Definition

1. Definition Energy is defined as the ability or the capacity to do work. Energy lights our cities, powers our vehicles, and runs machinery in factories. It warms and cools our homes, cooks our food, plays our music, and gives us pictures on television, powers our video games and iPods.

2. Forms? • heat (thermal) • light (radiant) • mechanical • electrical • chemical • nuclear energy

3. Types? • stored (potential) energy • working (kinetic) energy. e.g. (e.g. energy stored in body to be used when we move, work, play, etc.) • Energy is stored in different ways in the energy sources we use every day: • renewable: energy source that can be depleted in a short period of time • Non-renewable: energy source that we are using up and cannot recreate in a short period of time

4. Renewable/non-renewable soureces of energy

5. Renewable and nonrenewable energy sources can be used to produce secondary energy sources including electricity and hydrogen.

6. most of our energy from nonrenewable energy sources, which include the fossil fuels -- oil, natural gas, and coal. Another nonrenewable energy source is the element uranium, whose atoms we split (through a process called nuclear fission) to create heat and ultimatelyelectricity.

7. Uses • Energy sources to generate the electricity we need for our homes, businesses, schools, and factories. Electricity "energizes" our computers, lights, refrigerators, washing machines, and air conditioners, etc. • We use energy to run our cars and trucks. Both the gasoline used in our cars, and the diesel fuel used in our trucks are made from oil. The propane that fuels our outdoor grills and makes hot air balloons soar is made from oil and natural gas. • Source: http://www.eia.doe.gov/kids/energyfacts/sources/whatsenergy.html

8. Wind power • Wind power is the conversion of wind energy into more useful forms, usually electricity using wind turbines. • Globally, wind power generation more than quadrupled between 2000 and 2006. • wind-powered generators account for approximately 18% of electricity use in Denmark, 9% in Spain, and 7% in Germany. • At the end of 2006, worldwide capacity of wind-powered generators was 74,223 megawatts; although it currently produces less than 1% of world-wide electricity use

9. Solar energy • Solar power is the technology of obtaining usable energy from the light of the Sun. • Solar energy has been used in many traditional technologies for centuries and has come into widespread use where other power supplies are absent, such as in remote locations and in space. • Power towers use an array of flat, movable mirrors (called heliostats) to focus the sun's rays upon a collector tower, The high energy at this point of concentrated sunlight is transferred to a working fluid for conversion to electrical energy in a heat engine • Solar energy converted to heat in a concentrating collector can be used to boil water into steam (as is done in nuclear and coal power plants) to drive a steam engine or steam turbine. The concentrating collector can be a trough collector, parabolic collector, or power tower.

10. Hydroelectricity • Hydroelectricity is electricity obtained from hydropower. Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. • The energy extracted from water depends not only on the volume but on the difference in height between the source and the water's outflow. • The major advantage of hydro systems is elimination of the cost of fuel. Hydroelectric plants are immune to price increases for fossil fuels such as oil, natural gas or coal, and do not require imported fuel. • Hydroelectric plants tend to have longer lives than fuel-fired generation, with some plants now in service having been built 50 to 100 years ago • Hydroelectric projects can be disruptive to surrounding aquatic ecosystems.

11. Methane • Methane is a chemical compound with the molecular formula CH4. It is the simplest alkane, and the principal component of natural gas. Burning one molecule of methane in the presence of oxygen releases one molecule of CO2 (carbon dioxide) and two molecules of H2O(Water): • Because it is a gas (at normal temperature and pressure) and not a liquid or solid, methane is difficult to transport from the areas that produce it to the areas that consume it. • Methane is the major component of a natural gas, about 97% by volume. It is highly flammable and may form explosive mixtures with air. Methane is violently reactive with oxidizers, halogens, and some halogen-containing compounds. • Methane is not toxic.

12. Hydrogen • Hydrogen is a chemical element that has the symbol H and an atomic number of 1. • At standard temperature and pressure it is a colorless, odorless, nonmetallic, tasteless, highly flammablediatomicgas (H2). With an atomic mass of 1.00794 g/mol, hydrogen is the lightest element.

13. Energy production in Iceland compared to Germany • 73% of Iceland’s energy is hydro and geothermal, produced by harnessing renewable energy sources such as water and subterranian steam, but the rest with oil and coal. In Germany it’s 10,2%. • Iceland produced 8680 GWh in 2005. 7014 GWh of that was hydroelectricity and 1,660 GWh was geothermal electricity but only 7,8 GWh with fossil fuels. Germany produces 500000 GWh annually, but in Iceland live only 308000 people.

14. History • Renewable energy has been used for centuries. • Egyptians used it to sail their ships irrigate their fields. • People used the solar power to process their food such as drying fruits and vegetables, fish and meat. • Wind mills were used to grind corn and wheat.

15. Precentation: Ágústa Lóa Jóelsdóttir & Vignir Ólafsson • Sources: http//:www.wikipedia.org • http//:www.eia.doe.dov/kids/energyfacts/sources/whatsenergy.html • Http//:edugreen.teri.res.in/explore/n_renew/ener.html