When Nigeria’s Geregu I power plant required maintenance and modernization to continue feeding critically needed electricity into the national grid, t
When Nigeria’s Geregu I power plant required maintenance and modernization to continue feeding critically needed electricity into the national grid, the project became a logistical challenge. Far from any urban infrastructure and under extreme temperatures, could Siemens successfully carry out the work entirely on site?
The Geregu I power plant in Kogi State, Nigeria, is surrounded by bush. There is no airport. It takes 3.5 hours to drive there from the capital, Abuja, and ten hours from Lagos, Nigeria’s largest city. Sections of the road are in poor condition; break-downs are common. It’s a rugged, humid place where temperatures often reach over 40 degrees: hard on machines and people.
Yet Siemens recently modernized three SGT5-2000E gas turbines in this remote spot entirely on site: Not one part had to be sent away to an external workshop. Some 1,100 tons of equipment were instead brought to the plant. After the service outage, each turbine produced more than 7 megawatts of additional power.
“It was the biggest Siemens service project ever in West Africa and probably Central and East Africa,” says the project manager, now head of the Siemens AG Service Project Management Office Sub Sahara, Christian Niederle. At peak times, up to 50 expats and a local support team of 60 to 80 people worked two shifts of over ten hours each, for six days a week.
The six-month overhaul involved replacing two generator rotors, installing a smart SPPA-T3000 control system that can feed data back to the Siemens Power Diagnostics Services team in Europe and exchanging the conventional blades and vanes of the SGT5-2000E gas turbines with the aerodynamic and efficient Si3D™ models – a technology only Siemens has in its portfolio.
The long road
A service of this nature, explains Niederle, “isn’t rocket science,” but the logistics required to carry it out in this remote village were complex. At the time of the outage, there was no Siemens service center in the country, so sending a part to an external workshop in Lagos would require sending a Siemens specialist along too for quality control (an energy service center has since opened in Port Harcourt). Working entirely on site saved time and costs.
Geregu I power plant, built in 2007 and privatized in 2013 as part of a government drive to increase capacity, is owned by Amperion Power, a subsidiary of Forte Oil Plc, and supplies power to the national grid. Improving electricity generation in Nigeria is something of a national imperative. Although Nigeria’s installed capacity has jumped from around 7.7 gigawatts in 2007 to 12.5 gigawatts in 2016, only 3.5 to 5 gigawatts is typically available for use due to problems such as gas shortages and difficulties with transmission capacity.
However, the aim is to boost capacity to 40 gigawatts by 2020. At this stage, every extra megawatt counts – and the overhaul at Geregu I has boosted power output by a useful 21 megawatts.
There are over 600 robust SGT-2000E series turbines in operation worldwide. One of their advantages is that they can be configured to run on every fuel from natural gas to heavy fuel oil. In Geregu, the SGT5-2000E turbines cope with numerous shut-downs caused by the unstable national grid (its frequency can rapidly leap from 49 to 51.5 hertz, says Niederle) as well as gas supply and quality issues.
The SGT5-2000E gas turbines “have performed well,” says Geregu Power Plc CEO Adeyemi Adenuga. “They can weather any storm and remain operational. The SGT5-2000E is very rugged, very strong.”
However, elements of the plant’s control system needed modernizing to meet conditions set by the government for feeding power into the national grid.
Best laid plans
The solution was to work on site. The Siemens team custom-designed a steel beam skid-and-check system (a kind of mobile crane) to lift the 55-ton rotors from the three turbines within the confined space of the machine hall and place them on a self-propelled modular transporter. The rotors were then moved to a mobile de-stacking hall, where they were serviced.
The devil was in the details: Getting all the equipment to work together in the tight space available, with just centimeters to spare in places, required considerable planning.
The scale of the operation is evident when Niederle explains that the first shipment of equipment consisted of 21 shipping containers. These travelled by road from Lagos to Geregu in a convoy of trucks. “It’s the only way to get the equipment there, you have no other choice,” says Niederle.
Far-away Geregu I is now also in direct communication with the Siemens Power Diagnostics Services team in Europe thanks to its new SPPA-T3000 control system. This allows for remote diagnostics. In essence, Geregu I now sends vast quantities of operational data to Germany every day. This is all sifted, assessed and diagnosed. It can help customers avoid potential issues – and resolve them more quickly. “Our team in Germany can look at the machine and see exactly what the customer can see,” says Niederle.
Could they do it all again, in areas with similar technical and commercial challenges? Yes, says Niederle. “Completing this job in these circumstances and in this environment shows that we are capable of performing difficult and risky projects.”
Source : https://www.siemens.com/customer-magazine/en/home/energy/fossil-power-generation/more-power-for-nigeria.html