ECE 333 Green Energy Systems Lecture 6: Power System History and Operations Dr. Karl Reinhard Dept. of Electrical and Computer Engineering University of Illinois at Urbana-Champaign reinhrd2@illinois.edu

Announcements Be reading Chapter 3 Quiz today on Hmwk 2 Homework 3 posted Quiz on Thursday Feb 8 Material from Power Systems history and operations will be covered on exams Short answer or true/false Drawn from homework questions

To Know: Power Systems History T. Edison and G. Westinghouse advocated AC and DC power systems respectively. Outline their reasoning (pros and cons for each). Why did AC become the standard? What was Samuel Insull's electric power industry insight and how did it lead to public utility commissions? What led to the PUHCA of 1935 and what was the Act's aim? What led to the PURPA of 1978? What were the Act's two key provisions? How did the Act impact the renewable energy industry? What were the major provisions of the EPAct of 1992? What was the main thrust common to PURPA and EPAct? What were the main provisions of EISA of 2007 ?

To Know: Power Systems Operation What legislation institutionalized the term “Smart Grid?” What were the major objectives / provisions relating to “Smart Grid” Outline the concept of balancing energy supply and demand. Describe normal load fluctuations and the affect that energy imbalances have on system frequency. Explain the roles that "must run – baseload", "load- following","peakers", “reserves”, and "re-newable" power plants have in the power system. Give examples of each. What role does "demand response" play? Describe how grid instabilities occur.

History – Early Utilities First practical electricity uses began with the telegraph (~ Civil War) and then arc lighting in the 1870’s (Broadway, the “Great White Way”). Central stations for lighting began in 1882 – dc (Edison) system, but stations transitioned to ac (Westinghouse) within several years. Chicago 1893 World’s fair had an important early electricity demonstration High voltage ac appeared in the 1890’s w/ the Niagara power plant transferring electricity to Buffalo; also 30kV line in Germany Frequency standardization in the 1930’s

History – Large Utilities & Regulation Electric usage spread rapidly, particularly in urban areas. Samuel Insull (had served as Edison’s secretary) played a major role in the development of large electric utilities and their holding companies Public Utilities Holding Company Act (PUHCA) of 1935 essentially broke up inter-state holding companies This gave rise to electric utilities that only operated in one state PUHCA was repealed in 2005 For most of the 20th Century electric utilities operated as vertical monopolies

History – Vertical Monopolies Within a particular geographic market, the electric utility had an exclusive franchise Generation Transmission Distribution Customer Service In return for this exclusive franchise, the utility had the obligation to serve all existing and future customers at rates determined jointly by utility and regulators It was a “cost plus” business 6

History – Vertical Monopolies (cont) Within its service territory each utility was the only game in town Neighboring utilities functioned as colleagues (rather than competitors) Utilities gradually interconnected their systems so by 1970 transmission lines crisscrossed North America, with voltages up to 765 kV Economies of scale reduced electricity rates, so most were happy… but all good things come to an end Customers could not have on-site generation and remain connected to the utility 7

History – Utilities 1970’s 1970’s brought inflation, increased fossil-fuel prices, supply shortfalls (Arab oil embargo), calls for conservation, and growing environmental concerns  Electricity rates began to climb U.S. Congress passed Public Utilities Regulator Policies Act (PURPA) in 1978, which mandated utilities purchase power from independent generators located in their service territory (modified 2005) PURPA introduced competition, but implementation varied greatly state to state Allowed customers to build on-site generation & be grid connected Required Utilities to purchase from qualifying facilities (QFs) Gave birth to the electric side of renewable energy industry 8

History – PURPA and Renewables PURPA* enabled the significant small producer renewable energy production growth in the 80’s: Req’d utilities to purchase from qualifying facilities (QF): < 80 MW and 75% renewable energy source wind, solar, geothermal, etc. During the 1980’s, California added ~ 6000 MW of QF capacity : 1600 MW wind, 2700 MW geothermal, and 1200 MW biomass In the 90’s, 10-year QFs contracts (@$60/MWh in 80’s) were no longer competitive (profitable) @ $30/MWh in 90’s …  many sites were retired or abandoned * Public Utilities Regulator Policies Act (PURPA) 1978

History – Abandoned PURPA Wind Farm – Hawaii Source: Prof. Sanders

History – Electricity Prices, ‘60-2014 Source: EIA, Monthly Energy Review, https://www.eia.gov/todayinenergy/detail.php?id=20372, accessed 30 Jan 18

History– 1990’s & 2000’s Major opening of industry to competition occurred as a result of National Energy Policy Act of 1992 (EPAct of 92) Goal was to set up true competition in generation Mandated “nondiscriminatory” access to the Hi Volt transmission Major electric power industry restructuring – breaking industry into 3 segments – Generators, Transmitters, Distributers EPAct of 2005 repealed PUHCA; modified PURPA Energy Independence and Securty Act of 2007 (EISA 2007) aimed to promote the production of clean renewable fuels, the efficiency of products, buildings, and vehicles, research on and deployment of greenhouse gas capture and storage options 12

History – IL Energy Markets (’97-’07) Two main electric utilities in Illinois are ComEd and Ameren In ’97, vertically integrated & IL electricity rates in highest 10 among the states In deregulated markets, utility owns the infrastructure & distributes power, but Alternate Retail Electricity Suppliers (ARES) buy it from the generators and sell it to customers. In ’97, IL law changed – restructuring Electric Power industry – forcing competition; full implementation in ’07. In 2014, there were 87 ARES operating in IL – IL power rates in 2013 were in lowest 10 among the states….. Avg $0.099 / kWh

State Electric Rate Variations 2017 https://www.elitefixtures.com/blog/post/2652/compare-electricity-rates-state-elitefixtures/, accessed 30 Jan 18 14

Urbana Electric Rates 2018 https://www.electricitylocal.com/states/illinois/urbana/ , accessed 31 Jan 18 15

Illinois 2012: Municipal Aggregation Urbana and Champaign residents started seeing substantially lower electric bills as a result of municipal aggregation This was approved by a 2-1 margin in 3/2012 referendum Municipal aggregation means all residents of a community get their electricity from a third party supplier chosen by the city (as opposed to the local utility) unless they specifically opt out. They still get bills from Ameren, and do pay an electricity delivery charge (about 30 to 40% of total bill) Recently Ameren rates have dropped, making third party options less attractive

U.S. Electricity Generation by Type BkWh/Yr 4000 3000 2000 1000 Source: EIA https://en.wikipedia.org/wiki/Electricity_sector_of_the_United_States#/media/File:US_Electricity_by_type.png Accessed 31 Jan 18

The Rise of Renewables: Wind Source: AWEA Wind Power Outlook 4th Qtr, 2017 https://www.awea.org/4q2017, accessed 31 Jan 18

U.S. PV Electricity Installed Capacity & Generation Recent Growth in Solar U.S. PV Electricity Installed Capacity & Generation Source: DoE 2016 Renewable Energy Book https://www.nrel.gov/news/press/2018/data_book_shows_continued_growth_of_renewable_electricity.html accessed 31 Jan 18

Recent Solar Installation Costs NREL PV system cost 2010–2017summary (inflation adjusted) https://www.nrel.gov/news/press/2017/nrel-report-utility-scale-solar-pv-system-cost-fell-last-year.html accessed 1/31/18

The Smart Grid EISA 2007, Title 13 Introduced “Smart Grid” w/ key provisions: Use of digital information and control techniques Dynamic grid optimization with cyber-security Deployment of distributed resources Customer participation and smart appliances Integration of storage including Plug-in Hybrid Electric Vehicles (PHEVs) Interoperability standards development https://en.wikipedia.org/wiki/Energy_Independence_and_Security_Act_of_2007 accessed 31 Jan 18

Smart Grid Perceptions (Some of Us Like the Term “Smarter”)

States Setting “Renewable Portfolio Standards” Source: http://www.dsireusa.org/ accessed 31 Jan 18

Power System Operations: One-line Diagrams Most power systems are balanced three phase systems. A balanced three phase system can be modeled as a single (or one) line. One-lines show the major power system components, such as generators, loads, transmission lines. Components join together at a bus. 24

Substation Bus 25

Power System Time Frames Next few slides will consider the power flow (quasi-steady) time frame Image source: P.W. Sauer, M.A. Pai, Power System Dynamics and Stability, 1997, Fig 1.2, modified

PowerWorld Simulator Three Bus System Load with green arrows indicating amount of MW flow Note the power balance at each bus Used to control output of generator Direction of arrow is used to indicate direction of real power (MW) flow 27

Power Flow A common power system analysis tool is the power flow It shows how real and reactive power flows through a network, from generators to loads Solves sets of non-linear equations enforcing "conservation of power" at each bus in the system (a consequence of KCL) Loads are usually assumed to be constant power Used to determine if any transmission lines or transformers are overloaded and system voltages Educational version PowerWorld tool available at http://www.powerworld.com/gloversarmaoverbye

Metro Chicago Electric Network 29

Power Balance Constraints Power flow refers to how the power is moving through the system. At all times in the simulation the total power flowing into any bus MUST be zero! This is know as Kirchhoff’s law. And it can not be repealed or modified. Power is lost in the transmission system. 30

Power Balance Constraints Power flow refers to how the power is moving through the system. At all times in the simulation the total power flowing into any bus MUST be zero! This is know as Kirchhoff’s law. And it can not be repealed or modified. Power is lost in the transmission system. 31

Basic Power Flow Control Opening a circuit breaker causes the power flow to instantaneously (nearly) change. No other way to directly control power flow in a transmission line. By changing generation we can indirectly change this flow. 32

Transmission Line Limits Power flow in transmission line is limited by heating considerations. Losses (I^2 R) can heat up the line, causing it to sag. Each line has a limit; Simulator does not allow you to continually exceed this limit. Many utilities use winter/summer limits. 33

Overloaded Transmission Line 34

Interconnected Operation Power systems are interconnected. Most of North America east of the Rockies is one system, with most of Texas and Quebec being exceptions Interconnections are divided into smaller portions, called balancing authority areas (previously called control areas) Balancing authorities sometimes correspond to a single utility, but increasingly they include a large number of utilities. NERC Reliability Coordinators are charged with overseeing the reliable operation of the grid 35

NORTH AMERICAN INTERCONNECTIONS 36

NERC Reliability Coordinators Illinois is split, with the ComEd part in PJM, with the rest of the state in MISO Source: http://www.nerc.com/page.php?cid=5%7C67%7C206

Balancing Authority (BA) Areas Transmission lines that join two areas are known as tie-lines. The net power out of an area is the sum of the flow on its tie-lines. The flow out of an area is equal to total gen - total load - total losses = tie-flow 38

North American Balancing Authorities Source: http://www.nerc.com/AboutNERC/keyplayers/Pages/default.aspx

Area Control Error (ACE) The area control error is the difference between the actual flow out of an area, and the scheduled flow. Ideally the ACE should always be zero. Because the load is constantly changing, each utility must constantly change its generation to “chase” the ACE. MISO ACE| (in MW) from 9/19/12. At the time the MISO load was about 65GW https://www.misoenergy.org/MarketsOperations/RealTimeMarketData/Pages/ACEChart.aspx 40

Automatic Generation Control BAs use automatic generation control (AGC) to automatically change their generation to keep their ACE close to zero. Usually the BA control center calculates ACE based upon tie-line flows; then the AGC module sends control signals out to the generators every couple seconds. 41

Three Bus Case on AGC 42