Energy Basics and the Electrical Grid

What is Energy?

  • Energy is the power to do work.

  • It has two main types:

    • Kinetic Energy: Energy of things moving (like a car or heat).

    • Potential Energy: Stored energy that can turn into kinetic energy.

Types of Potential Energy

  • Chemical Energy: Stored in bonds of food or fuel. It makes heat when burned.

  • Nuclear Energy: Stored in an atom's center. Splitting atoms makes heat for electricity.

  • Gravitational Potential Energy (GPE): energy from how high something is (like water behind a dam).

  • Elastic Energy: Stored in stretched or bent things (like a rubber band or spring).

Types of Kinetic Energy

  • Radiant Energy: Energy that travels as waves (like sunlight, X-rays).

  • Sound Energy: Energy from things vibrating, moving through air or water.

  • Thermal Energy: Heat energy; how hot or cold something is.

  • Electrical Energy: Energy from moving electrons (like in wires).

  • Motion Energy: Energy from things moving (like wind or a thrown ball).

Energy Transformations

  • When a light is turned on: Moving a switch \rightarrow Electrical energy \rightarrow Heat \rightarrow Light \rightarrow Sound (click).

Forms of Energy by Source

  • Non-renewable Energy:

    • Oil, Coal, Gas: Chemical energy.

    • Uranium: Nuclear energy.

  • Renewable Energy:

    • Biomass (from plants): Chemical energy.

    • Hydropower (water): Gravitational and Motion energy.

    • Wind: Motion energy.

    • Solar (sun): Radiant energy.

    • Geothermal (earth's heat): Thermal energy.

Energy Grid Concepts

  • Utility: Companies that give us electricity.

  • Load: Anything that uses power (like a home).

  • Baseload Power: The basic amount of power always needed.

  • Peak Demand: Times when lots of power is needed.

  • Rolling Blackout: When power is turned off on purpose for a short time to save the whole system.

  • Total Blackout: When power goes out everywhere unexpectedly (due to bad weather or broken parts).

  • Energy Efficiency: Things that make us lose energy:

    • Making energy: Some energy turns into heat or gets lost.

    • Moving energy: About 5\% of energy is lost as heat in power lines.

    • Using energy: Old appliances can waste energy.

  • Big power plants take 9-12 hours to start fully, sometimes making more power than needed.

Energy Storage

  • We need to store energy, especially from sun and wind which are not always on.

  • Pumped-Storage Hydroelectricity: Water is pumped up a hill (stores potential energy). When power is needed, water flows down to make electricity (kinetic energy). This is 70-80\% efficient.

  • Batteries: Used for small things now. Big batteries for the power grid are getting better, but are still costly.

Moving Electricity

  • How electricity gets to us: Power plant makes electricity \rightarrow Big box (transformer) makes power strong for travel \rightarrow Power lines carry it far away \rightarrow Another big box (substation) makes power weaker \rightarrow Local lines send it to homes \rightarrow Small boxes near homes make power safe to use.