How much solar would it take to power the U.S.?

Critics claim that there simply isn’t enough land in the U.S. for solar to power the country. While it’s not an immediately practical question, it’s still fun to ponder. So, ignoring practical constraints like storage and grid technology, let’s explore whether we can fit enough solar to electrify the U.S.

One approach would be to start with data points like the size of solar panels, the wattage they produce, and the number of sunny hours per year. Unfortunately, this approach produces wildly different answers depending on assumptions. A better approach is to look at real-world data captured from real-world solar arrays and just extrapolate from there.

Starting with some conservative assumptions from a 2013 National Renewable Energy Labs (NREL) report, we know that it takes, on average, 3.4 acres of solar panels to generate a gigawatt hour of electricity over a year. Given the U.S. consumes about 4 petawatt hours of electricity per year, we’d need about 13,600,000 acres or 21,250 square miles of solar panels to meet the total electricity requirements of the United States for a year.

The yellow square is approximately 21,000 square miles. Map courtesy of Google Maps.

How much are 21,250 square miles?

This may seem like an impractically large amount of land but not when you put it in perspective. 21,250 square miles is a square about 145 miles on each side . The U.S. has 3,797,000 square miles of land. Only about half a percent of that would be needed to provide enough solar energy to power the country.


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Here are some other examples of land use in the range of tens of thousands of square miles:

  • 40,223 square miles – this is the size of the land leased by the oil and gas industry (according to the US Bureau of Land Management).
  • 18,500 square miles – the amount of federal land offered for lease to the oil and gas industry in 2017 alone.
  • 13,000 square miles  – the US land that has been impacted by coal surface mining1
  • 49,300 square miles – the land used to grow corn for ethanol (USDA reports 91 million acres of farmland produced 14.99 billion bushels of corn in 2021, of which 5.2 billion bushels were used to for fuel alcohol)
  • 17,120 square miles – the estimated surface area of US roads (8.8 million lane-miles at an average 10 feet wide).
  • 49,400 square miles – the total amount of US land used for lawns (NASA reports there are 128,000 square kilometers of lawns in the US).
  • 22,000 square miles – the size of the Mojave desert, located in southeast California.
  • 2,200 square miles – the amount of Appalachian forests that have been cleared for mountaintop removal coal mining by 2012.
  • 3,590 square miles – a best guess at how much land is used for parking lots.

Actually, we probably only need about 10,000 square miles

Fortunately, we wouldn’t need to use all 21,250 square miles. NREL has another report conservatively estimating that rooftop solar alone could generate 34% of all U.S. electricity requirements.

Additionally, the solar arrays in NREL’s 2013 survey had efficiency levels of 13-14%. Modern solar panels average 16-17% efficient with widely available models easily exceeding 20%. Revising the estimates using higher efficiency and including rooftop coverage, only 10,000 square miles is required.

The total area needed to power the entire US with solar energy
The blue square is approximately 100×100 miles or 10,000 square miles. Maps courtesy of Google Maps.

Interestingly, Elon Musk shared a nearly identical metric during a speech to the National Governors Association.

“If you wanted to power the entire U.S. with solar panels, it would take a fairly small corner of Nevada or Texas or Utah; you only need about 100 miles by 100 miles of solar panels to power the entire United States. The batteries you need to store the energy, to make sure you have 24/7 power, is 1 mile by 1 mile. One square-mile. That’s it.” — Elon Musk

Elon Musk speaking at the National Governors Association in 2017
Elon Musk speaking at the National Governors Association in 2017

The Freeing Energy Perspective

Between land and rooftops, there is more than enough space to build all the solar panels necessary to power the United States. Realistically, though, the future of clean energy won’t be entirely solar. Hydro, geothermal, and, particularly, wind, will contribute their fair share as well. But, if we want to move quickly, solar is the fastest path to clean energy. It can be installed as small, easier-to-finance projects. It can be built faster than any other kind of energy. Solar’s small footprint projects are easier to permit and there are more places to put them. Unlike wind and hydro, solar can be built in virtually every state, town, and county in the country. And, as the cost of battery storage continues to decline, it will quickly become feasible to store daytime solar energy for use at night. 

Additional reading

  1. Large coal mines,” How much land has been disturbed by all surface mining in the United States?, retrieved July 14, 2019 []



75 Responses

  1. What about using solar to power all cars, trucks, etc., if we converted all gas vehicles to electric, and how do we get solar energy to remote locations for all vehicles?
    How much more solar than 101 sq miles?

    1. Great question. I’ll do some quick math here. According to the US Bureau of Transportation statistics, vehicles drove 3.2 trillion miles in 2017. Using a Nissan Leaf as an average, an electric vehicle gets about 30 miles per kilowatt hour. This means it would take 106 billion kilowatt-hours or 106 terawatt-hours or drive those 3.2 trillion miles.

      Since it takes 21,250 square miles of solar for 4 petawatt hours (or 4,000 terawatt hours), each terawatt hour takes about 5.3 square miles per terawatt hour. So, very roughly, if all US cars and trucks converted to electric vehicles, it would take 5.3 square miles x 106 terawatt-hours, or 562 square miles of solar panels to power them all.

    2. The first problem is that everything is looked as just needing to change energy source and even needing more energy for population growth. You really need to look at the problem from the beginning. Why do two people or even a family of six need to live in such large houses?

      No one talks about the ridiculous excess that we live, they just talk about continuing on with it and power it all in a different way.

      How many square feet do you really need to sustain life? The way that homes are built for energy efficiency is a complete joke. Why do we need clorinated and heavily filtered swimming pools sitting unused in back yards? How much energy and resourses are used when millions of people are driving millions of miles to huge stadiums where they watch others who are paid outrageous sums to throw balls around or those who do the same to see how fast cars can race around a track.

      Stop and think. It’s pure insanity so let’s all idolize a guy and and and an electric car that can do zero to sixty in 3.5 seconds and reach 160 mph. At the same time this guy is saying save the world from fossil fuels and says how his electric car can out run an ice. Wouldnt the bragging points be about how the new vehicle used minimal resourses to transport people at no more than the legal speed limits? Its insanity.

    3. The rough math — to cover the 3.22 Trillion Miles driven in the US, with about 250 Watt-hours per mile — works out to about a 20% increase.

      But then when you take away all the Electricity now used to Drill, Pump, Refine, and Retail that Oil — as Gasoline and Diesel — the net increase is more likely to be around 10% Net Total — to replace all US Ground Transportation as Electric.

      We normally plan on increasing US Grid and Generation Capacity at least 1 to 2% per year, but recent improvements in LED Lighting and other Energy Conservation is leaving much of the US Grid at surplus, already. So this would all be covered in a few years.

    4. LOL you are using 2013 data in an industry that doubles its efficiency every 2 years !. If it needed 21,000 acres before. Its likely been close to cut in half three times since the 6 year old data. 21,000 down to 10,500. 10,500 down to 5,250. 5250 down to 2,625. I bet my answer is WAYYYYY closer than yours. In 3-4 more years we will have a very good working battery and the acres needed will be manageable. Go do some work. LOL

    5. It is possible that the solar energy evolution will produce vehicles with built in solar panels and converters, thereby making vehicles self-refueling and consequently reducing the need for charging stations and acreage for solar panels. Buildings will also provide roof top solar panel stations and thus reducing land use as well.

  2. I think that the title may be a bit misleading… there are lots of energy uses which are not included in that 4 petawatt-hours/year figure (which mearly looks at “electricity usage”.

    Total U.S. energy consumption (all end-uses, so this includes transportation that Steve was asking about as well) is about 97.3 quadrillion BTU or 28.519 petta-watt hours.

    That works out to needing about 151,500 square miles (not including battery area) which is nearly the area of California.

    I think this points to the need to pursue a balanced clean-energy portfoilio including solar, wind, batteries, hydro, and nuclear. (it would take around 3,255 square miles of nuclear plants, for example)

    1. Thanks for sharing these insights. I had hoped by using the term “power” rather than “energy” that it would be implied I meant electricity and not all energy sources. Either way, you raise a very intriguing point about the fundamental challenges of accelerating electrification in transportation and industrial heating. Can you point me to some sources that go through more of this math in depth? For example, how does energy to power transportation change (higher or lower) when it becomes electrified? Also, are the EIA data you cite the energy delivered or energy used? For example, for transportation is that data how much energy is used by the vehicles or is the potential energy available in the gasoline before it is combusted? I ask because converting to the equivalent electricity may or may not be 1:1 (because electric motors are more energy efficient than combustion engines)? Thanks for raising this and I look forward to exploring it more.

    2. (I don’t see a reply button on your comment – so I’m commenting above)

      That’s a good point – they seem to be measuring fuel consumption, not energy produced! For transportation (and for heating for that matter) you aren’t getting 100% of the possible heat out of the fuel. Typical modern ICE cars get around 25% thermal efficiency ( ) by contrast a modern natural gas power plant gets around 62% efficiency. That means that electrifying transportation is a massive savings in carbon even if those cars are charged with natural gas power plants. (around 2.5 times more energy per unit fuel)

      After generator, transmission, distribution, and charging losses – electric vehicles get around 85% of the power that is generated into their batteries (around 15-20% of the power is lost

      So if transportation makes up 27828 trillion BTU, at ~25% thermal efficiency, only around 2.038 pWh were generated (instead of 8.155). With charging/transmission losses, we’d need to generate about 2.4 pWh to actually charge 2 pWh worth of EVs.

      In other words, you save about 5.75 pWh through increased efficiency by moving away from ICE cars. Reducing your total generation need from 28.5 pWh to 22.75 pWh.

      Natural gas heating is pretty damn efficient – so you don’t get much savings there. Maybe 0.5-1 pWh.

      There is already around 300 tWh of hydro installed in the U.S, and around 800 tWh of nuclear. So that helps a bit.

      So the problem is a little less bad then I let on before… 109,393 sq-miles instead of 151,000. I still think this would be an envioronmental disaster to use that much land for solar/wind, not to mention the unbelievable amount of rare earth metals it would require ( ). I don’t think there is very much hydro resource to develop in the U.S. – so that leaves Nuclear (and realistically a little natural gas for flexability) to fill in the base load generation in my opinion.

    3. Great points all around. A few more thoughts…

      Heating, particularly industrial heating, strikes me as one of the largest challenges in transitioning away from fossil fuels.

      I think we’ll see electric vehicle charging become more and more local with community scale solar reducing the need for long haul transmission (and the associated energy losses from natural gas, distribution, etc). The fact that cars are idle most of the time, especially during the strong mid-day sun, means solar charging can be very flexible, somewhat mitigating the intermittency challenges. This isn’t a panacea but I think it’ll help a lot.

      Your point about hydro is spot on but one expert I interviewed reminded me that there are 73,000-ish dams in the US, the vast majority of which don’t have hydro. Collectively, these dams could add microhydro facilities and hydro could once again see its contribution rising.

      I too struggle to with how much land might be needed but given how much is already used for oil and gas leases as well as growing corn for ethanol (an economically and environmentally debatable practice), it’s arguable that the land could be put to better use.

      Lastly, on the rare earth materials, my research leaves me increasingly encouraged that running out of this stuff is less an issue than I had thought. I touched on this a little bit in my recent article:

    4. I believe Jared is making a valid calculation. We need to consider all energy uses if the plan is convert all industry, transportation, residences, etc. to renewable electric energy. I checked his numbers and they look accurate according to the link given which is to the EIA (Energy Information Agency). So to initiate the Green New Deal, to convert everything to solar would require at minimum 151,500 square miles of panels not including batteries. So for the panels we need at minimum 400 miles by 400 miles. For batteries, assuming Musk is right, 4 miles by 4 miles. Still doable. I yes, panels can go on roofs. I’m ignoring the recalculation below because the population if growing and if look to the future, more energy will be required.
      Jareds statement, “I still think this would be an environmental disaster to use that much land for solar/wind,..” is something to think about. The number is a little less than the entire State of California. How much land and water and air has been polluted and destroyed by mountain top removal, strip mines, coal mines, oil drilling, fracking, ??? But still we can’t cover that much land with panels or even anything close to it. Even half of that. So, with that in mind, I think the only solution besides returning to pre Industrial Revolution lifestyle, is to develop nuclear power plants that 1) will never meltdown, and 2) do not produce ridiculous amounts of radioactive wastes, and better, use the waste materials from the nuclear plants currently operating as fuel. We need a Manhattan Nuclear Power Plant Redesign Project. Note that such designs do exist but need work. For example; Lead Cooled Fast Reactor. See Wikipedia.

    5. the 20K square miles was off by a factor of 2 and way out-of-date.

      It was covered in the Article above.

      More realistic numbers are 10K square miles — but that is dropping all the time.

      But far worse, trying to mix in “Energy Equivalent” units between sources turns your numbers into total nonsense — sorry.

      The supposed “Embodied Energy” or such of Oil (especially) and Gas (some what less) are So Lossy when put into use — that your likely numbers beyond the simple Electricity equations are likely to be off by as much as a factor of 10X.

    6. I’m aware embodied energy =/= energy produced; that’s why I included a thermal efficiency of ~25% for ICE cars and ~60% for power plants. Because that represents how much of the embodied energy gets extracted.

    7. Even with 25% as the through put from fuel tank to wheels, it ignores the losses before retailing. The overall path from “Well-to-Wheels” (which would be the “embodied energy” on the front end to what it actually produces on the final end) is more likely down around 10%. Dunno if you follow how much internal process energy it takes to refine Oil?

      But when the numbers are getting that wild — a better path than trying to guess “equivalents” is to just add up the actual path from Solar Cells to Wheels — if that is what one is actually trying to model. Those numbers are now pretty well known. Sampling Tesla(s) and Chevy Volts/Bolts — you can reasonably allow 250 Watt-hours per mile, with the 3.22 Trillion Miles driven. That is what the complete Solar Cell to Wheels model actually looks like — without having to hearken back to any existing equivalents.

    8. By all means, let’s cover the State of California ! Just kidding. Very interesting discussion. Glad to see thoughtful points of view. So, if there was a solar field @ 151k miles, what is the useful life of such a large construction? I seem to remember a $billion dollar+ Solar Facility (mirrored rays focused on a tower) near Tonopah, Nv that didn’t last and was monthballed way before it’s end-of-life.

    9. Our math assumes photovoltaic solar panels, which have a lifespan of 30+ years. Newer panels are starting to offer even longer warranties. The system you mentioned is very different… it’s a concentrating solar thermal system. This has lots of moving parts and a very different economic model as well.

  3. I believe the environmental impact of solar and wind energy is far more devastating than just leaving things the way they are and building a new type of car engine or cleaning up the exhaust. The last innovation in that direction was the catalytic converter and unleaded gas in the 1970s – 50 years ago. I see beautiful, tree-covered mountains blighted with these gigantic science-fictional monstrosities and hillsides and fields filled with glass. Both have a terrible effect on wildlife, especially birds. And how much power, really, does a solar panel or windmill produce? Honestly? What a horror it would be to the environment instead of putting our heads together and coming up with an alternative. Where is the ingenuity that built the internal combustion engine or nuclear power plants. All innovation today is geared towards coming up with the next fastest computer chip or cell phone network. Innovation that made this country great is dead.

    1. Keep an eye out for an upcoming article we’re writing on the environmental impacts of solar. Here’s a quick preview: lots of land (as you point out) but less than we currently use to grow corn for ethanol, 70-90% recyclable, novel applications like roads and parking lots that use land already allocated for something else. But there is also great research going into better ways to use fossil fuels. One of my favorites is NetPower and their zero-emission natural gas turbine.

    2. This is a fatalist approach to scientific advancement in energy. There could be one million fatalist views on any prospective subject, solar panels on mountains shouldn’t be a disqualifying factor. Government regulations exist for such reasons.

    3. You are right. Read Robert Bryce or Roger Pielke Jr. They are both experts. Bryce has his background in oil, Pielke has no ax to grind.

      Solar power won’t work. The money machine is set up. Too many subsidies, people are making mass amounts of money on two already hopeless technologies. Nuclear is a great answer, but for some reason it isn’t being built.

      To fulfill his vision of an emission free grid by 2035, the U.S. needs to increase its carbon-free capacity by at least 150%. Expanding wind and solar by 10% annually until 2030 would require a chunk of land equal to the state of South Dakota, according to Bloomberg and Princeton University estimates. By 2050, when Biden wants the entire economy to be carbon free, the U.S. will need up to four additional South Dakotas to develop enough clean power to run all the electric vehicles, factories and more.

      Here is a link to this Bloomberg article.
      You should be able to open it if you haven’t used up your free views. Otherwise copy and paste the headline into google as it is reproduced in other publications.

  4. The land currently used for parking lots could be used for solar with the side benefit of providing covered parking.

    1. Fantastic idea. In fact, I just finished doing a podcast interview with the founders of Quest Renewables, whose company is providing canopy solution, largely for turning parking lots into solar farms. Keep an eye out for this later in June.

  5. Are these numbers based on this area operating at 100% capacity all the time? In 2017, wind and solar operated at 100% capacity about 30% of the year. So whatever number they cam up with, probably needs to be tripled. And does that area also contain the batteries? Or does that also need to be factored in? What about transmission and substations?

    1. These numbers are based on the energy produced by actual solar projects, so they include bad weather and nighttime. In other words, the approach used here takes existing (albeit old) projects and just extrapolates them to country-scale.

  6. Just 1 problem, Bill… in the first 3 pages of the NREL linked doc, you are off by a factor of 1000. MW, not GW. There is a stark difference between arithmetic and mathematics, as well as science and engineering. It’s called accountability. Zero emission combustion of any fuel is impossible… basic thermodynamics. Do yourself a favor and befriend some application engineers. If you can stand the brutal peer review based in facts, you’ll learn something.

    1. Brian, I really appreciate everyone who takes the time to join in and discuss these issues (and my math) – that’s exactly why I put these articles out there. In fact, I have had a few readers point out ways I can improve my logic or math (although, usually a bit more politely ) and I am delighted to update the articles in question.

      Let me address each of your points in turn.

      MW, not GW: I’m afraid you are reading the data and interpreting the article’s math incorrectly. This article uses a single piece of data that occurs in two places in the NREL report (, Table ES-1 (page v) and Table 9 (page 19). The data cited comes from the column titled, “Generation – weighted average land use (acres/GWh/yr)” where the unit is not gigawatts (GW) or megawatts (MW) but, gigawatt HOURS PER YEAR (GWh/yr). Multiplying the 3.4 acres/GWh/yr by the approximately 4 petawatt hours per year (PWh/yr) or 4,000,000 gigawatt hours per year (GWh/yr) of electricity used in the US results in the 13,600,000 acres of 21,250 square miles presented in this article. Since many other analysis on the topic of US solar results in a 10^5 scale answer (in square miles), I have some confidence that this article’s math is not off by a 1,000 (10^3). You’re probably not the only person who got the units confused so I will update this article to include the detailed math (and units) as well as more recent 2018 US electricity generation data. Of course, I may still be miscalculating something so please check my math again now that I’ve laid it out.

      Zero emission combustion: I’m afraid I don’t follow your point here or what it has to do with this article. Perhaps you’re referring to another article? Either way, I’m not sure I agree with your statement. For example, combustion of hydrogen is zero emission, that is unless you consider water an emission. Either way, I invite feedback so feel free to provide a bit more context to your point so I can update whichever articles you’re referring to.

      Application engineers: I am grateful to count all kinds of engineers among the Freeing Energy readers, including PhDs, scientists, practicing engineers and application engineers. These generous folks occasionally suggest ways to improve the logic or math of my articles, and I gratefully and humbly make updates accordingly. Fortunately, like all of us that want to see more clean energy in our future, their feedback has never had to be brutal. Regardless, in all cases, I most definitely learn something, as I have from your feedback, too.

      I respect and admire your passion for the accuracy of this important math. I hope you will continue to read our articles and offer your suggestions (and corrections where appropriate) so that this critical dialog on clean energy can be as high quality as possible.

  7. There are countries with deserts. They could produce natural gas from CO2 with solar energy. The distribution network already exists, and the consumers would not need to change anything.

  8. Available sq. mile are not as abundant as one would think. NJ has 967 people per sq. mi. We also have very little room to handle our ever expanding population growth without compromising protected areas.Our electric is overloaded during summer months. We also have a great electric demand just to power fossil fuel burning heating systems.The demand would grow at least 4 times what we now consume in electricity. Google earth our cities and look at what a challenge it would be to eliminate fossil fuels for heating our home and buildings.Don’t forget it takes at least four times the BTU’S to heat than to cool. The wattage needed to generate heat from electric is also much greater by at least three times. Methane gas is also worse than CO2. If we don’t burn it it would just be released

    1. These estimates are just an exercise to show that powering the US with solar requires a lot less land than most people think. In practice, the solar panels would be placed across the US, most likely very close to the population centers consuming the electricity. There are some studies on the transmission required for wind, which is far more sensitive to its location, but I have not seen a comprehensive study on transmission required for solar. Fortunately, the more distributed the solar resources, the less reliance on transmission lines.

  9. To get a good intuitive sense of the problem, watch this video:

    Unless we can built batteries that can store large amounts of energy for months, we actually need to build significant overcapacity, around 4x – 8x as much solar as is being shown above because of the seasonal variation in the solar flux and weather as well as the need for reliability. So we are really talking about over 500,000 square miles if we used just solar without counting the area needed for transmission and battery storage.

    The US, including Alaska, is only about 3,500,000 square miles. So using diffuse sources like solar that also suffer from intermittency may have far a greater environmental impact than most people realize. The truth is that we need a portfolio of different energy sources as over-dependence on any one type exacerbates its short-comings

    1. Great points. A lot of of work has been done on solar overbuild. This team puts the overbuild closer to 2x, or about 40,000 square miles, which is a great deal easier to imagine than more conservative approaches. Regardless, your point about relying on a very diverse set of generation sources is spot on. Check out our podcast this week on the incredible and untapped opportunity for distributed hydro. Lastly, I’ve interviewed several battery execs in recent weeks and I am increasingly optimistic that long term storage is coming sooner than most people are expecting.

  10. It seems your calculations are wrong. The Kauai island Solar farm mega project from Tesla is using 45 acres to produce 13Mw. If you calculate from that base up to 4 PetaWatts, you will need 13.600.000.000 Acres, 1000x more, or 21,250.000 sq. meters of land, roughly 5.6 times the size of United States.

    You would have to cover US almost 6 times over to get the same amount of energy.

    1. Thank you so much for catching this! There was a typo that mischaracterized the units being used in the math. It originally said, “4 petawatts” and it should have said “4 petawatt hours”. All the previous numbers were in energy (watt-hour based) and this sentence left off the “hours” by mistake. It’s now fixed. I’m assuming other readers clicked on the link to wikipedia and overlooked the incorrect unit type but I’m glad to have it corrected now.

      So, hopefully it makes more sense now. Just to be clear the US uses 4 petawatt HOURS per year, not 4 petawatts. Your numbers for the Kauai project are in power (watts) which is different than the (energy) watt-hours based math in this part of the article. So, fortunately, we can still power the US with 21,000 square miles of solar panels :-).

    2. Thank you so much for catching this! There was a typo that mischaracterized the units being used in the math. It originally said, “4 petawatts” and it should have said “4 petawatt hours”. All the previous numbers were in energy (watt-hour based) and this sentence left off the “hours” by mistake. It’s now fixed. I’m assuming other readers clicked on the link to wikipedia and overlooked the incorrect unit type but I’m glad to have it corrected now.

      So, hopefully, it makes more sense now. Just to be clear the US uses 4 petawatt HOURS per year, not 4 petawatts. Your numbers for the Kauai project are in power (watts) which is different than the (energy) watt-hours based math in this part of the article. So, fortunately, we can still power the US with 21,000 square miles of solar panels :-).

    3. Your math is wrong. The US is 3.8 million square miles. That is 9,826,675,000,000 square meters. Do you mean kilometers? It still doesn’t work out.

    4. Hi Craig, I’m afraid I need a bit more detail on where this page’s math is wrong. Your calculations on the square meters is correct but the page’s math never mentions square meters or square kilometers so it’s not clear how your calculation is relevant to the page’s math.

      The square miles of solar needed to power the US has been published dozens of times, from writers to national labs. There is some good debate within a range of 10k to 25k square miles but all the math results in similar orders of magnitude. If you would like to share your detailed math, we’ll happily review and correct this page if there is an error.

  11. At what cost? Solar power is perhaps the least dense source of energy in our world. As with any energy source, it needs to be available when needed so storage of this energy is at issue and battery technology is not there yet. It also has to be available where it’s needed, so transfer stations that convert the power to high voltage AC that tie into existing lines are at issue. Each step results in power losses. …and for those occasional weeks without sunlight batteries are not able to store enough power, redundant systems that can meet the daily energy demands are required (natural gas fired power plants). Any talk of hydropower or hydroelectricity will run up against environmentalists who are actively seeking to dismantle the hydroelectric capacity we currently have. Both solar and wind have environmental consequences that are not effectively addressed. Look what happened to endangered tortoises in this Mother Jones article ( The Audubon Society believes that Wind Power places hundreds of bird species at risk ( More energy is best and man has been seeking it from more dense sources since he began burning dung. These dense sources have improved the lives of 100s of billions of people across the globe. Are you (i.e., we) so certain that the move toward solar, wind, and the waves isn’t a giant leap backward for mankind? There are millions of people in Africa, India and China who still burn dung for fuel.and are dying as a result ( My $0.02

  12. This isn’t possible. To produce and deliver energy to consumers needs an intricate network of power distribution. The system that we use today needed expensive power electronics to function on the grid (Meeting 60hz at transmission level voltage). Power also degrades over distance, meaning to send power over the entire US would need a massive network of power storage. Battery and power storage technology is improving, but it is not capable of sustaining a system as we have now. There are so many problems with this solution that really don’t have realistic answers. If we would want to build a more sustainable energy future it would have to be nuclear.

    1. Fortunately, solar is easily distributed. Unlike nuclear, wind, or coal, it can be scattered across the country, often on the distribution feeders themselves. In many cases, solar will require LESS transmission than centralized power generation options. As power electronics and batteries continue plummetting in price, solar will become a much larger portion of the grid that it has today.

    2. Call me crazy, but how would a primarily solar-panel-supplied system fare when the way overdue super-volcanic eruption occurs? This is NOT an IF but a WHEN. We have positive historic proof they happen on a schedule. Ice-cores have indicated that near equatorial regions became ice-covered tundras when the volacanic ash suspended in the upper-atmosphere for years!
      If we build our energy infrastructure ignoring this, we are inviting planet-wide extinction.

  13. Bill, do you have an estimate of how much installed solar and LT storage would be needed given the different average and peak capacity factors currently and projected to be incurred on an aggregate or better yet, state by state basis. If you are serious about your answer, what are the numbers backing it up and are we looking at a comparable level of system reliability?

    1. By LT storage I mean two weeks plus which is not available currently using electro-chemical storage and most topological hydro sights have already been used. What is your estimate of build/overbuild and how did you derive it?

    2. Thanks for chiming in Gary. You are asking the single most critical question. I’m not a scientist but a lot of people pointed me to the work from Mark and Richard Perez ( I’ve interviewed Marc if you’re interested in a high-level view of his work ( Because overbuild and curtailment are a provocative idea, I created a non-scientific overview of how it works and why it makes sense ( Also, some recent work out of MIT indirectly answers your question by identifying the cost of long term storage that needs to be hit ($20/kwh) to make it cheap enough to allow for deep penetration of intermittent solar and wind ( Other sources that make me believe storage will be sufficiently available and affordable come from my interviews with Jeff Chamberlain (the protagonist in the Powerhouse book and now CEO of VC firm Volta) and with Bill Gross (Energy Vault). Also, the rise of V2G and EVs means the marginal cost of distributed storage is likely to go down dramatically and the volumes of storage available in the next 10-15 years are more than enough to substantially peak shave at a grid scale and lower overall electricity prices).

  14. So, here is my question. If every roof, residential, governmental, commercial, in the US was covered by solar; and if every parking lot or top floor of multistory parking lot, including industrial, university, etc., was covered by solar, how close could we come to taking care of the problem? Even a constitutional conservative would go along with mandates for this kind of effort, if the owners of such properties were able to either buy or lease the solar product, or alternatively to allow the utility to own the panels. Other than the constraints of how fast we could build the panels and install, this would seem to be 5-10 year potential solution.

  15. Jesus Christ, that is ridiculously large area. Its not about the area only, its about maintaining that. That would be a massive mistake. The way forward is Thorium with Solar and wind supplementing. Solar/wind/hydro/geo together cannot come close to meeting the demand of our consumption, and if you think so, you’re delusional as to what it would take to maintain such a stupidly large infrastructure. its called overhead and maintenance. You ALL need to get educated about Thorium or we are going to be doomed by coal for the next 100 years while finally buying out plants from China that got their original blueprints and data from USA Oak Ridge!

  16. I thought thorium reactors were still in the research stage. I didn’t think there were and commercial reactors.

  17. There is already free energy, been here all al along, Tesla proved it. I have a couple ideas, 216-414-6866 Chris S

  18. Hey, thanks for posting this useful content on how much solar would it take to power the U. S. presented here, I really hope it will be helpful to many. I hope you keep updating us with such great tips and information in future too. This is a great post; I will share as much as I can. Appreciative content!!

  19. Not much need to create “solar farms” that will only consume more precious open land. Solar panels should be employed to shade parking lots and every roof surface possible, which would also help with issues such as urban heat shields. Solar farms are only a way for the moneyed interest to maintain their control of the lucrative industry.

  20. And whose paying for all the retro fitting of homes and businesses? All the upgrades to each place? And whose paying for all these new cars? And whose paying for the special service setup to plug these vehicles into? It’s not just a setup of solar panels… whose paying for all the infrastructure? at simple minded people

  21. Calculations appear largely correct at face value, but how do we get the power generated in the middle of a New Mexico or Arizona desert area to demand areas? A tremendous percent of electricity generated, as much as 80%, is lost in transmission from power source to ultimate demand via the grid. Right now electricity generation is spread across the US, unless solar panels are positioned around the country in the same manner I believe there would be much, much more transmission loss, which would increase the implied demand numbers significantly.

    Right now there are significant areas of the US that do not have enough sunny days to rely on solar as a primary energy year round. Power would have to be generated elsewhere and shipped and the same transmission loss issues would arise.

    Lastly, electricity demand is unstable; demand rises and ebbs seasonally and even within the day, and solar power does not have “surge capacity” to meet peak demand during high demand. So solar panels would need to be built to cover peak, not average demand, which is much higher than stated, or other sources would need to be used to cover peak demand. Over reliance on solar and hydro power is a big contributer to rolling blackouts in California during summer peak demand now.

    I believe solar is (and should be) in the mix of sources of power as part of the base demand where it makes sense. I do not believe it is ready become the dominant much less exclusive source of electrical generation.

  22. Hi Bill, I found it conspicuous that you have left out basic losses of efficiency inherent in solar power. 1.) loss of power when converting PC to AC current (~30% loss)
    2.) loss of power when charging a battery for night time use (~20%)
    3.) loss of power during transmission (loss varies depending on wattage)
    By ignoring these very basic facts about solar power you’ve come to a flawed conclusion. It calls into question the veracity of the whole article for me.

    1. Hi and thanks for the feedback.
      1. The conversion loss is actually taken into account because the numbers I extrapolate are AC already
      2. I attempted to acknowledge the real world limitations of batteries in my upfront statement, “…it’s still fun to ponder. So, ignoring practical constraints like storage and grid technology…”
      3. See #2. Fortunately, transmission loss is fairly small 5-6% so even if I had included it, the numbers would not change materially

      This is just a fun exercise meant to show that the scale of solar panels are a fraction of what people expect (or have heard misinformation about). Fortunately, the actual solar panel size would be far smaller than I list here because the panels are increasing in efficiency every year.

  23. Super interesting! I was curious to see how fixed vs tracking might affect results, and was surprised to find this in the NREL study you cite: “land use per unit of generation would increase moving from fixed systems to 1-axis tracking systems and moving from fixed systems to 2-axis tracking systems.”

    Apparently trackers allow you to use fewer panels, but they require more land per panel, so their net effect is actually to *decrease* land-use efficiency! Not what I expected.

  24. How many square miles would be needed to be mined for the lithium, nickel, cobalt and mangenese used in ev batteries?

  25. How many children and slaves in other parts of the world will be needed to mine the toxic minerals and metals needed to produce the solar panels and batteries to power the U.S.? An incalculable number. How many will die in the process? How many are dying right now in this process? Questions that solar and other “clean energy” advocates will never ask since they don’t want to know the answers, or don’t care about the answers.

  26. You don’t need to generate a year’s worth of energy 8n a day or two.

    Think there is some major dysfunctional arithmetic going on here.

  27. The amount of solar energy required to power the entire United States depends on various factors such as energy consumption, geographical location, and technological advancements. However, with the increasing adoption of solar power and advancements in renewable energy technologies, solar has the potential to play a significant role in meeting the country’s energy needs.

  28. there are approximately 24,000 square miles of parking lot in the US, Just cover the parking lots with solar panels. no need to use some portion of unused land, just cover parking lots, mall and shopping center roofs and the roofs of government buildings and we’ve got all the space we need.

    1. Hello, C_MO, can you share your source on this information? As I’m sure you saw in this article, we could only find data that supported the total square miles of parking lots being about 4,000 square miles. Your data suggests parking lots would solve all solar needs and it would be great to update the article to reflect this. But we are sticklers for citing solid sources and we hope you’ll share yours with us.

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