Tight fit for a fast-track development

18 October 1996

'IT IS an absolutely traditional power station,' says Enea Pianini of Italy's ABB Sae Sadelmi. This modest remark belies the challenge that Pianini faces as site project manager for the expansion of the thermal power station at Aqaba on the Jordanian coast. The challenge is to squeeze the expansion into a narrow piece of land which is just 600,000 square metres. It sits one kilometre inland and 30 metres above sea-level. For good measure, it is in an active earthquake zone.

This is hardly an ideal location for a large thermal power station but it was the only one available to the Jordan Electricity Authority - now the National Electric Power Company - when it built the Aqaba 1 thermal power station, which began operations in 1986. Now the site is straining at the seams as construction of a second and, almost simultaneously, a third stage gets underway.

The second stage consists of construction and installation of two oil-fired units of 130MW each. This will require extensive civil works and the erection of four heavy fuel oil storage tanks each with a capacity of approximately 43,000 cubic metres. When the contract was awarded in May 1995 it included an option for a third turbine which could be added to the contracts which were signed with the stage two contractors in December 1995.

The two new stages sit beside the 2x130-MW turbines of the first phase, but will benefit from the improvements in technology over the past 10 years. The differences are not in the fundamental nature of the power station, but in its very much more sophisticated control and monitoring equipment. Pianini draws an analogy with the evolution of the car: 'You can change the design but the concept is the same,' he says.

All the station systems are digitally controlled as part of a distributed control system. The steam turbine has its own electro-hydraulic control system while the digital control directs the interface requirements of the co-ordinated boiler-turbine control system. Burner management controls and furnace safety instrumentation will be supplied with the steam generator. Data logging and system calculation will be performed by the digital control and supervisory system and a sequence-of-events recorder will also be provided.

The state-of-the-art control equipment will make a major contribution to the smooth running of the station. 'It gives a lot more information to the power station operator,' says John Mackertich of project consultants Merz and McLellan. 'For example if there is a fire alarm the operator can see any nonfunctioning equipment at once, rather than having to actually go looking for it.' Environmental concerns Sophisticated monitoring equipment is being installed to meet the concern of the government and funding agencies for the environment of an area where industry, a port and tourism jostle for space along 26 kilometres of coastline.

The first requirement was to ensure that the power station did no harm to the marine life of the Gulf of Aqaba which is rich in coral and tropical fish. Any rise in the water temperature due to the plant's cooling system was recognised as a potential danger to marine life.

The solution is a system similar to the one used for the first phase, which draws water from the surface and discharges it through a submerged pipe. The discharge velocity, which is critical, has been calculated to give maximum temperature dispersion to achieve a target of one degree centigrade at the surface when both units three and four are at full load. One advantage of the plant's awkward location 30 metres above sea-level is that the water which has to be pumped up to the site has to go through a hydraulic recovery turbine which generates 3-MW of power.

An even more crucial environmental concern is air quality around a power station which burns heavy fuel oil. A mathematical model which assumed a full-load operation of the power station for 365 days a year using fuel with a high sulphur content won the approval of the US Environmental Protection Agency. This has been reassuring as the actual operation will be at less than full load and for fewer than 365 days a year. In addition, the sulphur content of the fuel oil could be lower so there is confidence that the impact on air quality will be well within acceptable bounds.

One environmental hazard that is harder to quantify is the impact of the tanker trucks that will bring the fuel to the plant. Jordan currently transports all of its fuel by road from Iraq and by the time all five turbines are in operation about 3,888 tonnes of fuel will be needed each day. At 30 tonnes a truck, this adds up to a lot of extra traffic.

Studies are now underway on the possible refurbishment of Jordan Petroleum Refinery Company's oil jetty and the addition of a pipeline to the power station site. A proposal by the US' Enron Corporation to build a gas plant in Aqaba could be the best environmental option in the long run. Enron is proposing to import liquefied natural gas (LNG) from Qatar and the Aqaba power station, which is designed to use either heavy fuel oil or gas, would require only minor modifications to switch to gas.

Aqaba 2 has had something of a chequered history. It was originally tendered in the late 1980s and bids were duly submitted and opened, but implementation of the project was put on hold. The subsequent return of 300,000 expatriate Jordanians during the Kuwait crisis of 1990-91 pushed up Jordan's electricity consumption by 10 per cent a year and the scheme was promptly revived.

At the same time, work on the long planned regional electricity grid connection has gone ahead, with the Egypt-Jordan link as the first element. The 1993 PalestinianIsraeli peace agreement and Jordan's own peace treaty with Israel in October 1994 opened up the prospect of a further expansion of the regional grid.

With the growth in demand for electricity by the time Aqaba 2 was dusted off and re-tendered, the ability of contractors to mobilise quickly had become a key feature of the project. Turbine three is due for completion by 25 September 1997, turbine four by 10 December 1997 and turbine five by 27 October 1998.

With ABB and its fellow contractors chasing these tight deadlines, Pianini is grateful for anything that saves time. 'We don't have time to breathe,' he says, 'what we would usually do in one month we have to do in 20 days here.' Meeting this tight schedule demands tight planning and co-ordination. 'We have to compact all our activities,' says Pianini, 'this means more staff doing more things at once.' All plant is being sourced from within the ABB group which is a singular advantage as all member companies follow common management procedures, have the same information networks and apply the same quality control measures.

Technical advances in the construction equipment used on site are also helping.

'Where in the past a 60-tonne crane was special, now 140-150 tonnes is almost usual and with better equipment we can also prefabricate more because we can do preassembly on the ground,' says Pianini.

The demanding timetable means that staff on the project routinely work a 12-hour day, six days a week in order to meet the deadline, leaving them with little spare time to fill. When ABB has thought of organising social activities for their multi-national staff, many of whom live on-site, the physical limitations of the area loom once more.

Not only is it too small for sports facilities, but the town of Aqaba also has little to offer.

The question of social facilities and room to move may need creative solutions as the project moves to maximum mobilisation. At present ABB has 157 staff but the numbers will rise to a peak of 500-550. Some 50-60 per cent of the team will be recruited locally with the rest drawn from a dozen different countries.

Consolidated Contractors International Company (CCC) will have about 400 staff with the Romanian contractor adding a further 60, adding up to nearly 700 workers resident on site. For the time being, the workers take care of their own spare time, but ABB has introduced a very strictly observed, and very Italian lunch hour which gives staff the chance of a proper meal and a break in the middle of a long, busy day.

Planning for the plant also has to take account of Aqaba's location in an earthquake zone. Aqaba 1 has already proved its stability. 'During the 20 November earthquake last year the old station stopped automatically and a subsequent study showed no damage,' says Mackertich, 'it was robustly built, built to run continuously and to last, and the new station also has the foundations and the cranes designed to withstand any future earthquake.'

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