Combined Cycle Power Plant at a Glance – An interview which I have done with Mr. Dammika Nanayakkara for EESoc newsletter

Mr. Dammika Nanayakkara obtained BSc Eng Degree in Electrical Engineering with FIRST CLASS HONOURS from University of Moratuwa in 1995. He is a Four Years Coloursman of University of Moratuwa and was Captain of University Basketball Team in 1994. He was the First Vice President of EESoc. Mr Nanayakkara obtained MEng Degree from University of Moratuwa in 2001. After the graduation in 1995, he joined LTL Holdings (pvt) Limited (formerly known as Lanka Transformers Limited). Presently he is working as the Project Manager of 300MW Combined Cycle Power Plant, Kerawalapitiya. Mr. Nanayakkara is a Charted Engineer. He is a Corporate Member of Institution of Engineers (Sri Lanka), Institute of Technology (UK), and Institute of Electrical and Electronics Engineers (USA). This is an Interview with him.

1.) What are the specialities of this power plant comparing to the other existing plants in Sri Lanka?

Kerawalapitiya is a Combine Cycle Power Plant, which is a combination of Gas Turbines (GT) & Steam Turbines (ST). It produces 300 MW of Power (15% of Peak demand) with an annual contribution of 1800GWh (20%of National demand). The entire investment is 300 Million US Dollars. This plant has the multi-fuel capability and it can be driven from HFO (Heavy fuel oil), LFO (Auto Diesel), and LNG (Liquid Natural Gas). Now we are currently using low sulfur HFO (2% sulfur). That is because, HFO is the cheapest fuel available currently for Rs 42/liter. When it comes to the LFO, the cost is around Rs 70/liter. Therefore, the energy cost is Rs 9/kWh for HFO and 13.2/kWh for LFO. Hence it saves 10billion US dollars per annum to CEB and cost of the power plant is paid back within 3 years.

Configuration of this plant is 2+2+1. It means 2 Gas turbines and 2 Heat recovery steam generators and 1 steam turbine. First phase is open cycle and second is the combined cycle. Open cycle consisted on two gas turbines. And output was 200MW. That is in commercial operation since 11/2008. Then the combined cycle very recently included and another 100MW added.

Another specialty of our power plant is for cooling, we use seawater. Although we use sea water, it is not once through. We have a seawater cooling tower. However, if you take Norochchola power plant, it is a once through plant. Where, you do not have a cooling tower. For example, our water requirement is 250000 cubic meters per hour. But we take only 1000 from the sea which is used as the makeup water. For the rest, you have a cooling tower for the circulation. But if you don’t have a cooling tower, then we have to take entire 25000 from the sea. Due to environmental limitations, we cannot use ground water or we do not have the river water. Therefore, we use desalinated water for all our other needs (process water and service water). The technology we use is Reverse Osmosis (RO). We produce 70 cubic meters per hour for the process and service water requirement. We have our pump house on the shore and intake point is 400m off shore. You have to go to fairly a deep sea to avoid silt and debris coming in. Then we have around 1km pipeline coming to the power plant for this purpose.

Considering about this land, this is the famous Muthurajawela marsh. Therefore, any construction will have to come on pile. We have driven more than 1500 piles in this site in less than four months time. All the piles are 20m long going to the ground and 1.2m in the bedrock as well. Reclamation of the land had to be done by filling earth. We had to use 130000cubic meters of soil for that. We did the filling in less than one and half month. In addition, we have erected the equipment weight of 12000 tones and 1200 tones of pre-fabricated buildings. We have use more than 40000cubic meters of concrete.

2.) What are the major social and environmental impacts of this project?

Concerning about the emission for this plant, the heavy fuel oil that we use is 2% low sulfur heavy fuel oil. But the normal heavy fuel can have 3.5% sulfur. Due to the environmental dispersion modeling, we use 2% sulfur heavy fuel oil as they recommended. Dr. Saman Samarawikrama from University of Moratwa did the environmental modeling part of seawater dispersion modeling. In our environmental impact assessment, all the aspects are covered. Impacts on the air quality, impacts on the seawater, impacts on the ground water, traffic, social impacts, sound impacts and so on.

3.) Who are the equipment suppliers for this plant?

We have gone for the world renowned equipments. The reason is, we are running this power plant on IPP basis. Therefore, we have to maintain our reliability at a very high level. So we had to go for the best. Gas Turbine (GT) Package is from GE (USA/France), Steam Turbine (ST) Package is from GE (USA/France), HRSG and Steam System Package is from NEM (Netherlands), Power plant control system is from ABB (Germany), entire electrical balance of plant with medium voltage switch gear/ low voltage switch gear/ transformers are from ABB (Germany), Condenser/Cooling tower/ Cooling water system/ Seawater intake system are from SPX (Germany), and Seawater desalination system is from NALCO (USA).

4.) Who owns this company and what is the local contribution for the entire project?

The owner of the plant is West Coast Power (Pvt) Limited. Yugadanavi is the name of the power plant. Actually, Lakdhanavi wanted to do the power plant on Lakdanavi owned. But the foreign loan lending counties wanted the government guarantee for the loan. To fulfill that requirement West Coast Power company was initiated and now the West Coast Power is the owner of the project. Lakdanavi is the EPC contractor and OM contractor of the project. That is how West coast Power came in to the picture. Lakdanavi is also a part of West Coast Power (PVT) Limited.

Since Lakdanavi is a sri lankan company, all our designing, decision-making and entire work was done by our local engineers. When you buy the set of equipments, you have to integrate them in to a one big power plant. Therefore, that integration part is completely done under an engineering management of our engineers. We call Lakdavavi is the EPC and OM contractor of the power plant. EPC contractor means Engineering, Procurement and Construction contractor. This is the first time a local company did the EPC contract for any project of this nature. It was a big challenge and an enormous work. Other than moragahakanda reservoir in all other projects, foreign engineers do the EPC part.

5.) Who are the investors of this plant?

Employee’s Provident Fund, Employee’s trust fund, NSB (National Savings Bank), LECO (Lanka Electricity Company) and Lakdhavani Limited. In addition, the debt financier is HSBC bank from Hong-kong. This is the largest loan ever raised by a Sri Lankan company.

6.) What is the fuel supply system for this plant?

Fuel is supposed to come from Ceylon Petrol Cooperation terminal. But, at the moment this black oil is not available at that pipe line. Therefore, we are getting fuel from Kolonnawa by bowser daily. But, now they are laying a marine pipeline. It is still under construction. Then it will be directly from ship to the tanks.

7.) What will be the unit cost for this plant with the CCP and without CCP?

On average, the unite cost is around Rs 20.00. When it becomes combined cycle Rs 15.00. The capacity charge is around 120 million rupees per month.

8.) What is your personal opinion about the oil dominated power generation in Sri Lanka?

It is obvious that, we have to go for the cheap power sources. What is available right now is coal. My personal view is when we become really a developed country; we will need a capacity of more than 15000 MW. Until we reach the milestone of 10000MW, we should try to go for cheap sources. So the first is coal and the second is CCP. We are happy to say that, this plant is the first CCP in South Asia, which is running on cheap heavy fuel oil. Therefore, this is the next cheapest option. Then after the 10000MW, you can go for other luxuries, which are more environment friendly. Because, by that time, your buying power would very high. That is my personal opinion.