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DISTRIBUTED GENERATION (DG)-AN OPTION FOR SUSTAINABLE ENERGY Doaa R. Galal The Egyptian National Committee E-mail: [email protected], [email protected] Abstract This paper examines Distributed Generation as a new emerging technology in the Power Generation World. It comes to its definition and why it is so called, it states the different technologies used as Distributed Generation, whether they are based on the renewable resources, or based on the conventional type of fuels. The applications of Distributed generation are widely varies according to the customer needs or even the utility’s requirements to maintain its system reliability. One of the main benefits and advantages of DG is the elimination of new construction of Transmission and Distribution (T&D) systems, and so provides access to energy to the remote areas far from the transmission and distribution system. The environmental regulations and the great concern about the climate change are considered one of the main drives that lead to the emerging of DG today. DG is newly emerged and still has a lot of challenges and drawbacks either from the economical point of view, or technically. On the basis of the application and benefits of DG, and the requirements of sustainable energy a brief analysis has been made to find out how DG can be an option for sustainable energy. Cases of DG projects that were implemented by The Egyptian New and Renewable Energy Authority (NREA) have been stated. 1.0 What is Distributed Generation (DG) and what are its Technologies? Distributed generation is a terminology describes the broad set of electricity-generating units those are distributed throughout the network located near or on customer premises .It is also known as Distributed 1 Resources (DR), Dispersed Generation, or Embedded Generation . Distributed Generation include smaller-scale generation, combined heat and power, energy storage, load management, and energy efficiency. The generation capacity range from few KWs to 100 MW, connected to the distribution network, either on the medium voltage or the low voltage network level. It can be owned by a customer (load), a utility, or a third party (i.e., independent power producer). Technologies those involved in Distributed Generation; are Microturbines, Reciprocating Engines fueled by (gasoline, diesel, or natural gas), Fuel Cells, Gas Turbines, Biomass, Photovoltaic, and Wind Turbines 2.0 Why DG is emerging today? The idea behind the Distributed Generation is not a new concept. In the early days of electricity generation, Distributed Generation was the rule, not the exception. The first power plants only supplied electricity to customers in the close neighborhood of the generation plant. The first grids were DC based, and therefore, the supply voltage was limited, as was the distance that could be used between generator and consumer. Balancing demand and supply was partially done using local storage, i.e. batteries, which could be directly coupled to the DC grid. Later, technological evolutions, such as the emergenc e of AC grids, allowed for electricity to be transported over longer distances, and economies of scale in electricity generation lead to an increase in the power output of the generation units. This development in electricity generation ends up by a system consisting of huge transmission and distribution grids and large generation plants In the last decade, technological innovations and a changing economic and regulatory environment have resulted in a renewed interest for distributed generation. The major factors that contribute to this evolution are developments in distributed generation technologies especially the renewable resources with their decreasing cost and would decrease significantly under mass production, constraints on the construction of new transmission lines and the increasing of their marginal cost, increased customer demand for highly reliable electricity, the electricity market liberalization, and concerns about climate change and the increased pressures on utilities to be environmentally sensitive. 3.0 Applications, Services, and Benefits of DG The applications of DG basically come under one of 5 major categories: -Load Management -Emergency power -Base load operation -Ancillary services

-Micro-grids 3.1 Load Management Load Management is a general term, which implies modifying the load profile such as: peak load shaving, valley filling, load shifting, load reduction, and load building. Demand side management (DSM) means modifying energy use to maximize energy efficiency. The goal of DSM strategies is to smooth out the peaks and valleys in electric (or gas) demand to make the most efficient use of energy resources and to defer the need to develop new power plants. Peak shaving (Peak Load Management): Seeks to reduce energy consumption at the time of the peak load. Distributed Generation systems such as photovoltaic and solar-thermal power supplies can play a role in clipping the peak demand of the system if it coincides with the output of the DG. Distributed Generation systems offer a real solution as a supply-demand side management tool. Some of the benefits to the utility are: improving the load factor on some feeders, lowering distribution losses, maintaining feeder load-ability in some locations to safe limits, and deferring installation of new feeders and distribution transformers. In conjunction with other resources for energy storage and control, small-scale power generators can reduce utility capital investment and risk, cut planning horizons from years to months, enhance grid reliability and power quality, and give energy users greater control, choice, and flexibility in meeting their needs for power and thermal energy. Also DG contributes to DSM programs by employing standby generation and promoting co-generation, where and when it is more economical for the customer or the utility. The aims in such cases are to lower the overall cost of serving customer loads and to enhance service quality 3.2 Emergency Power There have always been some facilities and some loads at some facilities that could not tolerate any interruption in electric service. Medical facilities with critical life support equipment are one example. Also sensitive industries like paper industry, chemical industry, electronic devices, petroleum, refining need permanent power supply on the lose of the grid power by switching the electrical load to be supplied from DG units, and keep a constant voltage level Therefore, using DG units as standby or emergency reliable backup power for use during outages of more than a few minutes is necessary for such power interruption. Also Premium Power allows the customer to ride through short duration power outages of a few minutes or less 3.3 Base Load Operation In some cases, electricity users may install on-site generation facilities that operate essentially year-round. Remote locations with no access to central generation are one market for these systems. Locations with “free” byproduct fuel are another examples in which base load generation may be economic. In many cases, these locations may apply combined heat and power (CHP). In CHP, the input energy is used sequentially to generate both electricity and thermal energy. This increases the total efficiency of the system and reduces the energy cost and emissions relative to conventional systems. Finally, some facilities with highly critical electric loads may find that on-site base load generation is economically justified to provide the required power quality and reliability. For base load applications, the full range of DG technologies can be considered and the most efficient and lowest emitting technologies are often the best choices for end user. 3.4 Ancillary services The capacity to generate electricity and the energy actually produced are electricity’s two chief components, but the ability of the system to produce and deliver that energy in a usable form (at the proper voltage, frequency, etc.), is its ability to provide ancillary services. Ancillary services are needed to meet bulk system reliability needs. There are at least nine of them; which are Reactive Supply and Voltage Control from Generation, Regulation, Load Following, Frequency Responsive Spinning Reserve, Supplemental Reserve, And Backup Supply Practically not all of these services can be provided by all forms of distributed resources. Distributed generators, interruptible customers, and storage devices may best be able to provide Load Following and Supplemental Reserve services. Depending on their size and location, they may not be able to sell Reactive Supply and Voltage Control from Generation to the bulk power system.

The five remaining services (Regulation, Load Following, Frequency Responsive Spinning Reserve, Supplemental Reserve, and Backup Supply) deal with maintaining or restoring the real-time bal ance between generators and loads. These services are characterized by response time, response duration, and communications and control between the system operator and the resource needed to provide the service. 3.5 Micro-grids The micro-grid concept assumes a cluster of loads and micro-sources operating as a single controllable system. To the utility this cluster becomes a single dispatchable load, which can respond in seconds. 3.4 Environmental Benefits of DG We have mentioned above that one of the major reasons that lead to the emerging of DG today is the great concern of climate change. One of the claimed advantages of DG is superior environmental performance. Although the Renewable Technologies are of zero Nox and Co2 emissions, some other DG technologies such as Microturbines, fuel cells, Diesel generators. . Etc. have varying emissions levels Potential SO2 and CO2 emissions are purely a function of fuel characteristics. Gas has a negligible amount of sulfur and SO2 emissions are therefore negligible for any gas technology - less than 0.01 lb/MWh compared to 12 lb/MWh for central station fossil plants and 8 lb/MWh for all central plants. The sulfur content of diesel fuel varies. Highway diesel has very low sulfur and that level is expected to be further reduced in the near future. At current sulfur levels for highway diesel, SO2 emissions are about 0.5 lb/MWh - still much lower than central station generation. Some diesel engines may use higher sulfur fuel but SO2 emissions from diesel engines can be kept low through appropriate choice of fuel. All fossil fuels contain carbon and create CO2 as they are burned. Oil has lower carbon per Btu than coal and gas has less still. Beyond the choice of fuel, efficiency is the only determinant of CO2 emissions. CO2 emissions from gas technologies range from about 800 lb/MWh to 1500 lb/MWh depending on system efficiency. CO2 emissions from diesel engines are typically around 1500 lb/MWh. CO2 emissions from central station fossil plants average around 2000 lb/MWh. The NOx emission rates for gas turbine range from 0.3 to 1.0 lb/MWh. The NOx emission rate for small turbines might soon be dropping to the 0.6-lb/MWh ranges. Lean burn gas reciprocating engines have NOx emissions around 2.1 lb/MWh. Rich burn gas engines (similar to the system used on automobile engines) have emissions around 0.45 lb/MWh. The issue with diesel engines is clear from the 12-lb/MWh-emission rate for new diesel engines. NOx emissions from older engines can be significantly higher. NOx emissions from fuel cells are very low. In comparison to this performance, current NOx emissions from central station fossil generation are around 5 lb/MWh. NOx emissions for total generation are around 3.5 lb/MWh. In summary, all gas-fired technologies have NOx emissions that are lower than those of central station fossil units. The use of add-on control and the high efficiency of the combined cycle plant make its NOx emissions significantly lower than those of other conventional gas technologies. The NOx emissions of the large simple cycle peaking turbine, which does not typically use add-on controls and is not as efficient, are more comparable to those of the DG technologies. For the other pollutants, the DG technologies are significantly cleaner than the central station units. The combined cycle is somewhat cleaner due to its higher efficiency. 4.0 DG economics The biggest potential market for distributed generation is displacing power supplied through the transmission and distribution grid. On -site power production circumvents transmission and distribution costs for the delivery of electricity. These costs average about 30% of the total cost of electricity. This share, however, varies according to customer size. For very large customers taking power directly at transmission voltage, the total cost and percentage are much smaller; for a small household consumer, network charges may constitute over 40% of the price. Distributed generation has other economic advantages for particular customers. For example, customers with sizeable heat loads may produce both heat and power economically. Some customers have access to low cost fuel (such as landfill gas or local biomass), compared with commercially delivered fuel (which usually has a higher unit cost than for large central generators).

Distributed generation can also encourage greater competition in electricity supply, allowing even customers without DG greater choice in suppliers. On the other hand, small-scale generation has a few direct cost disadvantages over central generation. First, there is a more limited selection of fuels and technologies to generate electricity – oil, natural gas, or photovoltaic systems, and, in certain cases, biomass or waste fuels. Second, the smaller generators used in DG cost more per kilowatt to build than larger plants used in central generation. Third, the costs of fuel delivery are normally higher. Finally, unless run in CHP mode, the smaller plants used in DG operate at lower fuel-conversion efficiencies than those of larger plants of the same type used in central generation. 4.1 Is DG economically attractive to the utilities? A utility can be expected to see DG as an additional option to meet load growth and relieve transmission constraints. But a utility system may or may not be currently constrained in its ability to meet growing customer demand. If the utility is constrained—without enough capacity to meet demand—it must invest in its system. Constraints could be in generation, transmission, and/or distribution. Alternatively, if the system is not constrained, the utility will use the existing infrastructure to meet increasing demand. In the situation of Transmission and Distribution (T&D) constraints, DG might prove to be more cost-effective to the Transmission companies than building additional T&D capacity. But Transmission and Distributed Companies are not engaged in the energy production. If so, then even in cases where DG is the most costeffective option, it will not be chosen by the (T&D) companies. In most circumstances, there is little financial incentive for an electric utility to encourage DG installed on the customer side of the meter, unless the generation is separately metered and its output can be billed to a customer. Despite the fact that a (T&D) company does not sell energy, it still is responsible for determining a retail customer’s power consumption using an energy meter, and is compensated based on metered consumption. Therefore, if DG is installed behind the customer’s meter, the customer’s measured energy use will reflect a deduction of any energy provided by the DG resource. Without a business model that provides them with sufficient revenues, utilities would have strong incentives to avoid or prevent DG in the distribution system on both the grid side and the customer side.

4.2 Is DG economically attractive to customers? At a basic level, there are three main elements that determine the economic viability of DG: Grid Cost of Delivered Electricity-(DG capital Charges+ DG operating Cost) = DG Electricity Cost Savings To Customer Essentially, if the difference between the DG operating costs and avoided electricity costs is large enough relative to the investment required to meet the customer’s investment-return criteria, the project will go forward. In addition to the electricity cost saving, selling electricity to the grid is another add value to the customer’s investment payback 4.2.1 Still as mentioned above, the benefits that can be gained by the customer other than cost saving: § Reduced energy costs for thermal energy loads (steam, hot water, and cooling)— DG, through combined heat and power (CHP) can produce steam or hot water that can be used in manufacturing processes or for space heating and cooling requirements. § Increased power reliability—DG can avoid or reduce power outages associated with the grid that can cause operational downtime and health and safety concerns. § Power quality improvements —DG can provide very-high-quality power that reduces or eliminates grid voltage variation and harmonics that negatively affect a customer’s sensitive loads. § New source of revenues —DG may allow customers to sell excess power or ancillary services to power markets.

4.2.2 DG at the customer’s site can also provide benefits to the electric utility. DG benefits identified by utilities include the following: § Avoided increases in system capacity—DG can provide an additional source of power that could preclude the need to expand the generation, transmission, and distribution system to meet increased demand. § Reduced T&D electric losses—DG avoids electric losses associated with transporting power over the T&D system. § T&D upgrade deferrals—Utilities can use DG to meet growing demands and defer investment in T&D capacity. § VAR support—Some DG technologies can provide reactive power (VARs) that can aid utilities in maintaining system voltage. § Transmission congestion relief—B y generating power at or very near the point of consumption where there is congestion; DG can increase the effective T&D network capacity for other customers. § Peak shaving—DG can reduce customer demands from the grid during high demand periods. § Reduced reserve margin—By lowering overall demand levels for grid power and providing generation capacity, DG could reduce reserve margins. § Improved power quality—DG can eliminate demand that negatively affects the power quality of the grid system. § Increased power reliability—DG can reduce or avoid outages in certain parts of the distribution system. 5.0 What are the challenges facing DG? • Matching the generation and demand must be continuously monitored. The control system dispatcher monitors the system at the transmission and sub transmission level; the power fluctuations at the distribution level are not normally monitored. • With high conc entration of DG on a single feeder there exists the potential of reverse power flow and the possibility of harmonic current distortion, which could affect power quality. • Many DG units by their nature are not dispatchable and the system must accept the power whenever it is generated with the potential of overloading of cables or transformers. • There is a question as to what extent will the utilities be able to control the penetration of DG and ensure system security during abnormal conditions. Protection and safety must be carefully investigated. • There is always some risk with new technologies such as DG, which require market conditioning and assessment of failure. Policies and new regulations may have to be introduced to facilitate pushing DG into the marketplace. 5.1 Grid Interconnection Distribution networks traditionally have been designed to take power from high voltage grids and distribute this power to end consumers. The introduction of generating capacity connected to the distribution system nee d not cause great changes to this system, provided that the capacity does not actually send power into the network. Once power is sent into the network, the flows of electricity will be changed and even reversed from the normal design. This can lead to a number of technical problems that can affect the stability of the network and quality of electricity supplied. These problems include: 5.1.1 Voltage control Distribution network operators are normally obliged to keep network voltages within a certain range. Electricity sent into the distribution network tends to cause an increase in voltage. This can be beneficial in some instances (e.g. for some rural networks) where operators have problems with low voltages. But in a system operating under normal conditions, these electricity flows can cause difficulties. Difficulties can be alleviated by requiring connection at higher voltage or by upgrading transformers for improved local voltage control. There are related concerns with voltage fluctuations and their pot ential impact on neighboring consumers. 5.1.2 Reactive power Depending on the type of generation, DG can either supply reactive power or will be dependent on it. 5.1.3 Protection DG flows can reduce the effectiveness of protection equipment and create operational difficulties under certain conditions.

For example, while customers may want the ability to operate in “island” mode (separate from the grid) during a distribution circuit outage, restoring power to them involves important technical and safety considerations. Protection systems are required to ensure that DG systems are not supplying the network during outage conditions and can be resynchronized to the grid when power is restored. 6.0 How Distributed Generation can meet WEC’s Energy Goals After mentioning the concept of Distributed Generation, its technologies, applications, benefits, and the challenges; question arises now, how the Distributed Generation as a new power system configuration and technologies can meet or satisfy the goals of sustainable energy, and to how much extent DG can play a role in achieving the three interlinked goals which are Accessibility, Availability, and Acceptability Based on the above mentioned information, and on the definition of the three main goals, we can make a simple and brief analysis on how Distributed generation can be an option for sustainable energy for the future even so it is still we can say a new technology with many drawbacks and challenges, either economically or technically 6.1 Distributed Generation and Accessibility Accessibility is the first main issue of energy sustainability, which concerns mainly on the availability of energy at prices which are affordable, and at the same time reflect the real cost of the services. The main problem with the remote areas is that there is no access to electricity due to the limitations of transmission and distribution (T & D) construction, one of the main benefits of DG is the elimination of the need of (T & D) as DG can be placed near the load. Also DG can be competitive to the cost of upgrading or construction of new Transmission and Distribution system, where these costs average about 30% of the total cost of electricity. Renewable energy is available especially where the remote communities are found, although the technologies based on Renewable resources are still expensive but at far areas from the grid, they will be the best choice. The DG based on conventional fuel type mainly Natural Gas such as Gas Turbines are will be excellent implementation with the wide availability of natural gas, with its decreasing prices List some prices here 6.2 Distributed Generation and Availability The second issue of sustainability is Availability which aims to long-term continuity of energy supply at a good quality services. As Renewable Resources are unlimited supply of energy, DG based on Renewable resources is a good option of availability. Different parts of the world as Middle East, North America, Europe, and Asia-pacific have a large reserve of natural gas, which become more diverse than oil, and another conventional fuel types. Concluded here that the diversity of the fuel types used in DG, and the wide range of different technologies used starting from diesel engines ending by wind energy preserve the availability of energy according to the needs and application. Concerning the quality of services; the location of DG near the load reduces the energy loses through transmission and distribution, the availability of DG during power outages as an emergency application maintains reliability of the system, using DG in the load management maintains the efficiency of the power system, the ancillary services, which DG provides; raise the power quality needed by the sensitive loads such as electronic industries, and power security required for critical utilities such as hospitals 6.3 Distributed Generation and Acceptability Distributed generation embraces a wide range of technologies with a wide range of emissions. For fossil-fired distributed technologies, there are two key areas of concern: NOx emissions on local/regional air quality and greenhouse-gas emissions on climate change. Emissions per kilowatt-hour of NOx from distributed generation (except by diesel generators) tend to be lower than those from a coal fired power plant or a utility system using a large proportion of coal. At the same time, the emissions rate from existing distributed generation (except by fuel cells and PV) are higher than the “best available” central generation: a combined-cycle gas turbine with advanced emissions control. This disadvantage puts a serious limitation on distributed generation in areas where NOx emissions are rigorously controlled, even when DG could reduce overall emissions

The case of carbon-dioxide emissions is similar. Emissions rates for Distributed Generation are generally lower than those for coal plants, but not as low as those for new combined cycles – except for DG used in CHP mode. Measures can be designed that encourage distributed generators to reduce emissions. The use of economic instruments like carbon-emissions trading, for example, would give DG operators an incentive to design and operate their facilities in ways that minimize emissions of greenhouse gases. Distributed Generation, through CHP plants or by Renewable Resources, could have an important role in improving energy efficiency and reducing greenhouse-gas emissions. Various estimates suggest that CHP can reduce greenhouse-gas emissions from power generation and associated generation by 20%-30% compared with separate fossil fired power and heating systems

7.0 Case Studies in Egypt 7.1 Photovoltaic System for Pumping 7.1.1 A PV-Powered pumping system was installed at Wadi El-Natroun, a remote desert area about 100 Km far from Cairo was installed with a capacity of 14 KW. The system is a stand-alone combined AC & DC one, producing about 70-100 m3/day of water for irrigation. 7.1.2 A portable Photovoltaic water-pumping unit was installed at West Nobareya, near Alexandria, with a capacity of 2.2 KW for drip irrigation system. 7.2 Photovoltaic System for desalination 7.2.1 A stand-alone PV - Powered reverse osmosis system was installed along the Red Sea Coast, south of Hurghada, with a total capacity of 18 KWp .It produces 60 m3/day of fresh water. 7.2.2 PV - Powered reverse osmosis system was also installed at the High voltage laboratory / Giza Governorate, with a capacity of 7 KWp to produce 6-8 m3/day of fresh. 7.2.3 PV/Diesel Hybrid Ice making plant was installed at Wadi El-Raiyan Lake, a remote desert area which is about 12 Km far from the nearest rural area. It produces 6 ton/day of flake ice to preserve fish during the fishing season. The system is designed such that a 38 KWp PV array operates at sunshine hours, while a diesel unit of 50 KWp operates at night. 7.3 A pilot project for electrification was installed at a remote isolated satellite village 17 KWp PV Rural Electrification at Awlad Eshiekh Village, this project was implemented in 1994. This project was for electrification of 20 houses 7.4 Wind Energy In 1988, A Wind Farm with a capacity of (400Kw) was installed in Ras Ghareb on the Red Sea Coast serving one of the oil companies. The Wind Farm consists of 4 units 7.5 Using Biomass Energy There is a good potential for the utilization of biomass energy resources in Egypt. This is based on the fact that Egyptian rural areas depend upon biomass resources to meet 50% of their energy needs 3 A biogas plant of 220.00m digesters size constructed by General Organization for Sewage Treatment (GOST) is in operation since 1999, in El Gabal EI-Asfer Sewage treatment plant (within Greater Cairo). 7.6 Combined Heat Power (CHP)

The records of energy consumption in Egypt have always shown that the highest consumption is in the industrial sector, which consumes almost 50% of the total national primary energy consumption. Such consumption reached (29.5) MTOE in 1998/99 distributed among oil fuel (46.2%), electricity (16.8%) and natural gas (18.4%) NREA implemented two Solar Industrial Processes Heat (SIPH) pilot projects of low temperature in the food and textile industries. Each one included local manufactured flat plate collectors with total surface area 356 m2 producing 26 m3/day of hot water at 50 – 65°C. The two projects have been operating successfully since 1990, 1993 respectively, saving about 1800 TOE/Year. A Pharmaceutical company has been selected to host a pilot project for medium/ high temperature (up to 175°C). The project is using parabolic concentrators with single axis tracking system. The project mainly consists of: - Solar plant (parabolic trough collectors) for process steam generation at 175°C/8bar. - Energy conservation for condensate steam returns system, insulation of steam network and burners of boilers. The project is saving rate of about 1200 TOE/Year. 8.0 Conclusion Despite the limited penetration of Distributed Generation in today’s markets, the future will probably see an evolution to a much more decentralized power system. Such a system could have advantages with respect to security and reliability of supply. It could emerge from the present system in three stages: - Accommodation of Distributed Generation in the current system; - The creation of decentralized network system that works in tandem with a centralized generation system; and - A dispersed system where most power is generated by decentralized stations and a limited amount by central generation. There are a few signs that electricity networks are beginning this evolution. For example, new technologies are already being used to control output from distributed generation at several sites to respond to market conditions, creating a kind of “virtual utility”. The operation of a network with a large number of virtual utilities will require much greater real-time information flow than is now the case. For the present, however, there is a need to redesign distribution systems simply to accommodate DG. ACHNOWLEDGMENT The author acknowledge with gratitude support provided by Egyptian New and Renewable Energy Authority, and the support of the National Egyptian Committee

REFERENCES [1] Kame Y. Khouzam, “Applications of Embedded Dispersed Generation Systems in The Electric Utility Network”, Research Concentration in Electrical Energy, School of Electrical and Electronic Systems Engineering, Queensland University of Technology. [2] International Energy Agency, “Distributed Generation in Liberalized Market”. [3] An Arthur D. Little White Paper,” Distributed Generation: Understanding the Economics”. [4] An Arthur D. Little White Paper.” Distributed Generation: System Interfaces”. [5] Joel Bluestein,” Environmental Benefits of Distributed Generation”, Energy and Environmental Analysis, Inc. [6] Robert H. Lasseter, Fellow IEEE,” Integrating Distributed Generation Technology into Demand Management Schemes”. [7] Frederick Weston,” Accommodating Distributed Resources In Wholesale Market”, September 2001. [8] LUCIEN Y. BRONICKI,” Sustainable Energy for Rural Areas of the Developing Countries “, ORMAT INDUSTRIES LTD., world energy council, 18th Congress, Buenos Aires, October 2001 [9] ZANNOUN, MAHMOUD SAMI,” EGYPT'S RENEWABLE ENERGY STRATEGY, ACHIEVEMENTS AND PROGRAMS”, 18th Congress, Buenos Aires, October 2001 [10] G. Pepermans, J. Driesen, D. Haeseldonckx, W. D’haeseleer and R. Belmans,”DISTRIBUTED GENERATION: DEFINITION, BENEFITS AND ISSUES”, KATHOLIEKE UNIVERSITEIT LEUVEN, 19 August 2003. [11] Technical and Commercial issues affecting increased penetration of DG, chapter five, E “ conomic and Technical Interaction between Dispersed Generation and Power System” [12] World energy council, “Energy for Tomorrow’s World-Acting Now”, WEC STATEMENT 2001 BIOGRAPHY Doaa Refaat Galal received Bs. of Power and Electrical Machines from Ain Shams University in 2000.Currently register for the Master Thesis in control of Distributed Generation connected to the electric grid at Ain shams University. Worked as an Electrical Engineer at NREA in 2001