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Clean Power solar thermal tower

Published on July 21st, 2008 | by Michelle Bennett

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Clean Tech Intro: The Solar Family

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July 21st, 2008 by
 

solar thermal towerSolar power means more than solar panels. These days it can also mean collectors, towers, dyes, oh my! Here’s a guide to (most of) the different kinds of solar technologies that are out there today.

First, the basics: Anything that uses solar energy as a source of power is solar-powered. Simple, right? Well let’s not forget that the sun gives us more than a whole spectrum of light, it also gives us heat. Both are used for a wide variety of applications, not just electricity.

1. Solar Thermal

Solar thermal technologies use heat. Cleantechnica has already introduced solar thermal. The cheapest, easiest, and most financially sound solar investment you can make for a house is to install a solar thermal collector. It collects solar energy to provide warm water or warm air for your house, even in the far north. On a larger scale, mirrors can be used to focus heat from the sun to boil water and turn a turbine. Generating electricity with this method is called Concentrated Solar Power (CSP). Large scale CSP projects are already underway in deserts around the globe, and in some places they are invigorating the economy.

The cool thing about CSP is that it overcomes one of the major problems with renewable energy. It used to be true that solar farms stopped producing energy as soon as the sun went down. No longer. Heat is much easier and cheaper to store than electricity, so you can save it for the hours or days when the sun doesn’t shine. Power towers and molten salt are just two methods of producing solar power whenever we need it.

2. Photovoltaics

Photovoltaics are solar technologies that transform light into electricity. Certain elements and chemicals, called solar cells, can lose electrons when exposed to photons (light). Under the right conditions, these electrons are harnessed as electricity. For a more technical explanation, check out Wikipedia.

3. Silicon

silicon solar panelThis is the most widely used and recognizable material used to make solar panels. Paired with solar cells, silicon can produce high efficiency solar panels. However, silicon panels tend to be more expensive to make, transport, and install because they’re heavy, rigid, and require plenty of high-quality materials. Thin-film silicon panels attempt to overcome these obstacles. The downside: silicon panels work best on cloudless days when the sun is directly overhead. That’s why silicon panels are often positioned on racks to face the sun. The cost of these racks, and loading the panels on them, often consume 50% of the cost of silicon panel installation.

Another strategy to reduce the cost of silicon panels is to use less of them, but still generate plenty of energy. This is possible by concentrating sunlight onto the panel. More intense light means more energy… if you don’t melt your panel in the process. This technology is called Extreme Concentrated Photovoltaics (XCPV).

4. Thin Film

thin film solar panels Thin film solar panels are very thin and flexible; the solar cells can be placed on sheets of plastic or aluminum. They should not be confused with silicon thin-films, which use a different manufacturing method. Thin film solar panels tend to be easier to make, use fewer and cheaper materials, and are easier to transport and install. Some thin films absorb different wavelengths of light, which can make them more practical in cloudy regions. The downside: they’re still less efficient than silicon panels, so they don’t produce as much energy. Their efficiency can sometimes degrade over time, depending on the materials and environment.

5. Solar Dyes

Solar dyesHere is another promising technology that is still being developed. Invented by the Swiss in the 1990s, the idea is to produce solar cells in cheap, easy, attractive dyes that can be painted or sprayed onto almost any surface. The benefit is both cost and application: the dyes are only one tenth of the cost of silicon panels and you can boldly take them where solar has never gone before. Imagine painting your house with solar cells and reaping just enough energy to power your microwave. That is the downside: solar dyes are not yet as efficient as thin film solar, and many dyes only last several years instead of decades.

6. Radical Solar Technologies

AlgaeSome tech exists that push the definition of “solar power”. For example, algae can be used to produce biodiesel and ethanol. If you fill your car with this fuel, is your car solar powered? What about passive solar technology, which controls how and when sunlight affects buildings? Since the sun is a major engine driving our planet, the possibilities for harnessing its energy are infinite.

Have we missed a solar technology in this post? Let us know in a comment below.

Images via Flickr Creative Commons License: Solar Tower by afloresm, Silicon Solar by laurenatclemson, CIGS by Elsie esq., Algae by Rosa y Dani.   Solar Dyes via MetaEfficient.com

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About the Author

is an environmentalist who loves to write. She grew up across the southeastern USA and especially love the Appalachian mountains. She went to school in the northeast USA in part to witness different mindsets and lifestyles than those of my southern stomping grounds. She majored in English Lit. and Anthropology. She has worked as a whitewater rafting guide, which introduced her to a wilderness and the complex issues at play in the places where relatively few people go. She also taught English in South Korea for a year, which taught her to take nothing for granted.



  • Tombolo

    There is a very recent solution being thought about on building solar satellites. The satellites will be exposed to 24hr sunlight orbiting the earth. Using photovoltaic panels it will create electricity which will be beamed back to earth through lasers or microwaves and reconverted to traditional electricity electricity on time for Sunday roast.

    This is all very new, but not too far-fetched as one would assume. The technology does exist and it works, but will be very expensive to pull off on a large scale.

    These two articles below give more information but they are not too reliable..

    http://www.msnbc.msn.com/id/30198977/

    http://www.inhabitat.com/2008/10/20/solar-satellites-by-ben-bova/

  • Tombolo

    There is a very recent solution being thought about on building solar satellites. The satellites will be exposed to 24hr sunlight orbiting the earth. Using photovoltaic panels it will create electricity which will be beamed back to earth through lasers or microwaves and reconverted to traditional electricity electricity on time for Sunday roast.

    This is all very new, but not too far-fetched as one would assume. The technology does exist and it works, but will be very expensive to pull off on a large scale.

    These two articles below give more information but they are not too reliable..

    http://www.msnbc.msn.com/id/30198977/

    http://www.inhabitat.com/2008/10/20/solar-satellites-by-ben-bova/

  • Pingback: A Thin Film Solar Installation Revisited : CleanTechnica

  • http://www.totalsolarenergy.co.uk/residential-solar-power.html Total Solar Energy

    the solar dyes are quite exciting. i know nanosolar in the US and xerocoat in Australia are both developing this technology.

  • http://www.totalsolarenergy.co.uk/residential-solar-power.html Total Solar Energy

    the solar dyes are quite exciting. i know nanosolar in the US and xerocoat in Australia are both developing this technology.

  • http://url.ie/h1b?163609424 Susan Foxe

    Here is another promising technology that is still being developed. Invented by the Swiss in the 1990s, the idea is to produce solar cells in cheap, easy, attractive dyes that can be painted or sprayed onto almost any surface. The benefit is both cost and application: the dyes are only one tenth of the cost of silicon panels and you can boldly take them where solar has never gone before. Imagine painting your house with solar cells and reaping just enough energy to power your microwave. That is the downside: solar dyes are not yet as efficient as thin film solar, and many dyes only last several years instead of decades.

  • http://url.ie/h1b?163609424 Susan Foxe

    Here is another promising technology that is still being developed. Invented by the Swiss in the 1990s, the idea is to produce solar cells in cheap, easy, attractive dyes that can be painted or sprayed onto almost any surface. The benefit is both cost and application: the dyes are only one tenth of the cost of silicon panels and you can boldly take them where solar has never gone before. Imagine painting your house with solar cells and reaping just enough energy to power your microwave. That is the downside: solar dyes are not yet as efficient as thin film solar, and many dyes only last several years instead of decades.

  • Kevin

    Thanks for this article, Michelle. And I don’t mind tossing a few pointers over the fence for you:

    * Since some thin film modules do in fact employ silicon, we usually speak of the two primary photovoltaic technology families as Crystalline Silicon (so called because cells are cut from the crystalline form of silicon) & Thin Film.

    * The module shown next to your thin film category is actually a crystalline silicon module. Thin film modules can be seen by going to the websites of thin film manufacturers such as First Solar, Uni-Solar, Kaneka, and EPV, to name just a few.

    * Concentrating Photovoltaics (CPV) refers to any degree of concentration, from 2x (two times the normal amount of sunlight falling on a given surface) to many hundreds of times or even greater than 1000x. As far as I know, no one other than Sunrgi actually speaks of “extreme” concentrating PV; we usually refer to levels of concentration as low (LCPV) or high (HCPV). The higher the level of concentration, the more accurate all the system tolerances need to be and the more heat becomes a problem, but the promise is an even lower potential cost of energy.

  • Kevin

    Thanks for this article, Michelle. And I don’t mind tossing a few pointers over the fence for you:

    * Since some thin film modules do in fact employ silicon, we usually speak of the two primary photovoltaic technology families as Crystalline Silicon (so called because cells are cut from the crystalline form of silicon) & Thin Film.

    * The module shown next to your thin film category is actually a crystalline silicon module. Thin film modules can be seen by going to the websites of thin film manufacturers such as First Solar, Uni-Solar, Kaneka, and EPV, to name just a few.

    * Concentrating Photovoltaics (CPV) refers to any degree of concentration, from 2x (two times the normal amount of sunlight falling on a given surface) to many hundreds of times or even greater than 1000x. As far as I know, no one other than Sunrgi actually speaks of “extreme” concentrating PV; we usually refer to levels of concentration as low (LCPV) or high (HCPV). The higher the level of concentration, the more accurate all the system tolerances need to be and the more heat becomes a problem, but the promise is an even lower potential cost of energy.

  • Martin K.

    MIT’s Solar Concentrators, though in the early stages, may prove to be more economical than XCPV. They can even be added to existing solar panels to improve efficiency.

    Also, “Nanoantenna” solar panels look to be the most efficient technology on record. I mean, the panels even work at night! Obviously some kinks still need to be worked out.

  • Martin K.

    MIT’s Solar Concentrators, though in the early stages, may prove to be more economical than XCPV. They can even be added to existing solar panels to improve efficiency.

    Also, “Nanoantenna” solar panels look to be the most efficient technology on record. I mean, the panels even work at night! Obviously some kinks still need to be worked out.

  • http://www.elrst.com Edouard Stenger, France

    Congratulations for this most interesting article.

    But, to my opinion you don’t stress enough the importance solar passive can have.

    By maximizing the energy input of the sun within premises, the energy bill can be cut by 30 to 70 percent. ( depends of the location )

    Keep up the good work !

  • http://www.elrst.com Edouard Stenger, France

    Congratulations for this most interesting article.

    But, to my opinion you don’t stress enough the importance solar passive can have.

    By maximizing the energy input of the sun within premises, the energy bill can be cut by 30 to 70 percent. ( depends of the location )

    Keep up the good work !

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