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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.

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Presentation on theme: "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."— Presentation transcript:

1 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



4 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

5 U.S. Total Residential Energy Use 0 5 10 15 20 25 19701980199020002010 Energy Use (quadrllion Btus) Direct Use Direct Electricity Use Electrical system energy losses Grand Total Source: Energy Information Administration/Monthly Energy Review December 2007;

6 Definitions Energy: A measure of the ability to do work. Power: The rate at which energy is used.

7 Key Point ! POWER ≠ ENERGY Work = Force x Distance (Joules) Work = Energy Power = Energy (J/s = Watts) Time So Energy = Power x time (kWh)

8 What is ENERGY efficiency? Process Output Input Other outputs (non-useful) < 1.0

9 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?

10 Electricity (electric) Light (radiant) Useable energy Heat (thermal energy) (not useful energy)

11 Turn the light OFF Replace bulb with CFL Conservation Efficiency

12 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)

13 Focus on Increased efficiency Insulation improvements Fuel efficient commercial vehicles Efficient lightingEfficient water heatingCellulosic ethanolSugar cane ethanolFuel efficient vehiclesCarbon capture – new coal power plants WindForestationSolar 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)

14 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

15 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

16 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 Extraction Energy Flows Energy Efficiency of power plants: Coal 30-46% NG 33-53% Residual Oil 35% Biomass 32-40% 100 MJ ?? MJ “Losses” Did You Know? A pound of coal supplies enough electricity to power ten 100-watt light bulbs for about an hour.


18 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

19 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

20 CO 2 emissions - various fuels 020406080100120 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)

21 What are the consequences of fuel choice on GHG emissions? Electricity from Coal Hydroelectricity Nuclear Electricity ?

22 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 – Your home town (or school) East Hampton NY 11937Chicago IL60601 Boston MA 02129Kansas City MO 64101 Seattle WA 98101Atlanta GA30301 Los Angeles CA90001Denver CO 80012 Columbus OH43201Honolulu HI96801

23 Regional differences do matter

24 - summary tables - 2005 U.S. Total

25 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

26 Electricity from Coal Electric Power Transmission Electric car Electricity Use Coal from mining 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

27 LC GHGs vary by electricity fuel source

28 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+001.17E+028.74E-015.10E+001.24E+02 4.1% N2O 1.36E-021.82E-025.10E+005.13E+00 99.4% CO2 8.78E+027.56E+021.08E+051.10E+05 98.5% (g/million Btu)

29 Emission Factors for NY Energy Sourcekg CO2kg eCO2per Natural Gas 52.7652.92mmBtu Wood Chips 14.43155.46short ton Wood Pellets 14.43155.46short ton Gasoline Fleet 8.718.93gallon Diesel Fleet 9.9910.08gallon E85 Fleet 0.951.18gallon B20 Fleet 7.857.94gallon B100 9.469.55gallon Electricity (NY) 0.33 kWh Air travel 0.770.78mile Clean Air Cool Planet -

30 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?

31 Defining Priorities What sector(s) should we focus on? Why?

32 Further reading EPA –Energy and You – DOE –Energy and the Environment – where_ghg_come_from where_ghg_come_from World Resources Institute –Climate Analysis Indicator Tool –

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