1 Electrical Energy Transmission by High-voltage Direct Current (HVDC) and Prospects for an Electrical Market Mohamed Lakhdar HABIB and Rime BOUAROUDJ 18th APUA Congress Luanda, Angola, on June 2014 General Theme « The energy mix in Africa : challenges and prospects »

2 Introduction Characteristics of Algerian SPTE HVDC vs AC Configurations of HVDC systems Potential solar site in Algeria and Algerian transmission network Outline Applications and results Maghreb interconnections Regional integration of a power market Maghreb - Europe Interconnections Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market Conclusions and Prospects

3 Introduction Why interconnections? -Security of provision and functioning -Economical use of resources and reduction in investment costs Types of interconnections: - Synchronous via alternative current (AC) systems - Asynchronous via direct current (HVDC or DC) systems Areas where DC is used: - Long distance transmission of the production of power plants to consumption centers - Integration of renewable energy generation systems into electrical systems -Interconnections of asynchronous networks -Submarine/ subterranean links for distances > 50 km. Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

4 HVDC vs AC HVDC No reactive effects, (unit power factor.). Easy interconnection of networks, suffice it to have the same voltage everywhere. No « skin » effect, the cables and lines are simple and inexpensive. AC Possibility of using transformers to increase and decrease voltage. Facilitates power shut-down by the natural passage by zero, twice per period (available circuit-breaker). Transmission and consumption of direct production by the alternators. VS Impossibility of voltage generation or increase in the field of very high voltage, hence the significant losses on lines. Difficulty of switching off direct currents, hence the need for better performing and expensive power shut-off devices. Very expensive terminations. Implies inductive and capacitive effects (power factor <1 mainly). The interconnection of several networks requires the identity of the voltage, frequency and the phase. Implies a «skin» effect, hence the necessity of adapted and more expensive cables and lines. Advantage s drawbacks Each drawback of the AC syst e m is met with an advantage of the HVDC syst em and vice versa Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

5 For the same level of redundancy, two (2) HVDC conductors equivalent to 02 three- phase lines. The cost per « km » increases according to distance, up to a certain distance (600 Kms) and the alternative current remains more e conomical. Beyond this, transmission via direct current becomes necessary. HVDC vs AC Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

6 Configurations of HVDC systems Unipolar Bipolar Multi-terminals Back to Back Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

7 Potential solar site in Algeria and Algerian transmission network Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

8 Characteristics of the Algerian SPTE Demand for electricity: MW in 2013 at MW by 2030, (8%) Generation system: MW in 2013 at MW by 2030, dont MW in renewable energy. Power network transmission : 02 levels of transmission voltage : 220 kV and 400 kV In 2013 : km ( km kV and km - 400kV) 105 stations (11 in 400/220 kV and 89 in 220/60 kV) By 2025: km ( km kV and km kV) 245 stations (45 in 400/220 kV and 200 in 220/60 kV) Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

9 Applications and results Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

10 Maghreb interconnections Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market Caption 400 kV 400 kV in project 220 kV 150 kV 90 kV AlgeriaMorro co TunisiaLibya Technical and economic advantages of this interconnection : -instant power backup at each network in harsh situations -Reduction in generation cost by pooling the spinning reserve - Economies on investment But: limited energy exchange

11 Regional integration of a power market Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market In Maghreb, several enabling factors Functioning in interconnected networks for long years. Trade with neighboring countries for more than 10 years. ONEE and Sonelgaz are external operators on the Iberian electricity market (OMIE). Availability of primary power resources, namely renweable energy. Sustained growth of demand throughout the countries in the region.

12 Maghreb – Europe Interconnections Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

13 Conclusions and Prospects Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market Existence of a basic infrastructure to launch a Maghreb power market Massive development of renewable energies in Maghreb, an additional factor towards the establishment of a Euro-Maghreb power market. Construction of important links possibly in direct current to transmit solar energy from the South to the North of Algeria Construction of submarine links between Maghreb countries and Europe in view of a Euro – Maghreb power market Pursue efforts to remove institutional and legislative barriers relating to the implementation of a power market.

14 Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market