Bringing German IPP experience to Turkey

Groundbreaking for the twin-unit 1210 MWe Sugözü power plant, initiating the 39 month project term, took place on 4 November, 2000, with a ceremony conducted by Steag CEO Jochen Melchior and Turkey's deputy Prime Minister Mesut Yilmaz. It is the most ambitious project to be handled by Steag in its 60 year history of entrepreneurial power plant development and operation in Germany, and more recently in overseas markets.

There are clear parallels between the power generation patterns of Turkey and Germany in the mix of hydropower, lignite, imported coal and potentially nuclear energy resources.

Contracts for the $1.5 billion bituminous coal-fired power plant were signed in June 2000 in what was one of Turkey's biggest ever private finance deals. This is the first major power plant to burn imported coal rather than expensive indigenous deep mine lignite in Turkey (see Table 1). It is also the only one of the present programme of five new large generating stations to burn solid fuel rather than natural gas from Central Europe and Iran in gas turbine combined cycle plants.

The Sugözü power plant project (Figure 1 - not available at present) is located in a seismically active area of south-eastern Turkey, bordered by the sea and the main road from Ceyhan to Yumurtalik. This road acts as a feeder from the highway that runs from Adana (100 km away) to Iskenderun, not far from the Syrian border (Figure 2 - not available at present).

When MPS visited the site in July 2002 both the 100 m high tower boiler and the flue had been built for the first unit and the first ceremonial "boiler pressure test" was planned for the end of September 2002. The second unit is also well advanced. The two overhead 380 kV grid connection lines, which were subcontracted to Turkish concerns, were already established and very impressive.

International finance

With a net output of 2 x 605 MW, the project finance is based on a 20 year (including construction period) agreement between the Turkish project company Isken, whose shareholders are Steag AG (75 per cent) and RWE Power (25 per cent), and the Turkish public utility TEAS. The power will be paid for in Turkish Lira equivalent to US dollars and the payment obligations are guaranteed by the Turkish government.

The plant is planned to supply nearly 8 per cent of electricity demand in Turkey at an average price of 4.1 ¢/kWh including everything but use of system costs, which would make it the cheapest publicly supplied electricity in Turkey. This is quite remarkable for a plant with such high investment costs including offshore coal transshipment facilities, 0.6 km long coal transfer jetties and desalination of very highly saline seawater for make-up.

One quarter of the total investment in the 20 year build-operate (BO) project is financed by equity. The loans are provided by a consortium of banks led by the Kreditanstalt für Wiederaufbau (KfW), Dresdner Bank, WestLB and the South African bank ABSA. RWE Energie was also offered an option to acquire a 25 per cent stake in Isken, which it took up in December 2001.

The political risk for equity and loans is covered by a German capital investment guarantee and by the export credit insurance agencies OeKB from Austria, GKA and Hermes from Germany and GCIC from South Africa. This approach has facilitated project financing on a limited recourse basis.

The turnkey contract with a value of more than $810 million was awarded to a consortium led by Siemens Power Generation. The coal suppliers are RAG Trading and Rheinbraun. Babcock Borsig is supplying the Benson steam generators under licence from Siemens, with most of the manufacturing undertaken in South Africa at the former Steinmüller works.

Main cooling water pumps and boiler feedwater pumps have been supplied by Sulzer, South Africa, largely due to the large commitment of sovereign guaranteed development finance from ABSA. Initially much of the coal will be supplied from South Africa as well as Colombia. South African company Möller is supplying the flyash handling equipment and Koch the coal yard stacker/reclaimer and the coal unloading belt conveyor on the coal reception pier. Much of the main pipework is contracted to Voest Alpine of Austria. Civil works will be executed by the joint venture of Turkish contractors, Gama-Tekfen. Isken will be responsible for operation and maintenance of the plant. Figure 3 shows the project structure.

Rapid capacity growth

Turkey, which is seeking to join the European Union, is eager to develop its electricity supply system. In 2000, annual electricity output in Turkey amounted to 95 billion kWh while the electricity demand is expected to reach 130 billion kWh by the year 2001 and 270 billion kWh by 2010, according to OECD figures.

The Sugözü project is one of the current programme of build-operate projects which follows an earlier programme of BOT (build-own-transfer) projects leading into liberalisation of the electricity market, as in Table 2.

Under the liberalisation programme TEAS has now been divided into three entities:

• A power generation company TEUAS which operates state-owned generating facilities and sells electricity to TETAS for five years.

• An energy trading company TETAS which manages existing ESAs (electricity supply agreements) as well as buying and selling power.

• A public monopoly transmission company TEIAS, which operates the national grid.

Steag is committed to developing activities as an Independent Power Producer (IPP) and construction and operation of the Sugözü power plant offers an opportunity to make inroads into the Turkish energy market. It believes that further additional power generation capacity increments of some 3000 MW per year will by mainly fuelled by imported bituminous coal. This may be optimistic in the light of Turkey's radical economic setbacks in the last couple of years. The light at the end of tunnel may now be in view, but some authorities predict an electricity generation surplus for the next three years.

Further development of hydropower has been limited by disputes with Iraq on water rights and attempts to establish nuclear power in Turkey have been continuing for several decades, without success.

Two of the three companies that initially bid for the development contract for the first Turkish nuclear reactor at Akkuyu, submitted new proposals after the project's latest cancellation. An alliance of Westinghouse and Mitsubishi and an AECL-led consortium have agreed to relinquish Turkish treasury guarantees on the project, first tendered by TEAS back in 1997.

AECL has said that it would be prepared to construct the first 670 MW unit without guarantees, but would require security to the tune of $2 - $2.5 billion for the second phase due to be in construction in the period 2002 - 2004.

Westinghouse would have accepted a facility of around $100 million to initially start the project, but would forego further guarantees from the treasury. The third bidder NPI, an alliance of Framatome and Siemens, was not prepared to submit new proposals for the project, with an estimated cost of up to $4.5 billion. The project has been cancelled eight times.

International consortium

Commissioning and handover of the two Sugözü units to the purchaser is scheduled for 2003.

The scope of supply and services to be provided by the consortium leader, Siemens Power Generation, covers the entire planning of the new plant, supply of the two turbine-generator sets from the manufacturing plant in Mülheim and of the Teleperm XP instrumentation and control system. The order also includes the mechanical and electrical equipment, the flue gas desulphurisation plant and various auxiliary systems.

The supervision of the EPC contractor is performed by Steag Encotec of behalf of Isken, while Fichtner acts as the independent engineer on behalf of the lenders to the project.

The members of the Sugözü EPC consortium, formed in June 2000 between Siemens, Babcock Borsig Power and Gama-Tekfen, are jointly and severally liable for the performance of the EPC contract.

Siemens has already built a pioneering power plant in Turkey as leader of an international consortium. At the beginning of the 1990s, the Ambarli combined cycle power plant, with a capacity of 1350 MWe was the largest plant of its kind in Europe. Ambarli also claims to be the first power plant to attain an efficiency level of 52.5 per cent, which was more than one percentage point above the contractually agreed figure. As much as 53.2 per cent was demonstrated on peak-load duty.

The first boiler pressure test at Sugözü was due to be performed in September 2002, with the second boiler test following two months later. Both inspections will be performed by TÜV.

In November 2003 the power plant is expected to commence energy production. 250 men and women will be employed there, from administrative to operations manager.

Quick start

Shortly after receiving the notice to proceed Siemens set up a dedicated project team in Erlangen solely for the execution of the project.

Table 3 lists the main project milestones.

For the fixed project term an overall project manager is responsible for the team, which consists of representatives from all departments within the power plant sector, including project management, process engineering, plant layout and civil engineering, architecture, mechanical and electrical engineering, scheduling, purchasing and construction. At its peak, overall planning involved more than 70 Siemens personnel with planned engineering hours of approximately 500 000. Siemens internal process manuals describe the tasks and responsibilities of each team member and therefore control the teamwork, avoiding the normal problems associated with interfacing, competence, etc. With the introduction of Siemens' process orientated organisation the project planning will be supported by several prevailing computer systems to guarantee high efficiency and quality.

Site construction works started at the end of June 2000 with a team under the overall leadership of Siemens site management. The works proceeded in compliance with an integrated time schedule consisting of some 9000 activities and 18 000 logic links.

Civil structures

The site plan is shown in Figure 4 - not available at present.

The main structures are designed in accordance with Turkish earthquake regulations, ie the turbine foundation will be supported by spring elements under a steel structure. The plant is designed to survive and is insured against earthquakes of up to 6 on the Richter scale.

A major part of the civil works will be the offshore cooling water structure. The four discharge pipes will run up to 1200 m into the sea creating a mixing zone for the cooling water, whereas the four intake pipes have a length of about 300 m. Sea temperatures around the plant can be up to 26 to 28°C, and meeting the Turkish cooling water discharge limit of 36°C was one of the more difficult aspects of plant design.

Main components

The gross electrical capacity of each unit is 660 MW, with a net efficiency of 40 per cent.

Main technical parameters are listed in Table 4 and a steam/water schematic is shown in Figure 5 - Not available at present.

The steam generator is a once through boiler of the Benson-type, designed for single reheat, with balanced draft furnace conditions. The boiler is of the tower type configuration and wall fired (24 burners with low NOx combustion) with bituminous coal. Light fuel oil is used for start-up and flame stabilisation (24 retractable steam atomised burners).

Each boiler is designed for a maximum continuous rating of 524.3 kg/s steam flow. At full load rating the expected steam conditions at the superheater outlet are 185 bara and 541°C and at the reheater outlet 50.5 bara and 539°C.

The coal firing system for each unit consists of four coal bunkers for a minimum of eleven hours storage at BMCR, four gravimetric coal feeders and four pulverisers.

The boilers are designed to burn a wide range of world wide sourced coals. The capacity of the bunkers, feeders and pulverisers is based on the lowest grade coal. The air and flue gas systems are of the single train design.

Each boiler is equipped with an electrostatic precipitator (ESP) for the removal of particulates from the flue gas stream. The fly ash removal efficiency of up to 99.5 per cent for the ESP design coal in combination with the desulphurisation plant (FGD) ensures an ash content in the flue gases of less than 50 mg/Nm3.

The design satisfies the requirement for an appropriate margin for flue gas flow and temperature as well as an outage of one transformer/rectifier set.

The bottom ash is removed by means of a dry bottom ash extractor.

Flue gas desulphurisation

After fly ash has been removed from the flue gas by the ESPs, it passes through a Bischoff FGD plant before being discharged to atmosphere.

The FGD plant uses limestone as the absorption agent for SOx removal. The SOx precipitation is achieved in a spray tower forming gypsum as a byproduct. The gypsum will be used in the civil building industry in products such as wall board manufacturing.

The flue gas flow of about 1 800 000 Nm3/h (standard, wet, 3.7 per cent O2) coming from the boiler ID fan downstream of the ESP with a temperature of 140°C is fed to the absorber. The clean flue gas leaves the absorber at a temperature of 54°C through a two stage mist eliminator and is discharged via the 150 m high chimney.

Still listed as a developing country, Turkey does not have to meet the most stringent world emission control standards, but the limits set for this plant are well in line with World Bank limits, as shown in Table 5. SOx emissions are reduced to 400 mg/m3 (standard, dry, 6 per cent O2), which is well in line with European standards.

Steam turbine and generator

The standardised module steam turbine for each unit (Figure 6 - Not available at present) is a single reheat tandem compound design with one high pressure (HP), one intermediate pressure (IP) and two low pressure (LP) sections (Figure 7 - Not available at present).

The HP turbine is of the barrel-type. Main steam (176 bar, 524 kg/s, 538°C at MCR) is supplied via combined stop and control valves located laterally. The IP turbine is designed with double flow and will receive reheat steam at 49 bar 538°C, through two combined stop and control valves and expands the steam in two flows to the cross-over pipe to the LP turbine inlet.

There are two double flow LP turbine casings and each LP turbine is connected to a single-pass, box-type surface condenser. The two condensers are connected in series to the circulating seawater system (0.039/0.047 bar at 23/29°C cooling water inlet/outlet). Three 50 per cent capacity Elmo pumps ensure a constant vacuum.

The two-pole generators, type THDF 115/67 (733 MVA, 21 kV), use direct hydrogen cooling for the rotor winding and direct water cooling for the stator. The high initial response type excitation system is of the static type with a two channel digital voltage regulator.

Coal and ash handling

The coal consumption of the two units at BMCR will be around 400 tonnes per hour, ie some 3.2 million tonnes per year.

The coal used in the power plant is to be brought by 240 000 dwt max. transoceanic freighters with a length of up to 320m, from overseas to the Bay of Iskenderun. The coal from these ships will be reloaded at sea (two miles offshore) with floating transshipment equipment into unpowered barges, as in Figure 8.

The average unloading capacity of the transshipment equipment, consisting of one transshipper equipped with three grab-type cranes, two barges and two tugboats are designed for a capacity of 30 000 t per day. The barges have been built at a Gdansk shipyard (Figure 9 - Not available at present) and at the time of writing were on their long journey by sea to the Bay of Iskenderun.

The self unloading capacity for unloading operation of two barges (maximum 2000 t/h per barge) is limited in total to 2500 t/h (max. incoming capacity).

The incoming system is designed to unload 2500 t/h and to transport the coal from the jetty into the coal stockyard.

In a separate building screening and crushing equipment, a magnetic separator system, a metal detector system, a belt weighing scale and a sampling station are provided.

The power plant's coal stockyard (three piles), with a capacity of 800 000 t, is equipped with two sets of bucket wheel stacker/reclaimers. The coal can be stored in different areas of the stockyard for blending purposes.

The outgoing 1000 t/h system comprises one of the two bucket wheel stacker/reclaimers, the conveyor systems along the coal stockyard and the outgoing conveyor system to the raw coal bunkers in the boiler houses. A further set of magnetic separators, metal detectors, belt weighing scales and sampling equipment is provided.

A pneumatic pressure vessel conveying system is provided to transport the fly ash from the generating area to the silos.

The dry ash from the electrostatic precipitators and boiler bottoms is transported by a pneumatic positive pressure system (dense phase) to the ash silos, where it can be stored.

There are four ash storage silos. The silos will have a capacity of 4.5 days when burning the worst coals.

Each silo is provided with truck loading facilities for dry ash and wet ash loading onto a conveyor belt to transport the wet fly ash to a disposal area located about 750 m away from the power station boundary.

Prospects

Sooner or later, no doubt, Turkey will have to resort to CO2 separation and sequestration from power plant exhaust streams, just like everyone else, particularly when they are received into the EU, but this is a relatively simply retrofit for post combustion separation.

The main consideration is that the country has high degree of security of electricity supply with a good mix of energy resources and well proven, high efficiency, power generation technology which will add impetus to the country's economic recovery.
Tables

Table 1. Coal comparison
Table 2. Steps towards power privatisation in Turkey
Table 3. Main project milestones
Table 4. Main technical parameters
Table 5. Emissions standards