MEzairi Artworks | Moment | Getty Images

The world we live in would look a whole lot different without electricity. If humans had not found a way to harness and exploit its potential, everything from today's cell phones and televisions to traffic lights and tablets wouldn't exist. Here, CNBC takes a look at electricity: what it actually is, why it's so important, and how it impacts the environment.

The basics

Electricity can be described as "the flow of electrical power," as the U.S. Department of Energy (DOE) puts it. The DOE classes electricity as a secondary energy source that is produced by the "conversion of primary sources of energy." These primary sources include everything from fossil fuels to wind and solar.

The uses

"Electricity is the backbone of our society," Peter Palensky, from the Delft University of Technology in the Netherlands, told CNBC. "Health, transport, food, information: all of that relies on electricity nowadays." The U.S. Energy Information Administration (EIA) says that U.S. electricity consumption amounted to around 3.85 trillion kilowatt hours last year. To put things in perspective, the EIA said that electricity use in 2016 was "13 times greater" than in 1950. Breaking the figures down further, the EIA estimates that "space cooling" — in other words, air conditioning — was the single biggest use of electricity in the U.S. residential sector. In the U.S. commercial sector, the EIA estimates that refrigeration was "the largest single end use" of electricity.

The grid

As we've seen, a number of sources can generate electricity. Getting it to customers so that they can watch TV and freeze food requires the use of a grid, a crucial part of infrastructure. The DOE describes the grid as an "interconnected group of power lines and associated equipment."



It's used to move electric energy at "high voltage between points of supply" and points where it is either delivered to other electric systems or "transformed to a lower voltage" and sent to consumers. The scale of grids is considerable. To give one example, the U.K.'s National Grid — which operates the electricity transmission network in England, Wales and Scotland — says its networks are made up of approximately 4,474 miles of overhead line, 932 miles of underground cable, and 342 substations.

The impact