Qatar’s largest IWPP
In September 2004, a contract was awarded to build Qatar’s largest integrated water and power project. When fully operational, Ras Laffan B will produce 1025 MW of power and 273 million litres per day of desalinated water for the fast growing state.
Qatar is one of the fastest developing states in the Middle East. Growth in power demand in Qatar currently stands at seven per cent per annum and is expected to remain strong driven by the increasing population and rapid economic development.
In 2002, Qatar had an electric generation capacity of 1880 MW and produced 9.7 billion kilowatt-hours (kWh) of electricity. Most of the country’s power plants are natural gas-fired. The residential sector consumes around 70 per cent of Qatar’s electricity, but this share is declining as power demand associated with LNG export terminals increases. Since 1999, the Qatari government limited the provision of free electricity to Qatari-citizen households with payment required for consumption above a set threshold.
Figure 1. A 3-D model of the Ras Laffan B combined cycle power plant
In May 2000, the Qatari government took a major step towards privatization of its power sector. Assets owned by the Ministry of Electricity and Water (MEW) were transferred to the Qatar General Electricity and Water Corporation (QEWC). The government holds 43 per cent of QEWC’s shares while the other 57 per cent is controlled by local investors.
To meet the increasing power and water demand, Qatar is continuously increasing its power and desalination capacity. In May 2001, QEWC awarded a contract for the Ras Laffan A independent power and water project which is co-located with the Ras Laffan gas and industrial complex.
This project was awarded to Ras Laffan Power Company (RLPC) in which US developer AES Corporation owns a 55 per cent equity stake in the project and QEWC holds 45. Ras Laffan Power Company (RLPC) is running the 750 MW/30 MIGD plant, which began operation in May 2004.
In September 2004, another international consortium received a letter of award for a second IWPP in Qatar. Known as Ras Laffan B, it will be the largest power and water plant in the Emirate. The 1025 MW and 60 million gallons (MIGD) desalinated water per day project will be located at the Ras Laffan industrial site area nearby the IWPP already in existence.
Financial close of the project was achieved in May this year. The total project cost is estimated to be $900 million, which will be funded by a mix of debt and equity in an 80:20 ratio. The mandated lead arrangers for this financing are Bank of Tokyo-Mitsubishi, Calyon, HSBC, Gulf International Bank, Qatar National Bank and Royal Bank of Scotland.
Figure 2. Three Siemens SGT5-4000F gas turbines will be installed
Qatar Electricity & Water Corporation (Kahramaa) awarded the contract for the Ras Laffan B IWPP to a project company known as Q-Power, which is led by QEWC with a 55 per cent stake. Its partners are International Power, holding 40 per cent; and Chubu holding 5 per cent. With established partners like the local Qatar Electricity & Water Company and International Power. Q-Power will have ample experience in operating and maintaining the plant once it has been commissioned. Through its establishing partner, Chubu Electric Power Company, it also has excellent access to project financing. The electricity and water produced by the plant will be sold to the Qatar Electricity & Water Corporation, which will be responsible for distribution and billing to the consumers.
Mott MacDonald is owner’s engineer for the implementation of the plant. A consortium of Siemens Power Generation and Doosan Heavy Industries have been contracted to engineer, construct and commission the power plant and water plant on a turnkey basis, with the construction contract led by Siemens.
The plant will include three gas turbines, two 220 MW steam turbines and four 15 MIGD multi-stage flash distillers. A water transmission project will pump the potable water to Doha.
Ras Laffan B power plant is scheduled to run all three gas turbines by the end of May 2006. Two steam turbines will follow by May 2007. The project will sell electricity and water on a fast-track basis into the grid of Qatar under a 20-year power and water purchase agreement. The first unit of the desalination plant will deliver water by mid-April 2006. The complete facility will operate to produce power and water at full capacity by mid-June 2008.
Ras Laffan B IWPP is located at Ras Laffan Industrial City approximately 80 km north of the city of Doha, capital of the state of Qatar. It was here, back in 1990, that the Strategic Plan for Natural Gas Utilization in Qatar was drawn up. As a result the go-ahead for the construction of a 106 km2 Industrial City was given. Today, the Industrial City accommodates a large number of gas-based industries including gas liquefaction, processing and export; petrochemicals, refining of condensate and the construction of the world’s largest LNG exporting port to serve these industries. The gas for the turbines will be delivered from the North Field. Energy experts believe that the North Field is the largest single non-associated gas field in the world. Discovered in 1971, the North Field covers over 6000 km2 and holds 20 per cent of the world’s proven gas reserves. Its proven reserves of recoverable non-associated gas exceed 900 trillion standard cu ft (TCF).
Under its turnkey EPC contract, Siemens will supply three SGT5-4000F (previously marketed as V94.3A) gas turbines, two steam turbines, associated generators, the plant control system and various elements of the electrical installations. In addition, Siemens will supply three supplementary fired heat recovery steam generators (HRSGs), interconnecting piping, civil works and main cooling water systems together with specialized subcontractors. Doosan will supply the four multi-stage flash (MSF) water desalination units with the related equipment.
Exhaust heat from the gas turbines can be vented to the atmosphere directly in open cycle operation. The plant is expected to be mostly operated in combined cycle operation, but the bypass-stack also makes open cycle operation possible.
Siemens selected an arrangement of three gas turbines in connection with two steam turbines and an HRSG with supplementary firing to support the operational requirements. Doosan will deliver four desalination units of the MSF type.
The HRSGs are two-pressure units with 2-stages of supplementary firing. Steam from the HRSG is fed to the steam turbines which are of the back-pressure type in the 200 MW range. Steam from the power island is fed to the desalination plant at a pressure of about 3 bar and flow of 1400 t/h.
The key component in the power island is the gas turbine type SGT5-4000F being designed for maximum efficiency in combined cycle processes. The technical features of this proven machine are in brief: the annular, walk-in combustion chamber with 24 hybrid burners, ceramic combustion chamber tiles, 15-stage axial flow compressor with optimized flow distribution (controlled diffusion airfoils), advanced cooling technology, optional multiple fuel capability. The gas turbines have an output of more than 235 MW at 50°C with evaporative cooling.
More than 170 Siemens turbines of similar design are either in operation, have been shipped or ordered worldwide. Over 2.8 million operating hours of experience have been accumulated demonstrating their reliability under diverse operating conditions. The average fleet reliability level of the SGT5-4000F engines has been above 99 per cent for five consecutive years.
Figure 3. Qatar is one of the Middle East’s fastest growing states
The Ras Laffan B power and desalination plant is designed and will be constructed according to the strict directives and local regulations of Qatar. This means that the impact on the population, the environment and plant staff must be kept to a minimum. Therefore, dry low NOx burners were specified for the gas turbines. The noise requirements are also taken in to consideration in the plant design, and must be in line with the overall philosophy of Ras Laffan City.
The plant is based on Siemens’ reference power plant concept being a standard base design. Nevertheless, the plant design was adapted to specific local conditions accommodating individual site-specific and customer specific requirements. In particular, it must be capable of simple cycle operations at an early stage i.e. while large parts of the plant are still under construction.
The time schedule for construction of the plant, which began in February this year, was prepared according to the power and water needs of Qatar and to coincide with the Asian Games in 2006. However, to meet Qatar’s increasing power and water demand Kahramaa is planning to continue building new IPPs/IWPP’s in the future. MEE