Miles of wires bring life-saving energy: decoding the power grid

Electricity is essential to everyday life. It keeps us warm, fed, and informed

But the components that make up the grid and the terminology that describes it

can feel complex and, at times, hard to understand. Straight Arrow News energy reporter Keaton Peters created a guide of terminology

to break down the walls between energy consumers and experts. Say hello to Dr. Watts

Watts measure electricity at any given moment. A watt can measure what's needed to power personal electronics or home appliances

It also measures the output of power plants and equipment that generate electricity

But I need a nuclear reaction to generate the 1.21 gigawatts of electricity

1.21 gigawatts! Electricity uses metric prefixes to represent multiples of the base unit

So a kilowatt is 1,000 watts. A megawatt, that's 1,000 kilowatts. A gigawatt, like those shareable animated images, should be pronounced with a hard G, apologies to Doc Brown, and is 1,000 megawatts

And a terawatt is 1,000 gigawatts. A watt-hour measures quantity. It's the amount of electricity needed to provide a watt of power for an hour

So if a small appliance needs 50 watts of capacity to run, plugging it in for one hour will use 50 watt-hours of electricity

The average U.S. home uses roughly 900 kilowatt hours of electricity per month

while a large hospital can use 1.5 gigawatt hours per month, the equivalent of 1,666 homes

But data centers dwarf hospitals. For the purposes of demonstration, a data center with 100 megawatt capacity could use 73 gigawatt hours in a month

or 81,000 times that of the average home and 48 times the electricity of the large hospital used in this example

So how is electricity generated? The most common form of energy production is done at thermal power plants

At these plants, fuel is processed to create steam, which rises through a turbine, causing it to spin and generating electricity

For a long time, the fuel of choice was coal. Today, most of America's energy is produced by natural gas

Nuclear. It's pronounced nuclear. Nuclear plants also fall into the category of thermal plants. But rather than burning

fuel they rely on a nuclear reaction of splitting atoms to generate heat Thermal plants can supply baseload power which means as long as a plant has an adequate fuel supply or stable nuclear reaction it can provide electricity 24 hours a day Renewable energy

doesn't depend on fuel that needs to be mined, drilled, or enriched by other industries. Instead

renewables are powered by the Earth's natural features, sunlight, wind, and water flows

Solar and wind power are intermittent because the output depends on the weather

Hydroelectricity is generally considered baseload power because water flows through its dams at a consistent rate

But drought conditions can upend that situation and cause a reduction in power output

Oh, I love electricity. Eddie says we're going to get some soon. Geothermal power uses the Earth's naturally occurring internal heat to generate electricity

Geothermal power is unique because it can be categorized as providing both baseload and renewable energy

But it also falls into a third category, dispatchable power. Dispatchable power is when the electric grid can quickly add or reduce production

Essentially, output can be turned up or down like a light switch. A good example is batteries being called in to add capacity to the grid at a moment's notice

Gas and coal plants need more time to fire up and cool down than a battery

But they are also dispatchable because they generally operate below their max level and can add more power to the grid if needed

Nuclear can also be dispatchable, but often operates at one consistent level because it's more efficient

Ladies and gentlemen, AC DC. To understand how the electric grid works, you have to start by understanding different types of currents

Alternating current, or AC, flows continuously in both directions. while direct current or DC flows in just one direction

If you think of it like a road, AC is a major artery supporting traffic both ways

while DC is more like confusing one-way streets downtown. AC is also used to distribute power throughout most American homes

Many appliances and electronic devices utilize DC but get converted from AC by way of a power supply or transformer

What's that? The outlet? That's where the electricity comes out of. Ah, you mean the holes

A good example of this is a desktop computer's power supply. It takes AC power from the wall

The computer's power supply then converts that AC power to several low voltage DC power streams to individual components like the processor graphics card and motherboard Okay on to the wonderful world of electric grids The grid is made up of multiple levels

Grid interconnections are the outermost layer. Interconnection ties local and regional grids

together via AC power lines. The U.S. has two large grids, the western interconnection and the

eastern interconnection. Meanwhile, most of Texas is on its own grid that doesn't share AC connections

with its neighbors, but does import some electricity from neighbors on DC connections

Peeling the onion back within interconnections, there are independent system operators, or ISOs

and regional transmission organizations, or RTOs. These are the grid operators whose job is to

balance electricity supply and demand within their specific region. If there's a discrepancy

between the amount of electricity flowing and consumer demand, it can cause problems in the

frequency and voltage of the grid. This could break equipment and even cause blackouts

Okay, thank you very much. The ISO monitors the grid and maintains efficiency in buying and

selling electricity to make sure the lights stay on. Going deeper into the grid, there are two

separate systems for transmission and distribution of electricity. If we go back to comparing

electricity to roads, the transmission grid is like a major highway or interstate. It connects

energy generation to areas where it will be consumed on large transmission lines. These are

the huge towers you see along highways. Transmission lines have a higher voltage capacity than the

smaller distribution lines. They connect to substations to be converted to lower voltage

that the distribution system can handle. Then the distribution grid carries electricity along

smaller lines to destinations like homes and businesses. All of this infrastructure is managed

and operated by a regional utility company. Grid operators have an essential job of maintaining

a balance of frequency and voltage. Frequency, measured in hertz, is the speed at which an

electric current changes direction in an alternating current system. It measures how many times the

current changes direction per second. Think of it like the frequency of music. Plucking a guitar

string sends a wave back and forth. In music, the higher frequency, the higher the pitch. The low

frequency vibration of the grid is why you hear the hum around transmission lines and near substations

Meanwhile voltage is more like the pressure used to push the electrical current through the lines If we go back to shredding on the guitar voltage would be the force used to pluck a string

It's famous for its sustain. I mean, you can just hold it. Well, I mean, so you don't have to pull

You can go and have a bite. If voltage is too high, it can fry electrical equipment

If it's too low, the system won't be able to meet demand. Independent system operators are tasked with keeping the grid stable at 60 hertz

They use dispatchable power to compensate for sudden changes in supply and demand

Thermal plants use spinning turbines, allowing them to naturally fit into a frequency of 60 hertz

Those turbines can absorb slight changes in frequency, providing some flexibility to keep the system stable during fluctuations in supply and demand

Batteries, as well as wind and solar power, require an inverter to convert DC power to AC

so they don't have the same natural inertia that absorbs fluctuations in frequency

That's a serious engineering challenge for grid operators, but one that's actively being addressed with new technology being deployed alongside renewable energy

The power can go out for a number of reasons. Something simple, like a tree falling on a power line during a storm, can cause a small, localized outage

knocking out power to a few homes or a neighborhood. These small outages are usually

fixed by the local utility company cleaning and repairing lines. But larger-scale outages called

blackouts can also be caused by complex situations that can require years of studies to determine the

root cause. If the weather is severe enough, thousands of small outages can create a major

crisis. In 2024, Hurricane Beryl caused more than 2 million people to lose power. In some cases

it took the utility company, Centerpoint, upwards of a month to fix

Much of the northeastern United States is without power tonight. Back in 2003, the northeast portion of the U.S. faced one of the worst blackouts in North

American history. At the time, an Ohio power plant went offline, straining high-voltage lines

which came in contact with overgrown trees. This trip caused the load to move to different

transmission lines that couldn't handle the load. It created a cascading effect of trips that led to

a massive, hours-long blackout affecting 50 million people in eight states and parts of Canada

Meanwhile, a software bug in the utility provider system prevented the provider from

recognizing the problem as it was happening and taking the appropriate action