Libya is One of the World's Leading Oil-Gas Producing Nations with Significant Financial Reserves. Hence, Libya — situated in the centre of North Africa with one of the longest coastlines along the Mediterranean Sea and inhabited by a relatively small population — is now one of the world's fastest-developing countries. Although the public sector dominates most of the country's economy, General Electric Co. of Libya (GECOL), which operates under the newly formed Secretary of Electricity and Gas (SOEG), is a wholly government-owned electric utility responsible for operation of the entire power sector in Libya, from electricity generation to the end users.

SUPPLY AND DEMAND

Following unification of the four island networks built during the early stages of system development into one large totally interconnected system, GECOL serves around 1.4 million customers in the Libyan territory, which has a total land area of 1.76 million sq km (679,540 sq miles) and a population of 5.5 million. The available installed generating capacity in the existing power plants is 5500 MW. The current system maximum demand is approaching 4000 MW, a total that has been predicted to double by 2014.

Now regarded as a 100% electrified country, Libya is part of the African continent, where less than 15% of the population has access to electricity. While Libya has an annual consumption of 2900 kWh per capita, the annual average consumption per capita in Africa is around 550 kWh, which is relatively low when compared to the world average of 2300 kWh. Chad, a country that borders Libya on the south, has an average annual consumption of 17 kWh per capita, one of the lowest values in Africa.

The transmission system in Libya comprises four geographically well-dispersed, totally interconnected major island systems. These systems are supplied by 27 power plants with gas and steam turbines supported by some diesel generators located in rural areas of the Libyan Desert. The prime fuels used are natural gas, residual fuel oil and distillate. Moreover, crude oil is also used in some power plants situated near oil fields, deep in the desert remote from the oil refineries located in the coastal areas.

NORTH AFRICAN INTERCONNECTIONS

Libya is a large country that shares borders with six countries, four Arab states (Egypt, Sudan, Algeria and Tunisia) and two African states (Chad and Niger). Currently, Libya is only electrically interconnected with Egypt and Tunisia at the eastern and western network boundaries, where energy (300 MW) has been commercially exchanged in each direction through the tie lines since the circuits were commissioned.

The interconnection with Egypt was constructed as a double-circuit 220-kV line connecting the Tobruk substation in Libya, approximately 165 km (103 miles) inside the border, with the Salum substation in western Egypt, close to the city of Alamin. The transmission line extends across the Egyptian desert an additional 350 km (218 miles) before it reaches the areas of high energy consumption and the load centres of Alexandria. Therefore, the overall length of this 220-kV transmission line is 500 km (311 miles).

The transmission systems of GECOL and the Tunisian National Co. of Electricity and Gas (STEG) are interconnected via two 220-kV transmission lines. The first circuit, the Coastal Line, is a double-circuit, single-conductor 220-kV transmission line that interconnects Libya's Abukamash substation with Tunisia's Madneen and Abushama substations. The overall length of this circuit is 380 km (236 miles), with 26 km (16 miles) in Libya and 354 km (220 miles) in Tunisia.

The second 220-kV circuit, the Sahara Line, is a single-circuit transmission line connecting Libya's Rouais substation with Tunisia's Tataween substation. This circuit is 298 km (185 miles) long, with 37 km (23 miles) in Libya and 261 km (162 miles) in Tunisia. Construction of the two 220-kV transmission lines was done by Ketan Construction Ltd. (Gujarat, India).

EXPANSION PROJECTS

In response to load growth, which is in the range of 9% per year, GECOL's infrastructure plan continues to include major upgrades to the generation, transmission and distribution systems. This requires and represents significant investment by the utility to fund projects designed for satisfying the growing demand. GECOL plans to invest US$13 billion in upgrades from 2008 to 2015.

GECOL plans to position new power plants adjacent to load centres and an additional 8000 MW of capacity will be installed from 2008 to 2015. By 2012, a further 5550 MW of capacity will be needed to meet the growing demand of electricity consumption and to replace the capacity deficiency attributable to decommissioning time-expired generating units. To allow for generation plant lead times, a plant totaling 2400 MW capacity is already being commissioned in three various locations to fulfill the 5550 MW that will be required by 2012.

TRANSMISSION-SYSTEM VOLTAGE UPGRADES

GECOL's 220-kV transmission system has a total circuit length of 12,500 km (7767 miles). GECOL is currently upgrading the transmission-system voltage to 400 kV. The first 400-kV project in this program is under construction, a 430-km (267-mile)-long double-circuit transmission link connecting the Homs power plant situated along the Mediterranean Coast, close to the famous historical Greek city of Greater Lipts Magna, with the Man Made River substation deep in the Sahara Desert via the Beny Walid substation. Another 400-kV line is under construction to connect the Tripoli East substation with the Homs power station 130 km (81 miles) east of Tripoli and 50 km (31 miles) west of Zawia.

GECOL's subtransmission voltage level is 66 kV, with a total circuit length of 13,000 km (8078 miles), and the distribution networks use dual voltages, 30 kV and 11 kV.

TRANSMISSION-SYSTEM DEVELOPMENT

GECOL has reserved some $2.8 billion for upgrades to the transmission system. The utility plans to construct around 30 220-kV substations throughout the country and extend the system by some 2000 km (1243 miles).

Due to salt pollution from the Mediterranean Sea, GECOL has started a program to replace a coastal 220-kV conventional outdoor-switchgear substation built in the late 1970s with modern indoor gas-insulated (GIS) substations.

Furthermore, GECOL plans to reinforce the existing 220-kV cable network with an additional 160 km (99 miles) of cross-linked polyethylene (XLPE) single-core cable. (In 1984, Libya commissioned the first 220-kV XLPE insulated cable, a 48-km [30-mile]-long section of cable supplied by Siemens.)

Sumitomo Electric of Japan upgraded some sections of the existing transmission systems by replacing the old-phase conductors (Red Wing AASR) with aluminum zirconium alloy conductor types, G (Z) TA CSR (gap construction super heat resistant), with a similar cross section. The new conductors have double the existing circuit current-carrying capacity, and can use the existing towers for the majority of fittings without the need for additional civil work or rights-of-way agreements.

Following the upgrading of the main transmission-system voltage to 400 kV, the installation of another 18 400/220-kV substations, with a total load transformation capacity of 15,000 MVA, are being considered. To date, contracts are in place for nine 400-kV GIS substations, and 400-kV transmission line projects totaling 2450 km (1522 miles) will be required to interconnect these substations. For all national interconnections, extra-high-voltage transmission lines will be of double-circuit construction, whereas single-circuit construction will be used for cross-border tie lines with the utilities in Egypt (EEC) and Tunisia (STEG).

CONTROL CENTRES

GECOL is expecting to commission its state-of-the-art national control centre, which will operate and control the entire high-voltage power grid and Libya's cross-border interconnections. GECOL awarded Siemens Power Transmission and Distribution (PTD) a 180 million-euro contract to supply five district network control centres. The contract, signed by the ex-German Federal Chancellor Gerhard Schröder during his visit to Libya, is the largest so far received by the power systems control segment of the Siemens group. Siemens has already started erection of the five regional control centres at Tobruk, Benghazi, Tripoli, Zawia and Sebha.

These regional network control centres will collate all the data on the operating state of the grid. For this, remote terminal units (RTUs) integral with the switchgear will be installed in the regional 66/30/11-kV substations. Information gathered by the RTUs and transmitted commands will be exchanged by a communication network (also forming part of the order) with the power system control centres.

The power system control equipment is based on the Sinaut Spectrum range of software developed by Siemens PTD. Switching operations will be performed from the main control room, to provide a superior response to system disturbances and to minimize the risk of blackouts. The five control centres are scheduled to be commissioned this year.

RENEWABLE ENERGY

GECOL is striving to establish a generation mix by introducing various renewable energy technologies. Projects currently being considered include wind energy (25 MW of capacity) and photovoltaic cells (1 MW of capacity). Renewable energy projects will be used to supply remote areas where the diesel generator sets, used for continuous operation to cover base loads, commonly experience a large number of outages.

Extensive viability studies indicate that by the year 2020, the grid will receive some 500 MW supplied by renewable energy plants.

DESALINATION PLANTS

As Libya has a lack of rivers and natural lakes, GECOL also is responsible for the construction and operation of bulk water desalination plants erected with steam-power stations to supply turbines with clear boiler make-up water and to supply coastal cities and towns that have a shortage of clean natural-water reserves. The excess of distilled water from power station desalination plants is supplied to the municipal water-supply network.

GECOL has recently awarded several contracts to foreign manufacturers to construct 11 desalination plants in various locations that will desalinate 910,000 m³/day (32 million ft³) of seawater. Construction on some sites has already begun. GECOL has reserved a sum of $2.3 billion for investment in another 440,000 m³/day (15.5 million ft³) of desalinated water.

GRID REINFORCEMENT

GECOL, still being a vertically integrated utility, has a very demanding investment programme in place in which the utility has to consider new assets that extend from energy generation to energy delivery to the customers' terminals.

When all the 400-kV interconnections with the utilities of Egypt and Tunisia are completed and energized, GECOL is expecting to wheel through its network around 1000 MW, from both ends, East and West. This will reinforce the North African power grid and enhance the future commercial trading of electricity around the Mediterranean Basin.

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Labib Daloub received an electrical engineering degree from Malta University in 1979 and joined the electric utility of Libya (then SOE), where his positions included generation, transmission planning, distribution and consultancy. After receiving a Ph.D. from Bradford University in England, he returned to Libya and joined GECOL as a technical advisor and became a consultant to Kabas Engineering. Daloub then joined the University of Manchester Institute of Science and Technology as an academic visitor to undertake research related to the commercial trading of electric power across neighbouring countries. ldaloub@hotmail.com