Transcript Document
Physics and the Electric power industry Welcome Randy Bermke Electrical Maintenance Manager Alliant Energy – Edgewater generating station B.S.E.E. from UW-Platteville Registered Professional Engineer with the State of Wisconsin Member of the Institute of Electrical and Electronic Engineers (IEEE) 20 + years experience in the power generation field Overview Types of power generating technologies Wind power overview Steam cycle power plant overview (Coal) Power transmission overview (Generating plant to your house) Cost of energy usage. * (Hint: May need this in the near future) Questions Basic electrical theory Career fields at Alliant Energy Please feel free to ask questions. Types of power generating plants. Steam turbine – Generator (Steam supplied via a boiler) Coal fired Nuclear powered Natural gas fired Oil fired Combustion Turbine – Generator Renewable power Hydroelectric dams Wind turbines Solar Geothermal Biofuels (switchgrass, wood byproducts, etc.) Renewable Energy– Wind power One of the fastest growing and most visible forms of renewable energy today. Varity of capacity ranges – Typical utility size 1 to 3 Megawatts each unit “Fuel” is emission free Major parts of a wind farm Wind Turbine Tower Nacelle – Housing at the top of the tower Generator Gear box – connects blade assembly to the generator Auxiliary systems – lube oil, control system, etc. Blade assembly – Blades, Hub, Blade actuators. Underground distribution system – Connects the wind turbines to the substation. Substation – Connects underground distribution to the transmission grid Renewable Energy– Wind power Alliant Energy’s Wisconsin wind facility Cedar Ridge wind farm South of Fond Du Lac – Town of Eden 41 Vestas wind turbines 1.65 MW per turbine Total site capacity of 68 MW Turbines are spread over a 12.2 square mile area Renewable Energy– Wind power Example of wind power generation at Cedar Ridge Edgewater Generating Station (Coal) The Edgewater generating station is a coal fired power plant with 3 units. Units #1 and #2 have been retired and removed. Unit #3 is a 1950’s vintage unit with an output rating of approximately 60 Megawatts. Unit #4 is a late 1960’s vintage unit with an output rating of approximately 340 Megawatts. Unit #5 is a mid 1980’s vintage unit with an output rating of approximately 400 Megawatts. Simplified steam cycle power plant The power production cycle is governed by 2 very important laws of physics. Both are based upon the laws of conservation of mass and conservation of energy. The First law of thermodynamics: This basically states that energy can be changed from one form to another but it is neither created or destroyed. The total amount of energy is a constant. The Second law of Thermodynamics: This law effectively says that a system operating in a cycle (like below) cannot completely convert all of the heat energy into work (Electrical power). Example the heat rejected to the condenser. Edgewater Generating Station Fuel Example coal analysis (By weight) for Edgewater Unit #5 Carbon 55.8% Hydrogen (H2) 4.6 % Nitrogen (N2) 1.35 % Sulfur (S) 0.25 % Ash 5.4 % Oxygen (O2) 7.8% Moisture 24.8 % Total: 100% The heating valve of the coal is approximately 8400 Btu/Lb. A BTU is the amount of heat required to raise one pound of water one degree Fahrenheit at one atmosphere of pressure. At full load (400 MW) Edgewater #5 will use about 230 Tons of coal per hour! Generator Delivering the energy Electricity is produced at a generating station (as previously shown). As it leaves the generator it’s voltage is increased. This voltage is anywhere from 69,000 volts to 765,000 volts depending on the transmission system. From there it is sent over high voltage transmission lines. Delivering the energy continued… At the end of the transmission lines, the high voltage electricity is lowered at a substation to distribution voltages (Example: 7,200 to 12,500 volts). The electricity then “flows” at the distribution voltage to a power pole by the customers home. There it is lowered one more time to a usable voltage, typically 120 / 240 volt for homes. Electrical “Energy” is a rate of electrical usage (Watts) multiplied by a period of time (Hours). Customers are billed based upon their energy usage. This is typically measured in Killowatt-hours. Measuring electricity in kilowatt hours Kilowatt-hours (Wh ÷ 1000 = kWh) 1,000 watt-hours is a kilowatt-hour (kWh). Convert 300,000 watt-hours to kWh. Answer: 300,000 / 1,000 = 300 kWh If the utility charges 11 cents per kWh, what is the cost of 300kWhs of electricity? Answer: 300 x 0.11 = $33 Electric usage “story problem” It was very hot in July and you ran your airconditioner 8 hours everyday of the month (31 days) Your air-conditioner was 3500 watts and your utility charges 11 cents per kWh. How much did it cost you in July to run your air-conditioner? Remember: Watts / 1000 = kW and kW x Time x electric rate ($.11) = $’s 3.5 kW * 8 Hours * 31 days * 0.11 per kWhr = ? $95.48 Questions ? Common Electrical Terms Volt (E or V) - The unit of electromotive force, electrical pressure, or difference of potential Volts = Watts ÷ Amps V=W÷I Ampere (I) - The basic unit measuring the quantity of electricity or unit of current flow Amps = Watts ÷ Volts I=W÷V Watt (P or W) - The unit of electrical power. Watts is a product of amps x volts Watts = Volts x Amps P=ExI Ohm (“Omega” Ω or R) – The measure of resistance in an electrical circuit. Ohm's law pi chart P = Power in Watts E = Voltage in Volts I = Current in Amps R = Resistance in Ohms Why do we use high voltage for long distance transmission lines? Example: We want to provide 1 megawatt (1 million watts) of power from Sheboygan to Fond du lac (distance of 45 miles). The transmission line has a resistance of .168 ohms per mile of conductor. So: P (Power) = 1,000,000 watts D (Distance) = 45 Miles R (conductor) = .168 Ohm’s per mile R (transmission line) = D X R = 45 miles X .168 Ohm’s per mile = 7.56 Ohm’s Why do we use high voltage for long distance transmission lines? Option #1: Assume V = 22,000 volts (This is the voltage Edgewater #5 generates at) Using Ohm’s law: I = Power (Watts) / Voltage (Volts) = 1,000,000 watts / 22,000 Volts = 45.45 Amps From this we can calculate the power “lost” in the transmission line. Power = I^2 * R = (45.45)^2 * 7.56 Ohms = 15,616 watts Which is approximately 1.5 % of the total 1 Megawatt load. Option #2: Assume V = 345,000 volts Using Ohm’s law: I = Power (Watts) / Voltage (Volts) = 1,000,000 watts / 345,000 Volts = 2.9 Amps From this we can calculate the power “lost” in the transmission line. Power = I^2 * R = (2.9)^2 * 7.56 Ohms = 63 watts Which is approximately .006 % of the total 1 Megawatt load. Why do we use high voltage for long distance transmission lines? Answer: To minimize the amount of transmission line losses. Question: What is the large white “plume” that exits the stacks? Remember the coal analysis: Carbon 55.8% Answer: Hydrogen (H2) 4.6 % Nitrogen (N2) 1.35 % Moisture !!! Sulfur (S) 0.25 % Ash 5.4 % Oxygen (O2) 7.8% Moisture 24.8 % Total: 100% Our coal contains almost 25 % moisture by weight. As the moisture in the flue gas cools as it leaves the stack, it condenses into a visible plume. This is the same as seeing your breath on a cold winter day! Let’s take a look at a 400 MW steam turbine – generator. If you wanted to use a diesel engine to replace the steam turbine, how big of an engine would you need (Horsepower)? 400 MW’s = 400,000 Kilowatts = 400,000,000 watts 1 Horsepower = 746 watts 400,000,000 watts / (746 watts / HP) = 536,193 HP Questions ? Who is Alliant Energy? Serve over 1 million electric and over 500,000 natural gas customers Headquartered in Madison, WI with Corporate Offices in Cedar Rapids and Dubuque, IA - Nearly 5,000 employees –15 power plants Where are Alliant Energy’s Customers? Iowa Wisconsin Southern Minnesota Getting started Education Requirements: Many positions require the minimum of a high school diploma or GED, and a clean driving record Some highly specialized areas require training at a community college, while others like engineers require a 4-year degree Job Skills: Other important items: Course work in math, science, and technology A curiosity about how things work and how to solve problems The ability to safely operate equipment and use safety gear A cooperative attitude Strong listening skills and the ability to understand and meet customer needs A positive safety attitude. Our actions not only affect our own safety but the safety of our fellow employees and the public. Initial drug and alcohol testing as well as random testing during employment. What are the most common plant jobs? Maintenance Technician and Equipment Operator If you enjoy working with your hands, have good hand-eye coordination, like solving problems, and are comfortable using math, these jobs may interest you. High school courses in electronics, algebra, trigonometry, and physics Community college coursework in electro-mechanical technology/welding Related work experience Talk to your guidance counselor Paid apprenticeship Starting hourly wage of $26 Advancement opportunities What does an engineer do? An engineer uses scientific and mathematical knowledge to solve problems. There are many types of engineers, and all require a fouryear degree. You must select the type of engineering you want to go into when you enter college. Mechanical Engineer Electrical Engineer Civil Engineer Chemical Engineer • Starting salary of $55,000 • Advancement opportunities Other Careers at Alliant Energy Information Technology Accounting Finance Communication Environment Safety Supply Chain Get into energy & be part of a high-tech, high-growth industry! Check out the Get Into Energy website, where you can find career profiles, watch videos, take skills tests, and learn more about careers in the energy field. www.getintoenergy.com Get Into Energy! Any Questions????