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Gas turbine upgrade SIEMENS is modernizing Geregu I

Last year, Siemens partnered with Forte Oil’s Amperion Power to successfully complete a logistically challenging on-site modernization of the Nigerian power plant Geregu I. The $93-million upgrade required skills training, has seen the plant’s profitability jump 58 percent – and increased power output by 21 megawatts.

According to the World Bank, almost 60 percent of a population of 187 million – in other words, some 107 million people – do not have access to power. When the power generation division of Forte Oil Plc, Amperion Power, acquired Geregu I power plant in Kogi State, Nigeria in 2013 as part of a privatization drive, its new asset was due some much-needed attention.

The power plant runs three Siemens SGT5-2000E gas turbines. Since Geregu I was built by the Nigerian government in 2007, “the reliability and performance of the turbines has been high,” says Forte Oil Group CEO Akin Akinfemiwa, regardless the unstable national grid and regular frequency fluctuations. Adeyemi Adenuga, the CEO of Geregu Power Plc, agrees. “The SGT5-2000E is very rugged, very strong, and I believe it’s the right machine for the industry.”

At Geregu I, however, the turbines had reached their recommended equivalent operating hours and the power plant was due for maintenance works. The following modernization project became the biggest one ever for Siemens in West Africa – and it was achieved entirely on site. Two generator rotors were replaced, a new SPPA-T3000 control system was installed and the blades and vanes of the gas turbines were upgraded to the more aerodynamic and efficient Si3D™ model – a technology only Siemens has in its portfolio.

“Power producers require the services of a reliable technical partner for the provision of spares for the plant and a highly-skilled and quality workforce for its day-to-day running.”
Akin Akinfemiwa, Forte Oil Group CEO

Feeding a hunger for electricity
Nigeria’s population of about 187-million is hungry for power: the government’s stated goal is to raise the country’s installed power capacity to 40 gigawatts by 2020. Right now, installed capacity is 12.5 gigawatts, but the available generation is half that and a lack of gas can bring it down even further. In this environment, every extra megawatt counts.

Geregu I’s overhaul, explains Akinfemiwa “was premised on the need to provide improved service delivery to the public with respect to power generation.” The new SPPA-T3000 control system, along with a frequency response control mechanism, has improved connectivity to the national grid. And since the modernization, each turbine produces at least 7 megawatts more power, bumping up the total power output of the plant by 21 megawatts to 435 megawatts. “The additional 21 megawatts will provide more power to the national grid and Nigerians.”

The modernization has also increased returns to shareholders. “We have witnessed improved generation with the turbines and this has led to increased revenues and margins from the Geregu power plant to the Forte Oil Group”, says Akinfemiwa. Geregu Power Plc “recorded a 48 percent growth in revenues and a 58 percent growth in profitability in February 2017 when compared to February 2016.”

The SPPA-T3000 control system improved Geregu I’s connectivity to the grid and enables it to send information to Siemens Power Diagnostic Centers for analysis. Photo by Siemens AG

Challenges – and solutions
Amperion Power’s performance contract with the Nigerian Bureau of Public Enterprises requires the plant to maintain a minimum installed capacity of 414 megawatts over the next five years. But along with an unstable grid, Nigerian power producers like Amperion have other constraints: a lack of gas, and a lack of liquidity in the electricity market. Inconsistent payments from electricity distribution companies mean that generation companies are not repaid in full for the power they supply.

Geregu’s two pipelines (an older 24-inch-wide line and a 136-kilometer-long, 36-inch-wide pipe) can provide the power plant with sufficient natural gas to run their three turbines. However, there are wider gas shortages caused by instability and vandalism in the Niger Delta region. While Geregu’s pipelines are generally not directly impacted, gas is rationed while other pipelines are repaired. The volume of gas supplied “can only currently accommodate two turbines”, says Akinfemiwa. “We are currently working very hard to secure additional gas in order to be able to run all three.”

Over 600 SGT-2000E series turbines operate worldwide, and one of their benefits is that they can be configured to run on different fuel, from natural gas to heavy oil. Geregu I has chosen gas as the most economical option.

High tech, high returns
According to Akinfemiwa, there are, of course, advantages to operating in this market too: For example, “given the infancy stage of the industry in Nigeria,” there is a promise of high returns on investments.

Still, “the power market remains very competitive.” Generation companies need to operate a tight ship, keep maintenance costs down and, as with the Amperion/Siemens partnership, require “the services of a reliable technical partner for the provision of spares for the plant and a highly-skilled and quality workforce for its day-to-day running.”
During the modernization of Geregu I, the plant’s local staff had the chance to observe the Siemens engineers and received on-the-job skills training. “This is in the best interest of the mutually-beneficial relationship that exists, as it enhances the transfer of technical knowledge and skills,” Akinfemiwa says.

Overall, modernization boosted generation and revenues for Forte Oil, and Akinfemiwa has expectations for the plant’s continued success: “We believe this performance will be sustained and even become better as efforts are being made to ensure all three turbines are fired with adequate gas supply.”

For more information visit: www.siemens.com