James Van Wormer, GE Energy, USA booming industrial economy and rapid population growth are driving a need for increasing electricity and clean water in Saudi Arabia. Electricity use has been on the rise at a rate of about seven per cent a year, and the Ministry of Water and Electricity estimates that the Kingdom of Saudi Arabia will require up to 30 GW of additional power generating capacity by 2020.
Additionally, the state-owned Saline Water Conversion Corporation has estimated a cost of $50 billion for water projects through 2020, many of which will be integrated with new power generation capacity. Marafiq, the first privately-owned utility company in the Jubail Industrial City of Saudi Arabia’s Eastern Province, is addressing the current and future need for additional power with a series of projects designed to produce power and water. A highlight of that effort is the Marafiq independent water and power project (IWPP), the largest combined power generation and desalination plant in the world.
As part of a consortium, GE Energy is supplying four combined-cycle power blocks, including a complete plant control system, for the project. When completed, the plant will provide 2700 MW of power and 800 000 m3 of desalinated water per day for industrial use. The first of the four blocks is scheduled to enter commercial service during the third quarter of 2009, block two in the fourth quarter of 2009, block three in the first quarter of 2010 and block four during the second quarter, 2010.
Diversity Is Security
Drawing technological and logistical strength from several countries, the Marafiq project is owned and operated by a diverse, regional consortium of developers, comprising Suez Energy International of Belgium in partnership with Arabian Company for Water and Power Development (ACWA Power) of Saudi Arabia and the Gulf Investment Corporation of Kuwait.
Through an engineering, procurement and construction contract, the project developers extended the consortium to include Hyundai Heavy Industries of South Korea and Société Internationale de Déssalement of France, along with GE. These companies were commissioned to construct the new power and desalination plant.
Formed in 2000 to provide integrated utility services to industrial, commercial and residential customers in the cities of Jubail and Yanbu, the Marafiq project has become a major success story in Saudi Arabia’s development and privatization initiative.
Adopting GE Technology
GE’s equipment supply for the project includes 12 Frame 7FA gas turbine-generators, 12 heat recovery steam generators (HRSGs), four steam turbine-generators and a distributed plant control and protection system. GE also is responsible for design and engineering, project management, technical advisory services, performance testing, training and plant maintenance. The primary fuel used will be natural gas, with distillate as a back-up.
In an IWPP of this size and complexity, optimization and plant control are major operation management concerns. GE’s Mark Vle control system helps to mitigate these concerns by providing a common platform for the control of the rotating machinery, the HRSGs, the power island balance of plant and the desalination units. Providing a common control system for the power island and the desalination units simplified plant operation and maintenance.
The same control hardware and software mentioned above are used for the turbine, generator and plant controls, communicating on a common network. The control system combines the proven reliability, availability and speed of turbine and generator controls with the flexible and distributed properties available in a plant-wide distributed control system (DCS).
By reshaping the traditional segregation of plant and unit level controls into a single integrated network, the Mark Vle control system approach reduces system complexity, decreases start-up problems and allows for commissioning in a shorter time. The use of a single control system for all plant equipment also helps to streamline plant system planning. The integration of different systems and suppliers can lead to reduced cost and project risk.
The increased flexibility of the operator interface allows the plant control room to be set up on a block-by-block basis. Each interface station allows operator access to both the power and desalination plants. Operator productivity and operational awareness are increased through access to a common interface of all equipment, operator screens, process data, trend data, alarms and events.
Economies of Scale
Having a single control system provides better tools and data to diagnose and solve problems, helping to reduce the plant’s mean-time-to-repair cycle. The Mark VIe control system’s diagnostic features include sophisticated data collection and analysis tools and a common time-synchronized database resulting in data that can be analyzed more quickly and thoroughly.
The Mark VIe control system at Marafiq features remote connectivity, via GE OnSite Support technology. The remote connectivity switch can be enabled by site personnel to provide virtual site support for problem resolution, data analysis, remote software deployment and remote tuning of the control system. The design engineer can participate in the finer details of commissioning and also be available to the field engineer on an as-needed basis.
Once connected, an engineer at a remote location has access to the same control system data and diagnostic tools as the site personnel. When required, tuning analysis and remote tuning can be coordinated with the site team, improving the quality and consistency of plant operation. During the operating phases of the project, the OnSite Support system is available to the end user 24 hours a day, 365 days a year. In addition, a team of experienced power industry engineers is available to assist plant personnel with problem resolution.
GE Energy developed its single plant control philosophy out of technological necessity. Because GE’s advanced technology H System power island gas turbine uses steam to cool first stage nozzles and buckets, very tight coordination of the control between the gas turbine and the steam cycle is required. Design engineers evaluated a number of control scenarios, including traditional DCS control for the HRSG. In the final evaluation, it was determined that the best control could be achieved by extending the Mark VI control system from the turbine to the HRSG.
GE decided to expand this single control system technology beyond the H gas turbine, and began discussing this option with customers operating other GE gas turbine models, to gauge their interest. Feedback was positive, based on the benefits that the users envisioned. In 2001, the Santee Cooper John S. Rainey generating station in South Carolina, USA, became the first power plant where the gas turbine, steam turbine, generators, HRSG, electrical and balance of plant equipment were controlled with one system GE’s Mark VI.
Today, there are more than 120 power plants using GE’s Mark VI or VIe plant controls, including 34 in Africa and the Middle East
Specifically in the Middle East, the Mark Vle plant control is used in a variety of applications including simple and combined-cycle, integrated water and power plants such as Marafiq, and cogeneration plans at aluminum producing sites.
The Marafiq Award
For its role in the project, GE Energy has received the inaugural Marafiq Award for Sustainability from Marafiq. Created to celebrate and encourage sustainable practices that demonstrate and promote environmental protection and social and economic development, the award was presented to GE during the Saudi Water and Power Forum 2008.
“The Marafiq project is an outstanding example of how technology can be applied to meet both the world’s energy and environmental requirements,” said Joseph Anis, GE Energy’s regional executive. “The integration of water and power production at a single site is a growing trend, especially in the Middle East where population and industrial growth rates are exceeding most other regions of the world.” MEE