In its quest to generate more reliable, clean energy, Kenya has become the first country worldwide to pioneer new geothermal wellhead technology. The technique involves tapping steam from wells that are undergoing tests or awaiting connection to permanent plants. The technology not only helps to utilise the investment put into drilling the wells, which would otherwise be lying idle, but also benefits from early generation.
Kenya’s demand for electricity is driven by the recent, rapid economic growth and industrialisation, which has created the need to accelerate the drilling of geothermal wells to tap into the resource potential and avoid the over-reliance on erratic hydroelectric power. Kenya Electricity Generating Company (KenGen) related that “the long drought has reduced the capacity of main dams, forcing shutdowns and leading to reliance on costly diesel-powered generators, pushing up energy bills”.
Building on the success of the Olkaria and Eburru wellhead power generating units, KenGen now intends to install more units with an expected capacity to produce 70MW. Other geothermal areas targeted for this new technology include Menengai and Longonot. Chief engineer in charge of wellheads at KenGen, Johnson Ndege, explained: “We are taking advantage of these single wells to generate power using the steam, which would otherwise have gone to waste while the main plant is being constructed.” Initially, the single wellhead power plant technique was an experiment, which turned out to be a productive method to generate power from wells that would otherwise have remained idle for years awaiting exploration.
Going back to the origin of this newfound technology: according to the Geothermal Resources Council (GRC), twenty years ago KenGen drilled six geothermal exploration wells to an average depth of 2.5km. Then in 2009, the utility awarded the US-based Geothermal Development Associates (GDA) the contract for the engineering design, supply of major equipment, supply of materials, and commissioning of a wellhead geothermal power plant at Eburru, located northwest of Lake Naivasha. In efforts to increase localisation under a separate tendering process, KenGen selected Civicon Limited, a general contractor to construct the plant and install GDA’s equipment.
Prior to commissioning the Eburru plant, GDA provided training for KenGen personnel at its Reno facility during the manufacturing stage of the project. The training focused on operational and maintenance areas including the lube oil console; compressed air system; fire pump system; control valves; remote control panel; emergency power system; and process design and modelling.
The EPC also coordinated with KenGen to train the utility’s engineers at OEM factories, including the turbine, condenser and LRVP and the generator. In January 2015, KenGen announced that the plant was first synchronised to the grid, followed by the performance testing that was completed a few weeks later in that month. “We do not want to leave anything to chance and that is why we have started generating electric energy using wellheads as we keep developing more and more geothermal power plants,” KenGen’s Chief Executive Officer and Managing Director, Albert Mugo, said.
The wellheads technology entails the use of small power units, which are fitted next to the wells and ensures generation can take place within as little as nine months from the time the well is tested. Using one of the original six wells first commissioned in 2012, KenGen now generates 2.52MW of wellhead geothermal power from the Eburru plant. Notably, this plant has a bottom-hole temperature of 270ºC.
KenGen’s experts have highlighted that the technology partly helps in the utilisation of the investment put into drilling the wells, which would otherwise be lying idle. This technology has proved sustainable and the company has now commanded the lead into the next phase of power generation in line with the country’s vision 2030. To this end, the power utility has embarked on an ambitious 70MWe project, with the second wellhead plant confirmed to be at 75% completion.
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