Energy 2

pro

• renewable, non pollutant, non combustion

• installed on buildings, no transmission, no power plants

• cheap running costs: sun is free

contra

• amount of sun changes over the day => requires storage

• expensive to make + install

• not really efficient

• harmful for environment and people (mining process)

• electrical current is a flow of electrons driven by differences in potential energy

• in power plants: generated by wire coils rotating between the poles of a magnet

• transfer of electrons through an external circuit produces electricity

• conduct less well than metals but better than insulators

• increase conduction at higher temperature due to higher molecular movement

• difference between N-type and p-type

  • N-type:has an abundance of electron

  • p-type has a deficient in electrons

• electrons can move to fill the space

conduct very well, but only at very low temperatures

• metals share electrons among the nuclei => all atoms share electrons

• electrons are movable among the metal

• layers of atoms are packed in tight arrangement

• conduct electricity in solid stage

• a galvanic cell that produces electricity by converting the chemical energy of a fuel directly into electricity without burning the fuel

• fuel and oxidizer must constantly flow into the cell to continue the chemical reaction

• H2 + 1/2 O2 => H2O

• H2 => 2H+ +2e-

• 1/2 O2 + 2H+ + 2e- => H2O

reformer

• CH3OH + CH4 can be converted

• methanol fuel tan => goes to vaporizer with H2O => catalytic reformer => gas leaning => CO goes back

• CH3OH + H2O => CO2 + 3H2

• CH3 OH => CO + 2H2

• CO + H2O => CO2 + H2

electrolysis of water

• needs voltage and disolute salt lotion: H2O => H2 + 1/2 O2

sun energy to make electrolysis of water

• in metal hydrides, released with increased temperature or decreased pressure

• two layers of semiconducting materials are placed in direct contact to include a voltage in the Photovoltaic cell