New study says world can be completely powered by clean energy in 20-40 years


January 27, 2011

According to a new study, 100 percent of the world's energy needs can be met by renewable sources in 20-40 years

According to a new study, 100 percent of the world's energy needs can be met by renewable sources in 20-40 years

Here at Gizmag we cover a seemingly endless stream of renewable energy technologies designed to wean us off our reliance on fossil fuels and improve the health of the planet. As important as such developments are, for these technologies to have an impact they must of course be implemented – and on a large scale. What has been sorely lacking is a plan to accomplish such a Herculean feat. Now researchers from the University of California-Davis and Stanford University have published a study that details one scenario to completely convert the world to clean, renewable energy sources – and they say it could be done in 20 to 40 years using technology available today at costs comparable to fossil fuel-based energy.

Electricity the key

The two part paper coauthored by Stanford researcher Mark Z. Jacobson and Mark Delucchi, of UC-Davis, evaluates not only the technology required, but also the costs and material requirements for converting the planet to renewable energy sources. Their plan would see the world running predominantly on electricity, with 90 percent of this sourced from wind and solar. The remainder would be made up from geothermal and hydroelectric sources, which would provide around four percent each, while wave and tidal power would contribute the remaining two percent.

For our transport energy needs, cars, trucks, motorbikes, ships and trains would be powered by electricity and hydrogen fuel cells, while aircraft would be fueled by liquid hydrogen. Commercial processes would also be powered by electricity and hydrogen, which would be produced using electricity. Meanwhile, our homes would eschew natural gas and coal in favor of electric heaters, while water would be preheated by the sun.

20 to 40 years

"We wanted to quantify what is necessary in order to replace all the current energy infrastructure – for all purposes – with a really clean and sustainable energy infrastructure within 20 to 40 years," said Jacobson.

To that end, the plan would see all new energy generation coming from wind, water and solar by 2030, and all pre-existing energy production converted by 2050. The researchers say that the millions of lives saved by the reduction in air pollution and a 30 percent reduction in world energy demand – thanks to the conversion of combustion processes to the more efficient electrical and hydrogen fuel cell processes – would help keep the cost of such a conversion down.

"When you actually account for all the costs to society – including medical costs – of the current fuel structure, the costs of our plan are relatively similar to what we have today," Jacobson said.

Addressing variability of solar and wind

To overcome that variability of wind and solar and ensure there is a reliable base load of energy Jacobson says wind, water and solar energy sources could be combined as a single commodity as they are generally complimentary. Solar peaks during the day, while wind generally peaks at night, and hydroelectric could be used used to fill the gaps.

The plan also envisages the connection of geographically diverse regions using long-distance transmission to overcome energy shortfalls in a given area. If the wind or solar energy generation conditions are poor in a particular area on a given day, connecting widely dispersed sites would allow electricity to be provided from a few hundred miles away where the sun is shining or the wind blowing.

"With a system that is 100 percent wind, water and solar, you can't use normal methods for matching supply and demand. You have to have what people call a supergrid, with long-distance transmission and really good management," said Delucci.

Additionally, off-peak electricity could be used to produce hydrogen for the industrial and transportation sectors and, as it is today, pricing could be used to control peak demands.

Material considerations

While the large-scale construction of wind and solar power plants would require large amounts of materials, the researchers found that even rare materials, such as platinum and the rare earth metals, are available in sufficient amounts for their plan to be realized. They say recycling could also be used to extend the supply further.

"For solar cells there are different materials, but there are so many choices that if one becomes short, you can switch," Jacobson said. "Major materials for wind energy are concrete and steel and there is no shortage of those."

Crunching the numbers

The researchers also calculated how many wind turbines, solar plants, rooftop photovoltaic cells, geothermal, hydroelectric, tidal and wave-energy installations would be required to provide 100 percent of the world’s energy needs. They found that 0.4 percent of the world’s land would be needed – mostly dedicated to solar – and that the spacing between installations – mostly wind turbine spacing – would add another 0.6 percent, much of which could be used for other purposes.

"Most of the land between wind turbines is available for other uses, such as pasture or farming," Jacobson said. "The actual footprint required by wind turbines to power half the world's energy is less than the area of Manhattan."

Long way to go

Already 70 percent of the hydroelectric sources needed to realize the plan are already in place, but only about one percent of the wind turbines required and an even lesser percentage of solar power. But the researchers say their plan is doable.

"This really involves a large scale transformation. It would require an effort comparable to the Apollo moon project or constructing the interstate highway system," Jacobson says. “But it is possible, without even having to go to new technologies. We really need to just decide collectively that this is the direction we want to head as a society."

Th researchers two part paper appears in the journal Energy Policy.

Via Stanford University News.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

you know, 50-30 years ago when looking at the year 2000, they said we would have flying cars, robotic butlers and all manor of cool things.

some how, this article reminds me of those dreams from the past.

William Jolley

HAHAHAHAHAHA. Complete nonsense. The only way they make the numbers work is to fudge the \"evironmental\" costs of fossil fuels. The baseload claims are absurd. The boilerplate installed capacity will have to be at least double the actual demand to come close to ensuring a reliable power supply, and this doesn\'t even begin to address the added costs of a significantly expanded and upgraded transmission grid. And, please, please, please, please, get over the obsession with hydrogen. It\'s a crappy storage medium that is inefficient, leaky, and low energy density.

Plasma Junkie

It is too much optimism. Rven simple box type solar cooker which is more than 50 years old is stll to take off!

Dr.A.Jagadeesh Nellore(AP),India

Anumakonda Jagadeesh

The authors are not proposing anything fantastical, just the widespread implementation of what technology already exists. All it takes is the will to do it! Which of course the coal gas and oil companies will fight and lobby to the death to weaken and stop.


Total garbage. The footprint of wind and solar compared to nuclear is about a thousand to one. Then, the storage issue.

The title of the article should be \"clean energy 20-40 years ago\" if we had not allowed hippies to kill nuclear for no reason whatsoever. And now look at the terrible cost.

Todd Dunning

Very good new but wrong (as other people have said before) and anyway coming too late. In the next 30-40 years, climate change will have provocated some more wars, new diseases, thousands of hungry people and more than you can imagine about catastrophic events, of the earth and of the societies!


I can believe that some of this will happen for simply financial reasons. There is money to be made in renewable energy production. We have come a long way in the last ten years, from green energy being seen as a pipe dream of extreme environmentalists to now having gigawatts of installed wind farms, with significant tidal projects in development. All the turbine manufacturers worldwide are booked up for at least two years, there is simply not enough manufacturing capacity to meet demand. Green energy is mainstream now for one simple reason; its profitable.Having said that, coal will be a large part of the mix for the foreseeable future. Its profitable too, so the fact that it may well lead to the extinction of our species (among millions of others), just doesn\'t count. Money talks.


I think that\'s wishful thinking... Can you comprehend the changes necessary to bring \"green\" power to the back corners of India, Africa, China, Tibet? There are likely places here in the U. S. that still don\'t have telephones.

Harold Garey

Hydrogen is the deal breaker, for reasons already stated. Unmentioned is the source of hydrogen. Currently, we obtain ALL our hydrogen from oil. So this proposal does not free us from fossil fuels.

I support efforts toward clean energy. But this is pie-in-the-sky talk.

Facebook User

Unfortunately this excellent plan relies on people being unselfish but wherever wind farms are proposed there are always selfish people who don\'t want to see them ... or worse still, the local gliding club think it will interefere with half a dozen people\'s expensive part-time hobby!

Karrie Hidderley

@Todd Dunning - \"no reason at all\"? Really, terrible nuclear accidents, terrible safety record - no methodology for disposing of the waste other than \"let\'s tip it down a big hole and come up with a new language so that our ancestors in 100,000 years time will know when they read the sign that taking the seal out will be a really bad idea.\"

I\'m pro-nuclear, but only with a proper thru-life infrastructure in place too. Modern Fast-Breeder reactors theoretically should limit the amount of nuclear waste that needs to be processed, but that needs to be thought out now (or indeed 20 years ago), before we build the plants. However, it\'s too late I suspect, for nuclear to span the upcoming power gap...


As with all such studies, the authors overlook the fact that in order to undertake this massive effort we would have to greatly expand the expenditure of fossil fuels to build the infrastructure for a total renewable energy system. Since the total renewable energy supply currently at hand provides only a tiny amount of the total needed (less than 5% worldwide), any program that relies on a renewable \"breeder\" operation (building renewable components using only renewable energy) would take much longer (probably a couple of centuries).

There are other unrealistic assumptions as well: the roadblocks set up by regulatory agencies that prevent any rapid construction of any energy project; the difficulty of getting the end products to the individual consumers (conversion of millions of homes from oil or natural gas heating to electric alone faces hurdles of expense, regulation, and workforce availability); resistance to even renewable energy projects by environmentalist organizations (litigation against wind, solar, hydroelectric projects - look it up yourself).

Only a world totalitarian state could even attempt to undertake this project, and even then the practical realities faced would stretch the timeline to more like 50-75 years.

Pat Kelley

@harold, Not sure of your point. Are you saying it would be EASIER to get conventional energy sources to these places? Without the embedded infrastructure in place these would be the easiest places in which to adopt renewable technologies.

This article and most of the comments suffer from the same flaw. They assume the same infrastructure, i.e. universal use of automobiles, centralized energy production, etc. It\'s as if when the use of automobiles started gaining traction, we were forced to use railways instead of the goverment investing in roadways. I would like to see the study that is willing to abandon many more assumptions about what our energy and transportation infrastructure will look like in the future.


If we do reach such a panacea, it will be nuclear that does the heavy lifting for the base load. I doubt any of the readers will live to see most 18 wheelers powered with totally clean fuel...but maybe bio-diesel.


We must live in an instant gratification society to the extent that people are so polarized on both sides of the question as to whether or not this can work. I agree with the President that we have to spent alot more effort and resources on clean, renewable energy as opposed to \"clean coal\"--which is an oxymoron. Instead of dismissing this proposal out of hand, can\'t we work toward a renewable energy goal and just all get along? Or at age 66, am I just being too naive?

Facebook User

Pat Kelly makes the most important point: to do this will require the expenditure of great amounts of fossil fuels. That is why the (suborned!) media keeps harping on global warming and taxes on fossil fuels. Once the taxes are in place, fossil fuels will be too expensive to use for the building of a new infrastructure as envisioned here. The result: Can you say, \"Massive Die Off?\"

I have been a Libertarian most of my adult life, but clearly the \"free market\" will not fill this need without an intervening die off. Only the demands of the people for unilateral government action will get a program like this going in time to avoid a complete collapse of society. Why would those who run the media want such a catastrophe? There are groups of very rich and powerful people who think that after the die off, they would be the new kings.

Sweet, huh?


For generations, we have had the cleanest, most efficient power source already up and running. We all wish wind and sunlight worked. But they require over a thousand times the land and resource footprint of nuclear.

Power generation is not about being politically correct. It is about generating power. Alternative energy technology is already highly developed, but there\'s just not enough there.

You want to get off oil and coal? You can tomorrow by switching to nuclear. All the ad campaigns and Green This and That aren\'t going to make the unicorns dance hard enough to get electricity out of love and warm feelings.

Todd Dunning

I wish people would stop knocking hydrogen. It is well on its way to being practical for mobile equipment like cars, trains, etc. It stores indefinitely and can fill the gap that is currently held by diesel and gasoline. Batteries can fill some to the gap but you cant \"fill\" them quickly. Hydrogen is NOT a fuel source, it is a container for energy that can be produced a variety of different ways. It seems like people knocking the use of hydrogen are just making a brainless knee-jerk response. Its actually very useful. They have been using it as energy storage for decades in almost all space missions with the help of fuel cells. It also is the cleanest burning fuel around.

Rustin Haase

Changes to greater use of renewable sources is good sense as we become more efficient in extracting energy from various sources. I think that the predicted 2% for tidal/wave (and Ocean Currents which were not mentioned) should be higher. A high percent of the world\'s population lives close to the sea. The technology of overcoming problems of anchoring, corrosion and maintenence that need to be addressed before full industrial effort can be made in this direction.

Until about 10 years ago, China had to import most of its wind technology but once the engineers understood what was required, they were able to set up plants of their own. The same should prove true with ocean devices.

Adrian Akau

Technically, tidal energy is not renewable. There is only so much of it. I\'d like to see a study to see just how much energy there is in the earth moon rotation/orbit system. If we used all of it up, the earth\'s period of rotation and the moon\'s orbital period would be the same. (kind of silly sounding really) Regardless, tidal power slows the earth\'s rotation and there is only so much kinetic energy there. It is probably so much that we don\'t need to worry about it but I\'d like to see the numbers. :)

Rustin Haase

It\'s doable. If you accept a little less than 100% it\'s very doable. A pragmatic approach might be to accept some nuclear for base load generation and continue to use petroleum for specific purposes like transatlantic air travel. Nuclear won\'t serve anything other than base load--it has to run 24/7 to be economically viable. It may not even make the cut against solar and wind. Consider a real nuke project in planning, a twin reactor in Levy County, FL that now looks like about a Billion dollars per megawatt. Capital costs alone will be on the order of $.15/kWh. Add in operating costs and you\'re not far from power from photovoltaics.

w ferree

One wonders why the use of tide generation isn\'t in the mix. It is a constant, reliable energy source that is underused. Further to the nuclear question, checkout Thorium at to find a source that is greater than uranium and is far less damaging timewise when spent d;-)


I\'ve heard Einstein say something to the effect, \"Man has entirely too much power at his disposal and to make matters worse,he wants even more... and he can\'t even safely handle what he already has!\" Very paraphrased,of course.

Yet, I ask this-we have desire but do we really have need? I greatly prefer the benefits of technology to primitive conditions yet we are clearly demonstrating that as a race we assume that access to creature comforts and convenience devices are a right- not a privelege (those of us that have such privileges)

However, something as simple as the lack of fresh water causes unspeakable misery for a huge portion of this world\'s population while we prattle on about the various merits of hydrogen vs. nuclear,etc.

The earth is 3/4 water and we cannot even effectively remove the salt and distibute it?

We lived long without the benefits of electricity- let us remember that we DISCOVERED electricity- we did not invent it.

It is a privilege,not a right.

Our responsibility as stewards is to God,each other and this planet WITHOUT prioritizing those three responsibilities.

If you reject responsibilty to God, I still implore you to consider each other and our future.

We need to examine our behavior and our motivations and ask ourselves 2 simple honest questions: Are we a success as a race- are we really doing what\'s best for our world,each other and our future?

Do we really deserve more power- considering what Einstein observed, are we really handling what we already have any better than when he originally made his observation in the 1950\'s?

Be honest with yourself- I know what I believe.

I do what I can to make a difference and eventually, I hope to die trying and never retire. I encourage you all to do the same, to the uttermost.


This is a bad plan. We already have a much better one...

Google Patrick Kelly\'s Chapter10.pdf Look on page 50. Read about people who are running 5KW generators off of Hydroxy and Cold fog, zero pollution, zero cost after generator, electrolyzer, fog device purchase. All we need now is for people to find out about it. That is all.

Charles Michael Couch


Maybe we should stop looking at why it is theorized it can\'t happen and look at how we can make it happen. The fact is, if we continue employing the same insane methods of energy production and participate in wasteful energy use, we will cause our own extinction. The Earth has shown it can repair itself at the expense of putting a stop to the cause (species extinction). This is really not about how to better produce energy to save the planet, it is about how to better produce and use energy to save ourselves. It is better to focus on the real issue, address it, and solve it through innovation that bolsters the economy with as close to zero negative environmental impact as possible so that the Earth has the time and resources it needs to heal itself. It can be done.

Facebook User

The utopian dream using current technology would be devastating, from the absolutely filthy method currently prevalently used of extracting the rare earth metals to the immediate replacement of the infrastructure that would be primarily constructed using equipment and factories primarily powered by fossil fuels; we won\'t even discuss the shear expense of upgrading current end use of every public building to private residence as opposed to the eventual replacement as they age with higher efficiency new construction, we have seen the consequences of central planning with the ill conceived US cash for clunkers, higher income individuals prematurely replacing perfectly good vehicles that were destroyed, median to lower income forced to keep their older vehicles because the used car market became deprived of the vehicles destroyed . Free markets and industial innovation will eventually move us toward a far superior solution than central government planning ever could.

Michael Gene

Love all the comments!

I saw a very interesting way to encase nuclear waste in glass which is then encased in drums etc... And buried. Nuclear waste for each member of the family for a year is the size of a dime.

Zero would be best but honestly today\'s nuclear is the way to produce the most for the least. We only produce a little less than 19% of our total electricity with the cleanest source!

Coal accidents and associated health costs are pretty sad if you take a look at them, much worse than nuclear worldwide (including Chernobyl), but they just don\'t produce the images that come with the word nuclear.

Dr. Veritas

yeah, guys, what the other one said: just another \"study\"

did you realize you actually have to \"implement\" the plan and for the \"plan\" to be a \"success\" before a \"plan\" is more than just another waste of paper?

cheap plans are a dime a dozen

Fred Meyers

How amazingly weak this study is. I see no mention of many promising technologies and solutions - especially algae. Algae both absorbs CO2 from dirty fossil fuels such as coal and gas but is also sustainable, cost effective, clean and creates fuel that is dropable into todays engines, etc. It can also now be used for any and all oil based products such as pharma, chemicals, feed stocks, etc. This algae to fuel business is in test production sites around the globe particularly with dirty industries like utilities (coal based). It really is cleaning up smoke stake polution by diverting it to algae growth production, extraction and refinery systems. The airlines are particularly interested. Why is none of this in this very restricted \'study\'? Inquiring minds want to know.


I agree with the energy guru at RMI, Amory Lovins. He said we would have no energy problems if we had a level playing field, e.g., no government intervention. The market works just fine solving economic problems if left alone. How? We don\'t exactly know, but it seems that without gov regulation or interference of any kind, i.e., freedom, we have prosperity without limits.

One possible solution is to decentralize production. Distributed energy avoids the cost and loss of transmission. Local solutions for local problems would come about through individual innovation. In 19th century America, before suffocating regulations, it was called \"Yankee ingenuity\".


How many people posting here read the actual published papers?


this gizmag is terrific . lots of hope and ingenuity. I get lots of e mails from them, and you can subscribe. no i dont get $ for referring, just sharing

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