How do you use energy?

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 Perspectiveshttp://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-Conditioning17%

Space Heating11%

HVAC Appliances5%

Kitchen Appliances

29%

Water Heating10%

Lighting10%

Home Electronics8%

Laundry Appliances

7%

Other Equipment3%

Electricity is 42% of home energy use

U.S. Total Residential Energy Use

0

5

10

15

20

25

1970 1980 1990 2000 2010Ene

rgy

Use

(qu

adrll

ion

Btu

s)

Direct UseDirect 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 ≠ ENERGYWork = Force x Distance (Joules)

Work = Energy

Power = Energy (J/s = Watts) Time

So Energy = Power x time (kWh)

What is ENERGY efficiency?

ProcessOutputInput

Other outputs (non-useful)

𝑬𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚=𝑶𝒖𝒕𝒑𝒖𝒕 𝑬𝒏𝒆𝒓𝒈𝒚𝑰𝒏𝒑𝒖𝒕 𝑬𝒏𝒆𝒓𝒈𝒚

< 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)

ProcessUseful Energy OutEnergy in

Other energy outputs (non-useful) (e.g., heat)

Focus on Increased efficiency

Insu

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imp

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Fuel effi

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Effi

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Cellu

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Su

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Fuel effi

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Carb

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Win

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Cost

of

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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 combustionFossil

fuelturbineThermal

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 CO2 emissions

Coal75% Carbon30,000 kJ/kg1000 kg

CO2

?? kg/MWh

Electricity?? MWh

Coal-fired Power Plant33.3% efficient

2.78 MWh

2750 kg CO2

990 kg CO2/MWh

IPCC Estimation Approaches• Tier 1:

– All C atoms in fuel eventually ends up as CO2

– CH4 and N2O 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 CO2 eq./energy value– Emission factors vary

• by fuel • technology used to consume fuel• therefore, by country, region

– Emission factors from IPCC and other sourceshttp://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_1_Ch1_Introduction.pdf

CO2 emissions - various fuels

0 20 40 60 80 100 120

Natural GasLiquefied petroleum gas

PropaneAviation gasoline

Automobile gasolineKerosene

Fuel oilWood and wood waste

Coal (bituminous)Coal (subbituminous)

Coal (lignite)Coal (anthracite)

CO2 emitted (g/106 J fuel combusted)  

What are the consequences of fuel choice on GHG emissions?

Electricity from Coal

HydroelectricityNuclear Electricity ?

Example – CO2 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 CO2 emissions– http://epa.gov/powerprofiler

Your home town (or school) East Hampton NY 11937 Chicago IL 60601Boston MA 02129 Kansas City MO

64101Seattle WA 98101 Atlanta GA 30301Los Angeles CA 90001 Denver CO

80012Columbus 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 carElectricity

Use

Coal from mining

Air Emission

s

Air Emission

s

UseWater

Spills toWater/Soil

UseWater

Hydroelectricity

Transportation

Fuel Use

Air Emissions

and processing

Nuclear fuel mining Nuclear

Electricity

UseWater

UseWater

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 NYEnergy 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 CO2 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/