World Energy Sources Chapter 8, section 8.1 Read pages (top half of page) and

Goals: Understand primary and secondary, renewable and non-renewable energy sources Understand primary and secondary, renewable and non-renewable energy sources Understand, interpret, and sketch Sankey diagrams Understand, interpret, and sketch Sankey diagrams Understand energy density of fuel sources and specific examples Understand energy density of fuel sources and specific examples Describe basic features of fossil fuel power stations as well as wind generators, and hydroelectric (solar power cells and nuclear power will come during/after our quantum and nuclear unit) Describe basic features of fossil fuel power stations as well as wind generators, and hydroelectric (solar power cells and nuclear power will come during/after our quantum and nuclear unit) Solve problems related to energy, energy density, and, specifically, wind power generation. Solve problems related to energy, energy density, and, specifically, wind power generation.

Energy Sources Primary Energy: Fuel in its initial form; one that has not been transformed prior to being used by a consumer Primary Energy: Fuel in its initial form; one that has not been transformed prior to being used by a consumer Some form of fossil fuel (chemical potential energy):Some form of fossil fuel (chemical potential energy): Coal Coal Crude oil Crude oil Natural gas Natural gas Wind (kinetic energy)Wind (kinetic energy) Converted to electricity (wind generator) Converted to electricity (wind generator) used to do work (windmill) used to do work (windmill)

Energy Sources Secondary Energy: Secondary Energy: Energy sources produced from primary energy sourcesEnergy sources produced from primary energy sources Electricity—most important secondary source Electricity—most important secondary source unleaded gasoline unleaded gasoline Hydrogen Hydrogen

THE primary source… Nearly all sources of energy are originally derived from the radiation from the sun in one way or another. Nearly all sources of energy are originally derived from the radiation from the sun in one way or another. Radiation from the sun is used in photosynthesis by plants Radiation from the sun is used in photosynthesis by plants Plants also remove carbon dioxide from the atmosphere, and are what is known as “Carbon stores” as a result. Plants also remove carbon dioxide from the atmosphere, and are what is known as “Carbon stores” as a result.

Renewable vs. Non-renewable Non-Renewable Energy Source: Non-Renewable Energy Source: The energy source will eventually be completely used up and will run out.The energy source will eventually be completely used up and will run out. Even if there is still some of the energy source left, it will not be cost-effective to use it, so it essentially has been “used up”Even if there is still some of the energy source left, it will not be cost-effective to use it, so it essentially has been “used up” Examples:Examples: Coal; oil; natural gas; nuclear materials Coal; oil; natural gas; nuclear materials

Renewable Energy Sources: Renewable Energy Sources: The source of the energy cannot be “used up”The source of the energy cannot be “used up” The source of the energy is replenished so that there is a relatively constant supply of the source.The source of the energy is replenished so that there is a relatively constant supply of the source. Examples:Examples: Solar power (photovoltaic cells) Solar power (photovoltaic cells) hydroelectric power hydroelectric power Wind; biofuels Wind; biofuels Tides and waves Tides and waves Renewable vs. Non-renewable

World energy consumption What do you predict would be the breakdown of the world’s energy copnsumption of the following fuels: What do you predict would be the breakdown of the world’s energy copnsumption of the following fuels: HydroelectricHydroelectric NuclearNuclear Natural gasNatural gas CoalCoal OilOil Other renewablesOther renewables How about the US? How about the US?

World energy consumption peak-energy-demand/

Energy Density Specific Energy Specific Energy The amount of energy that can be released per kilogram of fuelThe amount of energy that can be released per kilogram of fuel Units  J·kg -1Units  J·kg -1 Energy Density Energy Density The amount of energy that can be released per cubic meter of fuelThe amount of energy that can be released per cubic meter of fuel Units  J·m -3Units  J·m -3

Energy Densities of some common fuels (table on p. 311) Fuel TypeSpecific Energy / MJ·kg -1 Energy density / MJ·m -3 wood coal20-60(20-60) x 10 6 petrol (gasoline)4535 x 10 6 Natural gas (at 1 atm)553.5 x 10 4 Uranium (U-235)8 x x Deuterium (Fusion)3 x x Water falling through 100 m in a hydroelectric plant

Sample Problem 1 A fossil-fuel power station has an efficiency of 25% and generates 1200 MW of useful electrical power. The specific energy of the fossil fuel is 52 MJ·kg -1. Calculate the mass of fuel consumed each second. A fossil-fuel power station has an efficiency of 25% and generates 1200 MW of useful electrical power. The specific energy of the fossil fuel is 52 MJ·kg -1. Calculate the mass of fuel consumed each second.