The ME generation

Despite a slight down turn in the local economy, activity in the power supply industry in the UAE remains at a high level and according to local political leaders will remain so for the foreseeable future. There is an ambitious building programme in place to keep up with projected demand, especially in Dubai and Abu Dhabi, and a long term plan to build the high capacity transmission links necessary to reconcile the local networks into a nationwide grid and eventually to the whole Gulf region including the 60Hz Saudi system and systems in the Levant, Egypt and Turkey.

In February UAE electricity and water minister Humaid bin Nasser Al Owais announced that billions of dollars would be invested over the next ten years to add 8 000 MW of power plant to meet a rising demand that at end 2000 topped 9200 MW and is expected to rise by 12 per cent for the next five years. The creation of a UAE national grid is the subject of a study due out early this summer, to be followed by a UAE grid project going to tender in August and expected to cost around $180 million. The next stage of this ambitious plan will be to link the UAE to the wider GCC, the Gulf Co-operation Council power network.

It is likely that generation in the area will centre on the neighbouring Emirates of Abu Dhabi and Dubai, where the huge power complexes of Jebel Ali, Al Taweelah and Shuweihat are undergoing rapid expansion. In the case of Shuweihat, that means construction of the first phase of 1500 MWe of a projected 5000 MWe. In 1971 on independence the UAE had a total installed capacity of a few hundred MW MW. Today it has around 10 000 MW, rising fast, to fuel the country's industrial and civic expansion. This reflects expansion in the region generally - Saudi Aabia, the largest consumer, recognises a need for $90 billion of investment duringthe next 22 years - and power equipment companies and power plant builders are among the greatest beneficiaries. ABB, Alstom and GE have all made major markets in the Middle East (ME), although the greatest share probably goes to Siemens. GE have around 200 gas turbines installed, but Siemens, boosted by the fossil power generation business unit of Westinghouse acquired in 1998, has supplied nearly 300 gas and steam turbines in the region, including 36 in the UAE, as well as substantial quantities of transmission equipment, mainly switchgear and substations. Installed capacity now amounts to around 30 000 MW.

The Westinghouse merger certainly had a big impact on Siemens activity in the Gulf because their core businesses complemented each other. Westinghouse was mainly active in the component business, while the majority of Siemens' business consisted of turnkey projects where Siemens was either the sole contractor or had a major share, usually as project leader, in an international consortium that was often established for strategic or financial reasons. Westinghouse technology had been favoured in the 60 Hz markets like Saudi Arabia and complemented existing 50 and 60 Hz designs developed by Siemens. By establishing its own package design based on Vx4.2 GTs and the rehabilitated 3A GT, and adapting existing Westinghouse designs for 60 Hz versions of the package Siemens has established a standard CCGT desalination package suitable for the Gulf's various regions.

First major CCGT

The company's first major turnkey contract for a combined cycle plant in the region, to generate steam for desalination, was for Jebel Ali unit G, Dubai, a plant equipped with five V94.2 gas turbines. Siemens PG has now supplied a total of eight gas and two steam turbines for two units of Jebel Ali as well as the electrical, and instrumentation and control equipment. It also has a long-term maintenance contract for the gas turbines.

The first four V94.2 gas turbines went on line in unit G in 1993. The fifth unit followed in 1996. This unit, which is also equipped with an alternative firing system for operation of the seawater desalination plant, produces a total of around 600 MW and about 273 million litres of drinking water daily.

The unit K combined-cycle power plant is currently being built on the same site at a cost of around E140 million. It is being equipped with three V94.3A gas turbines and two small back pressure steam turbines. Scheduled to start up in mid-2002, it will feed around 850 MW of base load power into the Emirates grid.

Beside power generation, the production of drinking water is particularly important in this region. It has become standard practice to connect a seawater desalination facility to each plant, powered by its steam production. ebel Ali K will have a daily production capacity of 530 million litres of desalinated water.

However, unit K was not the company's first installation of the design. A similar design with the same power generation arrangement consisting of three gas turbines and two identical backpressure steam turbines was was first realized at Al Taweelah A2, Abu Dhabi.

CCGT standard package

In October 1998 Siemens first put together what has become its standard CCGT design for the region in fulfilling its contract for its first 3A based combined-cycle power plant with desalination facility for the Middle East, Al Taweelah A2, for CMS Power, the first large IPP in the region. It incorporated the then new generation of V94.3A gas turbines with annular combustion chamber, and attained their highest to date efficiency levels. This plant went into commercial operation in mid-2000 with the first two gas turbines, the entire plant including desalination facility following in mid-2001.

This plant has since been established as a benchmark for the region. Since the autumn of 2001, it has been feeding around 710 MW into Abu Dhabi's power grid and supplying some 230 million litres of drinking water daily. PG supplied the three V94.3A gas turbines, two steam turbines, the entire electrical and instrumentation and control equipment, and the seawater desalination plant. The combined-cycle plant was built as a turnkey project by Siemens PG as consortium leader and the Korean company Doosan(Hanjung). In addition to the three gas turbines, the Taweelah A2 plant was outfitted with two small backpressure steam turbines rated at about 120 MW each. The same steam turbines have now been supplied to the Jebel Ali K plant and in the Fujeirah power and desalination plant, thus achieving a kind of standardisation in this particular configuration. The Westinghouse 501D and F designs have now also been converted for these standardised applications for 60 Hz regions.

Switchgear at Jebel Ali

The 145 kilovolt substation for Jebel Ali K is an important project for the Dubai Electricity and Water Authority (DEWA) power supply network and therefore a demanding specification concerning combined ambient stresses, high rated busbar and short circuit currents and busbar redundancy as well. Special attention was also paid to low life cycle cost. The solution was a fully metal-encapsulated gas-insulated switchgear (GIS) of the type 8DP3 for 145 kV specially tailored to meet the requirements. This switchgear type is designed for a busbar current up to 4000 A and a short circuit current up to 50 kA. To meet the special redundancy requirements the 14 bays were designed as a double busbar configuration with two bays working as bus couplers and two more as bus section couplers. Owing to its encapsulated design the GIS is very insensitive to almost all ambient stresses. This fact combined with what its installers call the high quality of manufacturing and erection has the object of minimal maintenance. A first major inspection is recommended after 25 years of service to keep the life cycle cost at a minimum level. Current Siemens T & D turnkey projects contain fifteen substations with more than 150 bays from 145 kV to 420 kV in the UAE and neighbouring countries.

Shuweihat contract

A major achievement for Siemens last year was the award in December of the turnkey contract for a 1500 MW combined-cycle power plant, Shuweihat in Abu Dhabi. The plant, which is scheduled to come on line in 2005, is the largest single order ever posted by PG in the Gulf region. Siemens will be the leader of a consortium with the Italian company Fisia who will be responsible for the desalination plant, capacity 100 MIGD. The power plant will be equipped with five large gas turbines rated at 265 MW ISO, of the same type as installed in Jebel Ali K, and two large steam turbines rated at 250 MW each derived from the large HMN (high, intermediate and low pressure) family of steam turbines. Since the turbines used in desalination applications provide steam at around 3 bar, this will be an intermediate-pressure unit from the HMN series. The Shuweihat power plant complex, 250 kilometers west of Abu Dhabi, is to be expanded in the long term into a power plant park with a total electrical capacity of around 5000 MW. The 1500 MW plant is the first phase of this project. After completion more than 450 million litres of drinking water will be produced daily in Shuweihat.

The contract for the 1500 MW plant is valued at about E1 billion.

It includes a long-term maintenance agreement and the high-voltage switchgear to be supplied by Siemens PTD. The consortium includes ADWEA, US IPP CMS Energy, and UK IPP International Power.

Turnkey strategy

As ong ago as the late 70s Siemens executed a major turnkey contract as consortium leader in Al Khobar, Saudi Arabia. This plant is nowconsidered the jewel in the crown of this customer and has proven its long-time reliability. It was designed as a steam plant with associated seawater desalination facility. Siemens put in a comprehensive integrated design involving engineering, planning, procurement, project management, documentation and accounting software platform, which handles all the activities from the proposal stage through design, engineering and execution up to and including further service activities throughout the lifetime of the plants supplied by Siemens.
Tables

Table 1. Current configuration of the Jebel Ali plant