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MedRing: Building an interconnected system across three continents [free access]

March 2, 2009

The Mediterranean region is assuming increasing importance in the energy strategy of the three continents it encircles. It is crossed by key energy routes from non-European countries that have huge energy resources and low demand to European Union countries that have high energy demand but fewer resources.

The opening of new routes for electricity exchange across the Mediterranean is now considered essential for energy security in the region. To that end, the Mediterranean countries are working towards establishing an energy corridor known as the Mediterranean Electricity Ring or MedRing. While the project has been under discussion for over a decade, it has made real progress only in the past few years.

Divergent interests on both sides of the Mediterranean are backing this project. On the southern shore of the Mediterranean, secure and efficient supply of electricity is seen as a key ingredient for economic growth. In the north, EU countries view North Africa as a critical source of diversification for Europe's energy needs, not only in terms of conventional energy sources (gas and oil reserves in Algeria, Egypt and Libya) but also for the development of renewable energy sources (solar and wind power).

In fact, European nations are driving the Euro-Med energy partnership. Over EUR55 million has been allocated under the EC MEDA programme over the past eight years to support the gradual integration of the European and Mediterranean energy markets. The European Investment Bank has lent over EUR2 billion to energy infrastructure projects in the region.

The MedRing project is central to the energy exchange plans between Europe and the southern Mediterranean countries. The project will link the power grids from Spain to Morocco, and travel through the North African and Arabian countries up to Turkey. From Turkey, the ring will then link back into the European grid via Greece or Bulgaria.

The MedRing is composed of four separate electricity blocks - Union for the Co­ordination of Transmission of Electricity (UCTE), South West Mediterranean Block (SWMB), South East Mediterranean Block (SEMB) and Turkey. The UCTE interconnects 26 European countries. The SWMB comprises Morocco, Algeria and Tunisia, whichhave been interconnected and are operated in synchronous mode for a long time. In addition, the SWMB is synchronously connected to the UCTE system via two Morocco-Spain interconnectors.

The SEMB comprises Libya, Egypt, Jordan and Syria. In 2005, an attempt to synchronously link the SEMB and SWMB via a 220 kV alternating current (AC) transmission line between Libya and Tunisia failed. The test is proposed to be carried out again in April-May 2009. If successful, the SEMB will be connected to the SWMB and the two blocks will constitute one long synchronous system, connected to the European UCTE system via Spain. Thereafter, the SEMB system would be connected through Syria to the Turkish grid, which would then be synchronously interconnected to the UCTE. The four interconnected blocks would then form an elliptical ring that would be 4,000 km east to west and 2,000 km north to south. Thus, the closing of the Libya-Tunisia link, the Turkey-Syria link and the interconnection of the Turkish grid with the UCTE system will complete the MedRing.

Several feasibility studies have already been conducted on the proposed project. A MedRing feasibility project (2001-03), co-financed by the European Commission, envisaged the closing of the electricity transmission superhighway by 2005-06. It also recommended 10 new AC cross-border lines, mainly at 500/400 kV, around the basin to be built between 2005 and 2010.

However, some of these timelines have not been met due to the unsuccessful attempt to complete the Tunisia-Libya interconnection in 2005. If the work could be accelerated, the entire ring could be completed over the next two to three years.

Once complete, the MedRing would increase electricity exchange in the region to 75 TWh by 2010 and the expected energy not supplied (EENS) would be reduced by 12 GWh per year, resulting in an estimated USD24 million of savings per year. In light of this, closing the ring is now getting a renewed thrust from the European Commission.

The interconnections under the MedRing are part of different projects: the Euro-Maghreb interconnections, the Maghreb interconnection, the Egypt-Tunisia-Libya-Algeria-Morocco (ETLAM) interconnection, the Egypt-Iraq-Jordan-Lebanon-Libya-Syria-Turkey (EIJLLST) interconnection and the Turkey-UCTE interconnection. Some of the interconnections form a part of the EuroMed Energy Action Plan 2008-13 launched last year.


Euro-Maghreb interconnections


The first interconnection of the MedRing was achieved in August 1997, when the 700 MW, 400 kV Morocco-Spain submarine AC link was completed. With this, the ­integrated grids of Morocco, Algeria and Tunisia in the Maghreb region were put into synchronous operation with the UCTE system. In July 2006, a second submarine AC link was put into operation between Spain and Morocco, increasing the capacity to 1,400 MW.


The plan is to expand the existing links between the Maghreb region and Europe under the Euro-Maghreb interconnection project. The proposed links under the project include Algeria-Spain, Algeria-Italy, Tunisia-Italy and Libya-Italy. These are all 400 kV direct current (DC) interconnections. The feasibility studies of all these DC links have been completed and the projects are at various stages of implementation.


These HVDC links will be a precursor for Europe's plans to import solar power, particularly from the Sahara desert, where solar panels would be capable of providing up to three times more energy than those in Europe. In fact, one of the priorities of the Union for the Mediterranean, formed in July 2008, is to develop the Mediterranean Solar Plan. European renewable energy developers are building large solar thermal plants (50-200 MW) in Algeria, Egypt and Morocco. According to the German government, HVDC lines from North Africa could carry 700,000 GWh of solar power annually by 2050. Strengthening of the Euro-Maghreb links is imperative to realise this plan.


Maghreb and ETLAM interconnections


The Maghreb countries have also been strengthening the electricity interconnections among themselves, mostly at the 400 kV level, to support larger anticipated electricity flows. There are three interconnections between Morocco and Algeria - two at 220 kV and one at 400 kV - that were put into operation in 2006. Algeria and Tunisia are interconnected through four lines between 90 kV and 220 kV and by one 400 kV line, put into operation in 2006. The 400 kV Algeria-Morocco and Algeria-Tunisia links are currently being operated at 220 kV but are scheduled to operate at 400 kV by 2011.


The Libya-Tunisia interconnection was completed in 2003 through two 225 kV lines. As mentioned above, the first synchronisation test was carried out in November 2005 but was unsuccessful. The power-transfer limits of the weak 220 kV network ruined the attempt to link the SWMB to the SEMB because of a mismatch in North Africa's AC frequency. A key test of North Africa's upgraded transmission infrastructure will take place in April or May 2009 when Libya is scheduled to once again try to connect with Tunisia. Libya is also planning a 400 kV link with Tunisia and to upgrade the link with Egypt to 500 kV (which will form a part of the ETLAM project) by 2012.


EIJLLST interconnection


The countries in the SEMB represent the next frontier for the MedRing. One of the key electricity infrastructure projects in this region is the EIJLLST project. Some of the interconnections already under operation in this block are the 400 kV Egypt-Jordan link, the 400 kV Jordan-Syria link and the 220 kV Libya-Egypt link. These existing interconnections are being augmented and strengthened under the EIJLLST project, which envisages interconnection between the North African countries of Egypt and Libya, the near-eastern countries of Syria, Jordan, Lebanon, Iraq and Palestine, and Turkey. While Lebanon, Iraq and Palestine are not a part of the MedRing project, the Turkey-Syria interconnection under EIJLLST is a key component of the MedRing. The 124 km, 400 kV Syria-Turkey link was completed in 2003. However, the line is expected to start operations after Turkey's connection to the UCTE system.


Turkey-UCTE interconnection


Turkey has been pushing for the integration of the Turkish grid with the EU network for a long time in order to get the benefit of synchronous parallel operation. Several studies have been conducted, which reveal that the synchronous connection of the Turkish power system to the UCTE is viable through Bulgaria and Greece. Turkey already has two 400 kV interconnections with Bulgaria. One 400 kV link with Greece is under construction.


The EUR1.5 million phase one of technical studies to connect Turkey to the UCTE system was completed in April 2007. The EUR2.5 million phase two of studies for the improvement of the frequency control performance is currently underway. As per the timelines finalised for the studies, the trial operation is scheduled for 2010. Until the Turkish system is interconnected with the UCTE, the tie lines with non-UCTE countries would be operated in an isolated mode.


Issues and challenges


The completion of the MedRing presents several technical challenges that are being addressed prior to starting operations. Linking the power grids that have varied operational and technical characteristics is a complex process. The existing mature networks in Europe are highly meshed, consisting of high-voltage lines, with predictable load patterns. In contrast, the grids in the southern Mediterranean region are typically low-voltage grids, serving fewer loads concentrated in highly urbanised areas. Therefore, the capability of the system to react to small and large disturbances needs to be built to ensure the stability of the interconnected network.


For reliable and secure operation of such a large system, several measures have to be adopted to avoid the spread of disturbances from the affected areas to the neighbouring ones. Installing devices that have the capability to control specific electrical quantities, such as static Var compensators (SVCs), back-to-back or HVDC links, enhance the dynamic security of the system. What is also needed is an independent "reliability council" in the region to look at two aspects of bulk power system reliability: system adequacy and system security.


There are a few potential problem areas: the UCTE-Turkey, Libya-Tunisia and Egypt-Libya interconnections. The opening of the UCTE-Turkey link may cause instability in the south-eastern part of the system in case of heavy power import by Turkey. If the test run of the Libya-Tunisia link fails again, the Mediterranean countries will have to opt for HVDC interconnections for completing the ring. In this event, the AC grids on the two sides would not need to be synchronised and could run at different frequencies. However, this would require significant additional investments. For now, the North African countries are more focused on the relatively economical frequency stabilisation that AC offers.


Another weakness in the system is the interconnection between Libya and Egypt. Due to technical constraints, the 220 kV line linking the two systems currently has a maximum power exchange capacity of only 180 MW against the design capacity of 600 MW. With a peak load of approximately 20,000 MW, the Egyptian power system is the largest in the southern Mediterranean area, and is therefore subject to higher fluctuations. In a synchronous structure, these fluctuations would be transmitted throughout the system. A back-to-back interconnection, which acts as a filter for normal power frequency fluctuations on either side has been proposed.


In addition to the purely technical challenges of synchronising the varied systems and ensuring sufficient interconnection capacities, there is also the issue of how to align the different institutional frameworks in the electricity sectors of the Mediterranean countries. Market deregulation is uneven with the incumbent owning and operating the transmission system in most cases. There is no regional electricity market yet. Moreover, the non-consistent approach to internal power sector regulation is a hurdle in the free trade of electricity in the region. Consequently, it is only natural to realise harmonised internal market regulation as the first step towards the establishment of a regional market.


Another concern relates to the doubts that have been rasied on whether the investments made so far have paid off. This is mainly because the volume of energy exchanged on a commercial basis has been small, with two exceptions - between Spain and Morocco, and between Egypt and Jordan. Also, commercial exchange within the Maghreb and Mashreq is minimal, consisting mainly of Algeria exporting to Morocco and Tunisia, and Egypt exporting to Libya. An initial analysis highlighted that North-South HVDC links were not profitable due to the huge investment costs and the fact that the North-South energy exchanges were heavily influenced by oil prices. However, given the recent plan of sourcing renewable energy from North Africa, the profitability of these interconnections may be justified in the long run.


Going forward, blueprints are bring drawn up to extend the Euro-Med interconnected system to the east with a 220 kV Egypt-Sudan line and to the Middle East by interconnecting Jordan and the western part of Saudi Arabia (which forms part of the Gulf Cooperation Council power grid project, to be put into operation soon). For now, all eyes are set on the second test run of the Libya-Tunisia AC line which will determine the next sequence of events.


MedRing: Planned Projects

Electrical line

Capacity (MW)


Line characteristics

Expected year of operation


Euro-Maghreb Interconnections








500 kV DC undersea cable



500 (1,000)

265-660 via Sardinia

400/500 kV DC undersea cable



600 (1,000)


500 kV DC undersea cable



500 or 1,000


400 kV DC undersea cable


ETLAM Project





Libya-Egypt (2nd line)            

500 or 1,000


400/500 kV AC overhead line


Reinforcement of ETLAM project



400 kV


SWMB/Maghreb Interconnections





Algeria-Morocco (3rd line)

600 (1,200)


225 kV AC (400 kV AC*) overhead line


Algeria-Tunisia (5th line)

600 (1,200)


225 kV AC (400 kV*) overhead line


Tunisia-Libya (3rd line)



400 kV AC overhead line







Egypt-Jordan (2nd line)



500/400 kV DC undersea cable





400 kV AC overhead line

To be decided









400 kV AC overhead line



*Rated voltage level
**Year of completion
Source: Observatoire Mediterraneen de l'Energie

Completing the MedRing: 3 Key Links



Source: Turkish Electricity Transmission Company