News on the Rise of Solar Concentrator Technologies in Energy Tech

I always try and keep an eye out on what other investors and analysts think is hot. We have been chronicling on Cleantechblog the rise in energy tech / cleantech venture capital investment in solar for some time. This has been driven primarily due to an exploding public capital markets in solar, creating attractive exit returns.

Well the “new” news in energy tech venture investing seems to be solar concentrators. Opportunities in solar collectors / concentrators have been coming across my desk in increasing numbers lately.

Solar concentrators basically put a lens (called a Fresnel lens) on top the solar cells, focusing sunlight onto a standard photovoltaic cell and making it tremendously more efficient. Not too different from using a magnifying glass and the sun to start a fire. However, concentrators tend to do better when the light source is a single point, and pointed straight at the cell.

There are literally hundreds of design concepts in the academic and commercial literature on ways to achieve this, but that’s the basic concept.

The advantages:
  • Solar concentrators at heart are attractive because they reduce the amount of cells needed to deliver the same level of power output (and thereby the cost)
  • In addition, many solar concentrators are trying to use a much larger part of the light spectrum to generate electricity.
  • They also deliver the promise of low capital cost for the manufacturing facilities (equipment to make concentrators is not as expensive as that to make cells on a per watt basis).
  • One of the biggest advantages, I think, is the potential to make much larger module sizes with concentrators than straight PV cells. This has long been a big knock in the solar industry.

The knock on solar concentrators, however, has proven tough to get over so far:

  • To be effective, they tend to need very high efficiency cells (most people are saying 25%+ efficient).
  • To be economic, they tend to need some sun tracking capability – which is tricky to do for systems designed to last 20 years.

However, advances in new high efficiency cells for the aerospace industry, long the province of niche solar players like Spectralab, are expanding the potential.

Some of the recent venture capital deals in solar concentrators include:

Energy Innovations raised $16.5 mm in 2005 for their Sunflower module array of concentrating mirrors that track the sun. http://www.energyinnovations.com/ Lead investor was Mohr Davidow.

Prism Solar raised a seed round for a holographic planar concentrator which passively tracks the sun and spectrally selects desirable wavelengths. http://www.directglobalpower.com/

Whitfield Solar in the UK received a funding round in 2005 including Carbon Trust for its solar concentrator technology. http://www.whitfieldsolar.com/

And given the level of new solar concentrator deals heading to venture forums like the Cleantech Venture Network, IBF and Clean Edge’s Cleantech Investment Conference, and NREL’s Industry Growth Forum, we are likely to see a lot more.

One of my favorite ones that hasn’t gotten major funding, but has been building full scale systems for several years is Solar Systems in Australia, http://www.solarsystems.com.au.

A few other solar concentrator energy news tidbits:

The National Renewable Energy Laboratory is sponsoring a Conference on Solar Concentrators for the Generation of Electricity or Hydrogen http://www.nrel.gov/ncpv/scc/ in May in Scottsdale with Arizona Public Service, one of the leading renewable utilities in the country.

Blog world is picking up the trend:

The Energy Blog just did a post on one that uses a flat Fresnel lens to collect the sun’s energy and focus it onto a copper block, Energy Blog Solar Concentrator Tech Post.

Future Pundit did an article on solar concentrators last July, Future Pundit Solar Concentrator News

EV World did a blurb on solar concentrators in July, EV World News Post

If you have any other concentrators, news, deals, or blogs, post them here in the comments section.

Despite all this, solar concentrators remain a minute portion of new solar installations, let alone the total installed base. So I guess the big question, still unanswered, is whether solar concentrators can be the elusive technology to take solar into 1:1 competition with grid power. The last solar technology class to wear that mantle, thin film, has yet to overtake the crystalline silicon market in cost or market share.

26 replies
  1. Jim from The Energy Blog
    Jim from The Energy Blog says:

    Excuse a few technicalities to keep the terminology clear. Solar energy devices can be divided into three types; 1) photovoltaic (PV) solar panels, composed of a number of PV cells, these are the type that are seen on the roofs of homes and covert solar energy directly into electricity 2) thermal systems that use concentrators to magnify the solar radiation so that it is more powerful. This concentrated thermal energy is then used to heat a fluid to a high enough temperature so that it can drive some sort of a generator to make electricity. These systems are of two types solar dish systems and solar trough systems and 3) concentrating solar photovoltaic systems that focus solar energy on an expensive, but very efficient PV cell, which can tolerate the more intensive solar energy. These systems can either use a lens or mirrors to do the concentrating. An overview of concentratrating solar power can be found in my blog at http://thefraserdomain.typepad.com/energy/2005/09/overview_of_con.html.I will keep most of my remarks addressed to concentrating solar photovoltaics which I believe you intended to be the subject of your post. Only some of these products use plastic Fresnel lenses, other use some form of a mirror which have less distortion and are more efficient. Most of these systems use advanced multijuction solar cells developed by NASA with an efficiency approaching 40%, compared to the 12-22% efficiency achieved by cells used in typical solar panels. Their high cost is justified by reducing the number of cells by a factor of 25 or more in most systems. The concentration factor is limited to 250 to prevent degradation of the cells.Energy Innovations was started by Bill Gross the entrepreneur behind behind NetZero, FreePC, CitySearch, eToys, Eve.com, FirstLook and several other dotcom companies. Their product, the the 25X Sunflower uses utilizes 25 – 1′ x 1′ mirrors that concentrate the sunlight by a factor of 25 and focus the light on a photovoltaic receiver which produces 200 watts of electricity. The system, as do most concentrating systems, uses an active tracking system to follow the sun in order to capture as much of the suns energy as possible. They claim their system would cost about $4.50 per watt installed, which is 25-50% less than traditional PV systems. My post on Energy Innovations is at http://thefraserdomain.typepad.com/energy/2005/08/the_25x_sunflow.html.I was not at all familiar with Prism Solar, but a brief look at their technology indicates that they are using two stage (read 2X concentration) mirror like optics combined with holographic techniques to both concentrate and divide the light into the most desirable spectrum’s. The ability to select the desirable part of the light spectrum enables them to collect more sunlight at dawn and dusk. They call this passive tracking. They claim their system reduces the number of cells required by 50 to 85% and cuts the cost about in half compared to traditional solar panels. Using only 2X concentration allows then to use normal relatively low cost solar cells.I couldn’t find any technical information on Whitfield Solar. They have artists renderings of their products on their website which don’t tell much. Three other companies in this arena, that you didn’t mention are Amonix, Sunball and SolFocus.Amonix, which was established in 1989, uses plastic Fresnel lenses to concentrate the sun by a factor of 250 onto 26.5% efficient solar cells to produce 5 kW panels that are mounted to a tracking system. Amonix is focusing on utility scale applications. They announced in 2005 that they have plans to install a 3 megawatt system in the southwestern U.S. They also have a joint venture with Spain’s Guascor to build a 10 megawatt system in 2006. Installed costs of $3.00 per watt at production rates of 10 megawatts per year are anticipated. Australian Green and Gold Energy has developed the SunBall rooftop solar concentrator which comes in two models, a 42 W model and a 1.3 kW model. They use a plastic Fresnel lens to achieve their concentration onto a high efficiency solar cell. They just started delivering the small unit and will start shipping the larger unit as soon as they iron out some supply problems. They anticipate that their units will be competitive with grid power in the sunniest parts of the country and slightly higher in the northern regions. Export to the US is anticipated later in the year. Initially their intended market is homes and small businesses. See my post at http://thefraserdomain.typepad.com/energy/2005/09/sunball_rooftop.html for more information.SolFocus who is collaborating with Xerox’s Palo Alto Research Center is the most recent and one of the most innovative of these companies. They use precisely shaped curved optical mirrors molded or stamped from glass to focus sunlight on the solar cell. They point our that their optics are more efficient than a Fresnel lens. They end up with modules that are only slightly thicker than a conventional PV panel. Their design has been highly influenced by the ability to mass produce their product. Initially the installed cost is expected to be $5.00 per watt but in mass production they are targeting an installed cost of $1.00 per watt which is competitive with grid power. See my post at http://thefraserdomain.typepad.com/energy/2006/02/post_1.html#more. Concentrating solar photovoltaic systems are still but one of several technologies in the run for the lowest cost solar technology. Currently the solar dish and solar trough technologies are believed to be the lowest cost of the solar technologies. A 354 megawatt complex built in California during the 80’s is still operating efficiently and delivering power to the grid with high reliability. Significant improvements in the optics, mechanical fabrication and the tracking system have been made since the original plants were built. There are about eight plants of over 100 megawatts in capacity under construction in California, Israel, Nevada, Portugal and Spain. Six different companies are suppling the plants. The cost of electricity from these plants will be less that that from natural gas plants but more than from conventional power plants or wind power. Efficiency of scale and cost reductions discovered during this construction boom are hoped to keep them competitive in the future. Thin film solar is finally coming into its own and production volumes are being ramped up to hundreds of megawatts of capacity. They are taking advantage of the severe shortage of silicon that is preventing significant growth of producers of the more expensive, but more proven conventional silicon solar cells. Cost projections by Daystar and ECD Ovonics, who are the leaders in this technology, indicate that costs of $1.00 per watt may be possible when they reach gigawatt production capacity. Daystar expects to reach that milestone by 2008 and Ovonics will lag by a few years. The technology seems to be very sound as compared to some questions that were raised a few years ago. A recent happening was that Shell sold off its silicon cell production facilities in order to concentrate on its thin film product.Sharp, the leading silicon cell producer, with capacity already near a gigawatt, expects that their costs will be cut in half by 2010. Evergreen who makes thinner silicon cells, by a different process than the rest of the industry, is making some inroads due to the lower silicon content of its cells.The eventual winner of the race to produce the lowest cost solar power is not going to be determined for quite awhile, but some strong indications should be available by 2010.

  2. Robert McLeod
    Robert McLeod says:

    I feel the need, as usual, to point out that solar concentrators don't work — at all — when it is cloudy. Scattering through clouds renders the insolation diffuse and impossible to effectively focus.

  3. Anonymous
    Anonymous says:

    I'm interested in Daystar's "proprietary concentrator" which nobody pays attention to because their foil mfg process garbners all the attention. Wish some knowledgeable folks would take a look at Daystar's concentrator and make some judgments.Thanks,Charlie SneedNorth Carolina

  4. Robert McLeod
    Robert McLeod says:

    Nick: While it's very nice to take a American-centric view of things, please remember that the USA is a bit player in the photovoltaics market. Japan and Germany are the two big markets, followed by Spain. With the exception of Murcia, those markets don't benefit from concentrators.Havlo: When light is diffuse it means it's coming from all different directions. It doesn't take much to render sunlight largely diffuse. Even the smog layer over LA is enough to have a damaging impact on the ability of thin-film lenses, Fresnel lenses, parabolic mirrors, etc, to focus light onto a collector. I made a blog post explaining this in more detail last year :http://entropyproduction.blogspot.com/2005/08/solar-concentrators-under-clouds.html

  5. eric blair
    eric blair says:

    I feel the need, as usual, to point out that solar concentrators don't work — at all — when it is cloudy. Scattering through clouds renders the insolation diffuse and impossible to effectively focus.At all? At All?Helostat systems can give you a 'moonburn' under a full moon. And I can burn paint (and my hand) with my 1 foot fresnel lens on cloudy days.And a PV junction will give SOME current and SOME voltage in lower photon levels.Simple physics supports my position. Not to mention my PV panels and the 1 foot fresnel lens supports my position.What evidence do you have to support your position?Now, what EVIDENCE do you have to support

  6. Erich J. Knight
    Erich J. Knight says:

    From what I understand of the direct solar to hydrogen fabrication technology it is a much greener process, and cheaper that silicon based PVs. ( Hydrogen Solar home http://www.hydrogensolar.com/index.html )Rupert Leach, Director, Newspath Ltd, from the UK posted me about his talking to the Chairman of Hydrogen Solar, Julian Keable, saying that they will be well over 10% efficiency in the near future with their Tandem Cell™, technology, and that they had initial issues with scale-up, but these seem to have been overcome and they were sounding rather optimistic a few weeks ago. They claim a theoretical efficiency around 35%,and that realistically 22% is achievable within a few years. That would produce 1 Lb of H2 for $0.75 or about $0.05/KWhr.And the nano-dot approach to PVs also promises full spectrum conversion efficiencies along with clean production processes. ( UB News Services-solar nano-dots http://www.buffalo.edu/news/fast-ex…rticle=7500… )"Recently I found this technology page on the Suncone, Sustainable Resources, Inc. – The Suncone Solar Power Generator http://www.sriglobal.org/suncone_intro.htmland The Claim of a 50 MW array producing at $.046/KWhr is the best I've seen for solar at this level of development, and the PV solar roofing technology they are acquiring looks solid too. Erich J. Knight540-289-9750

  7. Nick
    Nick says:

    Robert McLeod,I like your graphics, but it seems like only part of the story. Even cloudy areas are only cloudy part of the time, and when they are flat-panel PV will be affected as well. Further, concentrating systems have the advantage of following the sun. The NREL insolation maps I referred to suggest that concentrating does very well in at least 40% of the US, which seems like a pretty good market.Do you know of any comparable data for Germany and Japan?Utility scale concentrators depend on very cheap land, which basically means desert, which points to places like the Southwest US, Israel, and much of Africa and the Middle East (whoo! maybe an alternative for Iran's nuclear plans?). I suppose that means that Europe and Japan aren't really targets for that kind of system.

  8. E. Henry Beitz
    E. Henry Beitz says:

    Your statement:Solar concentrators basically put a lens on top the solar cells, focusing sunlight onto a standard photovoltaic cell and making it tremendously more efficient.is far from correct.The multi-junction cells at the focus of the concentrated sunlight are not standard photovoltaic cells. Go to Spectrolab's site at http://www.spectrolab.com/prd/terres/cell-main.ht… to learn more about these cells.

  9. jan
    jan says:

    Chairman of Hydrogen Solar, Julian Keable, saying that they will be well over 10% efficiency in the near future with their Tandem Cell™, technology, and that they had initial issues with scale-up, but these seem to have been overcome and they were sounding rather optimistic a few weeks ago. They claim a theoretical efficiency around 35%,and that realistically 22% is achievable within a few years. That would produce 1 Lb of H2 for $0.75 or about $0.05/KWhr.While checking the Hydrogen Solar web site for some commercial figures and estimates, I came across your post. Do you have any more detailed information how they have calculated their $0.75? I mean, this number is impressingly low and could finally bring the commercial break through for the hydrogen economy. Unfortunately, they did not answer my request directly.Regards Jan (business consultant from Germany)

  10. Anonymous
    Anonymous says:

    Solar concentration is only half the answer, the other half is to use sufficient heat storage mass, say concrete, water, or pcm, which acts to smooth out the charging cycle (similar to a capacitor in an electrical circuit).In short, concentrate the solar energy to heat the storage mass, then place the heat exchanger on the mass itself to produce steam, hot water, or direct electricity with thermionics or seebeck/peltier modules.If the sun is concealed by a cloud, or at night, the mass begins releasing its stored energy. Additionally, once the mass is heated to the correct temperature, you only need to maintain that temperature. Often, you'll find the sun provides surplus energy beyond heating the mass.The major problem I see with most solar implementations (even by the big players), is that they completely ignore adequate heat storage (you need a lot more than 80 gallons in your water heater) which makes the current solutions, at best, quirky and undependable, at worst completely unworkable in the extreme northern/southern regions.A recent experiment in germany heated 500 houses throughout the winter by drawing heat that was stored in an aquifer over the summer.

  11. chalacuna
    chalacuna says:

    Harnessing the enrgy from the sun is the best alternative and renewable source of energy. The sun is totally and 100% environmentally friendly.The only drawback to solar paower is the initial investment which is at present is not practical econoomically to many consumers.If advanced manufacturing techniques are developed to produce cheaper and more effecient solar panels, time will come most houses will be having roofs made of solar panels and that would help a lot in making a better and pollution free world.Related Sites:Alternative FuelsAutomotive WorldHybrid Cars

  12. Anonymous
    Anonymous says:

    Solar concentrators have been in the air rather than on earth. The reason is simple; they require tracking, which needs an electro-mechanical devices. May be, electricity is a more dependable commodity in the developed countries, but not so, even in India. Hence the thrust should be on a non-tracking concentrator, that works only on optics. I have one design, tried on a small scale, but needs upgradation.If some one is interested, I will be giving some details.Gadepalli Subrahmanyamsubrahmanyamg1@rediffmail.com

  13. Anonymous
    Anonymous says:

    I hope this research continues. There is a solar solution that consumers can take advantage of right now. I am a manager with a brand new company called CitizenRe. If you ever wanted to help the environment and get most of your energy from the sun and not from your dirty energy provider, this company will provide you a solar solution with NO UPFRONT COST! Please investigate and continue discussion in this thread:www.jointhesolution.com/yorkvilleAfter you get real excited about this program and want to help spread this GREEN solution, go to:www.powur.com/yorkville

  14. Anonymous
    Anonymous says:

    Both your statements:Solar concentrators basically put a lens on top the solar cells, focusing sunlight onto a standard photovoltaic cell and making it tremendously more efficient.is far from correct.The multi-junction cells at the focus of the concentrated sunlight are not standard photovoltaic cells. Go to Spectrolab's site at http://www.spectrolab.com/prd/terres/cell-main.ht… to learn more about these cells.are wrong. The record for highest efficiency was achieved by coupling a solar concentrator with a stirling heat pump. PV systems lose efficiency every year, so by 5-10 years in, they're only producing a fraction of their initial power. This has been the first application where stirling engines have actually worked, and worked well. Coupling a concentrator with any PV would be a waste of time since PVs suck balls. The physics by which they work means they constantly lose more electrons than they gain, and therefore lose charge. Stirling engines don't have this problem .http://www.stirlingenergy.com/whatisastirlingengine.htm

  15. David
    David says:

    First off, I do see the need for electric generation from solar ,but the existing systems are far to expensive and somewhat impractical for the regular Joe. For many home/business owners their greatest expense is heating whether electric or fossil fuel based. If that issue could be mostly supplemented by solar, fossil fuel demand would greatly be reduced. We have a system that has been implemented and refined for nearly 30 years. We have the most precise tracking system that has no over steer, tracks on optics, has totaling motor run time of 5 minutes a day each for 2 motors, and only consumes milli amps per day. Currently we only offer thermal heating systems for space and water heating along with storage. These Parabolic, 2 axis systems are over 90 percent efficient give or take a few points depending on ambient temperatures, operating temperates, wind, and rate of output consumption. You do have to use electricity to pump water through the tiny, low surface area, low loss, focal heat receiver. A typical power consumption of these is 11 cents a day to operate based on west Texas residential electrical power rates. Where available sun is 1000 watts per square meter or dish surface area, then collected energy will be about 950 watts approximately depending on ambient and operating temperatures. 1 watt equals 3.412 BTU. Under these types of efficiency's and costs, it seams logical to push for thermal solar applications until electric solar technology can compete. Of our three sizes of dish trackers available, our 8 foot tracking dish offers the most BTU per dollar spent. Totaling less than .65 cents per watt at peak power of 1000 watts per square meter. This is by far the cheapest solar energy available on the market to anybody. We do have a rotary steam engine under development which resides in the focal point of the dish, and will produce electricity, refrigeration and hot water. Visit us at http://www.acosolarlasers.com to see for yourself.

  16. switch and save $$$&
    switch and save $$$& says:

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  17. switch and save $$$’s
    switch and save $$$’s says:

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  18. polysun
    polysun says:

    Hi i appreciate this post. The time when the whole word is looking for a solution to the major problem of global warming we can also participate in this issue by making investment in solar heating system

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