Energy101_Module_18.pdf

8/14/2019 Energy101_Module_18.pdf

1/16

Energy 101Energy Technology and PolicDr. Michael E. WebberThe University of Texas at Austin

Module 18: Electricity I -- Overview


2/16

As a Reminder, Electricity is

a Form of Secondary Energy

Primary energy:original/unconverted fuel sources

!petroleum

!natural gas

!coal

!biomass

!hydroelectric, wind, solar,

Secondary energy:converted/stored en

!electricity

!hydrogen

!pumped hydroelectric


3/16

Need to Keep Track of Units

By convention

!BTU for fuels and thermal energy

!kWh for electrical energy

Power is important for electricity

!Rate of demand, load, generation...

!Watts (W), kiloWatts (kW), megaWatts (MW), gigaWatts (GW),...

!Horsepower (hp)


4/16

Electricity Is A Valuable Fuel

Electricity Enables Multiple End Use Functions:!Motion:The vast preponderance of all electricity is for electric motors

!Heat:Electric resistance heaters have >99% efficiency

!Information:Electricity enabled the digital age

Societies electrify over time!For cost, quality, convenience, and cleanliness

!Affluent people/societies prefer electricity


5/16

Is Electricity Expensive or Affordabl

Petroleum:

!$100/bbl

!5.8 MMBTU/bbl

!$16/MMBTU

Natural Gas:

!$2.50/MMBTU

Electricity:

!$25/MWh

!$0.025/kWh

!$0.10/kWh (r

!1 kWh = 3412 BT

!$7.35/MMBT

!$29.30/MMB

Source: Bloomberg, 2/14/2012

While electricity is expensive per BTU, the relatively hi

of electrical devices usually compensates for th


6/16

Electricity Prices Vary By Sector

and Customer Class

0

4

8

12

Residential Transportation Commercial Industr

ElectricityPrice

[/kWh(Nominal)]

2011 U.S. Average Retail Price of Electricity by Sector

Source: U.S. Energy Information Administration / Annual Energy Review 2011 Graphic: Michael E. Webber, The University of Texas at Austin


7/16

Net Generation Is Approximately 4,100

Electric Power Sector3,955

2011 U.S. Net Use Generation to End Use Flow [Billion kWh]Source: U.S. Energy Information Administration / Annual Energy Review 2011 Graphic: Michael E. Webber, The University of Texas at Austin

Retail Sales

3,726Total End Use

3,856Total Net Generation4,106

Re

Com

In

Commercial & Industrial 151Imports 52

Losses & Unaccounted 287

Dire

Tran

Exports 15


8/16

Consumption Has Leveled For Industry,

Has Been Growing For Residential/Comm

0

0.5

1.0

1.5

1951 1955 1959 1963 1967 1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2

AnnualElectricity[TrillionkWh]

Year

Michael E. Webber

19512011 U.S. Electricity Sales by SectorSource: U.S. Energy Information Administration / Annual Energy Review 2011 Graphic: Michael E. Webber, The University of Texas at Austin


9/16

Residential Use is 39% of Overall Consu

Space Cooling

Lighting

Water Heating

Refrigeration

TVs

Space Heating

Clothes Drying

PCs

Fans & Pumps

Cooking

Dishwashers

Freezers

Clothes Washers

Other Uses

0 100 200

Billion Kilowatthours

Electricity End Use

[3,886 billion kWh]

Residential39%

Commercial, Industrial

& Transportation

61%

Residential End Use

[1,451 billion kWh]

Michael E. Webber

2010 U.S. Residential Electricity Consumption by End-UseSource: U.S. Energy Information Administration / Annual Energy Review 2011 Graphic: Michael E. Webber, The University of Texas at Austin


10/16

Demand for Electricity has Diurnal a

Seasonal Variation: Factor of 3 Over

Load is anofor instantane

demand

!Load [MW], Dema

Air conditioni

peak demand

!Less efficient at h

temperatures

Electric Reliability Council of Texas


11/16

A Typical Energy Supply Curve Uses Coa

Nuclear for Baseload and Natural Gas fo

Electric Reliability Council of Texas


12/16

Electricity Generating Units (EGUs) a

Dispatched by Availability and Perform

High capacity factor sources that are harder to turn on anoffare used for baseload

!Steam cycle systems: coal, nuclear, geothermal, biomass,...

Sources that are easy to turn on/offare used for peaking

!Hydroelectric, natural gas combustion turbines

Other sources (wind, solar) must be squeezed in with the

!Wind power in Texas has an average capacity factor of ~20-35%


13/16

Total Installed Capacity is ~1,000 GW

Peak Load is 600700 GW

0

275

550

825

1,100

1986 1991 1996 2001 2006 2

ElectricityCapacity[GW]

Year

Michael E. Webb

19862011 U.S. Electricity Capacity and Seasonal Peak LoadsSource: U.S. Energy Information Administration / Annual Energy Review 2011 Graphic: Michael E. Webber, The University of Texas at Austin


14/16

Natural Gas Power Plants Comprise t

Majority of U.S. Peak Capacity

0

100

200

300

400

500

Natural Gas Coal Nuclear Hydroelectric Petroleum Wind Biomass Geothermal S

MillionKilowatts

M

2011 U.S. Electric Summer Capacity by SourceSource: U.S. Energy Information Administration / Annual Energy Review 2011 Graphic: Michael E. Webber, The University of Texas at Austin


15/16

There are Different Strategies

for Managing the Peak

Peak-shaving:Reducing peak demand!Remote-controlled ACs, hot water heaters, pool pumps, etc.

!Higher/real-time prices,

Peak-shifting:Move demand to another time of day

!Thermal storage: making ice or chilled water at night

!Potential energy storage: Pumped hydroelectric

!Electricity storage: Batteries, capacitors, flywheels

!Actually increaseselectricity consumption...


16/16

Dr. Michael E. Webber

Documents

Energy101_Module_18.pdf