How Much Land to Power The Whole World with Solar?

That's a humongous amount of land, actually. It would be vastly more efficient to use local, spread-out power in various forms combined with improved efficiency.

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editor note: The map just shows what it looks like, I don't think Matthias (the author) meant it as a blueprint for what to do. It's a way to visualize data.

Of course, solar can be distributed, and it doesn't have to use unused land (rooftops, etc), and at ~20% efficiency it would take less than half what's on that map, and there would also be wind, efficiency/conservation, wave, hydro, geothermal, etc.

Nice idea, it translates to roughly 180 square meters per person (or 1900” square)
By my estimates that is not practical at this moment.

" it translates to roughly 180 square meters per person "

Is that at 8% efficiency?

Lets say we have panels at 20%, that's starting to look better. Especially in conjunction with hydro, wave, wind, etc..

We'll get there eventually because most clean technologies are still improving quite a bit, the whole problem is to get there soon enough.

Out of curiousity, why is 8% used? I guess what I'm asking is, what is the current average effieciency of a solar panel these days?

Distribution would be a bit of a problem considering the amount of energy loss through the transmission lines.

Lizzy,

8% might have been used to be conservative, I'm not sure..

But I think that the average solar panel today is around 16-18%, and the best ones are around 20-22%. If I remember correctly, photosynthesis is only a couple of percent efficient.

"Distribution would be a bit of a problem considering the amount of energy loss through the transmission lines."

Only if it was centralized. In the real world, solar is usually less centralized than the current power plants we have (gas, coal, hydro, etc), so there is actually less losses.

There is a LOT of confusion evidenced in these comments: Lets put this another way:

6 Solar Power Stations could power the entire world.

Just place them in the densest solar areas marked by the 6 black spots.

Confusion reigns! Better titlewould be

"6 solar power stations could power the world"

The comments show no one gets it. They think you need to fill the entire orange area full of solar power stations.

How about having floating solar farms in the doldrums of the world's oceans.
No land used. Little threat from storms.
Some the highest solar irradiance is in the equatorial regions of the ocean.

With SunCube concentrated solar power module at over 35% efficiency now available for purchase (in Australia), Solar power is finally coming of age.

Those example areas are located in the hottest, sunniest spots on earth – one of them is in the middle of the Sahara, another in the Empty Quarter of the Arabian Peninsula, others in the Atacama desert, the Australian outback, the Gobi desert. They call them deserts because they're deserted, and they're deserted precisely because they're way too hot and sunny for human comfort.

Solar panels distributed in the areas where people actually need the power would take up several times that much land.

No one, anywhere near those places, needs anything like that amount of power, except maybe the one in the southwestern USA. So the concern about transmission losses is extremely apt – you'd lose a great deal of energy shipping it from those remote hot-spots to where people actually live.

About transmission losses, one commenter offered:
"Only if it was centralized. In the real world, solar is usually less centralized than the current power plants we have (gas, coal, hydro, etc), so there is actually less losses."

Quite correct. The best thing about solar is that it's easy to set up locally, so you save the cost of building a grid, finding land for transmission towers, etc..

But look at that insolation map, and check out the densely populated areas of the world, where large numbers of energy consumers live. Europe? Not sunny at all. North-eastern US? Japan? China? Nope.

The best prospects for solar as a mainstay are in India, Indonesia, Brazil, places like that, where energy consumption is going up, where there are lots of people needing it, and where there is still quite a lot of sun, if not as much as in those desert sunspots.

I'm happy to see solar power presented as a viable alternative, and not just a niche source. But there's no point in fooling ourselves about how easy it's going to be.

Remember the Inga dam on the Zaire River? Massive power generation capacity, unfortunately in the middle of nowhere. Cost over a billion dollars, added 25% to the existing debt of Zaire, enriched a few insiders – and got turned off after less than a year, because no one nearby needed the power. Aswan? Much the same, though at least it's still running.

Solar power is wonderful for many purposes, but we do ourselves no favours by ignoring practical realities in boosting it.

Why not just float them in the ocean? Seems like there is a ton of unused surface area to be used

Nobody has considered what the environmental impact of deferring that much solar radiation away from the Earth's crust would do. The same problems arise with wind generated power; interfering with the Earth's wind patterns could (and almost certainly would) have an unforeseen impact upon our environment. So if this is an alternative to fossil fuels, are we jumping out of the frying pan and into the fire?

Besides, we've got more than enough oil reserves to meet mankind's demands for the next few hundred years (including growth). I'm willing to mortgage the future on the assumption that someone will come up with a more efficient energy production mechanism than solar panels... :-)

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editor note: btw, trees "divert" a lot more sun and wind than we could ever "divert". Mountains and buildings and hill are interfering with wind an order of magnitude more than wind turbines.. Same with solar.

How about the land area for Concentrating solar powerSP?

Main Wikipedia article

I think it is just illustrative of the amount of land relative to the amount of available land. The difference between 8% and 20% efficiency is offset by many other factors in the negative direction; for example, losses due to transmission (up to 50% even in traditional power generation) and storage (for access at night). Further, electricity is not a replacement for all operations; gasoline, and the infrastructure around it, is going to be hard to replace even if we had effectively infinite energy.

I think distribution would end up being a huge problem. Only half the planet is lit up at a time. The other half is dark and would need power from the other side. Storing the energy is both inefficient and additional environmental burden. Also take into account some of the larger cities in the world that have seasons where they get very few sunny days. The power would have to be drawn from another region.

As I recall, A fairly vast amount of energy is used to actually go get the oil. Flame me if I am wrong but I seem to recall the industry has gone from 3 barrels spent, to acquire 10 barrels, to 7 for every 10. So unless the number is in these equations, the area drops dramatically again.

But, don't quote me, I am just remembering some lecture about the whole 'peak' oil concept from a while back. There are some funky numbers like this for nuclear too, amount of coal consumed to generate the power to follow nuke energy through the life time of plant building, mining, etc.

I really think everyone is missing the point.. its not a road map its a proof of concept. Ofcourse not putting panels where the map has them would reduce efficiency and therefore the proof of concept is kind of skewed. They're just trying to make a very visual very public (see hoping for bandwagon effect) point. Things like this peak public interest .. its got 401 diggs last time I checked .. its working.

There are more then :
6 power stations can power the world.

Ridiculously untrue.

-This assumes, we some how have non-resistance method of sending power to the rest of the world (that's called a super conductor... we don't have any at normal temperature at the moment).

- The little black dots... they are the size of several cities. For a solar panel to work properly, it needs to be cleaned. This puts places like the desert out or the sea, where rain or dust would make it dirty, and lessen their efficiency, by a lot.
Who or what is going to clean all of these everyday?

-Centralized energy is an ideal dream living in an idealized world, much like how only physicist will simplify a horse into a sphere for calculations.

It's something that needs to be built up and pre-planned, not something that we throw in later to fix problems.

I think some people may be missing the point of this. We are a long way away from powering the whole earth with solar power the way things are going. The picture shows just how possible it would be to completely power earth with nothing but renewable resources. The logistics of the whole thing is a lot more complicated than setting up 6 solar power plants. That was my first impression of the picture.

The Gobi desert isn't hot. The term desert applies because it is ARID.

http://en.wikipedia.org/wiki/Gobi_Desert

The Gobi desert is a cold desert, and it is not uncommon to see frost and occasionally snow on its dunes. Besides being quite far north, it is also roughly 900 meters (2,953 ft) above sea level, which further contributes to its low temperatures.

I wonder what effect there would be on the ecosystem to remove this much solar energy from those areas? Isn't solar heating one of the main things that drive weather patterns?

Why not just string a power cable from the Sun to earth?

Some people are really taking this too literally. Think of the roof top space in all of America, and compare that to the size of the dot. If we spread out the dot to every rooftop, you save tons on transmission costs albeit lose some to suboptimal solar rays.

Those dots look pretty small on this scale but the one in the SW USA is 170,455 km2, given infrastructure and workers quarters, this would be almost the size of the entire state of utah(220,000 km2), plus you'd only be able to build in certain areas, mostly the flat or gently sloping hills. Given these requirements, a solar powered north america would probably require the entire usable land of nevada and utah.

There will be no easy solutions to our energy problems, no single magic pill, only a complex combination of advanced, efficient technology and cultural change.

@Dunsie 1900 square inches? That's tiny. I think you mean 1900' square :-P or, more conventionally, 1900 sqft.

@Susan K Indeed.

@Dominic Brown No, see. You have to be clear with stuff like this, otherwise you get clueless people taking off from it:"We'd have to cover Texas with solar panels to power the world! Solar sucks!" Besides which, this really isn't a new calculation, it's been done plenty of times before, and it this incarnation lacks so much as others have pointed out. What would have been interesting would be to star from an established calculation, and then determine how much of that can be satisfied with roofs, parking lot trees, etc.

Personally, I still think satellite-based solar ("XPS") is a much better idea. You don't have to retrofit buildings, or smother deserts.There are other advantages too, such as being able to suppy continuous base load (regardless of local solar time) if the system is designed right.

i love the idea, but if some one gets greedy and cuts a major line, or if there is an attack, a whole continent goes down. not smart.

I believe that 8% was used because in the past it has been the standard efficiency.

Of course we would spread it out, put the panels wherever we could.

Panels could be placed in the unused land that borders free ways or in the median. During parts of the day they would act as a sunshade for drivers. They would have to be continuous, or the flashing light / dark would get very annoying.

This example is based on a centralized model of power distribution. The real advantage and key to the success of solar power is "Decentalized". Local, small and portable. Energy production needs to be controled by people and communities, not corporations or goverments.

Many of you are being too limited in your thinking. Just because you're generating electricity from the sun doesn't mean you need to keep the energy in the form of electricty. Much of that could then be used to generate hydrogen, which gives you additional alternatives for distribution and use (fuel cells, clean combustion, etc.)

Yes, you can't practically replace every form of energy with just solar. That's not the point. We could, however, replace a large part of our current usage.

I've heard of some bad ideas before but putting solar panels in a freeway median takes the cake... if someone loses control and crosses over they get to go offroading on solar panels with sharp pieces of metal, plastic, and chemicals adding to the danger. Not to mention that over a 10 year period most of the panels would have eventually ran over.

And there's no better way to improve highway safety than to have sunlight, streetlights, and car headlights reflecting at strange angles off solar panels.

How about, you set up TEN power stations, and use the excess power to separate hydrogen from salt water?

Knight2000 anyone?

Really, if you set up the equivalent of ten of these things and engineered it right, couldn't you maximize ground space, and shade a significant portion of the Sahara, and make it a little more hospitable?

Of course, the danger would be changing the ground surface temperature of a significant portion of a MAJOR climatological affector. It could eventually produce more (or less) hurricanes in the Americas...

For that matter, they could probably put a solar panel on every horizontal surface in the regions indicated, and charge batteries for electric cars and then ship those batteries around the world.

The upside to that plan would be a reduction of particulate reflective pollutants produced by burning fossil fuels. This reduction would reduce the effects of global dimming, and as the amount of ground surface light returned to pre-industrial age levels, the amount of solar power collection would actually INCREASE, which is a good thing, because we'll need more air conditioning, as the ground surface light will increase everywhere also!

There are two obvious problems with solar power generation that I see:

First, DC current doesn't transmit as well as AC current. You get a lot of power loss over just a short distance with conventional copper, or aluminum wire. That could be diminished if a major breakthrough in room-temperature superconductor technology were realized. But understand, most of the locations indicated on the example map are anything but "room temperature". It would have to be a SIGNIFICANT breakthrough indeed.

Second, we may not have the raw materials to make all the soar panels required for an equivalent of six to ten power stations, much less the material necessary for some kind of exotic and new super conductor technology. And I don't know if anyone's taken into account the amount of raw materials necessary to make all the batteries required to power all the automobiles in the world.

However, with cheap, renewable power, the possibility of a decent, safe, and reliable public transportation system is not entirely out of the realm of reason, with the remaining fossil and organic-based fuels reserved for high-torque applications, like earth-moving equipment and semi-trucks.

This is an amazing vision which 'may' apply to an ideal world under ideal lab conditions. Unfortunately 1. the cost of building those and grids (current grids cannot handle such a huge entry point) will probably be more expensive than digging into the center of the world (or stringing a power cable from the sun, for that matter), 2. the technology is not there yet: 8% is acceptable for wind, but not solar. We should be talking about 20%-30% before we move in, 3. Solar energy uses batteries; 3.a. We need to change the old good AC electricity, hence the foundation and who knows, move to DC-type storable electricity use, 3.b. Current battery technology sucks; can you imagine the waste after 20 years? How will you dispose of them later? Drop them down the hole towards the center of the world? Rocket them to the sun?

The vision is fancy, but solar can only be local. Use solar/wind/thermal locally and you will suddenly see that, it is not that hard after all. It is applicable locally everywhere and needs nobody else's decision, but yours. Hybrid cars are a joke, but self-sufficient, human/nature powered anything is the future. This is what all those big guys are fighting about nowadays; shall we say goodbye to fossil and huge money attached to it, or shall we simply fund the rersearch on alternative and not encourage but push people to buy it? I wish the latter but...

Middle East, Russia, South America will all produce and sell fossil as long as they have it. China and India will use fossil (as the US and Europe did in the past) no matter what we do/say and blow up the CO2 and claim their huge share in the global climate change. There is nothing that anybody can do about it. We have to wait for and watch those guys to become rich of their industrialization era. Do you really think those moguls care about the frogs in the forest (and the forest)?

Bottomline; do your part. I have thermal heating/cooling (yes cooling) installed for our family house and more and more riding a bike to go to work. Once we see the advantages ourselves and show it to people, it just becomes the way to go around. Now my neighbors are following the trend and chipping in to install similar systems...

If the government was seriously concerned about clean recyclable energy sources we would have all been provided with them by now. The sad truth is that they are holding us at a stand still right now. Not only would it save the American and world population from troubles in the future (Polution, costs of burning fuels, Wars...), other energy solutions would boost the economy tremendously. It would be almost like a new era of jobs and employment opportunities. The possibilities are there, but just unused. It wouldn't have to be solar panels across the country, which isn't a bad idea, most efficiency would come from solar paneled rooftops, a wind mill in the back yard (possibly one of the most power generating and location friendly energy solution), electric cars for each home! A little bit over time adds up. Just like bills, $5 a month for this $5 a month for that before you know it you are spending $30 a month on nothing. Same concept with energy. You could be saving so much if there was an attempt to save just a little bit of energy. And don't tell me that "Oh that would cost sooooo much money our goverment couldn't do all that for us. Blah blah blah" crap. No...they can. $300 Billion dollars + a day on a war in Iraq for how many years now? think they could supply their own country with the means to be energy efficient if they were set out to do it.

I think distribution would end up being a huge problem. Only half the planet is lit up at a time. The other half is dark and would need power from the other side...

That's right, so solar energy is only part of the near-term solution. Nothing is going to replace petroleum's convenience: it's liquid, easily transportable, and has very high energy per unit weight and volume. Clearly we can never make an airplane fly by using unconverted solar energy!

The point here is that the direct use of solar energy could make a very significant contribution without occupying unacceptable amounts of land area.

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editor note: We can make airplanes fly using biofuels (which are basically a converted form of solar power).

i am surprised at how many commenters missed the point of the illustration: that solar energization does not entail covering a large fraction of the planet with collectors. The picture does not intend to show locations of proposed centralized solar power plants; it's more like a pie chart: a graphic representation of a statistic designed to show relative scale.

That being said, it would be educational to see a similar illustration of the amount of the earth's surface devoted to strip mining coal or drilling, transporting and refining petroleum.

I once saw an old old animation where people build a satellite that collect energy all day non stop. Then at specific times of the year the satellite will just bean back the energy to earth. It's science fiction but to me that is actually the best way to farm sunlight. No land needed, no weather factor, and the satellite will always face the sun. Of course we still need to figure out how to bean the energy back :)

Take a drive from SoCal to Vegas or Phoenix and you'll glimpse thousands of square miles of sun-baked desolate land just perfect for a few gi-normous solar farms. One day...maybe 3 years, maybe 5, maybe 10, but it "will" happen, the total cost per solar KWh is going to fall to that magic threshold level of ROI viability--the economic tipping point--and the amount of investment (gasp-capitalism) is going to absolutely explode. Can y'all say "mo-back"? .. I thought we could. And this is virtually inevitable; semiconductor technology has gone and goes in one and only one directlion: cheaper and better. Oh, and the transmission line issue? One word: superconductors. Add to this equation all the nanotech-driven advances in electric-hybrid battery/supercapacitor/fuelcell technologies and we will have an unstoppable way forward to energy independence success. Once the economics fully align in this direction, the engine of market forces will be simply inexorable. And the important point? All this is brought to us by (would have been impossible without) our current, incredible, fossil fuel-based, global consumer economy...

Solar power is getting more and more efficient and smaller, just like cell phones and computers. Check out the Nanosolar company.

Bear in mind, all those dots put together are about the size of California. It's certainly not impossible, but it's no small feat. :)

Why do you have to buy those $20,000 solar system when you could rent with a small security deposit and no maint. worries.

I don't know what everyone else is looking at that says the black dots are the size of a couple of cities. The one black dot in North America alone looks like it would blot out the majority of Texas. Something tells me the people in all of Nevada wouldn't be too happy living under giant solar panels. Plus, you could have an array that is 100% efficient and it still wouldn't work too well on a cloudy day or at night. Also, it would take more energy put into constructing the arrays, building infrastructure, and necessary maintenance then you would get out of them for a long long time.

Sure these alternative energy ideas all sound neat, look impressive, and give us warm fuzzy feelings deep inside. However, at the end of the day we still us petroleum because of simple economics. If were to seriously go after one of these alternative sources of energy we would have to face the grim reality that quality of life would degrade significantly for an extremely long time. You just can't get something for nothing.