The Solar Economy & The Re-Greening of the Earth

June 30th, 2008 | Posted by paul in Uncategorized

Despite climbing gas prices, and an ever growing threat of global warming, I’ve become more confident that a clean-green sustainable economy is on it’s way.  As hard as the gas prices hit the wallet, these higher prices could not have come at a better time.  There’s nothing like the pocketbook that gets people’s attention. As the cost of using polluting resources climbs, cleaner alternatives become more attractive.  What’s kept kept this transition from taking hold is a combination of powerful oil interests combined with not-cheap-enough renewable alternatives.  That’s beginning to change.

The most significant challenger yet to our traditional energy scheme is a company called Nanosolar.  Although they are mum on specific details of efficiency and pricing, what is clear is they are now printing (rolling) solar cells off in their production facility in excess of 100 feet per minute using a single $1.65 million dollar conveyor system.  Nanosolar is claiming efficiencies as high as 14%, with at least an average of 10%.  According to a press release on June 18th, they are now capable of printing 1GW of solar capacity per year.  And that’s just for starters. According to their CEO, the speed of these conveyor systems could theoretically be ramped up to 2000 feet/minute.  Even if they achieved a quarter of that speed, that same facility would then be capable of 5GW/year.  The current annual global consumption of energy from all sources is 5 x 10^20 joules.  This translates into 15 Terawatts of ongoing power output every second of every day.  If nanosolar alone were charged with converting the entire world to solar over 10 years, they would need 300 production facilities of equivalent size. In the scheme of things, this isn’t very much, however we don’t have to rely on just Nanosolar for our energy needs.  There are many other sources including geothermal, wind, as well as solar-thermal (the current choice for large-scale solar installations). One thing is clear, there is no reason we can’t convert all of the world’s energy production to clean-green renewables over the next couple of decades.   The traditional view is that such a transition would require huge subsidies from governments.  If Nanosolar can achieve the 99 cents/watt prices they claim, then no subsidies would be needed. Anything less than a $1/watt makes it competitive with petroleum based power sources, especially if prices per barrel remain above $100 (It’s currently above $140/barrel).  Assuming the entire worlds energy production were being produced in a single location in North Africa, below is a map showing the area needed:


The larger square represents the whole world, and the middle square represents the 25 countries of the European Union.  As you can see the amount of land needed is rather minuscule   This area was calculating using a conservative 8% efficiency. Luckily for us, solar power decentralizes energy production, eliminating the necessity for centralized power sources.  Like the PC before it, cheap solar power gives everybody the ability to produce their own power on their rooftops, the same way the PC put centralized supercomputer power on every desktop and laptop.  Below is an image showing a variety of large-scale sources and how they could be tied into a network supplying all of Europe, Western Asia and Africa with power.


Although it’s not clear form this picture, a positive and very powerful benefit to cheap solar power is radically cheaper desalinization plants.  Not only would Africa benefit from the economic boon of massive solar farms in the northern Sahara, but a huge increase in fresh water into Africa’s arid region, long suffering from drought, desertification, economic hardship and starvation. Even before these benefits are felt, desalinization itself has become cheaper, with current prices now below 50 cents per cubic meter of water.  And just a few days agoSiemens Water Technologies reported a new technology that desalinizes one cubic meter of water while using only 1.5 kwh of energy, which, according to the report, is one half the energy that other processes use.  Include cheap solar into the mix, and water from desalinization becomes 5-10 times cheaper than from traditional municipal sources.  What this means, is that vast areas of arid regions throughout the world could become beautiful green paradises, lush with vegetation, lakes,streams, farming and life.  The Sahara,and most other deserts in the world could some day look like this:


The Sahara Desert is a notoriously hostile environment where it is almost impossible to survive – let alone grow and thrive. The Sahara Forest Project is an audacious environmental undertaking aims to change all of that. The Sahara Forest Project aims to provide a new source of fresh water, food and renewable energy in hot, arid regions, as well as providing conditions to re-vegetate any desert region. Using an inspired combination of solar power and seawater, an ambitious collective of environmental designers, architects and engineers has plans to convert part of this harsh desert into a thriving plant paradise that will bring food, water and power to one of the most unlikely places on the planet.


The first critical move is to use concentrated solar power bring in vast amounts of solar energy via huge arrays of mirrors that will supply the installation with electrical power and heat. The second essential step is the employment of seawater greenhouses which uses seawater rather than tapping into the depleted underwater freshwater sources via wells. The solar power is used to evaporate the seawater, clean and cool it, and to spread the conditioned air throughout a system of greenhouses.

The result: cool air, plenty of freshwater moisture, and copious plant growth. What can be grown? Essentially anything you can imagine, including most kinds of staple produce found in your local grocery stores. Best of all, the seawater being used is rich in nutrients which can be used in the growing process which in turn minimizes the need to bring in external nutrient sources from outside of this closed system.

And outside of the system? Extra clean water can be released into the local atmosphere and create a regional microclimate that can sustain the growth of some kinds of plants that can live outside of the greenhouses. In the long run, then, not only can the greenhouses themselves provide food but the entire operation can improve the regional climactic conditions and repair environmental damage (such as fresh water depletion) slowly change the local ecosystem back to something closer to what it was thousands of years ago.

Along with abundant supplies of clean energy, transportation and other high power energy use can either be converted to electric or hydrogen.  Hydrogen can be produced by applying electrolysis to water. Everything from large transports to hypersonic aircraft can run on hydrogen fuel.  Meanwhile electric cars could be powered by solar generated electricity produced on the rooftops of the average home.

The average daily use of electricity of the American home is 30KWH.  In order to produce this much electricity daily using an 8% efficient solar cell would require approximately 500 square feet.  Each square foot would generate about 9 watts, which equates to 4500 watts for 500 square feet.  This would require less than 7 hours of sunlight a day.  Obviously many days of the year are cloud covered, and this is not considering the more northern climates which get less sun still.  However, 8% efficiency is very low, and I used it as a conservative baseline.  If you double the efficiency to 14% you only need 3.5 hours a day.  Also keep in mind, 30KWH/day is an American use, which is more consumptive than any other countries household in the world. Nanosolar is claiming an average of 10% efficiency, with highs of 14%.  With additional research there is no reason to think these efficiencies can’t go higher.  Some companies have already achieved 40% efficiency with some materials.  500 square feet of nanosolar cells at their current price would cost $4500, not counting installation and dc/ac inverters.  Still, as this technology goes mainstream, which it will, the costs will only go down.  Nanosolar is saying that once they scale up another factor, prices could drop as low as 30 cents/watt of production, or less than $1500 to have you total energy independence for yourself.  No more power bills, and with an electric car, no more gas bills either, not to mention the radical reduction in global carbon emissions.


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