President Mahinda Rajapaksa unveils a plaque declaring open the final stage of the power plant, while Senior Presidential Advisor Basil Rajapaksa, MP and MInisters John Seneviratne and Felix Perera look on (PHOTOGRAPHY BY NALIN HEWAPATHIRANA)
By Madhushala Senaratne
President Mahinda Rajapaksa declared open the final phase of the Kerawalapitiya Power Plant. With the completion of the final phase of the project, the power plant now generates its full capacity of 300 MW of electric power to the national grid.
Located at the Southern tip of the Muthurajawela marsh (a protected wetland, South of Negombo) the Kerawalapitiya Power Plant is built on 33 acres of reclaimed land. Accompanied by a seawater intake system and designed and constructed using local talent and expertise, this mega project is truly a Sri Lankan marvel, explains Dammika Nanayakkara, Project Manager of Lakdhanavi, the EPC contractor of the project.
Regarded as Sri Lanka's largest combined cycle power plant, the project is implemented by West Coast Power, a subsidiary of the Government of Sri Lanka at a cost of US$ 295 million. The project is funded by the Export and Import Banks of USA, Germany, France and Netherlands, the countries from where the main equipment was obtained.
The power plant operates on two types of power generating equipment - gas and steam turbines. The first stage saw the installation of two gas turbines generating 200 MW to the national grid, while the second stage focused on the installation of the steam turbine producing 100 MW. In the second stage, the exhaust from the gas turbines is converted into steam. Thus the steam turbine does not consume any fuel. Two Heat Recovery Steam Generators (HRSGs) that act as boilers generating the steam required have also been installed.
Construction work on the power plant began in 2007 and the first stage commenced operations in November 2008.
With its two gas turbines, two heat recovery steam generators and steam turbine, this power plant comes into operation at the right time, Nanyakkara goes on to say, adding that the project was in fact included in the Long Term Electricity Generation Expansion Plan of the Ceylon Electricity Board (CEB). With the demand for electricity gradually increasing, the power plant was deemed a necessity. "With development the need for electricity grows. Therefore, had this power plant not been constructd, there would have been power shortages," says Nanayakkara explaining the reason for the power plant.
According to the 2006 report of the CEB generation planning branch, the estimated peak demand for electricity for 2010 is 2,000 MW. Sri Lanka has an installed power capacity of approximately 2,400 MW. With the power plant generating 300 MW, 15% of the peak demand for electricity in the country will be met.
"In 2008 it was predicted that the country's peak demand would reach the installed capacity," he says, adding that the 300 MW would now ensure an uninterrupted power supply to the Nation. In addition, in terms of electricity units, Sri Lanka consumes 8,000 GW hours per annum. The Kerawalapitiya Power Plant is geared to produce 1,800 million units of electricity or 1,800 GW hours. "Therefore, looking at it from an energy point of view, we can provide 20% of the national demand," explains Nanayakkara.
A special feature of the Kerawalapitiya Power Plant is that it runs on heavy fuel oil or furnace oil. "Heavy fuel oil, as the name implies, is not a clean fuel. We are the first in South Asia to use gas turbines that are operated on heavy fuel oil," Nanayakkara says. Usually, gas turbines are operated on either natural gas or light fuel such as auto diesel.
However, the high cost of fuel was the main reason for the use of heavy fuel oil, he explains. "The cost of heavy fuel is almost half of the cost of light fuel or auto diesel." More significantly, he adds, that as a result of the fuel selection, approximately Rs 10 billion will be saved per year. With that, he says, "The entire cost of the power plant is Rs 30 billion, thus in three years time, the initial investment will be recovered due to the saving in fuel."
Although there was criticism against the use of heavy fuel oil, Nanayakkara states that in countries where indigenous clean fuel is not available, heavy fuel oil is used. A heavy fuel oil treatment plant that will refine the oil to the required level is also available on site.
The requirement of water, for the uninterrupted operation of the plant and for domestic use within the complex, is drawn from the sea. A seawater intake system, fitted with two duty pumps and a pipeline buried at a depth of over 2 m under the seabed has been built in this regard. The length of the pipeline is 400 metres off shore and 1,000m on shore. The seawater will be filtered and demineralised as necessary, according to the various requirements of the plant.
As all power plants require cooling at Kerawalapitiya, seawater is used for this purpose. "A seawater-cooling tower has been installed on site. This is the first time such technology has been utilised in the country. Our cooling water requirement is 25,000 cubic metres per hour," Nanayakkara explains.
The project was steered by local engineers and the role played by them throughout to ensure the success of the project was immense, says Nanayakkara. "All project activities, from designing to planning, construction, management and commissioning, were carried out by local engineers. They are all well-qualified. They have the technical knowledge and required training," he adds.
Speaking of the challenges faced during the project, Nanayakkara says, "Every step of the power plant was a challenge."
Among the challenges was the transportation of heavy equipment. A feasibility study was conducted for the power plant by an international consulting firm. According to that report, the heavy equipment such as the gas turbines, generators, transformers and steam turbines were to be transported along the main Katunayake road and an access road was to be built in this regard. However, this proved difficult. "To build an access road you have to acquire land on a temporary basis. Access road construction is in itself a project," he says, adding, "The report also proposed that the equipment be transported along the Kelani river bridge. Yet, the bridge cannot take such a heavy load."
However, changing the concept with the help of the expertise of the local engineers, a method that was suited for the country was adopted. A barge was used from Colombo Port along the Kelani River to Hamilton Canal to transport the equipment. "This was completely due to the experience we had gained during the construction of the power plant in Puttalam. In that instance we transported heavier equipment such as engines. A gas turbine weighs 210 tonnes while an engine is around 280 tonnes. The experience we had gained was crucial for our success at Kerawalapitiya," he concluded.
With the implementation of this project, the technology and the technical knowledge is transferred back into the country.
Walking around the power plant in the scorching sun, I was overwhelmed by its sheer magnitude. Here was a powerhouse, reflecting the strengths and capabilities of the local engineer, implemented at a crucial juncture and vital for power generation.
"A seawater-cooling tower has been installed on site. This is the first time such technology has been utilised in the country. Our cooling water requirement is 25,000 cubic metres per hour," Nanayakkara explains.