Alternative Energy - Understanding Alternative Fuels

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