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Could These 2 Breakthroughs Solve Solar Power's Biggest Problem?

Editor's note: A previous version of this article stated that it would require 214 million Gemasolar stations to meet the world's energy needs, when in fact it would only require 214,000.

Solar power holds the theoretical potential to solve all the world's energy problems. For example, in just one hour the sun shines enough light on the earth to power the world for a year.

The problem is harnessing this nearly limitless, clean, and renewable power when and where we need it. I recently wrote about Japan's innovative efforts at solar space-based power. This article brings the concept of solar breakthroughs down to earth and looks at two exciting technologies that could allow solar power to come into its own as a practical future power source.

Solar power at night
One of the major weaknesses of solar power is that it's intermittent. Clouds, storms, and the setting of the sun can lower or eliminate power output. This means that traditional power sources such as gas, nuclear, or coal are required to maintain a base load. 

Concentrated Solar Power, or CSP, potentially offers a way around this issue by combining solar power with mirrors and a liquid energy storage medium. 

Source: Torresol Energy 

Terrosol Energy, a Spanish concentrated solar company, has designed the Gemasolar station to generate 20 megawatts of power -- enough for 30,000 homes. 

Mirrors, a total of 2,650 of them, concentrate sunlight by a factor of 1,000 onto a tower where molten salts are heated to 1,050 degrees Fahrenheit. The molten salts can be stored in tanks and used to generate steam to spin electricity generating turbines up to 15 hours after the sun has set. This technology allows for solar power to be generated around the clock and has a capacity factor of 75% (generating maximum output 75% of the time). This is in between gas-fired power plants, whose capacity factors range from 25%-50%, and nuclear plants which run at 90% of maximum capacity.

All told Gemasolar can produce 60% more power than a similarly sized solar panel installation, but there are two problems with the design. First, the size of the installation is enormous, requiring 480 acres of land. Given that in 2012 global power demand was 23,500 TWh, this means to generate all the power demanded by the world using this design would require around 214,000 Gemasolar stations and take up 103 million acres of land.

Second, the cost of the station is estimated to have been $260 million, or $13 billion per GWh of capacity. To put that into perspective it's 2.7 times as expensive as traditional solar power and 13 times as expensive as gas-fired power.

Gemasolar is expected to achieve a positive return on investment in 18 years, but Terrasol Energy is attempting to bring down the cost by scaling up concentrated solar with its Valle 1 and 2 plants, which together generate 100 megawatts of power, enough for 80,000 homes.

Source: Torresol Energy

Unlike the tower design of the Gemasolar station, the Valle power stations use a parabolic trough design. Sunlight is focused onto a glass

parabolic concentrated solar source Torresol Energy

tube containing thermal oil, which is then heated and used to generate steam. Like the tower design, this technique can generate power when the sun isn't shining and the cost is 44% less per gigawatt of capacity than the Gemasolar station. Unfortunately this method also has major drawbacks. 

For one, the cost, though lower, is still $7.3 billion per gigawatt. Second, the area required is mind-boggling with a total of 1.1 million square meters of solar collectors. Finally, the heat storage capacity of this system is just 7.5 hours, meaning it can only operate around 4,000 hours per year, vs 6,000 for the solar tower design of Gemasolar (and 2,000 hours for traditional solar technology).

Concentrated solar may offer a way for solar to provide all day power, but its enormous land area requirements and uneconomical cost make it unlikely to ever solve the world's power needs.

Massive solar cost savings needed
A Durham, North Carolina start-up called Semprius is working on a way of stacking miniature solar cells (each just a millimeter across) together to achieve unheard of efficiency and cost savings. By growing layers of different semiconductor materials, each capturing a different frequency of light, the company has been able to build a solar cell with 44.1% efficiency. Semprius thinks it can eventually achieve efficiency beyond 50% (double current solar cell efficiency) within three to five years.

According to Scott Burroughs, vice president of technology at Semprius, with sufficient economies of scale his company's technology could result in solar power costing just five cents/KWh. That's 22% less than the cost of a new gas-fired power plant (6.4 cents/KWh) according to the U.S. Energy Information Administration.

Solar power, despite its amazing potential, still has a long way to go to overcome its two largest hurdles -- constant output and high cost. However, advances in innovative solar engineering techniques and material sciences are helping to solve those issues and may one day usher in an era where the sun may be all we need to power the world.

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Read/Post Comments (28) | Recommend This Article (19)

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Help us keep this a respectfully Foolish area! This is a place for our readers to discuss, debate, and learn more about the Foolish investing topic you read about above. Help us keep it clean and safe. If you believe a comment is abusive or otherwise violates our Fool's Rules, please report it via the Report this Comment Report this Comment icon found on every comment.

  • Report this Comment On August 17, 2014, at 12:16 PM, PeakOilBill wrote:

    Good solar articles. I like nuclear plants, myself. To people who complain about the high cost of both of them, ask them if they would rather have expensive electricity, or no electricity after the fossil fuels start to get scarce. We can't wait until then to decide to build a replacement electrical generating system. That day isn't as far away as many ignorant people believe. They can't seem to grasp the definition of the word, 'finite'.

    I would guess that photovoltaic cells will continue to get more efficient. That could change the world, and possibly save it. You don't want to try and survive on this planet without electric power.

    People say that they do it in third world countries. But they forget the vast amounts of food and other products that such poor countries get from places where the electricity stays on, in order to build and transport all that stuff. People in developed countries can't go back to subsistence farming. Try to do that, and the vast majority of the population would starve to death. Food doesn't grow instantly.

  • Report this Comment On August 17, 2014, at 12:56 PM, hygro wrote:

    Look at GTAT which has just released a very thin silicon solar material, also integrates conductive material into the panels for direct energy capture.

    Also have doing the iPhone sapphire screen and various other interesting technologies. Just starting to take off.

  • Report this Comment On August 17, 2014, at 1:57 PM, Freddyfreebe1 wrote:

    Is it fiction to think that this planet don't need those same energy resources we are pulling out of it. This planet is (like ) a big battery that could go dead , this could be what the rich and greedy are doing you and your family's future. To not use and move to the sun, wind and water movement, is about as stupid as shooting yourself in the foot.

  • Report this Comment On August 17, 2014, at 5:43 PM, AdamGalas wrote:

    Not only is nuclear a great base load, carbon free power source, its also the safest form of energy by far. In fact its 4 times safer than wind and 11 times safer than solar, in terms of deaths per TwH.

    I recently wrote about GTAT and its immense potential.

    Does the earth "need" oil to remain in the ground? Well from a climate perspective you could argue that burning the 7-10 trillion barrels left would kill us all.

    But geologically speaking the earth isn't much altered by removing oil.

  • Report this Comment On August 17, 2014, at 6:31 PM, FrostedFlake wrote:

    I am disappointed the shortcomings of concentrated solar power that do not relate to money received no mention. Let's fix that.

    The mirrors blind pilots and attract migrating fowl by resembling water. The pilots fly one handed. The birds collide with mirrors and fly into thousand degree sunlight. Poof. Also, insects navigate by keeping a light in one lens of a compound eye. Works great if it's the Moon or the Sun. Not so well if it's a porch light, or a power plant. Poof. Small birds chase insects to eat them. poof. Large birds are attracted to a free meal, flash fried sparrow, and in their turn get flash fried too.

    The biggest shortcoming CSP has is, there isn't someones house under the solar panels. this means it is taking up space somewhere else. Totally stupid.

  • Report this Comment On August 17, 2014, at 7:28 PM, Windharp wrote:

    Is Adam's math right when he says "Given that in 2012 global power demand was 23,500 TWh, this means to generate all the power demanded by the world using this design would require around 214 million Gemasolar stations and take up 103 billion acres of land, or 180% of the world's total surface area."?

    The Terrosol website says the Gemasolar is going to supply 110 Gwh per year. Since 1,000 Gigawatts equals 1 Terawatt you would only need 10 Gemasolar type plants to produce 1 TWh per year.

    So producing 23,500 TWh per year would require 214,000 plants not 214 million. Or am I making a mistake somewhere?

  • Report this Comment On August 17, 2014, at 7:29 PM, AdamGalas wrote:

    Thank you FrostedFlake for pointing out some interesting, but under looked issues with CSP.

  • Report this Comment On August 17, 2014, at 7:43 PM, luckyagain wrote:

    Few mention the cost of the wars for oil in the Middle East. The US has just spent between $1 and $3 trillion on the Iraq war and it produces not a drop of oil or energy.

  • Report this Comment On August 17, 2014, at 8:03 PM, AdamGalas wrote:

    Thank you for catching my mistake.

    Indeed it would only take 214,000 Gemasolar's to supply all the world's power in 2012.

    That's only 103 million acres, not billion, which comes to 161,000 square miles or a square 400 miles on a side.

    That is not to say that concentrated solar is a practical answer to the world's energy problems.

    It would still cost $2,782 trillion to construct all those stations, which is 387 times the entire global economy in 2012.

    There is a chance that the cost might come down a bit with sufficient scale, however, as far as solar goes, there's more promising cost reductions to be found outside of CSP.

    For example, there's a hard limit to how cheap you could build a CSP station, no matter its size.

    At a current price of 7-13X natural gas and twice the cost of utility scale solar in the US (which is also coming down in price quickly) CSP isn't ever likely to become a practical answer.

    Rather energy storage is likely to be a better answer to smooth out solar's intermittent nature. I'm actually researching another article highlighting some breakthroughs in that area.

  • Report this Comment On August 17, 2014, at 9:24 PM, AdamGalas wrote:

    Luckyagain, its important to not throw good money after bad.

    Comparing the costs of competing energy solutions is important, lest we follow up a $2 trillion mistake with several that are even more expensive.

  • Report this Comment On August 17, 2014, at 9:26 PM, AdamGalas wrote:

    I do however see your point, in the sense that $2 trillion would pay for a lot of solar panels and had we invested in distributed solar as opposed to Iraq, we'd have a lot more to show for our money.

  • Report this Comment On August 17, 2014, at 9:51 PM, Tillerman1976 wrote:

    Each country needs to create electricity in the best manner for their country. CSP is just one piece of the puzzle. 214,000 stations would take up the State of Nevada and half of AZ. But we aren't powering the world from there. Lets start with say 500 of these plants around Hoover Dam, (Lake Mead is running dry now anyway), and tie them into the existing grid via Hoover Dam. Combine these with wind farms, ocean based wave generators, nuclear, conventional roof top solar, etc., etc and we can get to the point of a fossil fuel independence. First, lets get self sufficient from energy imports than work on fossil fuel independence.

  • Report this Comment On August 17, 2014, at 9:56 PM, phillipzx3 wrote:

    " The pilots fly one handed."


    All pilots fly one handed. If you have both hands on the yoke, you're doing something wrong.

    One hand on the yoke, the other is for the throttle, mixture, prop setting (whatever). The ONLY possible time I'd consider using both hands is during a landing when (elevator) force can be pretty high. A little C-150 can be landed one handed...a 182 starts taking some umph. :-)

  • Report this Comment On August 17, 2014, at 10:51 PM, devbahadurdongol wrote:

    Have a water filled or solid round object (works as a convex lens) in front of curved solar panel

    of suitable size and positioned right way to collect sun rays.

    That way the solar power can be available from the sun rise to sun set without any differences,

    and adjustment would not need throughout the year.

    for solution to power crisis and climate change visit:

  • Report this Comment On August 18, 2014, at 12:20 AM, speculawyer wrote:

    CSP is dead. PV is too cheap right now for CSP to compete.

  • Report this Comment On August 18, 2014, at 1:16 AM, greenknight32 wrote:

    @ Nickodell16 - Solar power represents less than 4% of US electric power, but that's a huge increase in a short time. Solar increased 418% from 2010 to 2014.

    Renewables have to be subsidized? Their costs keep falling, soon no subsidies will be required. Meanwhile, fossil fuels get perpetual subsidies.

    Wind power doesn't use that much land, the land in between the turbines can still be farmed; the turbines and their access roads take up only a small percentage of the total project area.

  • Report this Comment On August 18, 2014, at 5:16 AM, Likefacts wrote:

    Your fuzzy math needs to be increased by 30X, then the amount of power for 30,000 homes would be correct. The world estimate is so far off the average person wouldn't be able to understand the number displayed in a basic form. For solar energy will have a chance the efficiency will have to be above 60% and the electrical rates would still be 2 and 1/2 time present retail price of electricity.

  • Report this Comment On August 18, 2014, at 6:31 AM, Rhetttt wrote:

    So the answer to the question posed in the title is: No.

  • Report this Comment On August 18, 2014, at 8:31 AM, coyote1 wrote:

    Solar is viable RIGHT NOW. Were it included in the mortgage of every home sale in the latitudes where it works, it would be a savings producer from day one. Everywhere south of Lake Erie should be installing it. Besides, the economies of scale are beginning to kick in; just like 15 years ago a 42" HDTV cost $9000 and today can be had for nine hundred bucks, so that will also occur with renewables.

    The two items making solar/wind less than optimal are a) consistency, and b) storage.

    Interestingly, so many opponents of renewables exclaim that we have no right to imagine the storage issue will ever be resolved - even as those same opponents place enormous faith in oil companies working out ways to economically extract oil that is currently beyond our ability to extract cost-effectively. But the storage component will be worked out eventually.

    As to the massive solar farms: Making solar a centralized, infrastructure-delivered power source is exactly the wrong approach. Decentralized power is far more SECURE and cost-effective in the long run. Developing infrastructure correctly (look up such problems as "reactive power") to handle it would be a multi-trillion dollar endeavor that would have to be paid by the taxpayer because no energy company or even consortium of companies could afford it.

    And such a centralized model leaves us open to all sorts of things like sabotage, massive system failure, etc. Storm Sandy resulted in nearly $30 billion in outright losses and $70 billion in rebuilding costs. But if every homeowner had had solar and/or wind? Some individuals certainly would have seen their power lost, but many would not. Think about how many homeowners and restaurants and markets threw away food that might have been saved had so much of the grid not gone down.

    As for nukes, thorium, coal, oil? Their day is done. The smartest thing we can do is make a collective effort to get to renewables. Instead, the energy industry is trying to wrap us ever more thoroughly in those old technologies! Think of this: The fertilizer that drives mass agriculture is mostly made fom natural gas. The gas industry is trying to convince us to use natural gas as a replacement for home heating oil... if we continue to deplete that resource at ever-increasing rates, we more quickly wind down the clock on the agriculture that feeds us all.

    I know this doesn't work for investors, who are dependent on massive centralization in order to feel safe. But it's the reality of where things should be going. Decentralization, local renewable power, local storage are the future.

  • Report this Comment On August 18, 2014, at 10:29 AM, alcorenilth wrote:

    When people speak of Concentrated Solar as a "baseload" solution, they neglect two facts: 1. Solar Photovoltaics can also serve as a baseload solution if you couple them with battery storage. 2. Concentrated Solar incinerates birds. It's REALLY bad for any sort of life that flies during the day. It is, in fact, far worse for birds than Wind Turbines... which are having their own environmental problems.

    Geothermal and Nuclear are both solid baseload solutions that don't pollute. (I neglect Hydro, because fresh-water resources are rapidly becoming needed for simple hydration purposes. and therefore become unavailable for baseload power generation.)

  • Report this Comment On August 18, 2014, at 11:53 AM, SeaDog wrote:

    Solar power plants scorch birds in mid-air:

  • Report this Comment On August 18, 2014, at 11:53 AM, SirDuude wrote:

    Another problem with this design is birds that fly in its path are burned to death. We have a similar plant in California that is seeing what they now call "streamers" one every two minutes.

  • Report this Comment On August 18, 2014, at 1:53 PM, rocket7777 wrote:

    I think combined solar/gas is better than storage since gas price is so low.

  • Report this Comment On August 18, 2014, at 9:06 PM, AdamGalas wrote:

    Great to see such a lively debate going, a few points.

    1. On oil companies receiving subsidies, this is largely a myth (one I'm actually writing an article about now).

    2. Distributed solar will never be as cheap as utility scale, because of lack of economies of scale.

    First Solar estimates that by 2020 PV solar will be down to 2-3 cents/KWh vs. distributed 5-6 cents.

    3. A growing world will need many forms of energy, this is true. However, I feel to argue that we must simply focus purely on renewable is economically unwise.

    Solar may be coming down in price, but right now it’s still almost 5x as expensive as gas. Given the US's fracking gas miracle, we should exploit our resources and switch from coal to gas, even if gas isn't a perfect solution.

    Take a look at Germany and how they have the some of the highest electricity costs in Europe and how it stunts their economic growth if you want to see a warning of how not to run a nation's energy policy.

  • Report this Comment On August 20, 2014, at 5:22 PM, devoish wrote:


    I would like to express my disappointment in this article for giving us Gemasolar' land area in acres (480) and the Vaile 1 and 2 plants in square meters (1.1 million).

    I think it would be nice to all your readers to convert the area units all into acres in order to draw a clear and more easily understood relationship between the two plants.

    The Gemasola plant produces 20 megawatts on 480 acres.

    The Vaile 1 and 2 plants produce 100 megawatts on 272 acres.

    The Hoover dam produces 2080 megawatts on 160,000 acres, but it also stores water.

    Best wishes,


  • Report this Comment On August 20, 2014, at 6:09 PM, AdamGalas wrote:

    Thank you for your comment and your calculations. I'll make sure to be more uniform in the future.

    Valle 1 and 2 indeed offer 9x the energy density in terms of KW/acre and at nearly half the cost.

    I've recently learned that US solar thermal stations cost $5.1 Billion/GW, according to the EIA.

    That shows the trend moving in the right direction, however solar thermal is still the least cost effective method of solar energy.

    In fact solar thermal is 31% to 132% more expensive to construct than other forms of renewable energy and 68% to 380% more expensive to operate.

    Given sufficient investment and time perhaps its costs can be brought down even further but the costs of other forms of renewable, such as Solar PV, are likely to keep dropping as well, probably faster.

    Thus solar thermal isn't likely to ever be as cost effective, even when energy storage costs are included.

    Its a lot like the debate between battery electric cars and fuel cells. Right now fuel cells are less efficient, far costlier to build and operate but proponents state that with enough time and investment that those prices can be brought down significantly

    While true they fail to see that battery tech is likely to advance faster than fuel cell tech, and so even if fuel cells could be improved with government grant money, its still a better economic use of funds to focus on the superior technology.

  • Report this Comment On August 21, 2014, at 12:41 AM, DINEROne wrote:

    That was an excellent article. I think solar energy is the way to go in the future. As battery technology and efficiency of cells improve, we will slowly be able to leave fossil fuels in the dust. I think it is only a matter of time.

    As you throw other renewables into the mix - wind, hydro, and geothermal...all we need is to continue to innovate and we will get there.


  • Report this Comment On August 21, 2014, at 9:23 AM, jargonific wrote:

    Cool. Thanks for writing this.

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Adam Galas

Adam Galas is an energy writer for The Motley Fool and a retired Army Medical Services Officer. After serving his country in the global war on terror, he has come home to serve investors by teaching them how to invest better in order to achieve their financial dreams.

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