The Viability of Supplying an Industrial Park with Thermal Energy from Menengai Geothermal Field
Author: Jack Muthomi Kiruja
Year: 2016
Supervisors: Páll Jensson & Páll Valdimarsson
Abstract
Kenya has an installed geothermal capacity of about 600 MWe, with more projects under development. One of the fields under development is Menengai, which is owned by the Geothermal Development Company (GDC). Besides electricity generation, GDC intends to establish and industrial park in Menengai powered using geothermal energy. The industries located in the park will not only benefit from green electricity but they will also utilise the other by-products of electricity such as excess heat in separated brine and/or low pressure wells, dissolved substances in the geothermal brine, non-condensable gases such as carbon dioxide and hydrogen sulphide among other by-products.
Analysis of the demand for industrial process heat in the park resulted in three scenarios with a demand of between 6 MWt and 22 MWt. Five possible options for supplying this energy to the industries were also analysed. The options considered were separated brine, low pressure wells or a combination of both. This energy would be extracted through heat exchangers and delivered to the industries through pipes, a distance of 6 km. the energy was cascaded among different thermal processes in order to achieve a high degree of efficiency. Approximately 40% of the energy was cascaded two or more thermal processes.
A suitable tariff for the thermal energy was determined to have a floor of around 2 $/m3 and a ceiling of around 5 $/m3. The floor was determined using the operating costs as the basis while the ceiling was determined using the price of alternative sources of fuel for industrial applications. All the analysed scenarios and options proved to be profitable after 25 years of operation with a payback period of around 10 years and an Internal Rate of Return of between 18% and 25%.