Energy 101
Energy
Energy – defined as the capacity to do work – can be categorized into two forms: kinetic energy and potential energy. Kinetic energy refers to the energy available as a result of motion. Wind – which is the movement of air particles – is an example of kinetic energy. Potential energy can be thought of as energy stored in an object. A book resting on a table has potential energy. The potential energy would be converted to kinetic energy if the book was knocked off the table and fell to the floor.
Electricity Basics
Everything in the universe is made up of atoms. An atom consists of a central nucleus – containing positively charged protons and neutrons – and negatively charged electrons that spin around the nucleus. Electricity is the flow of electrons between atoms – making it a form of kinetic energy. Electricity is secondary energy source, meaning it must be generated from other energy sources. Electricity can be generated through conventional fuels, which include coal, petroleum (oil), natural gas, and uranium (nuclear), or through renewable energy sources, which include wind, solar, biomass, hydropower, and geothermal.
Electricity generated at power plants must travel through transmission lines to reach your home or business. The electricity from the power plant is sent to a transformer that converts the electricity from low voltage to high voltage. Electricity can be moved more efficiently using high voltage. Transmission lines carry the electricity to substations with transformers that convert the high voltage electricity to lower voltages. This electricity enters distribution lines where transformers – placed on distribution poles – lower the voltage before the electricity enters a home or business.
Electricity is measured in a unit of power called a watt. A watt represents the capacity to generate or use electricity. Other common measures include the kilowatt (equal to 1,000 watts) or megawatts (equal to one million watts). The size of a power plant is represented in terms of megawatts (MW), and generally ranges from 25-2,000 MW.
A kilowatt-hour (kWh) represents how much electricity is being generated or consumed. One kilowatt-hour is equal to the energy of 1,000 watts working for one hour. For example, a 60-watt traditional light bulb on for 8 hours a day, 5 days a week, would use 2,400 watts or 2.4 kWh per week. An equivalent 13-watt compact florescent light (CFL) bulb would use 520 watts or 0.52 kWh per week.
Additional Resources
This page adapted from Electricity Basics at the Energy Information Agency.
