# How do you use energy?

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24 Νοε 2013 (πριν από 4 χρόνια και 7 μήνες)

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How do you use energy?

How do you use energy?

Rank order the energy use by highest to lowest
amount.

Rank order them in GHG emissions

How do you use electricity?

http://www.eia.gov/emeu/aer/pdf/perspectives_2009.pdf

http://www.eia.doe.gov/energyexplained/index.cfm?page=us_energy_home

How we use Electricity

Per average household

Household Electricity

Consumption

Air
-
Conditioning

17%

Space Heating

11%

HVAC Appliances

5%

Kitchen

Appliances

29%

Water Heating

10%

Lighting

10%

Home Electronics

8%

Laundry

Appliances

7%

Other Equipment

3%

Electricity is 42% of home energy use

U.S. Total Residential Energy Use

0

5

10

15

20

25

1970

1980

1990

2000

2010

Direct Use

Direct Electricity Use

Electrical system energy losses

Grand Total

Source: Energy Information Administration/Monthly Energy Review December 2007; www.eia.doe.gov

Definitions

Energy:

A measure of the ability to do work.

Power:

The rate at which energy is used.

Key Point !

POWER
≠ ENERGY

Work

= Force x Distance (Joules)

Work

= Energy

Power

= Energy (J/s = Watts)

Time

So
Energy = Power x time

(kWh)

What is
ENERGY efficiency
?

Process

Output

Input

Other outputs

(non
-
useful)

𝑬𝒊𝒄𝒊 𝒏𝒄𝒚
=
𝑶 𝒑

𝑬𝒏 𝒓𝒚
𝑰𝒏𝒑

𝑬𝒏 𝒓𝒚

< 1.0

Light Bulb Energy Use

Consider a 100 watt light
-
bulb:

100 watts for one hour is 100 watt
-
hours or 0.1 kWh

Since 1 kWh costs approximately 17 cents,
operate for an hour

\$31/y if on 5 h/d; 365 d/y

How can you decrease your cost?

Electricity

(electric)

Light

Useable energy

Heat

(thermal
energy)

(not useful
energy)

Turn the light OFF

Replace bulb with CFL

Conservation

Efficiency

Focus on Efficiency

Less than 1/4 energy used in stove reaches food

Waste heat from US power plants could power the
Japanese economy

15% of energy in
gasoline
reaches wheels of a car

2.7 mpg increase in light vehicle fleet would
displace Persian Gulf imports

(Amory Lovins)

Process

Useful Energy Out

Energy in

Other energy outputs

(non
-
useful) (e.g., heat)

Focus on
Increased efficiency

Insulation

improvements

Fuel efficient

commercial vehicles

Efficient lighting

Efficient water heating

Cellulosic ethanol

Sugar cane ethanol

Fuel efficient vehicles

Carbon capture

new

coal power plants

Wind

Forestation

Solar

Switch

coal to

gas power plants

Carbon capture

retrofit coal power plants

Cost of Carbon Savings (Euros/tonne CO
2
)

50

0

-
50

-
100

-
150

(The Economist June 2, 2007)

What Makes our Energy Use
“Efficient”?

Most of energy input converted into most
useable form of output.

Our use of the process is “efficient”

The technological product itself is

efficient

The production of the energy we use

is efficient

What makes a system NOT
efficient

Heat related

Seals not shut tightly

Poorly insulated

Power / electronics

Not turned off when done

Conversion process creates un
-
useable forms of energy

Heat

Vibration

Noise

To fix inefficiencies

Change the user habits

Change to better technology

processing

Efficiency of electricity generation

Electricity is a Secondary Energy Source

Coal

electricity

home = very inefficient

Fossil fuel

combustion

Fossil

fuel

turbine

Thermal

energy

engine,

turbine

Mechanical

energy

Conversion to

electricity

electricity

Extraction

Energy Flows

Energy Efficiency of power plants:

Coal

30
-
46%

NG

33
-
53%

Residual Oil

35%

Biomass

32
-
40%

100 MJ

?? MJ

“Losses”

“Losses”

“Losses”

Did You Know?

A pound of coal supplies enough
electricity to power ten 100
-
watt
light bulbs for about an hour.

Estimating CO
2

emissions

Coal

75% Carbon

30,000 kJ/kg

1000 kg

CO
2

?? kg/
MWh

Electricity

??
MWh

Coal
-
fired Power Plant

33.3% efficient

2.78
MWh

2750 kg CO
2

990 kg CO
2
/
MWh

IPCC Estimation Approaches

Tier 1:

All C atoms in fuel eventually ends up as CO
2

CH
4

and N
2
O from IPCC default emission
factors that vary by technology and fuel

Tier 2: Region
-
specific Emission Factors

Primary
fuel X emission X equivalency

consumed

factor

factor (GWP)

= mass CO
2

eq./
energy value

Emission factors vary

by fuel

technology used to consume fuel

therefore, by country, region

Emission factors from IPCC and other
sources

http://www.ipcc
-
nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_1_Ch1_Introduction.pdf

CO
2

emissions
-

various fuels

0

20

40

60

80

100

120

Natural Gas

Liquefied petroleum gas

Propane

Aviation gasoline

Automobile gasoline

Kerosene

Fuel oil

Wood and wood waste

Coal (bituminous)

Coal (subbituminous)

Coal (lignite)

Coal (anthracite)

CO
2

emitted (g/10
6

J fuel combusted)

What are the consequences of
fuel choice on GHG emissions?

Electricity from
Coal

Hydroelectricity

Nuclear

Electricity

?

Example

CO
2

from Electricity

Questions:

How much GHGs do you generate with electricity use?

Does it matter where you live?

Explain Why or Why not

What can you conclude about New York State?

Procedure:

Explore fuels used and resulting CO
2

emissions

http://epa.gov/powerprofiler

East Hampton NY

11937

Chicago IL

60601

Boston MA

02129

Kansas City MO

64101

Seattle WA

98101

Atlanta GA

30301

Los Angeles CA

90001

Denver CO

80012

Columbus OH

43201

Honolulu HI

96801

Regional differences do matter

http://cfpub.epa.gov/egridweb/reports.cfm

-

summary tables
-

2005

U.S. Total

What is a lifecycle perspective?

Typical approach

Reduce environmental impacts in one
component

Create new and different environmental
impacts in another component

Better approach

Consider the whole systems rather than small
and isolated parts of a system

Electricity from
Coal

Electric Power
Transmission

Electric car

Electricity

Use

Coal

from mining

Air
Emission
s

Air
Emission
s

Use

Water

Spills to

Water/Soil

Use

Water

Hydroelectricity

Transportation

Fuel Use

Air

Emissions

and processing

Nuclear

fuel mining

Nuclear

Electricity

Use

Water

Use

Water

Petroleum Fuel

Fuel Use

LC GHGs vary by electricity fuel source

Coal Lifecycle Emission Factors

Coal Mining
and Cleaning

Coal Mining:
Non
-
Combustion
Emissions

Coal
Transportation
to Power
Plants

IGCC
Turbine

total for
coal

% at
combustion

CH4

1.09E+00

1.17E+02

8.74E
-
01

5.10E+00

1.24E+02

4.1%

N2O

1.36E
-
02

1.82E
-
02

5.10E+00

5.13E+00

99.4%

CO2

8.78E+02

7.56E+02

1.08E+05

1.10E+05

98.5%

(g/million Btu)

Emission Factors for NY

Energy Source

kg CO2

kg eCO2

per

Natural Gas

52.76

52.92

mmBtu

Wood Chips

14.43

155.46

short ton

Wood Pellets

14.43

155.46

short ton

Gasoline Fleet

8.71

8.93

gallon

Diesel Fleet

9.99

10.08

gallon

E85 Fleet

0.95

1.18

gallon

B20 Fleet

7.85

7.94

gallon

B100

9.46

9.55

gallon

Electricity (NY)

0.33

0.33

kWh

Air travel

0.77

0.78

mile

Clean Air Cool Planet
-

http://www.cleanair
-
coolplanet.org/toolkit/inv
-
calculator.php

Energy/GHG
-

Key Points

Energy demand and GHG emissions
continue to grow

US relies a great deal for generating
electricity on coal
-

(~50%) on the worst
fossil fuel in terms of CO
2

emissions

Efficiency of our energy systems low

What do we do to “fix” this?

Defining Priorities

What sector(s) should we focus on?

Why?

EPA

Energy and You

http://www.epa.gov/cleanenergy/energy
-
and
-
you/index.html

DOE

Energy and the Environment

http://www.eia.doe.gov/energyexplained/index.cfm?page=environment_
where_ghg_come_from

World Resources Institute

Climate Analysis Indicator Tool

http://cait.wri.org/