Alternative Energy - Understanding Alternative Fuels by RG

VIEWS: 253 PAGES: 27

									Alternative Energy?
Understanding Alternative fuels and the challenges of supplying future energy needs

Different Types of Energy
Kinetic: doing work Potential: ready to do work

it's pulling cars, heating up the


surrounding air, and giving off light Compressive

World Energy Consumption
 Hydrocarbon Fuels (Oil, Coal, Natural Gas) make up 86% of total world energy production.
 Current World Consumption:

450 QUAD
 1 BTU = 1050Joules  1 QUAD = 1015 BTU  1 QUAD = 290 Billion Kilowatt Hours

US Energy Consumption

 The US accounts for approximately 100 Quads of total US energy consumption  US share of total energy is falling as industrialization worldwide continues. Asia is currently the fastest growing.

US Energy Demand
Source % of Total Energy Demand
Total US Energy Consumption By Type
Biomass biofuel Geothermal Hydro Wind Nuclear Coal Petroleum Solar

Natural Gas Coal

23.9 22.6

Nuclear Biomass/biof uel Hydro Geothermal Solar Wind

8.0 2.9 2.76 0.32 0.07 0.06

Natural Gas

US Electrical Usage
Source % of Electrical Demand 3.4 16.9 51.2 20.7
Nuclear Hydro
Biom ass/biofuel

Petroleum Natural Gas Coal Nuclear
Biomass/biof uel

US Electrical Production
Geothermal Solar Wind Petroleum Natural Gas

Geothermal Solar Wind

0.37 0.01 0.16


US Transportation Sector Energy Demand and Imports
50 44 Quads 40 2.0% Annual Growth Rate 30 27 Quads

US Transportation Sector Energy Consumption (quads)

79% Imported


66% Imported


0 2001 2025

Transportation Energy
 Roughly 25% of US energy consumption comes from transportation.  Transportation includes personal transportation (Gasoline) and commercial (Diesel, Kerosene, Fuel Oil)  The overwhelming majority of this energy comes from petroleum products. (Small contributions from Natural Gas and Biodiesel)

Non Renewable energy sources
    Coal Oil Natural Gas* Nuclear*

*These sources are normally listed as non-renewable although they tend to be very clean.

 Primary Source of electrical generation in the United States  Fastest growing Electrical Source on the planet.  Advantages:
 28.9MJ/kg (vs 141MJ/kg for H2)

 Disadvantages:
 Smog/Pollution  Coal Mining

 40% of all energy consumption  Refined for plastics and other consumer goods  Advantages  Disadvantages

Natural gas
 Light Hydrocarbons that occur much more frequently than Oil.  Used for Cooking and Heating  Advantages
 Light Weight  Cheap  Clean Burning

 Disadvantages
 Greenhouse Gas  Limited Distribution

 Uses process of nuclear decay to generate heat  Accounts for 7% of Energy production  Advantages
 Cleanest form of energy production in common use  Highly efficient

 Disadvantages
 Nuclear Waste products can remain hazardous for millions of years  Nuclear accidents pose the threat of rendering areas hazardous for decades  By products can be used to create WMD

Renewable Energy
         Hydroelectric Biomass Solar Heat Solar Voltaic Biodiesel Wind Geothermal Tidal Hydrogen

What does 7% Renewable mean?

Solar Voltaic Geothermal Biodiesel Wind Solar Heating

Hydroelectric Biomass

3% 4%

Solar Heating

0.30% 0.20%



Solar Voltaic


 Rotating a magnetic field within a set of metal coils can induce an electric field.  Electric motors are electric generators operating in reverse.  Most common form of electrical production

 Credited to Alessandro Volta in 1800  Based on charge resulting from different reactivity's in acid.

Chemical Potential Energy
H2 + ½ O2  H2O + Energy
ΔH = 285.83 kJ/mole
Chemical P.E.

H2 + ½ O2


Chemical Potential Energy to Thermal Energy

H2 + 1/2O2

H2O + Heat

Fuel Cell
 Similar to chemical cell with one significant difference: No chemical breakdown of anode or cathode.  First discovered in 1836

Chemical Potential Energy to Electric Energy???
H2 + 1/2O2 H2O + Heat
Mechanical Energy

For each conversion, we will lose energy!!!

Electrical Energy

How Fuel Cell Works?
Electrolyte Membrane

O2 from Air

Anode: H2  2H+ + 2e-

Cathode: ½ O2 + 2H+ + 2e-  2H2O Net: H2 + ½ O2  2H2O + Energy Exhaust


Electrical Energy Much Higher Efficiency “Cold Combustion Reaction” • Electrochemical cell converts chemical energy of fuels into electrical energy • In principle, same as a battery  But chemical energy is continually replenished

Energy Density

Energy Density of Some Materials (KHW/kg) Gasoline --------------> 14 Lead Acid Batteries ----> 0.04 Hydrogen ---------------> 38 Compress Air ------------> 2 (per meter3)

Sources of Hydrogen
 Hydrogen is highly reactive, and thus must be separated through other means. Some sources are:
    Water Methane Petroleum Biomass

Potential Problems
 High pressure, volitile gas  Fuel Cells require precious metals  Manufacturing process does not eliminate need for fossil fuels.


Thank s

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