Solar Shakeout Continues: Stirling Energy Systems Files for Chapter 7 Bankruptcy

While it is true that this technology is too expensive for short term investors, it is not totally without merit if the maintenance issues are cleared up. Instead, it could be a long term solution to high energy states such as Arizona and Oklahoma, and perhaps Texas. In such states, the longer hotter summers make this technology work better, and if Warren Buffet were to see the effacy of such a venture, he could eventually cash in a large value for a reasonable price, since it would pay back in about 10 years, and continue working for another 10 years, making the long term very promising. The trouble is getting enough area to work with, without harming air traffic via reflection blindness, and such oddities of liability that might come from such extraordinary concentrations in rural areas.
Still, it seems like it would be worth it to buy the remaining manufactured components already made by this bankrupt company and then build your own support facilities to ensure they do return the full investment and offer a profit after the 10 year term is fulfilled. In so doing, perhaps the bankruptcy could be mitigated and a need for solar could be filled in the Utility scale level. Oklahoma already has incentives for building systems that generate more than one Mwh of power for utility energy consumption. That with a 30% credit from the federal government would reduce the long term costs also to acceptable levels. So Warren, if you see this, consider this a good deal.

Well, it's great to hear that the price of PV is diving.BUT,I've got to assume that some thermo-technologies can be cost effective.
In Spain recently there is a CSP power plant that runs 24 / 7 "scrubbing out" the heat in eutectic salts at night. So as to produce electricity long after the sun has set.
Love PV.
But don't stick a fork in other technologies just yet.

Well, this particular technology was IIRC aimed at instantaneous use of heat, rather than heat storage. So it's another unsurprising consequence of the Low-Si technologies failing to scale before the Si feedstock manufacturers did.

I seem to remember a Chinese version of either this technology, or of thermophotovoltaics, which allowed the heat engines to be fed with natgas at night, aiming to capture the base-load bridge technology market... there may be some interest among such ventures in acquiring the IP associated with SES's advanced gensets.

I would be interested in hearing about any Chinese ventures into Stirling tec or any externally heated engine/generator units. The Stirling tec field involves many interrelated variables that do not easily scale or copy.
Still, I am sad to hear about the demise of this company. The solar to electric efficiency of advanced heat engines is far higher than PV.
Is this company's project a free piston adaption, or the STM four cylinder derivation? Fastenating machines. I've built 16 different versions.

I was involved with a group who wanted to use the Stirling system and for the area it was the best bet, however the cost of transmission including the environmental impact study costs killed the project. The beauty of this system located in a high altitude desert where the day time temps remained low made it a better bet than most other solar applications. There was geothermal resources in the area that could be coupled with this technology producing 24/7 generation. The biggest obstacle was the sage grouse and pygmy rabbit with transmission cost a close second.

Very interesting to follow this PV vs CSP, much like the old PC vs Mac of old.

The choice between CSP (concentrated Solar Power thermal) versus CPV (Concentrated photovoltaic) is pretty much decided. CPV scales easier can be installed faster and is cheaper. According to
(http://www.cpvconsortium.org/Portals/0/Board/CPVC-Altaterra-Webcast.pdf page 11, the time for permitting is 6 months for CPV and 6 months for construction. For CSP it is 18 months for permitting and 12 months for construction. With CPV continually dropping in price; if you use current-day estimates for cost and performance, with CSP overruns are common, and projects less than the initial cost estimate are not common. With CPV, it is common to have projects come in under budget due to lower costs.
At this point I assume that CPV projects use forward pricing like the semiconductor industry has used for a few decades to give lower more accurate estimates. With CSP since each of these units are usually uniquely designed, the prices are unlikely to get lower. Nuclear is also quickly dropping by the wayside. A typical CPV installation in high DNI locations need about twice the land to produce the same power. Would you rather have a solar farm or nuclear facility near your house? Finally CPV still has a lot of room for higher efficiency and lower costs. Higher concentrations and/or better efficiency which can be achieved by more junctions, better current matching or separating and concentrating the sunlight (see the Rainbow Concentrator www.sol-solution.net) will continue to lower the cost of CPV.

I'd adjust my comparison to that of mainframe (like CSP) vs distributed computing (like PV). Here I mean PV on rooftops, not concentrated. Regardless, it is interesting to follow all three ways of doing it.

What does DNI stand for?

I remember talking to a guy several years ago who was a head engineering honcho at Rocketdyne/Boeing, one of the partners in Stirling Energy Systems. His comment was pretty blunt. It will never work in that environment (high desert, wind, sand, dust) and was dubious about ever getting the MTBF down to a reasonable level. He considered all their research more or less wasted capital. This was sometime in 2005 I think. Yet, here we are again with another failed DOE-sponsored project.

The temperature changes as well as the rain shadow in this high desert gave the edge to the stirling system over PV. The tests showed continuous generation with the stirling (due to temperature differences of the inert gas used) when the pv was shadowed with thin clouds. I believe there are situations where the CSP will work, also the geothermal though limited made the difference. (The geothermal aspect was useless with the PV) The project is on hold until future transmission development reduces the distance.

In Oklahoma, distribution of energy is a big issue with wind powered systems, but for solar CPV it isn't as critical, because there is adequate land for solar to cover without necessarily reducing the use of that land. CSP, however, takes more dedicated land area and it isn't condusive to put it near a population, both for safety reasons and for sheer size of the systems. It is then a distribution issue, when some distance from the users. In some areas where coal has trashed out the land, it is perfect, since nothing else can be done with such polluted land, so in a sense, coal could actually make such a system more beneficial, because dumping of coal ash has made the land poisonous to anything but industrial uses. In short, that land could rise in value if such a project were to develop and thus you might have the best advantage of high density power with locality of a large economic center close by, within 50 miles or so. In that way, Utility grade power CSP, could replace some of the coal fired systems used and within a 20 year plan, be extremely cost effective for a Utility. Such oddities will benefit CSP projects, when CPV is not as attractive due to multiple use land and space needs, while the need for on-site maintenance offers alternatives, versus distribution costs. My hope is that these discussions will help end coal use as a fuel in Oklahoma, slowly and progressively, as Solar projects begin to make cost effective sense to Utility level projects, versus going to natural gas or coal fired expansion. EPA already saw serious long term problems in Oklahoma, and here is a solution that would cost far less than expensive sulphur scrubbers for coal fired production.

Although PV price declines may have been a factor in the BK of SES, more was at play. Dish-Stirling is a complex machine compared to PV, with negligible advantage in capacity factor. A lot of big names spent a lot of years trying to develop Dish-Stirling, and Stirling engines have never been in the kind of production envisioned for the recently proposed projects. Complex, noisy, the choice of difficult-to-manage hydrogen as a working fluid - the thing was doomed from the start. Even the California Energy Commission which, it seems, would like mice on exercise wheels, had reservations about 'reliability'. (Read: Will a hundred thousand of these things actually sit out in the desert in the sun for 40 years without an army of support technicians?) Yes, doomed from the start. Its demise is no surprise.

@ Phil - I believe SES was using an old Kockums Aplha-configuration Stirling with a crank shaft, which is why it's so noisy and hard to maintain. The largest free-piston I'm aware of is Infinia's 3kW unit.

@ Donald - DNI = Direct Normal Irradience

There are far better applications for the sterling engine than converting the heat from concentrated sunlight to electricity. I spoke with Sterling on several occasions in hopes of incorporating their technology into our utility-scale energy storage product, but they were uninterested because of purported lack of capacity due to rapid wide deployment of their SunCatcher technology.

I've been following this company in hopes it could compete. Nevertheless, always thought that CPV would win out in the end... because GaAs is twice as efficient as crystalline silicon, and less moving parts than CST (which would have been just as eff as the NASA stuff). Weird, though, I thought they would have simply switched over to CPV... guess we need a smaller dish, or even just a Fresnel for those though, to minimize heat problems.
I would imagine that it would be easier for a robotic factory to do smaller parts for cheaper too... But then again, the experts should know WAY more than I could ever imagine, thus "all this" should have already been figured, financed, developed and powering the world by now...

I beleive some people miss the strong possibility of sterling engine, when there is no sun run with natural gas or other (sterling is perfect for biomass). If you combined both technology, you do not need storage system making the package more attractive for utility. All CSP thermal should be design like this other wise they could not compete against PV low maintenance. This was the mistake of this project. I hope some company could buy this project and run it as bi-generation system.

Interesting thought using a changeable heat source.

I suppose the sterling engine could be separated from the dish and replaced by some type of heat collector and heat pipe able to transfer heat to the remote engine.

You would have other options than just switching to all gas / biomass as the heat source when there is no sun. You could get a faction of the heat from another source when the sun in less bright (i. e. late in the day or early in the morning.)

John

@Geldner As far as we can tell from this article, there is no mention of DOE involvment in this company or its projects. Do you know something about it that we don't?

@Phil "The solar to electric efficiency of advanced heat engines is far higher than PV"

This is incorrect, and why I wrote off Dish-Stirling 5+ years ago. You get more kWhs from your investment in mirrors, structure and tracking motors with 40%+ efficient multi-junction PV cells than sub-30% Stirling engines. SES was doomed when multi-junction cell efficiency climbed above the low 30% range. Even if their Stirling engines had been cheap and reliable (hardly the case) SES had no way to match CPV's economics.

Concentrating solar thermal (CSP-T) still has one advantage over CPV: cheap energy storage via molten salt or other medium. But Dish-Stirling has no storage, so bye-bye to the only possible advantage.

Daniel's idea to burn gas and keep the Stirling engines running at night is interesting. But it's probably cheaper to buy a single 250 MW gas turbine than to run gas pipe up 10,000 separate Dish structures to heat 10,000 separate 25 kW Stirling engines, and the large gas turbine would be more efficient to boot.

An unrecognized potential use of Stirling engines is with revolutionary cheap green thermal energy fueled by miniscule amounts of powdered Nickel and Hydrogen.

See CHEAP GREEN on the Aesop Institute website for an overview of this new technology.

It is not yet conclusively proven as practical, but might be soon, possibly by the end of this year.

I will suggest to confront apple with banana not tomatoes.... The 25kW sterling engine running with a pellet biomass when there is no sunshine is hard to beat for small factories however if you want a grid solution probably it might be better to run classical CSP solution with parabolic unit going to centralized unit where you could manage only one larger sterling engine and use heat from extra fuel when there is no sunshine. The problem for small is beautifull, is to get the 25kW at good pricing for private user you need a volume than only bigger power plant could involved but it is not competitive with larger centralized CSP. This is the classic case where some public fund is need to support the technology until it fly itself but in crisis time, it is hard to do,we see the results...Another bad point for parabolic concentration is high direct sunshine which is not full available everywhere as PV without tracker, work better with global radiation.

The problem is not cost efficiency of CSP. Parabolic Trough (as in Spain) etc, are cost efficient it is the short sidedness of investors who want instant gratification when it comes to return on investment. The cost of CSP is similar to that of conventional power because of the infrastructure required to sustain the facilities for the long haul 30+ years. When a utility builds a gas or coal fired plant they know that the return is slower to break even due to expenditure but that over long term the profits & dividends pay out longer & outweigh short term disposable technologies like PV. This is just Candy for Babies. This PV influx & drop of material cost was a death knell to any hope of getting a bona fide utility scale CSP built in the U.S. & will set our renewable energy & independence back 25 years. BRAVO CHINA, YOU GOT OVER ON US AGAIN!

Is a shame this technology went into bankruptcy, I had huge expectations since several years ago, the stirling is simply more efficient than PV, but after all this financial whirlwind it is clear that PRICE is the 1st and only factor to regard this days and deep into the future.

Another approach to a new technology might be to start by using it in a small niche where it has a distinct advantage. An example is the use of PV in satellites for decades.

I don't know just where the sterling would have an advantage over PV, but the Stirling's output is mechanical energy so perhaps an application like pumping or conventional air conditioning would have some advantage by not needing an intermediate electric motor.

The problem here is the Stirling engine, (and its mechanical output) is on the focus of the dish which moves.

John

I am very sorry to note that Calico Solar is going bankrupt. My suggestion to Mr.Sean Gallagher is that the technology of Stirling Engines should be kept alive as the technology can be applied to any form of heat energy. So,although the PV cells are becoming cheaper it should not affect the Stirling Technology as it can be applied to any heat source, not necessarily solar heat.
So, Mr Sean Gallagher,you may expand your business to apply your Stirling Technology in several other applications where heat sources are available but wasted at present.Some of the examples where Stirling Tech can be applied, are utilising the waste heat coming out of the chimneys of millions of factories in the world. These are mostly free heat sources wasted to the atmosphere that can be effectively utilised by a hot air engine and converted to useful electricity improving the efficiency of the entire process.Besides, it will be pure green technology where no additional carbon is burnt to generate electricty.
One can even try to install such huge capacity Stirling Engines in power plants before the entry of the hot material to massive cooling towers not only reducing the load of cooling towers but at the same time generating useful energy from free waste heat !!!

Please give it a thought. You may retain the name Calico Solar but start a new division to use Stirling Technology in non solar applications.Please do not consider bankruptcy now.
I would very much like to see that Stirling Technology is kept alive and well.

T.C.Chandran

Regarding T. C. Chandran's comment, could another fit for a small sterling energy be recycling waste heat in a hybrid car? The salient metric for hybrid car is miles per gallon (i. e. efficiency).

Conventional hybrid cars get all of their energy from an Internal Combustion Engine (ICE) and a well designed ICE is around 30% efficient. Thus 70% of the combustion energy is available as waste heat. If this waste was converted to usable energy at 30% efficiency with a Stirling engine, then .7*.3 = 21% additional energy would be realized.

The improvement would be new efficiency over old efficiency = (.3 + .21) .3 = .70%. Thus could new mpg = (old mpg) * 1.7. For this application, the Stirling engine and ICE could both turn the same EXISTING electrical generation components. The ICE and Stirling could be be clutched such that each is connected only when adding energy.


John Sotack

Lots of good ideas here.

On the subject of waste energy here is an interesting link:

http://www.recycled-energy.com/main/what_it_offers.html

http://www.recycled-energy.com/_documents/media-kit/RED-ProPlanet_ProProfit.pdf

Note on acronyms, once defined by writing out the words, put the letters immediately after (LIA). I almost did an internet search on ICE before I realized it was defined just a few words earlier.

I would love to see a user friendly commercial version of a sterling engine that home owners could use where they have waste heat. Is there something out there like that?

mitch3, such an version would have been useful in Texas this past summer of 2011, where we had a record 90 days over 100 degrees in the afternoon. The old record was 69 days, with 68 days in 2009.

@Mitch - Enatec, Bosch, MTI, and Rinnai are piloting a residential gas boiler with Infinia's free-piston Stirling.

@Chandran - The Stirling engine design used by SES is not their original IP, they licenced it from Kockums, a Swedish submarine manufacturer.

I enjoy Rinnia's hot water system now but use so little gas with that system it would be useless. We do burn wood on green days during the winter but again that is periodical, however my outdoor green house is heated with a passive solar collector which averages 241'f during sunny winter days (static without opening the air vents)heat storage is held in the collector cones which are concrete and lasts until about 11pm at which time a small heater maintains the temp. It would be interesting to enlarge the passive system and see if it would run a sterling system to offset the energy used after the sun goes down. Something to think about anyway.

Very Stimulating observations. I have wondered about the viability of using a 3 to 6 KW stirling coupled to a parabolic trough through a heat pipe. The lower profile could be more acceptable for residential use. Any thoughts?

Stirlings operate on heat differential. In other words, it needs a source of heat and a cooling path to obtain the difference. The greater the differential, the more power potential.
Most developed Stirlings involve much expense, IE, exotic metals and ceramics, and helium or hydrogen as the working fluid, and high pressures to increase the working potential. The power produced in proportional to the pressure of the working gas. Most problems have been in the static loads of these pressures that limit motive bearing life.
I have developed a design that has no static bearing load and can be pressurized to the burst strength of the metals used, has nine separate working parts, has a low vertical profile, and eliminates the heavy "hot piston" problems, and is compact. An ideal entry for multi-fuel hybrid auto apps.

@phil,
Its not going to work in my back yard with passive solar; my problem is a high water table so there is no room for underground heat storage. In the western Utah desert it did show promise and the total output was better than CPV mostly do to the tracking advantage. One day when transmission is available and sage grouse have recovered we'll build a 200mw system.

CSP-Stirlig is all about high scale production with maintained quality. and about getting the MTBF down to a reasonable levels. This is today done, proven with new technology in low scale and therefor possible! It´s all about increasing volumes. If/when you are able to produce electricity in utility scale with CSP-Stirling the price will be at about 50% compared with existing PV (not subsidized Chinese PV)

SES is down but Infinia is still running right? Theirs is more applicable to home users. Stirling technology needs to gain acceptance on trusted products and ramp up from there. The whole idea of renewable energy is to make do with what energy sources are available in your local and the sterling engine does have a lot to offer. PV has had a massive amount of cash thrown at it though and is easier to understand by the people who have the money...

comment # 35 & 36 , We here in America should acknowledge that a massive amount of cash has been run into PV. First, thank the Germans. Second, thank the Chinese. Third, get on board.