Fitness regimen for a power plant

In Colombia, CES is retrofitting and modernizing Termopaipa IV.

Financed and constructed as the first overseas project in 1999, the hard coal fired power plant Termopaipa was a reliable source of energy for industry and households in the north-east of Colombia for 20 years. Now, STEAG has overhauled the 165 megawatt unit and increased its output – the continuation of a success story.

 

„We have a firm principle here: ‘in time, in quality and in budget’‘“

Dr. Peter Weiss, Head of the Generation division at STEAG

With the utmost care, centimeter by centimeter, the huge rotor and drive shaft are lowered into the turbine housing by a massive crane boom. That demands steady hands and absolute finesse. After all, the workpiece, which weighs around 30 metric tons, was specially manufactured in the Polish town of Elbląg, transported by sea for three weeks via Rotterdam to Cartagena on the Caribbean coast of Colombia and from there by truck to the power plant in Paipa. An assembly error would be an absurdity given the high costs already involved, and would jeopardize the further schedule. And Dr. Peter Weiss and his team are regarded almost as superheroes locally. “We have a firm principle here: in time, in quality and in budget,” explains the head of STEAG’s Generation division. And that means that the turbine should be operational in mid-November, with all the components reassembled and the hard coal fired power plant ready for operation. And no more money should be spent than was originally budgeted. Termopaipa IV will then generate 170 megawatts, five more than in the past, making it a guarantor of energy security in the Latin American country, which produces three quarters of its electricity demand from hydro power. As ecologically sustainable as the use of hydroelectric power plants to supply electricity to Colombia’s 50 million inhabitants may be, in dry periods the rivers carry less water, the output of the hydroelectric power plants drops, and therefore requires compensation from thermal energy plants. “This is the El Nino effect,” Dr. Peter Weiss explains. “Around every five to seven years, this climate phenomenon leads to very heavy precipitation off the South American Pacific coast, which, however, falls on the western side of the Andes only. In Colombia, it mostly stays dry.”

Dr. Peter Weiß
Born in Bad Mergentheim, Dr. Peter Weiss grew up in the Baden part of Franconia. After graduating from high school, he studied mechanical engineering at the University of Stuttgart, and in the mid-1990s he moved to the Ruhr area for professional reasons. Employment with the chemical company BASF was followed by a move to STEAG. This is where Dr. Peter Weiss began his work in power plant design – his first project was the design of the mechanical equipment for the Leuna refinery power plant. His other duties also had a high degree of practical relevance: abroad, he was senior site and commissioning manager for a power plant project in Nigeria and power plant manager in Colombia. In Germany, he headed projects in Hamburg, Upper Bavaria and Saxony-Anhalt as well as in Duisburg as senior site and commissioning manager for Walsum 10, STEAG’s currently most modern power plant in Duisburg. Today, the 50-year-old, together with Dr. Hüseyin Rall and Stefanie Rehpöhler, is Head of the Generation Division of the STEAG Group and in that position he is responsible for the management and control of all the generation plants of STEAG GmbH. This also includes generation plants based on renewable energy sources, such as wind farms in Romania and Turkey as well as the Arenales concentrated solar power (CSP) plant in Spain.

Secure energy supply for almost 20 years
In 1996, the Colombian government introduced a capacity market in order to guarantee a secure energy supply in the El Niño era, thereby creating the basis for power plants such as Termopaipa IV. Since then, the electricity generated there has been sold to a regional utility on the basis of a 20-year electricity supply contract. This provides for a fixed remuneration for the provision of capacity – regardless of how much energy the power plant supplies. However, the condition of this agreement is that Termopaipa IV can be used for at least 80 percent of the hours per annum (availability guarantee) at full load – not only in theory, but also in practice. “This availability has been tested regularly,” says the STEAG generation manager. “In the almost 20 years of the past, we have passed all the availability tests. They were required by the customer at various times of the day and night without prior notice. In years of El Niño, for example in 2015, the power plant was continuously dispatched and achieved a very good capacity utilization and availability of over 99 percent. This shows how important the power plant is for Colombia’s energy needs.”

The current Power Purchase Agreement expires on January 7, 2019, but the electricity generated in Termopaipa IV will still be needed. The owner and operating company Compania Electrica de Sochagota S.A. E.S.P. (51 percent of the shares are owned by STEAG, and 49 percent by the American company ContourGlobal), with the support of STEAG’s Trading and Optimization division, has concluded freely negotiated contracts with new customers, primarily from industry. This secures the power plant’s electricity sales for the next five years. If electricity prices on the market are high, the power plant will generate the electricity itself; if prices are low, the electricity will be purchased on the market.

In order to prepare the power plant, now two decades old, for the coming requirements, Termopaipa IV is now being subjected to a retrofit measure. “A major turbine inspection/ overhaul was pending anyway. Now we are using the time for extensive measures,” says Dr. Peter Weiss. Because the state of the art today is naturally different from 20 years ago, the turbine in particular has developed further. “New calculation methods and manufacturing processes enable us to extract more energy from the same input as a result, and that is the aim of retrofitting. In this case, we are rebuilding the rear drive section using new mediumpressure and low-pressure turbines.”

„In 2015, the power plant was continuously dispatched and achieved a very good capacity utilization and availability of over 99 percent.“

Two years of preparation and ten million euros of investment
STEAG employees in Colombia and Essen have been working on the plans for two years now. The conceptual design, led by the graduate mechanical engineer, was followed by an invitation to tender for the production of the new turbine parts. The turbine manufacturer General Electric won the award. A few years ago, the US company took over Alstom, into which the turbine specialist ABB had also merged – and it was ABB which had originally produced the Termopaipa turbine. “The modernization will therefore be carried out by the manufacturer who knows the turbine best,” says Dr. Peter Weiss. This project is also a kind of flashback for the 50-year-old engineer: From 2001 to 2005 he was the power plant manager at Termopaipa IV. “At that time I knew practically every screw there by name.”

The production of the new turbine parts took one year – including regular inspections by STEAG technicians at the production facility in Poland. At the same time, preparations were underway at the site in Colombia. Since October 2, the systems there had been shut down so that the power plant could cool down. “We used the opening of the turbine housing to test and overhaul other units as well,” Dr. Peter Weiss explains. For that purpose, parts which are particularly stressed during operation were removed and subjected to ultrasonic or radiographic testing in order to locate any incipient cracks. Prior to that, the ‘scaled’ surfaces were cleaned and prepared for the tests – an oxide layer had formed on them during operation of the power plant. “We’ll do a kind of full-body check to make sure the power plant meets the requirements.”

STEAG and its partner ContourGlobal have invested around ten million euros in this retrofitting measure. STEAG technicians and their partner companies need about six weeks to overhaul and upgrade Termopaipa IV from top to bottom. The coal-fired power plant is scheduled to go back into operation in mid-November. “Then we would have two weeks left in reserve until the start of the new energy year on 1 December,” says Dr. Peter Weiss. If he succeeds, however, he will hardly have time to breathe a sigh of relief: In 2020, the STEAG hard coal fired power plant in Iskenderun, Turkey, is to undergo a retrofit. “So the next exciting project is already waiting for us.”

A view to the future:
The rising demand for energy and the challenges arising in the use of hydro power are creating new growth opportunities for STEAG in Colombia. We are considering taking part in an auction in January. If successful, STEAG could construct a second power plant unit – Paipa 4.2.