UNIT 10: ENERGY ISABEL CORONADO ROMERO

Transcription

1 UNIT 10: ENERGY ISABEL CORONADO ROMERO

2 1. WHAT IS ENERGY? Definition: Energy is a physical quantity which produces a change or an effect Unit: International System Joule (J) Other Calorie (cal) 1cal =4,19J

3 1.1 CHARACTERISTIC OF ENERGY Energy can be : Stored to use it when we need. Transported energy can move from one place to another through a transfer system. Transformed there are different types of energy. One type of energy can be converted into another type. Transferred when two objects are in contact, energy can flow from one to another object. Preserved the energy neither is created or is destroyed, only is transforms. Degraded In the process of transformation from one type of energy into another part of the energy is lost in form of heat.

4 1.2 TYPES OF ENERGY Chemical energy: This is stored energy contained in chemical compounds. It is released during chemical reactions. Electrical energy: This is the energy produced by the flow of electric charges. Thermal energy: This is energy which is released as heat. Electromagnetic energy: This is energy stored in electromagnetic waves or radiation. Nuclear energy: This is energy stored in the nuclei of atoms. It is released in the process of nuclear fission or nuclear fusion. Mechanical energy (Em= Ek+Ep): This is the combination of two energies: Kinetic energy (Ek= ½ m v 2 ) : is the energy that an object possesses due to its motion Potential energy (Ep=m g h): is the energy stored in an object due to its position Where: m=mass v=velocity g= gravity h= height Unit: m kg vm/s g 9,8 m/s 2 h m

5 2. ENERGY SOURCES Are sources from which energy can be obtained Energy sources can be classified in two groups: Non-Renewable Energy Sources Energy from the ground that has limited supplies They cannot be made again in a short period of time. They are being used faster than they can be replenished. One day these sources will run out. They are highly polluting Renewable Energy Sources Energy that comes from a source that s constantly renewed. Can be replenished naturally in a short period of time. Because of this we do not have to worry about them running out. They have less impact on the environment.

6 2.1 ORIGIN Most of the energy available to us come from the Sun. This energy produces a series of phenomena from which we can use their energy. ORIGIN PHENOMENA ENERGY RESOURCE ENERGY SOURCE Water cycle Water Hydroelectric energy Renewable Air in motion Wind Eolic energy Renewable Light and heat Sun Solar energy Renewable Photosynthesis Gravitational attraction Heat of the earth`s formation Remains of living things Remains of living things Biomass Renewable Tide Tidal energy Renewable Internal heat of the earth Fossil fuels (Oil/ Coal/ Natural gas) Geothermal energy Thermal energy Renewable TYPE Non -Renewable Chemical elements Uranium Nuclear energy Non -Renewable

7 3. NON-RENEWABLE ENERGY SOURCES There are two types: fossil fuels and uranium FOSSIL FUELS Origin: Fossil fuels are formed from the remains of microorganisms, plants and animals buried millions of years ago. Over time the effects of heat, pressure and bacteria transformed this organic matter into fossil fuels. The main fossil fuels are: Oil: A naturally occurring thick, flammable liquid formed from plankton. Coal: An organic sedimentary rock formed from plant material Natural gas: A gaseous fossil fuel. It is found in oil fields, natural gas fields and coal beds. OIL COAL NATURAL GAS

8 3. NON-RENEWABLE ENERGY SOURCES FOSSIL FUELS How does thermal power stations work? In thermal generating plants, fuel is converted into thermal energy to heat water, making steam. The steam turns a turbine, creating mechanical energy to run a generator. Generator produce electric energy.

9 3. NON-RENEWABLE ENERGY SOURCES There are two types: URANIUM Origin: Uranium is a naturally occurring element found in rock, soil and water. Uranium is used to provide nuclear energy. How does a nuclear plant work? At nuclear plants, uranium atoms are split by nuclear fission in a nuclear reactor. The energy released is used to heat water. The vapour produced by the hot water drives a turbine that move a generator which generates electrical energy.

10 3. NON-RENEWABLE ENERGY SOURCES NON-RENEWABLE ENERGY SOURCES ADVANTAGES DISADVANTAGES USES COAL -The most abundant fossil fuel -Easy and cheap to convert into energy -Extraction canbe dangerous -Pollution: combustion produce CO2 emissions Production of electricity and heat OIL -Produces more heat than coal -Easier to extract than coal -Easy to transport -Resources are limited -Extraction and transformation can harm the environment -Pollution: burning oil releases Production of electricity, automobile fuel, heat, chemical such as fertilizers, plastics, etc. CO2 GAS -Cleaner than coal and oil -Easy to transport in pipelines -Require extensive processing -Very toxic -Leaks can cause explosions Production of electricity, heat (for homes), automobile fuel URANIUM -Small amounts of uranium produce large amounts of energy. -It does not pollute the atmosphere -Generate highly contaminating nuclear wastes. -An accident can release dangerous radioactive substances Production of electricity

11 4. RENEWABLE ENERGY SOURCES Are energy sources which are replenished continuously and naturally There are six types: biomass energy, hydroelectric energy, solar energy, eolic energy, geothermal energy and tidal energy BIOMASS -Biomass is organic material that comes from plants and animals. Biomass contains stored energy from the sun. Plants absorb the sun's energy in a process called photosynthesis. The chemical energy in plants is passed to animals and people after the plants are consumed. -Origin: -Energy crops: high yield crops grown specifically for energy applications -Waste from: domestic activities (paper, cardboard, food waste...), agricultural (straw, weeds...) livestock (excrement, animal remains...) and forestry (branches, leaves...) -The energy is obtained when biomass is burnt and also, biomass can be transformed into other types of fuel.

12 4. RENEWABLE ENERGY SOURCES HYDROELECTRIC ENERGY This is energy produced by the movement of water. Electrical energy is generated at hydroelectric power stations. How does hydroelectric power station work? Water is stored behind a dam. When the water is released into the river, it flows through a turbine. The turbine then drives an electrical generator which produces electricity

13 4. RENEWABLE ENERGY SOURCES SOLAR Solar energy is the sun s rays (solar radiation) that reach the Earth. This energy can be converted into other forms of energy, such as heat and electricity. How does hydroelectric power station work? When converted to thermal (or heat) energy, solar energy can be used to: Heat water: for use in homes, buildings, or swimming pools Heating system: Heat spaces inside homes and other buildings

14 4. RENEWABLE ENERGY SOURCES SOLAR How does hydroelectric power station work? Solar energy can be converted to electricity in two ways: Photovoltaic or solar cells change sunlight directly into electricity. Can be use at home or in photovoltaic solar power plants Solar thermal/electric power plants generate electricity by concentrating solar energy to heat a fluid and produce steam that is used to power a generator.

15 4. RENEWABLE ENERGY SOURCES EOLIC ENERGY Origin: Wind is simply air in motion. It is caused by the uneven heating of the Earth's surface by the sun. Because the Earth's surface is made of very different types of land and water, it absorbs the sun's heat at different rates. Eolic energy is produced in wind farms which consist of dozens of wind turbines placed in rows How does wind turbine work? Wind turbines use blades to collect the wind s kinetic energy. The wind flows over the blades which causes them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity.

16 4. RENEWABLE ENERGY SOURCES GEOTHERMAL ENERGY This is energy generated by the heat from within the Earth Geothermal station are built in areas with volcanic activity or with geysers and hot-water springs How does geothermal station work? AS A CURIOSITY: GEOTHERMAL ENERGY IN TIMANFAYA

17 4. RENEWABLE ENERGY SOURCES TIDAL ENERGY This is energy generated from ocean movement, mainly from tides How does tidal power station work? Energy is generated by the difference in height between high and low tide.

18 4. RENEWABLE ENERGY SOURCES RENEWABLE ENERGY SOURCES ADVANTAGES DISADVANTAGES USES BIOMASS - Unlimited source of energy -Produce very few residues, mainly biodegradable -Less contaminating than fossil fuels -Low efficiency -Large volume makes handling and transportation difficult Provides heat, electricity and fuels HYDROELECTRIC -Unlimited source of energy -Cheap to produce -Not pollute the environment -Help to control flooding -Provides water during dry seasons -Depend on weather conditions -Negative environmental impact -Risk of dam breakage and potential flooding Production of electricity SOLAR -Unlimited source of energy -Low maintenance cost -Clean energy source -Availability affected by latitude, seasons, cloudiness, etc. -Require large area to collect -Production of heat -Transformed directly into electricity

19 4. RENEWABLE ENERGY SOURCES RENEWABLE ENERGY SOURCES ADVANTAGES DISADVANTAGES USES EOLIC -Unlimited source of energy -Low installation and maintenance costs -Clean energy source -High efficiency -Wind is intermittent and inconsistent -Wind turbines are loud -Danger to bird Transform directly into electricity GEOTHERMAL -Clean energy source -Not dependent on weather conditions -Negative environmental impact -Installation is difficult and costly Transform directly into electricity TIDAL -Unlimited energy source -Clean energy source -Not dependent on weather conditions -Low efficiency -Negative environmental impact -Limited to certain coastal areas -Transform directly into electricity

20 5. TO SUMMARIZE, HOW ELECTRICITY IS PRODUCED? Producing electricity is very easy, just need: TURBINE SHAFT GENERATOR RESOURCE ELECTRICITY WE USE A SOURCE OF RENEWABLE ENERGY OR NOT- RENEWABLE ENERGY ONLY DEPENDS ON THE FORCE THAT MOVE THE TURBINE!!

21 6. ENERGY USE Energy is essential in our life. It is embodied in everything we use.

22 7. FUTURE Use energy saving light bulbs