Update of Air Quality Dispersion Model for Gothermal Power Plants and Wellhead Generation Units at Olkaria in Kenya
Joshua WERE, Cornelius NDETEI, Nigel HOLMES
[Kenya Electricity Generating Company, Kenya]
The Kenya Electricity Generating Company PLC (KenGen) is the main producer of electricity in Kenya, generating 1631MWe of electricity as at 31st December 2018. The Company uses various power generation mix ranging from hydro (50%), geothermal (32%), thermal (16%) and wind (2%). Due to the increasing demand for electricity and in line with Kenya’s Vision 2030, KenGen has embarked on an ambitious strategy to inject into the national grid an additional 721MWe by 2025, mainly from geothermal resource. Kenya is endowed with geothermal resource in excess of 10,000 MW and only 677 MWe has been harnessed for power generation. The Olkaria Geothermal Field has a potential of over 1,200 MWe, out of which 534 MWe has been developed by KenGen. The power is harnessed from 14 wellhead generation units and four power plants (Olkaria I, Olkaria II, Olkaria I additional units 4 & 5 and Olkaria IV) located within/near Hell’s Gate National Park, which is an ecologically sensitive area. In additional, there exists a commercial flower farm about 1km to the North West of Olkaria II and Lake Naivasha which is a ramsar site is about 5 km to the North. Hydrogen sulphide gas is one of the bye-products of geothermal exploitation, and is nuisance at detectable levels due to the rotten egg odor and toxic at high concentrations. This paper seeks to assess air quality dispersion model due to the operations of the existing Olkaria Power Plants and well head generation units, and the potential impact associated with the proposed geothermal development. The study uses Calmet and Calpuff computer-based dispersion model to investigate the air quality effects due to the existing 531.1MWe geothermal power plants and 81.1 MWe wellhead generation units, and anticipated effects from the proposed 140MWe Olkaria VI PPP, 140MWe Olkaria VII and the 61MWe modular power plant at Olkaria geothermal field. Five modelling scenarios and some minor variations to the five cases have been considered.
|        Topic: Environmental Aspects||Paper Number: 02052|