Energy Production

Basic Processes Electromagnetic Induction: Transforms mechanical energy into electrical energy Electrochemical Cells: Using chemical reactions to transfer electrons through a circuit Photoelectric Cells: Direct conversion of light into electricity at the atomic level through the photoelectric effect.

Electromagnetic Induction A turbine is moved by steam, water or wind. The turbine moves magnets near copper wires which stimulates the flow of electrons in the wire = current of electricity. Video

Energy Sources for Electromagnetic Induction

Fossil Fuels: Fuels: Coal, Oil, Natural Gas Pro: Infrastructure already exists Technology if finely tuned – fairly efficient Cons: Non-renewable – running out Air quality Environmental impact of mining and drilling Acid mine drainage Oil spills Deforestation and habitat destruction

Hydrofracking Hydrofracking Pro Hydrofracking Con

Biomass Burning of wood, grass or peat Pros: Carbon neutral Renewable Can use waste materials from agriculture Cons: Air pollution Land used for fuel rather than food

The story of peat

Nuclear Reaction Material: Uranium 235 Mined and Refined to make it more concentrated. Placed in the reaction chamber and hit with neutrons. Neutrons break the uranium atoms apart (fission) releasing large amounts of energy and more neutrons.

The energy is used to heat water to make steam to turn a turbine to make electricity. The neutrons break apart more atoms causing a chain reaction (super critical point). The reaction is kept in check by the control rods which are lowered into the reaction core to absorb the neutrons. Without the control rods the reaction would continue to increase until there was a nuclear meltdown. Hot water left over from the power production is sent to cooling towers and then reused. Video

Nuclear

Nuclear Power Pros: No CO 2 output 1 pound of uranium = 1 million gallons of gasoline Safe Technology is advancing quickly – smaller power plants – reuse waste as fuel a nuclear fuel pellet measures 0.07 cubic inch (about the size of your fingertip) and contains the energy equivalent of 1,780 pounds of coal Cons: Waste material – extremely long half-life Potential for melt down Expensive Start up cost

Hydroelectric VideoVideo

Hydroelectric Generator

Tidal Power VideoVideo

Hydroelectric Dams/Tidal Pros: Produce very cheap electricity No pollution or emissions Secondary benefits of the lake behind the dam – recreation = economy Cons: Dams are expensive to build Can block migratory routes of fish Cause the build up of silt and debris behind the dam which can limit the distribution of nutrients down stream Not consistent – low water/drought Possible flooding if dam fails Tidal plants built on estuaries – dependent on tides – can’t be tied to peak usage hours (tides on 12.5 hour cycles)

Salmon Steps Salmon Jumping Salmon Jumping

Wind Power

Wind Energy Pro: Clean Wind is free Con: High start up cost Inconsistent (low and high winds) Harmful to birds and bats Not suitable for some areas Less efficient than fossil fuels Noise

Geothermal

Pro: Renewable Low energy production cost (almost free except for maintenance costs) Con: Limited to certain areas that tend to be geologically unstable Can release H 2 S (hydrogen sulfide gas – poisonous) from under the earth’s crust High start up cost Less efficient than fossil fuels

Solar – Oil Heating

Solar – Molten Salt - VideoVideo

Solar – Molten Salt

Photovoltaic Cell Substance absorbs photons of light and releases electrons. Electrons are captured as electricity.

Non-renewable Alternatives Photovoltaic Cells Pros: Clean – no pollution or CO 2 emissions Can be used in remote areas away from power plants Cons: Use rare earth metals (cadmium telluride, copper indium selenide, gallium arsenide) for energy production - expensive and often toxic inefficient

Renewable Energy Solar Energy - Harnessing the energy of the sun Passive Solar Energy Using the sun to heat buildings and water without mechanical aid to distribute the heat South facing windows Dark colors Water Barrels

Active Solar Heating: Solar energy is absorbed by a liquid and then transferred to a mechanical heat pump that circulates the heated liquid to heat water

Solar Heating Pros: Sunlight is free No air pollution Cons: Dependent on sun – cloudy days are bad Expensive Set up

Electrochemical cells Electrons from the cathode transfer through the electrolyte solution to the anode and then into the circuit. The circuit completes the flow of electrons back to the cathode. Transfer of electrons is accomplished by a transfer of electrons from the two chemicals causing a chemical reaction.

Electrochemical Cell Video Video

Electrochemical Cells Pros: Portable Cons: Short life span Use non-renewable resources (some very expensive) Less efficient than fossil fuels

Biofuels Pros: Carbon Neutral: not introducing new CO 2 into the atmosphere Renewable Growth in technology – Algae, biotechnologyAlgae Cons: Currently more expensive to produce than using fossil fuels – inefficient production – generally uses fossil fuels in production methods Use up land that could be used to grow food Encourages deforestation of land to grow crops for biofuel production – may lead to greater CO 2 levels