When you look at solar panels, it’s unclear what they are really capable of. How many panels would it take to power a house? What about New York and the United States? Can we build a solar installation for the entire world? Let’s do some fun math.
Let’s start small and take one solar panel. Modern models are rated at around 350 to 600 Watts of power. The amount of energy that one panel produces in a day depends not only on its wattage, but also on positioning, weather, shading, and the number of peak sunlight hours in the area. Peak sunlight hours aren’t the same thing as daylight hours: it’s the time when the panel gets maximum irradiance and thus works at its full potential.
Let’s say, we have a 500-Watt solar panel in Los Angeles. It is installed correctly and nothing shades it. The average number of peak sun hours per day is 5.6. Knowing the wattage and peak sun hours, we can calculate how much energy one solar panel can generate per day:
500 W x 5.6 psh – 25% energy losses = 2,100 Wh per day
How can we use these 2 kilowatt-hours? We could watch a 50-inch TV for 24 hours or, if we store them in a battery, we can use them later to cook dinner on an electric stove or do the laundry.
How many solar panels would it take to power a house then? An average American house requires around 900 kilowatt-hours per month which is roughly 30 kilowatt-hours per day. A 7-kilowatt solar system often covers these needs. You would need from 12 to 20 panels to build it, depending on which modules you choose.
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But what if our power appetites are larger than one house? This is where we get into the territory of commercial solar systems. There is no single definition of a commercial PV project yet but generally, systems that are over 15 kilowatts in size are considered commercial. Business solar systems require high-output solar panels and take months and years to construct.
What if we want to power an entire street or city? For such a project, you will need megawatts of power, and to produce them, you will need a solar farm. Depending on how ambitious your project is, it’ll require from a few to hundreds of acres of land.
Generally, one megawatt of solar power with the inclusion of roads and necessary spacing between modules requires from 5 to 10 acres. It’s like two Walmart Supercenters put together. Putting together a 1-megawatt solar farm would require 1,500-2,000 panels. Built in a sunny place, this farm would produce about 5 megawatt-hours per day which would be enough for, say, 150 houses — a small village or a long city street.
What if we go further? How many solar panels would it take to power a big city, such as New York?
Fair warning: what you read from this point is a gross oversimplification. Since powering New York with solar only cannot be a serious project at this point, we’ll make our calculations as easy as possible just to get an idea of its scope. That’s why we’ll ignore factors such as variability of solar, daily and seasonal consumption patterns, transmission and conversion energy losses and many more.
Big Apple needs around 51 terawatt-hours of power per year, according to the New York Building Congress. That’s around 4.5 terawatt-hours per month and roughly 140 gigawatt-hours per day. This means that our imaginary system will need to produce 140,000 megawatt-hours daily to cover all the needs.
The average number of peak sun hours in New York State is 3.8 hours. Thus, we’ll need roughly a 40-gigawatt or 40,000-megawatt system. If we were to use our 500-watt panel, we would require 80 million PV modules. Let’s say that we’ll need 5 acres of land for 1 megawatt of solar power. The system would occupy 200,000 acres or 312.5 square miles of land. It’s like 50,000 Walmarts put together or five Districts of Columbia.
73.5 GW
installed solar capacity in the US by 2023
Technically, there is enough installed solar power in the US just for New York. Utility-scale solar capacity of the United States amounted to 73.5 gigawatts in 2023, according to EIA. Solar makes up 6% of the U.S. total energy generating capacity.
Now since we’re done powering New York, why stop? How many solar panels would it take to power the United States then?
Electricity consumption in the United States totaled 4,050 Terawatt-hours in 2022. This translates to a little over 11 terawatt-hours per day. We’ll deploy our system in a sunny place with 5 peak sun hours per day. What we need is 2.2 terawatts of solar power — 2 million megawatts. The number of panels in this system would come close to 4 billion. To build it, we’ll need 11 million acres of land. That’s over 17,000 square miles, more than Massachusetts, Connecticut and Rhode Island combined.
Time for the final challenge: how many solar panels would it take to power the world?
The world’s total electricity consumption is around 25,500 Terawatt-hours per year, according to the International Energy Agency. Thus it needs a mere 69.8 Terawatt-hours daily.
1 TW
total global installed solar power capacity
Let’s say that we’ll build an installation in a desert where panels would receive 7 hours of full irradiance per day. It means that we’ll have to build a 10-terawatt solar system. We’ll need to find 50 million acres of free land which translates to over 78,000 square miles. That’s bigger than the majority of European countries. Imagine North Dakota or the state of Missouri, but fully covered with solar panels.
Needless to say, we are quite far from ever building such a system. The total global solar power capacity amounts to roughly 1 terawatt, according to SolarPower Europe’s report. The experts say that this number will more than double, hitting 2.3 terawatts by 2025.
Our calculations are, of course, just funny numbers. Still, there is one more thing to point out: efficiency is the one thing where solar panels lag behind other energy types — you do need a lot of space to build a powerful installation. Still, panels get more modern and efficient, which means you get more energy for less space. Check out our article “5 new solar technologies to change the future of energy landscape” to learn more about our prospects to use solar energy!
Andrey had been a news editor and freelance writer for a number of medias before joining A1SolarStore team. Climate change and its impact on people's lives has always been among his interests and it partially explains his degree in Philosophy and Ethics.
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Years of experience in translation and a love of nature help Julia find the right words to encourage going solar. She joined the team in 2023 and is happy to make her contribution to a greener future.
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