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

Gravitational
it's pulling cars, heating up the

Chemical

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

Petroleum
Natural Gas Coal

39.4
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
1.6
Nuclear Hydro
Biom ass/biofuel

Petroleum Natural Gas Coal Nuclear
Biomass/biof uel

US Electrical Production
Geothermal Solar Wind Petroleum Natural Gas

Hydro
Geothermal Solar Wind

6.6
0.37 0.01 0.16

Coal

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

20

66% Imported

10

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.

Coal
 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

Oil
 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

Nuclear
 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

Hydroelectric Biomass

3% 4%

Solar Heating
Wind

0.50%
0.30% 0.20%

Biomass

Geothermal

Solar Voltaic
Biodiesel

0.20%
0.04%

Hydroelectric
 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

Biomass
 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

E
H2O

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

Fuels

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.

Questions?

Thank s


								
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