Effect of electrical alternative energy sources on power grid

Abstract

Recent geopolitical unrest in the Mideast, high consumption of fossil fuel by new large industrial bodies and their environmental impacts encouraged many countries to find alternative sources of energy. Wind, solar, wave and geothermal energy have received most of the attentions in recent years. However, except geothermal energy, these energy alternatives are cyclical and cannot produce energy at any time readily and reliably. Storage systems such as battery banks have been used to store the energy for future use. One of the most widely used alternative sources for electric energy production is solar energy. Solar cells are used to harness the energy from nature and produce electricity. Solar cells are connected in series and parallel and assembled into a panel. Electric output power of solar a panel is a function of location, time of the day and season. Average daily output of a flat plate collector at latitude tilt in the contiguous United States is 3-7 kWh/m2/day and the performance is less in high-altitude areas like Europe. Solar cells produce direct current (DC) which must be converted to alternating current (AC) using a grid tie inverter in existing distribution grids that use AC. This incurs an energy loss of 4-12 percent. However, high voltage DC grid transportation has less energy waste than AC grid; so, there is a trade-off consideration in deciding to construct high voltage DC grids and apply the inverter at the consumers' end. The behavior solar and wind generators as well as their effects on the load and power grid can be studied utilizing MATLAB-SIMULINK®, commercially available DIgiSILENT® PowerFactory and Homer software. MATLAB-SIMULINK® can readily perform calculation and simulation of individual units while the power flow and grid stability analysis can be done utilizing PowerFactory. On the other hand HOMER software package is capable of handling overall system feasibility and cost analysis. A graduate course is developed and offered to address hybrid energy and battery systems. Students in Hybrid and Battery System course are required to investigate hybrid electric systems with alternative energy sources such as wind and solar. This paper presents: • Modeling and simulation of solar cell panels • Power Grid Simulation • Voltage profile for bus • Controlling real and reactive power via wind turbines and solar panels • Power flow analysis results obtained from PowerFactory software • Integration of MATLAB, Homer and PowerFactory software packages into a graduate course • Student Survey regarding the use of Simulation Software Packages.