Case study: Largest wind farm in Africa

September 27th, 2019, Published in Articles: EE Publishers, Articles: Energize

The Lake Turkana Wind Power (LTWP) project, located in Marsabit County, Kenya, is the country’s single largest private sector investment at €685-million; and the largest renewable energy project ever undertaken in the country. With 365 turbines spread over 40 000 acres and a maximum installed capacity of 310,25 MW, the wind farm is also the largest in Africa.

Nestled between the slopes of Mount Kulal to the north, Mount Nyiro to the south and at the south-eastern tip of Lake Turkana, the winds which blow over the project site are considered some of the most unique in the world and allow the wind farm to operate at capacity factors above 60%.

Fig. 1: Some of the wind turbines on site.

Construction of this mega project began on 25 October 2014 and continued until July 2017 when erection of the wind turbines and all associated infrastructure was officially completed. The blades, towers and nacelles for the turbines had to be transported from the port town of Mombasa to the project site in Sarima, almost 1200 km away. For the most part, the terrain was tough and the roads so narrow that it was virtually impossible for the large trucks transporting the turbines to get to the project site. Therefore, construction had to include road works, specifically the 208 km c-77 Laisamis to Sarima public road, over 140 km of internal access roads, a 33 kV overhead collection grid, 365 wind turbine generators (WTGs), installation of 365 step-up (1,69/33 kV transformers), a sectionalised 33 kV substation, step-up power transformers 33/220 (400) kV, three dynamic reactive power compensation systems (Statcoms), a SCADA system, and an accommodation village.

Fig. 2: PSCAD system diagram.

LTWP is one of the most complex project infrastructure financing projects ever undertaken in the region and was completed within budget and on schedule, thereby setting a standard for large-scale public-private infrastructure projects. The successful completion of the project showcases Kenya as a safe and reliable investment destination which embraces large-scale private sector infrastructure investment and demonstrates a strong ability to implement successful public-private partnerships. The wind farm is connected to the Kenyan national grid via a 435 km 400 kV double-circuit transmission line. This line was energised on 24 September 2018 when the wind farm began injecting power into the national grid.

Fig. 3: Aerial view of the substation.

On 19 July 2019 President Uhuru Muigai Kenyatta inaugurated the 310 MW Lake Turkana Wind Power plant and commissioned the 435 km Loiyangalani-Suswa line in a colourful ceremony attended by representatives of the national and county governments, members of the diplomatic corps linked to the projects, lenders, project contractors, LTWP and Kenya Electricity Transmission Company (KETRACO) staff.

During the inauguration, the president lauded the success of the private-public partnership model which had made the project a reality and called on more private investors to consider the country for other large-scale infrastructure projects.

Speaking during the inauguration, the president said, “This project will increase electricity supply by approximately 13% and will reduce our reliance on thermal generated electricity and insulate Kenya from supply constraints during periods of lower water level. Indeed, it should be noted that without the wind power project, the fuel cost charge (FCC) would have been as high as KES 5,75/kWh in May 2019 as compared to KES 3,75/kWh, the cost that was applied in that particular month. This is a combined saving to Kenyans in the amount of KES 8,5-billion in the first eight months of the wind farm’s injection to the grid.”

Fig. 4: Simulation in a Microsoft Excel spreadsheet.

The wind farm currently supplies between 15 and 17% of the country current peak demand and up to 30% of the country’s off-peak demand. The injection of the wind farm to the national grid, as well as the inauguration by the president, have paved the way for a new dawn in the country’s move towards energy sufficiency and have propelled the country towards meeting its 100% green energy transition by 2020.

Power System Dynamics played a significant role in the project from its early stages.  During the project’s earliest stages, the company performed dynamic EMT studies associated with the three 100 Mvar Statcoms.  The company conducted numerous PSCAD studies to investigate the actual control interactions of the wind turbines and Statcoms in the extremely weak grid conditions.

Statcom design reviews of the primary plant component design, control and protection system, valve and cooling design and yard layout were also carried out.

Company representatives witnessed the factory tests and took responsibility for site supervision and commissioning of the Statcoms.  The company provided technical support and joined forces with Kenya Power (KPLC) and KETRACO to mitigate various operational issues of the project and its interface to the overall Kenyan grid.  The company also performed the commercial operation testing of the 300 MW project and assisted in site training of the operators.  For training purposes, the company developed a load-flow simulator tool in Microsoft Excel which enables the operators to simulate the grid.

Contact Sep Boshoff, Power System Dynamics, Tel 011 807-1598, sep@powersystemdynamics.com

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