in Ethiopia. All sugar factories (Metahara, Wonji/Shoa and Finchaa) produce electricity from cogeneration to meet the power needs of their plants. However, they also use electricity from the national utility for irrigation and powering residential houses for the factory workers. There are plans to expand the sugar industries, which include expansion of cogeneration for the site’s own use and for sale to the grid.
Sudan has 638 MW of installed electricity capacity, and the country’s total electricity generation was 2450 GWh in 2002. Its main generating facility is the 280 MW Roseires dam located on the Blue Nile river basin. The facility also suffers from drought-induced low water levels, which often cause its output to fall to 100 MW.
Sugar being collected at a factory in Uganda. Agricultural cogeneration is a local alternative to expensive oil-fired power generation during periods of low hydro power output
Sudan is one the largest sugar-producing countries worldwide. It has four operational sugar factories and an additional two under construction. Three of the existing factories (New Halfa, Gunied and Sennar sugar factories) are owned by the state and managed by the Sudan Sugar Company. The fourth is Kenana Sugar Company, which is a privately owned factory. The original design of each of the sugar factories under construction includes a cogeneration plant. There are plans to move into high-pressure advanced cogeneration systems to diversify the country’s power supplies.
Power in Swaziland is supplied and distributed by the Swaziland Electricity Board (SEB). SEB is the agency responsible for the generation, transmission and distribution of electricity in the country and operates as a state corporation under the Ministry of Works, Power and Communications. Swaziland’s installed capacity is mostly hydro-powered, with the bulk (90%) of its electricity imported from South Africa. As South Africa’s own demand for power has begun to outstrip its generation capacity, Swaziland needs to expand its own generation capacity. Cogeneration is one of the options that are currently being evaluated.
Swaziland has a sizeable sugar industry producing more than 600,000 tonnes of sugar in 2005. This production is shared among three sugar factories, namely, Simunye Sugar Mill, Mhlume Sugar Mill and Ubombo Sugar Mill. The three factories have a combined capacity of 26,400 tonnes of cane per day, and the cogeneration systems use bagasse and coal as fuel. Coal is used during the milling season to stabilize combustion in the boilers and during the off-milling season for other activities such as ethanol production and refinery.
Despite the huge amount of bagasse generated by the process, the sugar factories import electricity from the SEB. The electricity from SEB is mostly used to power irrigation equipment at the sugar cane factories. The electricity import costs and the production of electricity using coal, which is imported from South Africa, are a large expense in the operating costs of these factories. With growing power shortages in South Africa and a tariff increase mooted for the future, cogeneration is an important option for Swaziland.
If sugar companies and other agro-industries in the seven countries are given the right incentives to exploit the cogeneration potential and to generate additional power for sale to the grid, then cogeneration plants using bagasse and other biomass could partially replace planned high-cost oil-fired plants that use fossil fuel, and mitigate the impacts of drought on hydro power availability. In addition, cogeneration plants could deliver significant CO2 benefits.
Currently there are insufficient incentives given to project owners/developers to implement efficient and high-capacity cogeneration systems in these countries. The proposed Cogen for Africa project is expected to assist the government and the private sector in creating the right stimuli. It should also transform the market conditions to promote a major cogeneration industry.
BUILDING ON PAST SUCCESS
In the sugar sector alone, there is about 200 MW of cogeneration capacity in the seven participating countries, mainly using inefficient and low-pressure boiler systems. However, there have been successes in the installation of high-pressure boiler cogeneration systems in the region, notably in Mauritius’ sugar industry which has successfully installed such systems of up to 70 MW.
Cogen for Africa will build on the success of cogeneration in Mauritius, which currently meets close to 40% of the country’s electricity needs. The project plans to replicate Mauritius’ success in other countries of the region as well as in other key agro-processing sectors found in eastern and southern Africa. The initiative will also take on board relevant elements of the European Commission-supported regional cogeneration programme in south-east Asia, which has been successful in promoting numerous efficient cogeneration installations.
The initiative will work with promising and profitable agro-industries with a solid track record and that have demonstrated commitment to expanding their cogeneration investments in Africa. Notable agro-industries that are expected to actively participate in the project include private-sector-owned and profitable sugar companies as well as private sector entities involved in agro-processing industries such as pulp and paper, forest products, palm oil, ground nuts, sisal and rice.
STRUCTURE OF THE INITIATIVE
The initiative will be co-ordinated by a regional ‘Cogen Centre’ hosted by AFREPREN/FWD and staffed by local, leading regional and international cogeneration experts. The Cogen Centre is expected to be the centre of excellence for cogeneration in the region. At the national level, national cogen offices staffed by experienced national cogen experts are to be established in each of the participating countries, to co-ordinate national-level activities as outlined in the strategic work programme of the regional Cogen Centre.
Through the regional Cogen Centre and the national cogen offices, the initiative plans to provide support to cogen business development and investment promotion which will include appropriately targeted capacity-building, technology transfer and financial incentives. Key activities of the initiative are designed to lead to the following outcomes:
- developing and enhancing the capacity of project developers, technical service providers and local manufacturers of modern and efficient cogeneration systems
- making financing for cogeneration projects available and accessing it in terms and conditions that are favourable for investments
- demonstrating the commercial, technical, economic and environmental benefits of modern and efficient cogeneration systems in a number of new cogeneration plants and enhancing the confidence in the cogeneration market
- promoting more favourable policies and institutional arrangements that support cogeneration.
During the initial six-year phase, Cogen for Africa is expected to result in an additional 40 MW of modern and efficient cogeneration capacity as full-scale promotion projects (FSPPs). The installation of new cogeneration systems in the region requires a long lead time as it is a huge investment for the sugar factories and quite some time is needed for a supportive policy and regulatory environment to take shape.
By the end of the six years, Cogen for Africa is expected to have set the stage for accelerated cogen investments through the promotion projects. These projects will be used as showcases to convince other potential project developers of the technical reliability, economic viability and environmental soundness of more efficient cogeneration systems.
Another 20 MW of cogen projects will be directly supported through the provision of advice, services and training. These projects are expected to be under construction or at the advanced stage of project development at the end of the six-year project period. Beyond the initial six-year phase, Cogen for Africa is expected to stimulate a total installation of an additional 200 MW of cogeneration capacity in the medium to long term.
Stephen Karekezi and Waeni Kithyoma are with AFREPREN/FWD, the Executing Agency for the Cogen for Africa project, Nairobi, Kenya.
- AFREPREN/FWD, 2004 African Energy Data and terminologies Handbook Year 2003-2004, AFREPREN/FWD, Nairobi.
- Davis H. and Hough P., 2006. ‘Sugarcane as an energy crop’, Presentation on Guyana Sugar Corporation at the Combined Heat and Power Workshop, 18-20 April 2006, Bridgetown, Barbados. Available on www.caricom.org/jsp/projects/Guyana%20Presentation.ppt
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- Karekezi S. and Kimani J., 2002. ‘Impact of Power Sector Reforms on the Poor’, in Energy Policy Journal – Special Issue, vol. 30, no. 11-12, Elsevier Science Limited, Oxford.
- WADE, 2004. Bagasse Cogeneration – Global Review and Potential, June 2004. Report available on the WADE website www.localpower.org
- World Bank, 2003, World Development Indicators. World Bank, Washington, D.C. Available on www.worldbank.org/data
If you are interested in participating in project implementation and can demonstrate expertise and experience in cogeneration project development and implementation, please get in touch with the authors with details on your area of interest.
Cogen for Africa
Cogen for Africa – an innovative and first-of-its-kind regional initiative – was recently provisionally approved by the Global Environment Facility (GEF) Council for funding as a full-size project. It will be implemented by UNEP/GEF and executed by the Nairobi-based AFREPREN/FWD – the Energy, Environment and Development Network for Africa – which incorporates the regional programmes of the African Energy Policy Research Network (AFREPREN) and the Foundation for Woodstove Dissemination (FWD).
The six-year initiative seeks to significantly scale up the use of efficient cogeneration options in seven eastern and southern African countries, namely: Kenya, Uganda, Tanzania, Ethiopia, Sudan, Malawi and Swaziland.
For more information on the project, please visit the project website at https://cogen.unep.org/