You may have heard that Benjamin Franklin discovered electricity. He did not. Electrical forces had been recognized for more than a thousand years. What his experiment did was show the connection between lightning and electricity. Lightning is a kind of electricity. It happens when electric charge builds up in a storm cloud and then jumps to the ground. How often does that happen? As of November 2026, there can be as many as 2,000 thunderstorms across the globe at any given moment. NASA satellite research indicates that thunderstorms produce lightning flashes about 40 times a second worldwide. That is down from the 100 a second estimated in 1925, so the newer number is lower than the older estimate.

Moving a magnet through a coil of wire can make electricity flow in the wire. Michael Faraday found this in August 1831, and it is called electromagnetic induction. He passed a magnet back and forth through a coil, and the needle of a galvanometer registered a current. Why does it work? Here is the idea in plain words, and it has to do with the metal itself. Metals such as copper and aluminum have loosely held electrons. Moving a magnet around a coil of wire pushes the electrons in the wire. That creates an electric current. Power generation depends on that discovery. In 1826, Faraday also founded the Christmas Lectures for young people at the Royal Institution.

Now to see how a generator gets turned. There is more than one way to do it. A generator turns the energy of motion into electricity. In a turbine generator, a moving fluid pushes blades on a rotor shaft. The fluid can be water, steam, combustion gases or air, and the spinning shaft turns a generator. A wind turbine blade works like an airplane wing. Air pressure drops on one side. The lift is stronger than the drag, so the rotor spins. Wind is caused in part by the sun heating the air unevenly. A hydropower plant makes more electricity with more water flow and a bigger drop in height. That drop is called the head. In a solar cell, sunlight’s energy creates electrical charges that move in response to an internal electrical field in the cell. This causes electricity to flow.

Electricity travels at different voltages for different jobs. Higher-voltage electricity is more efficient and less expensive for long-distance travel. Lower-voltage electricity is safer to use in homes and businesses. A transformer raises or lowers the voltage of electricity. In 1882, Edison’s Pearl Street Station in New York City began sending out electricity. It was designed to run up to 1,400 lamps continuously. It served an area of about one square mile. Edison’s direct current (DC) was not easily converted to higher or lower voltages. Alternating current (AC) reverses direction 60 times a second in the U.S. It can be converted with a transformer. Most of the electricity we use today is AC.

The electricity we use is a secondary energy source. It is made by converting primary sources like coal, natural gas, nuclear, solar and wind energy. Electricity is called an energy carrier. It can be converted to other forms of energy such as mechanical energy or heat. Here are some numbers, and they are all about the United States. In 2025, about 58% of U.S. utility-scale electricity came from fossil fuels. About 18% came from nuclear energy. About 19% came from nonhydroelectric renewables, and about 24% from renewable sources. That is the picture as of November 2026. U.S. electricity transmission and distribution losses averaged about 5% of the electricity transmitted and distributed in 2018 through 2022, as of November 2026.

Who keeps the lights on?The U.S. grid in the Lower 48 states has three main interconnections. They are Eastern, Western, and the Electric Reliability Council of Texas (ERCOT). For the grid to stay stable, the amount of electricity supplied must match the electricity demanded. If they fall out of balance, local or even widespread blackouts can happen. The day-to-day operation of the electric system within regions is managed by balancing authorities. They ensure electricity supply constantly matches power demand. In short, what the grid makes must match what people use at the same time. Wind and solar power plants generate electricity only when wind and solar energy resources are available.

Words to know

• galvanometer: current meter
• voltage: electric push
• transformer: voltage changer
• alternating: reversing
• interconnections: linked grids