Lubezine Magazine Vol. 9 April - June 2014

COVER FEATURE recourse than exploring alternative energy solutions to supplement hydro-electricity to meet the surging energy needs. Diesel, a popular alternative to hydro-electricity, is also proving expensive, besides the pollution it causes to the environment. Consequently, geothermal, a hitherto underexploited power source, whose development is taking off in Kenya and elsewhere in Africa, is set to take over as one of the most reliable green energy alternatives to supplement on-grid power. Besides its unmatched reliability, geothermal power is harmless to the environment, why it is also receiving backing from global environmental conservation agencies as a better alternative to nuclear energy. According to the Geothermal Energy Association projections, Kenya is set to become a global leader in geothermal energy production, particularly on account of the fact that the country distinguishes itself with the Olkaria Geothermal plants, the largest geothermal projects in Africa, a distinction likely to be taken over by Ethiopia. Power potential In 2013, the Government of Ethiopia signed a 25-year agreement with Reykjavick Geothermal, paving the way for the development of what could be Africa’s largest geothermal project in Addis Ababa, set to generate up to 1000 MW capacity in what will provide more power for the country’s industrial and economic development prospects. It is a trend sweeping across Africa, with several geothermal projects under implementation in other parts of the continent, and Kenya in the vanguard, providing consultancy services on geothermal power development to such countries with geothermal power potential as Sudan, Rwanda, Uganda and Tanzania. In addition, underway geothermal projects in Ghana, Djibouti and Nigeria point to the potential and rising interest in geothermal power development opportunities, which are also interlinked to the emerging gas and oil discoveries. According to the World Bank, East Africa’s Rift Valley geothermal capacity alone could power 150 Million homes. In February 2014, the Kenya Electricity Generating Company (KenGen) said it had successfully drilled at Olkaria in Kenya’s Rift Valley one of the biggest geothermal wells in the world, in what is set to triple the 18 company’s output by three times to 5000 Megawatts. In Tanzania, the Mauritian, Geothermal Power Limited, established by leading German geothermal consultants together with Mauritius, Australian and Singapore partners, currently holds six prospecting licences through its subsidiary, Geothermal Power (Tanzania) Limited, and is actively inspecting potential in neighbouring countries. For lubricant marketers and manufacturers in Africa, the growth of geothermal energy use promises new opportunities as geothermal plant equipment and machinery require specially formulated lubricants and lubrication solutions that can ensure plant machinery efﬁciency in the extremely high temperature and pressure environments. The lubrication of geothermal plants is a unique process in comparison to other industrial plants as it consists of a system with some distinctive characteristics which makes it very different. The ﬁrst is that geothermal plants are very expansive and occupy large areas. The equipment used in the plant is very expensive and hence proper maintenance and lubrication is vital to ensure the expensive assets achieve the expected life cycle time. Further, given that the production of power is characterized by meeting the power demand on a continuous basis and considering the volume in use, any contaminant or lubricant-related problem would lead to high losses. The volume of lubricants used in the systems is also huge, especially for turbine systems which consume huge volumes of lubricants depending on the size and capacity of the plants. In addition, most power plants have supply contracts with the local energy supply utili- According to the World Bank, East Africa’s Rift Valley geothermal capacity alone could power 150 Million homes. ties, which have hefty penalties when a plant does not meet the required supply threshold capacity in MWh to the grid. The spares and labor cost is also quite expensive, making any downtime very costly. Finally, lubrication systems utilized in such power plants are large and expensive. Critical equipment in the system requires very accurate and precise lubrication systems. Typical power plant lubricant requirements For geothermal plants, lubricants can be classiﬁed into two broad categories. First there is the transformer oil with insulating properties. Second there is a range of lubricants suitable for the lubrication of the machinery generating the energy such as turbines oils Transformer oils Transformer oil is a highly-reﬁned mineral oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil-ﬁlled transformers, some types of high voltage capacitors, ﬂuorescent lamp ballasts, and some types of high voltage switches and circuit breakers. Its functions are to insulate, suppress corona and arcing, and to serve as a coolant. Turbine Oils Turbine lubricants should have good thermal and oxidation resistance at moderate and high oil temperatures typical in gas or steam turbine. Turbine lubricants should control the rust and corrosion that could destroy precision surfaces, resist foaming and air entrainment, which could impair lubrication and lead to equipment breakdown, and have high viscosity indexes that allow more uniform lubricating performance over a wide range of ambient and operating temperatures. They should also be easily ﬁlterable without additive depletion. Turbine lubricants should be versatile, able to provide both lubricating and hydraulic functions for various turbine systems, generator, gear unit and other auxiliary components. Some critical properties that require to be monitored for the turbine oils

Lubezine Magazine Vol. 9 April - June 2014 | Page 20