Energy conversions The animation above shows the many energy conversions taking place during the production of electrical energy. It is strange to think that the electrical energy that comes from the power company originated from solar energy. Plants are the only organisms on Earth that can harness solar energy and convert it into a more usable form called chemical energy. Chemical energy is trapped in the form of wood and other plant matter. Coal is a source of chemical energy because it is composed of plant matter that has been subjected to high temperatures and pressures. We recover the coal and burn it in huge furnaces. Inside the furnace chemical energy is converted into heat energy. This heat energy is used to heat water into super hot steam inside boilers. Inside the boiler another energy conversion takes place, heat energy is converted into kinetic energy. As the super fast steam travels through the turbines it causes the generator to spin and produce electrical energy. The generator is the place for the last energy conversion where kinetic energy is converted into electrical energy. The huge cooling towers condense steam back into water. Some of the steam escapes, creating huge clouds above the cooling towers. When visiting the Hazelwood open cut coal mine you will see many conveyer belts taking the coal (chemical energy) straight to the Power Station. Before the coal is placed into the furnace it must be dried and pulverised. Electrical energy is made available to our homes via huge transmission towers. The law of conservation of energy states that energy can not be created nor can it be destroyed. It can, however, change forms as from electrical into heat. Take the conversion outlined in the animation below. At every step we have a loss of energy. The efficiency of the conversion is given as a percentage and clearly an indication and not precise. The more comversion steps throughout the process of generating electricity the greater the energy losses. 1) What process captures solar energy? evaporation photosynthesis respiration condensation 2) Which is the most inefficient energy conversion step in the process outlined above? kinetic into mechanical chemical into heat mechanical into electrical solar into chemical 3) The more steps in the process of generating electrical energy the less electrical energy that is generated the more electrical energy that is generated 4) The energy lost is in the form of electrical heat chemical mechanical 5) What type of energy is carried by steam electrical chemical mechanical kinetic 6) Click to see how electrical energy is generated in a hydroelectric power station. Why is a hydroelectric power station more efficient in generating electrical energy than a coal fired power station? 7) What is wrong with the term "energy generation"? 8) Explain the steps involved in generating electrical energy from solar energy. 9) Losses occur when electrical energy is transmitted in high tension power lines. In what form is the energy that is lost? 10) The light globe on the right provides us with electrical energy chemical energy mechanical energy light energy heat energy 11) An incandescent light globe like the one shown on the right works on heating a metal filament until it glows brightly. What are the energy conversion taking place int he globe? electrical -> heat -> light chemical -> electrical -> light -> heat light -> heat light -> heat-> electrical heat -electrical -> light 12) This type of globe is only 2% efficient. What does this mean? 13) Most of the energy coming into the light globe is transfromed into electrical energy chemical energy mechanical energy light energy heat energy