How the Electricity Grid Works?
The
electricity grid is complex enough to make your head spin, but once you know
its basic parts and functions, you’ll be well on your way to appreciating the
complex nature of this system. The grid itself consists of three major
components that you need to understand in order to appreciate how it works:
generation, transmission, and distribution. These are the essential functions
of the electricity grid, and they play critical roles in keeping our lights on
every single day.
The Importance of the Electricity Grid
We’ve
come a long way from candles and oil lamps, but one thing that’s still as
important today as it was in ancient times is energy. Think about how many
people go to bed at night with their smartphone charging by their side. Think
about how many things we do on a daily basis that require electricity—even for
simple tasks like boiling water for coffee or heating food in a microwave. Then
there are those fun-but-energy-guzzling things like watching TV, reading on
your tablet or computer, or playing video games. It turns out that today’s
modern world relies on electricity more than ever before—and none of it would
be possible without an electrical grid to deliver us all electric power.
The U.S.
The electric grid is a network of electricity
cables and substations that bring electricity to homes, businesses, and
factories. The U.S. grid has three main parts: transmission lines, distribution
lines, and generation plants (where electricity is produced). Most of it is underground or in man-made structures like concrete towers—which helps protect it from storms, heat damage, and mechanical damage from things like
fallen tree limbs. The electricity generated by these plants travels through
high-voltage transmission lines to get to people’s homes and businesses. It's
even possible for more than one power plant to supply a single home or business
with electricity through multiple sources.
A distribution line is a lower-voltage
wire—usually below 69 kilovolts. Distribution lines carry electricity from
transmission lines to people’s homes and businesses. Sometimes, more than one
distribution line will be run to a single home or business, which is why you
may have multiple electric meters in your basement. That way, if one power
plant goes down for some reason—such as extreme weather or mechanical
damage—the other distribution lines can make up for it. It's common for
businesses to have multiple distribution wires coming into their buildings too,
huge ones like hospitals and factories that require a lot of
electricity.
The Electricity Supply Chain
An
electricity grid is a network of high-voltage power lines and associated
infrastructure that carries electricity from where it's generated to where it's
needed. This can be done through a direct connection or may use smart electrical
devices that allow for power to be transferred over long distances without
using wires (known as wireless transmission). The electricity itself usually
flows along at 60 Hertz alternating current but can be changed to suit local
needs via step-up/step-down transformers. With a few exceptions, most regions
rely on large central plants known as power stations or generating stations for
their electricity—these plants convert fuel (usually fossil fuels like coal,
natural gas, or oil) into steam which in turn spins turbines and generates
electricity.
Before
entering a home or business, electricity is distributed by low-voltage lines to
secondary distribution points such as sub-stations or medium-voltage lines to
local substations. It may also pass through a meter that measures power in both
directions and records consumption, for billing purposes. Once it reaches its
destination, it is distributed by consumer wiring and appliances. When you flip
a switch, electricity from your wall socket travels through wires inside your
house (or between buildings) until it reaches an appliance connected to an
outlet. If more electricity is drawn than what’s available from your current
source, then more electricity will be delivered from elsewhere on the grid
through another path.
Energy Sources That Feed the Grid
In order
to understand how power is transported through your neighborhood, it’s
important to know where that energy comes from. Every day, utilities are
responsible for getting enough electricity onto transmission lines in order to
meet demand. While utility providers have a number of strategies for meeting
peak demand — which typically hits right after work and just before dinner —
they generally rely on one of three major energy sources: nuclear plants,
coal-fired power plants, and natural gas-fired facilities. The exact mix depends
on location and what's most cost-effective in a particular situation. It's
important to note that these facilities aren't like personal generators; they
don't create energy just when it's needed but rather constantly produce
electricity at all hours of the day.
Natural gas–fired facilities are responsible
for much of today's electricity generation. As of 2016, natural gas-fired
plants supplied 24 percent of all U.S. power and were more cost-efficient than
any other energy source. As a relatively clean-burning fuel, natural gas is
also considered safe and reliable — after all, it plays an important role in
our everyday lives, from cooking to heating water. So why not use these power
sources all day every day? The problem is that producing energy at these plants
requires fuel, which costs money to produce and maintain, so if too much power
is produced but not enough is needed at any given time, there’s no way to store
it until it’s needed later.
The Power Delivery System
The
electricity grid is a complex system that makes it possible to connect
thousands of power plants and millions of customers together, across an entire
continent. It includes power plants that convert fuel into energy,
long-distance transmission lines, substations where voltage levels are adjusted
for transport over varying distances, distribution lines to get power close to
ending users, and transformers that change voltage levels at your home or business.
Although many people think electricity flows directly from a power plant to
their house or business when they flip on a light switch, in fact, electricity
must be transported by two different systems before it reaches our homes or
businesses. These are 1) Transmission and 2) Distribution.
The transmission system is composed of
high-voltage lines that carry electricity over long distances (up to hundreds
of miles) from power plants to substations near towns and cities, where it is
then transferred to lower-voltage distribution lines. The grid contains two
main types of transmission lines: 1) Overhead power lines and 2) Underground
cables. The type used depends on how far and at what voltage electricity must
be transported. Overhead lines are supported by towers along which high voltage
direct current electric current travels, while underground cables consist of
many thin insulated wires bundled together to form a cylindrical tube, also
called a cable. Underground cables can only carry DC electric current and are
cheaper than overhead wires because they don't require support towers.
The
distribution system is composed of smaller overhead or underground lines that
carry power to substations in neighborhoods, apartment buildings, and
businesses. This system delivers electricity at lower voltages between 100
kilovolts (kV) and 13,000 kV. From a distribution substation, transformers
further reduce voltage levels so that they can be used safely in homes and
businesses. Power flows from high-voltage transmission lines to low-voltage
distribution lines via transformers. By changing voltage levels, these devices
enable electricity to travel long distances along transmission lines and then
convert high-voltage current for safe use at low voltages for customers.