Gigawatt: The solar energy term you should know about

What's a gigawatt and what does it have to do with solar energy?

AJ Dellinger Contributor
AJ Dellinger is a contributor to CNET.
AJ Dellinger
4 min read

Learn more about how solar energy is measured.

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The United States and many other countries around the world are investing heavily in solar power as an energy source as part of an effort to shift to renewable energy sources and ditch fossil fuels. In order to accomplish that, there is going to have to be a massive expansion of solar infrastructure that will need to generate lots and lots of energy. According to a recent study published by the United States Department of Energy, it hopes to produce 45% of all electricity via solar power. That will require generating 1,600 gigawatts of power.

This raises an important question: What is a gigawatt, exactly? 

As we see an increasing shift toward solar and other renewable energy sources, understanding how this power is measured, generated and harnessed will be important. So let's take a look at what a gigawatt is, how many gigawatts of power the US is currently generating, and how many it will need to generate in order to achieve its future goals.

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What is a gigawatt?

A gigawatt is a unit of measurement of electrical power. For some context, a gigawatt is equal to one billion watts. 

You're probably more familiar with the measurement of watts in reference to lightbulbs. Check around your home and you'll find bulbs in your lamps and lighting fixtures that likely range from 60 to 100 watts. While we sometimes think of this as how bright the bulb gets, it is actually a measurement of how much energy is required to power it. (Lumens is how the brightness of a bulb is measured.)

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Solar panels generate watts of electrical power by absorbing sunlight through either photovoltaic panels or mirrors that work to concentrate solar radiation. This energy is then converted into electricity, which can be used to power everything from that lightbulb in your lamp to an entire power grid. According to the Department of Energy, it takes over three million solar panels to generate one gigawatt of power, which can be stored and dispensed as needed.

How much power is one gigawatt?

So what exactly does one gigawatt of power get you? Well, it's a whole heck of a lot of light bulbs, that's for sure. Revisiting those 100 watt bulbs that are around your house, you could power about 10 million of those. Switch to LED lights, which have a much lower energy consumption, and you can power over 100 million of them. 

You could fully charge more than 9,000 Nissan Leafs, among the most energy-efficient electric cars on the market. For those who are looking for more power, how's this: One gigawatt is equivalent to 1.3 million horsepower.

Here's a more practical measurement, though: One gigawatt is enough energy to power about 750,000 homes.

How many gigawatts of solar energy are currently generated in the US?

Currently, the US generates about 97.2 gigawatts of electricity from solar panels. That is enough to power 18 million American homes, according to the Department of Energy. That is a huge increase from just one decade ago, when the country got less than one gigawatt of power from this renewable energy source, driven largely by the rapidly declining price of solar panels and improved availability for residential buildings. It is projected that one in seven homes in the US will have solar panels by the year 2030.

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How many watts does the average home need to be completely powered by solar?

The average American home uses 10,715 kilowatt-hours (kWh) per year, which works out to about 29 kWh per day. Since the average solar panel generates between 250 and 400 watts of power, the average home requires between 20 to 25 solar panels. This will vary depending on geographic location, sun exposure and the energy capacity of the panels. Regardless, solar energy helps to lower electrical costs for most people.

You can determine how many panels your home would require by using CNET's guide to how many solar panels you need.

How many gigawatts are needed to reach the US goal for 2050?

Under the current administration, the United States government has set out a goal of generating 45 percent of energy through solar power by 2050. That will require 1,600 gigawatts of power and lots of solar panels. Many will end up on houses and property around homes, but the government will also pursue opportunities to establish solar panel farms on land that is considered unsuitable for other purposes. As much as 0.5% of land surface area in the contiguous US would need to be occupied by solar panels in order to meet these goals with the current energy capacity that most panels offer.

Solar power is continuing to grow, both for personal use at homes and through government expansion to help power the electrical grid in a clean and sustainable way. In order to shift to renewable energy, generating lots of solar energy will be key. That means you should expect to hear a lot more about gigawatts in the future -- the more we are generating, the closer we get to the goal of a sustainable energy future.