Energy is the ability to do work. The two different types of energy are kinetic and potential. Kinetic energy is energy in motion and potential energy is energy that is stored. Energy is measured in units which are BTU (British thermal unit) and a joule. The Law of Conservation of Energy states that energy can’t be created or destroyed, but it can be changed in form. Heat is a form of energy that comes in different forms such as conduction, convection, and radiation. Conduction is when energy is passed directly from one item to another. Metals are excellent conductors of energy. Plastics or other materials aren’t. These are called insulators. Convection is the movement of gases or liquids from a cooler spot to a warmer spot. Radiation is the final form of movement of heat energy.
Electricity is the flow of energy from one place to another. Atoms have electrons circling them. Some are loosely attached. When electrons move among the atoms of matter, a current of electricity is created. Electricity flows through some objects better than others. Copper is a good conductor of electricity. The electric force that “pushes” electrons is measured in volts. Batteries store chemical energy. An electric circuit connects the positive and negative poles of the battery and allows an electrical current to happen. Static electricity doesn’t move. It is the energy that can stick a balloon to a wall if you rub the balloon across a sweater. Lightning is another form of static electricity.
Fuels are used to heat water in a boiler to make steam. That steam turns a turbine. The spinning shaft of the turbine drives the generator. Many types of fuels are used in the boiler to heat the water. When a wire or any electrically conductive material moves across a magnetic field an electric current is produced in that wire.
The inside of the earth has a core, a hot liquid mantle, and a crust. The earth and an egg have layers that look alike. The upper portion of the mantle is hot liquid rock called magma. In some areas of the earth water seeps below ground and is heated by the hot rock. This hot water or steam can be used to turn a turbine that drives the generator to make electricity in a geothermal power plant. Geothermal means “earth-heat”. California generates one-half of the world’s geothermal electricity.
Fossil fuels were formed during the time of dinosaurs when plants and animals died. Their decomposed remains gradually changed over the years to make coal, oil, and natural gas. Fossil fuels are usually found below ground and must be either dug out or pumped from below the ground. California produces about one-half of the oil it uses. The rest comes from Alaska and other countries. Oil is transported in huge pipelines and tanker ships to places where it is made into other products. Many products like plastic and fertilizer come from oil. Natural gas is found near oil. Natural gas runs through a series of pipes until it comes to our homes, schools, and businesses. Fossil fuels are not renewable. They can’t be remade.
Hydro power uses the kinetic energy of moving water. The moving water can be used to turn wheels to grind grains or in a hydro electric power plant, to make electricity. Moving water goes through a turbine spinning the shaft, which turns a generator to make electricity. California’s hydroelectric power plants are found along dams on rivers, and in the mountains.
Nuclear fission means splitting an atom apart. Splitting an atom releases heat and light energy. In a nuclear power plant, an atomic chain reaction is controlled to produce heat to boil water. That water boils water in pipes to make steam to turn a turbine and a generator to make electricity. Nuclear fission means combining atomic nuclei to make a larger nucleus. The sun uses nuclear fusion of hydrogen into helium to make light and heat energy. Scientists are trying to create nuclear fusion to make a cleaner source of power.
The oceans energy can be used in three basic ways. Wave energy systems use the up and down motion of waves to turn a turbine or a generator. Tide energy systems traps high tides in a reservoir. When the tide drops, the water behind the reservoir can flow through a power plant, just like a regular hydroelectric plant. Ocean thermal energy conversion uses the difference in temperature between warm surface water and cold deep ocean water to make electricity.
Sunlight has always been a source of energy for plants, animals, and humans. We use sunlight and heat from the sun to dry clothes outside. The sun’s heat can be used to heat water flowing through pipes on a roof. More than 500,000 solar water heating systems are used in California. Sunlight can also be focused in a thermal system to heat water or other fluids to make steam. The steam can be used to turn turbines to make electricity. Sunlight can be used directly in solar cells or PV cells to make electricity.
Wind energy can be used to do work. Wind has been used for many years to drive boats and windmills to grind grains or pump water. Wind turbines are being used today to make electricity. Wind spins the large blades which turn generators inside the turbine to make electricity. California’s nearly 13,500 wind turbines can supply enough electricity to power an entire city.
Electricity from power plants is sent through a transformer and boosted to a very high voltage. The high voltage power lines carry electricity into cities and towns to substations and to transformers to reduce the voltage. That lower voltage power then goes to a smaller transformer near our homes, where power is reduced further. The lines can go underground into our houses. At our homes, the power goes through a meter so the electricity company can bill us for the power that we buy from them. Electrical wires are not to be touched because they can cause injury or even death.
Natural gas is sent to us from the “fields” where it is found through a series of pipelines. The pipelines carry the gas to factories, businesses, schools, and our homes. The gas passes through a meter so the natural company can bill us for the natural gas that we buy from them just like the electrical power. Natural gas burns very cleanly with very little pollution.
One-half of California’s energy goes into powering vehicles. Oil made into gasoline and diesel fuels are the main source of energy for cars, trucks, busses, and other vehicles. Gasoline and diesel are transported to service stations in large tanker trucks. Fuels other than gasoline and diesel are being used in alternative fuel vehicles.