المدرسة الوطنية للمهندسين بتونس CONNECTING RENEWABLE ENERGY WITHIN THE GRID المدرسة الوطنية للمهندسين بتونس Ahmed S. Bouazzi École Nationale d’Ingénieurs de Tunis (ENIT) University of Tunis El Manar PO Box 37, Tunis 1012, Tunisia

المدرسة الوطنية للمهندسين بتونس The new context of increased concern over urban air pollution, global warming and fossil resources depletion pushes the states and the regional alliances to introduce renewables into their energy resources to feed their industry and their population with energy. Despite the fact that the Arab states are the biggest oil and gas producer in the world, it is wise to prepare a safe future for their children by introducing renewables among their energy sources and hence safeguarding the environment from pollution. A clean environment will represent a treasure in the future if we take into account the overpopulation and the scarcity of clean spaces. In this frame, this paper presents a study about the world photovoltaic (PV) production and net metering. In the case of Tunisia, it simulates the PV energy production depending on the site and on the amount of sunshine and estimates its profitability.introduction

المدرسة الوطنية للمهندسين بتونس Range of typical retail prices of electricity is 40 to 80 mEuro/kWh Comparison of external costs of electricity

المدرسة الوطنية للمهندسين بتونس An estimate of the physical impacts of global warming, for 2xCO2 (2.5°C warming) Type of damage Damage indicator Agricultural production loss 0.23% of GDP Loss of forest area 10 6 km 2 Fishery, reduced catch 7  10 6 t Increased electric demand350 TWh Reduced water availability 230 km3 Coastal protection expenditures $ 10 9 /yr Dry land loss 0.1 * 10 6 km2 Wetland loss 0.3 * 10 6 km2 Premature deaths 140,000 Migration millions Deaths due to hurricanes thousands/yr

المدرسة الوطنية للمهندسين بتونس Pollutant Impact Cost, €/kg PM10 (primary) mortality and morbidity 15.4 SO2 (primary) crops, materials 0.3 SO2 (primary) mortality and morbidity 0.3 SO2 (via sulfates) mortality and morbidity 9.95 NO2 (primary) mortality and morbidity small NO2 (via nitrates) mortality and morbidity 14.5 NO2 (via O3) crops 0.35 NO2 (via O3) mortality and morbidity 1.15 VOC (via O3) crops 0.2 VOC (via O3) mortality and morbidity 0.7 CO (primary) morbidity As (primary) cancer 171 Cd (primary) cancer 20.9 Cr (primary) cancer 140 Ni (primary) cancer 2.87 Dioxins, TEQ cancer 1.85 × 10 7 CO2Global warming Typical damage costs per kg of pollutant emitted by power plants in Europe

المدرسة الوطنية للمهندسين بتونس Cost of environmental damages for various power generation cycles. €-cents/kWh

المدرسة الوطنية للمهندسين بتونس Net Metering Schematic Diagram

المدرسة الوطنية للمهندسين بتونس Any producer may sell the energy to the distributor at the gross rate while the distributor (the utility) transports it to the consumer and sells it at the retail price. A PV system that produces during the day more than the owner consumption spins the meter backwards during the day while the meter spins forwards during the night since the major individual energy consumption happens during the evening. The PV system owner may sell then the energy in excess to the utility like any other energy producer. THE ECONOMICS OF NET METERING

المدرسة الوطنية للمهندسين بتونس Cumulative installed PV Power (MW)

المدرسة الوطنية للمهندسين بتونس

Production and consumption of fossil fuel in Tunisia

المدرسة الوطنية للمهندسين بتونس Installed PV systems in Tunisia from 1997 to 2003

المدرسة الوطنية للمهندسين بتونس Installed PV systems in Tunisia

المدرسة الوطنية للمهندسين بتونس In the frame of the new economic policy, Tunisia opened its market to the private sector in many domains, especially in the energy production sector. A tender has been launched in 1997 for a build-own- operate (BOO) electrical power plant to provide electricity for the fast growing energy market. The winner of the bid is CEA (Community Energy Alternatives), which invested in Tunisia to achieve the 470 MW BOO Combined Cycle Power station in the site of Rades in the north east of Tunisia, near the capital Tunis, together with all the additional installations. The construction of the plant has been completed last winter, the cost is estimated at 260 Million USD, and it is expected to supply 23% of the National demand for electricity. Tunisia has produced in 2002 more than 12 Terawatt-hour. المدرسة الوطنية للمهندسين بتونس

The national company STEG will continue to distribute and sell the energy to the customers. The gross price will be near Tunisian Dinar while the retail price is near TND (1 TND equals roughly 0.8 USD). This way of energy business opens a real opportunity to renewables to be among the producers of energy, and net metering is no more a special operation since the renewable energy plant owner may sell the energy like any other producer. Already a 20 MW wind farm, owned by the national electric company (STEG) is connected to the grid. It is expected that more wind farms will be installed by 2006 to produce 100 MW. المدرسة الوطنية للمهندسين بتونس

Portability: many kinds of PV systems can be moved about easily. Reliability: they operate for long periods with little maintenance. Low operating costs: the fuel is free and there are no (or few) moving parts. Low environmental impact: they are quiet and nonpolluting (no greenhouse gas emissions). Modularity: power output can be increased by adding more modules. Safety: they are not flammable. Versatility: they operate well in almost any climate. Ease of installation: no heavy construction equipment is required Short lead time: prepackaged PV systems are available, and utility easements aren't needed. Stand-alone capability: they operate in remote areas far from power lines. Why PV ?

المدرسة الوطنية للمهندسين بتونس Tunisia has now a large government funded PV program aimed to bring electricity to remotes rural houses. By the end of 2002, the national agency for renewable energies (ANER) installed already more than 10,000 stand-alone PV systems to electrify remote houses in the countryside. It is foreseen that around 10,000 more remote houses will be electrified in the same way by Many demonstration PV installations has been installed since 1980, among them a 28 kW peak PV plant to supply the village of Hammam Biadha, 150 km southwest of Tunis. This plant installed with the help of US AID and owned presently by the National Electric Company (STEG) will be connected to the grid in the near future.

المدرسة الوطنية للمهندسين بتونس Average amount of sunshine (hours/year)

المدرسة الوطنية للمهندسين بتونس Daily Global In- plane Irradiation (Wh/m2/day)

المدرسة الوطنية للمهندسين بتونس We made the simulation for the case where we have panels with a peak power (P P ) of 85 Watt under an incident light of 1000 W/m 2, dc-ac inverters with efficiency (  In ) of 93% and a maximum energy need (E N ) of 7000 Wh per day. E P is the energy given by a panel, it is given by: The number of PV panels to satisfy one house need is: THE OUTPUT OF 1 kWp PV SYSTEM OVER ONE YEAR

المدرسة الوطنية للمهندسين بتونس Incident Energy on a tilted panel E 35° (Wh/m²/day) K 35° Incident Energy (Tunis-Carthage Site) E 0 (Wh/m²/day) Month ,682,444J 5,1341,453,541F 6,2381,245,031M 6,7241,056,404A 6,6990,927,281M 6,5780,877,561J 6,5530,97,281J 6,3400,996,404A 5,8361,165,031S 4,8871,383,541O 3,8621,582,444N 3,4371,682,046D

المدرسة الوطنية للمهندسين بتونس Number of PV panels needed to produce 7 kWh/day (85 peak-watt each) Output Energy (AC) E P (Wh/ day/ panel)Month 22349J 17436F 14530M 13572A 13569M 13559J 14557J 14539A 15496S 18415O 23328N 26292D

المدرسة الوطنية للمهندسين بتونس Monthly output energy from a PV system made up of 17 panels, each panel has a peak power of 85 W, connected to the grid through a dc-ac inverter with an efficiency of 93%. The simulation was made with the meteorological data of Tunis site (36°48 N, 10°11 E)

المدرسة الوطنية للمهندسين بتونس A map of Tunisia, the blue lines show the annual output of 1 kWac PV system (in MWh/yr)

المدرسة الوطنية للمهندسين بتونس The market price of an installed 1,445 Wac PV system is presently around 15,000 TND. One peak watt of this system produces an amount of energy from 34 to 44 kWh over 20 years depending on the site. If we assume a 4% fixed interest rate long-term loan over 20 years, a 5% rate of discount and a 3.7% inflation rate, one can extract the components of the cost of one kWh. The amortization cost is TND per kWh, the maintenance cost is TND per kWh and the interest rate costs TND per kWh. This gives a grid connected PV kWh price of TND, which represents the cost covering price. COST-COVERING PRICE

المدرسة الوطنية للمهندسين بتونس Cost-covering price of 1 kWh PV (TND) Energy output of 1 Wac during 20 years (kWh) Annual output of 1 kWac PV system (kWh/yr) The cost-covering sell back price of the PV kWh for six cases in Tunisia. The lifetime of the system is supposed to be 20 years

المدرسة الوطنية للمهندسين بتونس Net metering is a way to allow people to buy photovoltaic energy within the grid. The present PV kWh price is too high to make it cost effective by itself. Funds must be found from the collectivity to pay the difference between the conventional kWh price and the PV kWh price. External costs of energy from fossil fuels could be used to subsidize PV electricity producers.

المدرسة الوطنية للمهندسين بتونس Introducing PV systems among the sources of energy production is a must. Developing research on renewables and pollution is a must. By doing this: We will master the technology of the PV connection to the grid. We will safeguard our environment by using less polluting sources of energy. A clean environment will represent a treasure in the future if we take into account the overpopulation of the globe and the scarcity of clean spaces.