How do you use energy?

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24 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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How do you use energy?


Your life



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?


READ: U.S. DOE Energy Perspectives

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

Energy Use (quadrllion Btus)

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)

𝑬𝒊𝒄𝒊 𝒏𝒄𝒚
=
𝑶 𝒑

𝑬𝒏 𝒓𝒚
𝑰𝒏𝒑

𝑬𝒏 𝒓𝒚

< 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,
your 100 watt bulb costs about 1.7 cents to
operate for an hour

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


How can you decrease your cost?

Electricity

(electric)

Light

(radiant)

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


Phantom loads

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





Your home town (or school)




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?

Further reading


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/