ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Static electricity = an imbalance of positively and negatively charged atoms. Electrons then jump from atom to atom, releasing energy. Examples of static electricity Lightning Shocks from scuffing your feet across the carpet on a dry day and then touching a metal surface such as a doorknob ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Current = a flow of electrons along a pathway Direct current (DC) means that electrons flow in one direction. Batteries provide DC. Batteries consist of two or more cells filled with chemicals. As the chemicals react, electrons are removed, leaving behind positively charged ions. The separation between the electrons and the ions creates voltage. ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure The voltage produced depends on the chemicals used. A “D” cell flashlight battery uses an alkaline reaction. A car battery uses a lead-acid reaction. The voltage of a cell drops over time as the chemical reaction slows down and the battery dies. ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure 1 Coulomb = 6.25 x 1018 electrons; symbol is C 1 Ampere of current = the movement of 1 Coulomb of electrons past one point, in one second; symbol is A Load: device or customer that receives power from the electric system. Load should not be confused with demand, which is the measure of power that a load requires ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Voltage is the “push” behind the movement of electrons (current flow) Unit is the Volt Symbols DC Voltage Source AC Voltage Source ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Resistance is the opposition to current flow Unit is Ohm (Ω) resistor : A component used to limit current flow in a circuit or to provide a voltage drop Symbol : R ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure A simple DC Circuit consists of a source, a load, control and conductors connecting the three parts. ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure A series circuit has a single path for current to flow. (When the switch is open, the circuit is incomplete and the electrons cannot flow.) ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure A Parallel circuit has multiple paths for current to flow. ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Capacitor: a device with the ability to store electric charge (Ex: condenser in a car) and release it; used in electronic circuits for blocking DC while allowing AC to pass Transformer: transfers electricity from one circuit to another with an increase or decrease in voltage Inductor: a coil of wire that can store energy in its magnetic field and resists any change in the amount of current flowing through it; when the current flowing through an inductor changes, it will create an opposing or reverse voltage ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Alternating current (AC) means that electrons flow in two directions. Power plants provide AC. AC current is generated when a conductor—often a coil of wire—is rotated in a magnetic field. The magnetic field has polarity (north and south poles). As the coil rotates between the opposing poles, the change in polarity causes a change in direction of the current flow. The directional change happens at regular intervals. In the U.S., 60 full 360º rotations through the field (cycles) happen every second. ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Thomas Edison’s power plants provided DC to customers but could only send it about 1 mile before it lost power. Edison hired Nikola Tesla to find a solution and Tesla delivered, but then Edison allegedly refused to pay him. Tesla quit and investors helped him establish a competing industrial laboratory where he manufactured the prototype for today’s AC generation and transmission system. ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure DC was difficult to convert from higher to lower voltages and required separate transmission lines for different voltages; AC could be “stepped down” easily through the use of transformers Separate transmission lines meant great cost and more danger to the public from overhead lines DC required power plants to be located close to the end user (electric load); AC could transmit high voltage over long distances requiring fewer plants AC motors are simpler in design than DC motors ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Economies of scale in generation, when cost of production falls because output has increased Load diversity, when the peak demands of a variety of electric customers occur at different times ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure Batteries and power systems http://www.eng.cam.ac.uk/DesignOffice/mdp/ electric_web/DC/DC_11.html Electrical components and systems http://science.howstuffworks.com/electricitychannel.htm Inventor Nikola Tesla http://www.pbs.org/tesla/ ENERGY INDUSTRY FUNDAMENTALS: MODULE 1, UNIT A --The Evolution of the Power Industry and Its Regulatory Structure