ECE 476

POWER SYSTEM ANALYSISLecture 1

Alejandro D. Dominguez-Garcia

aledan@ILLINOIS.EDU

Material borrowed from Prof. George Gross

OUTLINE

The importance of electricity

The US electricity industry – past and present

Electricity generation

Nature of electric demand

The energy supply and demand picture

A brief overview of renewables

CRITICAL IMPORTANCE OF ELECTRICITY

Energy is the lifeblood of modern society

The importance of electricity is on the rise, e.g.,

electrification of transportation

Efficient and environmental electricity services

are key or the nation’s global competitiveness

Electricity is a $247 billion plus business annually

in the U.S.

U.S. ENERGY AND ELECTRICITY DEMAND

0

50

100

150

200

250

300

1980 1990 2000 2004 2010 2020 2030

CO2 emissionselectricity use

energy use

1980 = 100%

historical forecast

A VIEW OF THE POWER GRID

“I worked on aerospace problems for many years before converting to power systems, and, in my opinion at least, power problems are tougher in many respects....The number of variables [in a power system] is huge, and many types of uncertainties are present....Few if any aerospace problems yield such a challenging set of conditions.”

– Fred. C. Schweppe, 1970

Fred C. Schweppe (1934-1988)Professor of Electrical Engineering, MIT US Power grid

IMPACTS OF ELECTRICITY

The National Academy of Engineering, the U.S.’s

most prestigious collection of outstanding

engineers, named electrification – the

development of the vast networks of electricity

that power the world – the most important of the

twenty engineering achievements that have had

the greatest impact on the quality of life in the

twentieth century

IMPACTS OF ELECTRICITY

Electricity ranked ahead of the automobile,

airplane, safe and abundant water, electronics,

computers and space exploration

The widespread electrification implemented in

the twentieth century gave us power for our

cities, factories, farms and homes, forever

changing the lives of people

OUTLINE

The importance of electricity

The US electricity industry – past and present

Electricity generation

Nature of electric demand

The energy supply and demand picture

A brief overview of renewables

Commercial use of electricity began in the late

1870’s with the development of arc lamps for

street lighting and lighthouse illumination

The first complete electric power system,

comprising a generator, cable, fuse meter and

loads, is considered to be Edison’s Pearl Street

Station in New York in 1882

DC system with a DC generator supply

59 customers in a 1 mile radius area

THE BEGINNINGS

1882 EDISON POSTER ON ELECTRIC LIGHTING

You can find this plate in the washrooms of the Courier Café in downtown Urbana.

THE BEGINNINGS

Actually, George Roe had founded in 1879 an

electric company in San Francisco, which later

became part of PG&E

the first plant in the nation to offer central

station electric service to the public

two brush arc-light dynamos supplied 21 lights

for service from sundown to midnight –

Sundays and holidays excluded – for $ 10 per

lamp per week

Frank Sprague developed electrical motors in 1884;

within a short time, he incorporated them into the

electricity system

The major limitations of DC systems became

apparent by 1886:

ability to deliver power over only short

distances

need for high voltages for longer distance

transmission; such voltages were too high for

generation and consumption

MAJOR DEVELOPMENTS

Gaulard and Gibbs developed the transformer and

AC transmission, the forerunners of the AC

transmission systems in use today

George Westinghouse bought U.S. rights

immediately to the technological developments of

Gaulard and Gibbs

In 1889, the first AC transmission line in North

America was put into operation between

Willamette Falls and Portland – a single phase

4–kV 21–km line

MAJOR DEVELOPMENTS

A major important development was Tesla’s

invention of induction motors and polyphase

systems

Westinghouse purchased the rights to Tesla’s

inventions on AC motors, generators,

transformers and transmission systems

Westinghouse was instrumental in the

construction of the basis of today’s AC grid

MAJOR DEVELOPMENTS

AC won out over DC because

the ease of transformation of voltage levels

thereby providing the flexibility of using

different voltage levels for generation and

transmission consumption

the increased simplicity of AC over DC

generators

the increased simplicity and lower costs of AC

over DC motors

AC replaced DC over a very brief time period

MAJOR DEVELOPMENTS

In 1893, the first three–phase transmission line in

North America went into service; it was a 2.3–kV,

12–km line in Southern California

Niagara Falls was connected to Buffalo – a 30–km

distance – using AC since DC was not practical

MAJOR DEVELOPMENTS

Pressures to transmit larger amounts of power

over larger distances led to higher voltages early systems: 12, 44 and 66 kV (RMS line–to–

line) 1922: 165 kV 1923: 220 kV 1935: 287 kV 1953: 330 kV 1965: 500 kV 1966: 735 kV (Hydro Quebec) 1969: 765 kV (American Electric Power)

TECHNOLOGICAL DEVELOPMENTS

Standardization of voltage levels led to voltage

classifications

115, 138, 161 and 230 kV are high voltage ( HV )

345, 500 and 765 kV are extra high voltage ( EHV )

The development of mercury arc valves in the

early 1950’s makes HVDC economical in specific

cases: transmission of larger blocks of power over

longer distances

TECHNOLOGICAL DEVELOPMENTS

Eventually, the various frequencies in use – 25,

50, 60, 125 and 133 Hz – standardized to 60 Hz in

North America; there are many parts of the world

where the frequency is 50 Hz today

DC becomes economic over AC for distances

greater than

500 km for overhead lines

50 km for underground/submarine cables

TECHNOLOGICAL DEVELOPMENTS

Legend

Cooperatives

Federal

Independent Transmission Companies

Other Public Power

Shareholder-Owned

ELECTRIC TRANSMISSION LINES IN THE U.S.

Copyright 2003 Edison Electric Institute. Source: POWERmap, © Platts, a Division of the McGraw Hill Companies. 20

THE ELECTRIC POWER SYSTEM

21

INDUSTRY STRUCTURE

Brutal and inefficient competition was rife in

electricity

24 central station power companies were

established in Chicago between 1887 and 1893

exhaustive duplication and fierce competition

led to high costs

INDUSTRY STRUCTURE

Samuel Insull built a monopoly over all central

station production in Chicago and is considered

the father of the regulated monopoly:

“exclusive franchises should be coupled with

the conditions of public control, requiring all

charges for services to be based on a cost

plus a reasonable profit”

In 1907, New York and Wisconsin set up commis–

sions to regulate electricity

customers

self-generation

Independentpower producers

THE VERTICALLY INTEGRATED UTILITY INDUSTRY STRUCTURE

Generation

Transmission

Distribution

Customer Service customer service

distribution

transmission

generation

COMPETITION IN THE GENERATION MARKET

The 1978 Public Utility Regulatory Policies Act (PURPA) unleashes competition through the introduction of qualifying facilities (QFs)

PURPA mandates each investor–owned utility to purchase power at avoided cost from QFs located in its service territory

Implementation of PURPA was left to individual states resulting in non-uniform implementations

The once fledgling private power enterprises constitute today a multibillion dollar industry whose role in the electricity business is critically important

Source :Energy Information Administration, Existing Electric Generating Units in the United States, Source :Energy Information Administration, Existing Electric Generating Units in the United States, 20052005

ENERGY SOURCES OF NON UTILITY GENERATION (NUG) CAPACITY

coal 17.8%

nuclear 8.3%

oiloil 5.75.7%%

otherother 3.13.1%%

hydrohydro 2.12.1%%

windwind 1.71.7%%

waste waste 1.51.5%%geothermal geothermal 0.70.7%%

natural gas natural gas 59.059.0%%

INCREASING ROLE OF NUG

Source : EIA, Net Generation by Energy Source by Type of Producer, 2006

non-utility utility

bill

ion

k

Wh

0

1000

2000

3000

4000

5000

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

120.76

0.00116.87

0.730

20

40

60

80

100

140

residential

commercial

industrial

other

U.S. ELECTRICITY CUSTOMERS

total consumers = 138.4 million

mill

ion

co

nsu

mer

s

Source : Energy Information Administration, Form EIA-861, “Annual Electric Utility data” released November 2006

120

US ELECTRICITY SALES IN 2005

total sales: 3,660 million MWh

total revenues: $ 228 billion

residential1,356 TWh

industrial1,275 TWh

commercial1,019 TWh

other7.5 TWh

residential$ 128 billion

industrial$ 110 billion

commer-cial $ 58

billion

other$ 0.6 billion

Source : Energy Information Administration, Form EIA-861, “Annual Electric Utility data” released November 2006

9

884

219

2,015

0

1000

2000

U.S. ELECTRIC UTILITY INDUSTRY

Source : Energy Information Administration, Form EIA-861, “Annual Electric Power Industry Report,” November 2005

total number = 3,285

investor

owned coope-

rativefederal

publicly

owned

nu

mb

er o

f en

titi

es

power

marketer

158