SolarMission Solar Tower Video

SolarMission Technologies (OTC: EVOMY.PK,  ASX: EVM.AX) and its Australian subsidiary, EnviroMission Limited produced this 5 minute video about its early pilot plant in Spain. It is an older video (2000) but gives a basic understanding of the solar tower concept. The designs have changed and technologies added, but it gives an introduction to the solar tower concept.

The power plant consists of a very large glazed solar collector with a chimney in the center through which the hot air generated in the collector rises.  The hot air wind drives turbo-generators located at the base of the chimney.  The floor of the collector absorbs heat during the daytime and release the heat during the night, so that the power is produced on a continuous basis.  Cold air enters the collector, with an upward sloping ceiling, from its outer perimeter, is heated and rises through the tower at 50 feet per second (15 meters per second)

Several other videos about Solar Missions Technologies are available at the same site. Their system is described in greater detail in this earlier posts here and here.

Comments

[Beek]

$1M for 60 KW turbine? That is $16M / MW output. Compare that to hydro, which is $2 M / MW and wind which is about $3M / MW.

This is 8 times as costly. Even if they can halve the cost upon scale up, they are still 4 times more costlier than hydro.

Nobody is going to put their money behind this technology. Unless of course it is taxpayer money. Socialists believe that all technologies should be equally funded, so as to not discriminate against any one technology. IOW, diversity in technology and tolerance for other technologies.

[Clint LeRoy]

It may be more costly at this moment, and this is the first one as a demonstration model. What you don't mention is that we are running out of Hydro potential sites, we surely aren't running out of potential sites for these projects! The first one of any single project always costs more to produce. Mass production will bring the costs down significantly.

[Stephen]

The wikipedia article on solar updraft towers says that the lower efficiency of these towers compared to solar thermal can be partially offset by the lower initial capital investment.

I wonder if, with the large Stirling dish systems coming online, the cost of concentrating solar power (CSP) will come down. It might be easier to reduce the CSP price per watt than doing the same thing with solar photovoltaic for industrial scale power generation.

Stephen

[DG]

"Socialists believe that all technologies should be equally funded, so as to not discriminate against any one technology."

That doesn't even make sense. Do you actually know anything about socialism, or do you just like to make stuff up?

If anything, socialist economics is usually derided for the exact OPPOSITE problem, that whoever is in charge of making decisions favors one technology and expects it to act as a panacea, at the expense of other technologies that may be better in certain niches.

[amazingdrx]

As long as they already have a tower, they need a ducted venturi wind collector on top. When the wind blew it would create suction at the top that would increase the wind speed through the system.

The power produced would go up with the cube of the windspeed in the tower. So even modest winds could really boost the power output.

And why not add solar PV on the ground under the glazing, that could boost output also.

[bogyom]

I agree, PV or biomass production under the glazing would make a very efficient system.

[Beek]

DG there is a certain school of leftists who have developed a "technological relativism" idea - namely that all technologies are equal and they should be equally funded, and if the market prefers one technology over the other, it is because of politics and the urge to dominate and that it reflects a political move by the powerful.

But technically, you are right about classical socialists wanting single state enterprises, even though it is does not conflict with the idea of technological relativism. So pls. substitute socialist with "post-modern leftists".

[Kit P.]

Very cool. If pot could be grown the plastic then "post-modern leftists" could deny the environmental impact. While economy of scale might reduce the cost per KW, it will not reduce the environmental cost. "

[jeremiah]

I am not a solar engineer but I am wondering why not add other turbines further up the chiminey thereby increasing the output? the wind is still flowing by at the same rate why not catch it??

In addition why not add heat-sink type materials under the white plastic to increase the night time release. I realize that this will add cost but it could increase efficiency and eliminate plant growth that may eventually need maintenance.

Good luck with this concept. Our future generations need all the innovation we can develop.

[brian hans]

Jeremiah,
Because you would be restricting air flow. An example of plugging your car muffler, back pressure is part of the system. But what about wind turbines going up the tower?

I was thinking that this tower can also be thought of as 'infrastructure' to other forms of energy production. Algae, PV, Wind, halophytes, etc or even food/feed/habitat. This new ecosystem can be easily managed to produce a multi purpose facility offering habitat where habitat maybe isnt as productive or even non-existant (deserts). Getting a 2fer or even 3fer, thereby reducing costs for all.

I dont think that 8x the cheapest source of renew energy (hydro) is a fair fight for a prototype, Mr Beek. Even tho the prototype isnt very efficient, its still worthy and should definately be explored. The very first prototype is never optimized. After a 25yrs of running these systems, we will have efficiency up to 50% solar uptake which will really be producing some Gigawatts for pennies and created jobs where there was only smog and war...
Where do i sign up?

[Ronald Brak]

Putting turbines further up the tower will reduce the power generated by the one near the base and complicate construction.

The current design includes hypersaline ponds to store heat to provide nighttime power. Being able to provide baseload power is one of the advantages of the design. A full scale solar updraft tower is supposed to be able to produce power as cheaply as coal. I don't know if this is true, but it's probably worth finding out.

[George]

Beek wrote: DG there is a certain school of leftists who have developed a "technological relativism" idea - namely that all technologies are equal and they should be equally funded, and if the market prefers one technology over the other, it is because of politics and the urge to dominate and that it reflects a political move by the powerful.

Oh,Bullsh*t. You're still just making this up. Or are you talking "leftists" like ADM or Raytheon? The only time I've ever seen anything like this it was driven by good old American pork barrel politics, with plenty of GOP involvement.

[Ken]

I think the smart money will go on Photovoltaics - nothing else has PV's potential to end up being cheap to mass produce and able to be incorporated into existing and future man-made surfaces without interfering with other uses - and there are some very promising developments already happening. I think we'll see roads paved with solar cells before we see more than a couple of demonstration solar towers.

[amazingdrx]

I think solar cogeneration is the best technology. Use trough concentration to boost solar PV to 40% efficiency, this happens at only 10 suns.

Then collect the heat for heating/cooling or to run a turbine generator on refrigerant.

I think road surface solar is better with heat tubing running through the asphalt. The heat collected could be used to run turbine generators. The efficiency would be less than cogeneration, but considering the huge road surface available it would still be a huge source of power.

The space on rooftops alone would provide more than enough power in sunny climes, a survey of San Diego rooftop solar locations proves it. Adding space over parking areas would power all serial plugin hybrids even if every internal combustion vehicle were converted.

Mass production of concentrating solar cogeneration would bring the cost down right around the current cost of wind power. The increased efficiency and the fact that only about 1/8th the amount of solar PV cells would be needed to provide twice the power compared to flat plate PV cells does the cost reduction.

Not to mention using the waste heat too. Total efficiency of electricity and heat collection could get up around 70% with this technology.

Then there is the other cogeneration element of algae grown in solar collectors, it sequesters cO2, produces biodiesel and powdered cellulose biofuel (that runs in solid oxide fuel cell/turbines), and recycles and cleans waste water. This can be combined with concentrating solar PV. the whole system mouted on rooftops or over parking lots.

Solar furnaces systems that concentrate sunlight with fields of mirrors can be used for manufacturing and recycling, with the waste heat stored in the molten silicon, glass, or metal (for instance) driving turbine generators to provide grid power after the sun goes down. molten heat storage salt or wax could be added to extend the power generation all night long. Another form of solar cogeneration.

[Kit P.]

George needs a reality check, because Beek got it right. In general, engineers are conservative. We like to do what works. It is not that we can not make solar work. After your done building a 1000 MWe of solar generating capacity, the place should not look like a steel mills in Gary, Indiana.

[Beek]

Kit P, not only are engineers conservative, meaning they only deal with empirical facts (at the risk of their careers and their sense of self-worth) and engineers make sure the stuff they build is cost effective, but they are also progressive and they wish to see advancement in the material wellbeing of society.

This contrasts to leftists who have no idea how things work, who have never learnt how to deal with numbers in their lit-crit and cultural relativism classes, and who are loaded with regressive ideological values that says material well being is not important, and that its just fine to stop progress, lest one new plant gets constructed and some engineer incidentally receive a benefit.

[Jeff Becker]

All sweeping generalization are worthless. ;-}

[Chin Hsien]

This is like an open ended solar thermal plant with air as medium. The efficiency is still limited as carnot engine, right? How's about painting the groud in black to enhance the heating?

[Mouseplatterman]

Beek--as both a hardcore leftist and aspiring engineer, I have to disagree with you. While there are a great many leftists out there who are just plain retarded and disregard economic progress (im under-educated here, but i think Cubans when they became communist, and maybe now as well, would be a good example.), there are also many others who simply scorn short-term, few-winners progress (aka harmful oil, coal, and minerals mining--not all is necessarily harmful btw--and things like destructive logging) and strive for things more perpetually beneficial, like many solar technologies. And knowing a few engineers myself, I must say some of them are pretty misguided about what's really best for society, which surprised me given their mental prowess. So please avoid such blatant generalizations, and be specific when you throw around accusations.

Chin Hsein-- the modified plans include many 'solar pools' to capture and store heat for release at night, so that would remove the capacity for "black ground". Also, the potential fertility of the land underneath the skirt would provide economic payoffs (possibly including tourism) to boost the cost effectiveness of the tower.

[Philipp]

Are you sure this video is from 2000? The video quality, the graphics, the guys funny outfit and last not least his mustage look much more like the eighties. That would also explains why a west(!) german ministry commissioned it. Or it just took them over a decade to build this thing.

[Philipp]

I almost wrote 70ties... but it's 80ties in fact. A quick search brought up this entry in wikipedia: http://en.wikipedia.org/wiki/Solar_updraft_tower

Quote: "There are no solar updraft towers in operation at present. A research prototype operated in Spain in the 1980s." And was "decommissioned in 1989".

There is some more information for the interested reader...

A quick look on the companies homepage sais the video is only named "beyond 2000". That was probably because nobody believed it was ever going to be build?

This looks so fishy. They quote the same data the wikipedia entry quotes. I can't even find out the market capitalisation of this company. Is this real? Or are they just frauds riding the solar wave?

[Ender]

Philipp - "A quick look on the companies homepage sais the video is only named "beyond 2000". That was probably because nobody believed it was ever going to be build?"

Beyond 2000 was an Australian TV show that reported on Science and Technology. They once (I am pretty sure) had an article featuring the Solar Tower hence the reference to Beyond 2000. Nothing fishy.

[Chin Hsien]

http://thefraserdomain.typepad.com/energy/2006/08/solar_tower_sta.html
from this link, I quote some data and analyze.
50MW / (3.14 x 1.6^2 x 1000^2)m2 = 6.2 W/m2
In Australia, the average solar power per area land is about 250W/m2 (averaged over three years from 1991 to 1993 (24 hours a day)

http://en.wikipedia.org/wiki/Image:Solar_land_area.png

In other words its efficiency is only about 2.5%. In fact I am not sure the reported 50MW power is averaged value or higest achieavable value.

Such efficiency is considerably low compared to solar cells, even organic solar cell, but its capital cost may be lower which I do not know.

However, can anyone answer me whether the thermodynamic limitation of this system is due to carnot cycle? Ans is that the reason taller chimney could results larger temperature difference between top and ground level and improves the efficiency.

[greg woulf]

The carnot cycle is the reason Chin, the first proposed tower was going to be even taller, but the company had to scale back because contruction methods for that tall a concrete tower didn't exist and raised the risk.

This is a tested technology, the good side is that it will last for 100+ years with limited maintenance and uses zero elements that are limited in supply.

The 50kw testing site was damaged in a storm, which is why it was shut down. That's why it's better in deserts, like SW US or Australia. It was just a test, the higher the stack, the greater the efficiency.

Dams are limited, and cause a lot of damage. You can't compare to a Dam.

It's fair to compare to Solar Troughs and concentrators, but this is fairly competitive. I'm not saying it's the answer to all our problems, but I don't think it's a dead end. There's a lot of potential for the side benefit of fresh water in the desert as well.

[Philipp]

I didn't think the video itself was fishy. Just the fact that they host a video on their website to illustrate their project that shows somebody elses research tower from 25 years ago. They only use stock fotos and meaningless computergraphics on their website. No "real life" fotos from within the company or their work.

So what does this company actually do? They claim to collobarate with the construction company Schlaich Bergerman who did the first research Prototyp. And whenever they refer to the techology they refer to them or get very silent and vague. So what's SolarMissions "intelectual property" in this if there is any?

Press releases from 2002 said they wanted to start the construction in january 2003. Yet nothing has happened. Even worse. On their other webpage they say they are still in the feasability stage http://www.enviromission.com.au/project/project.htm and don't even have a final design. But who is doing the feasability studies and the final design? According to the financial report from 2006 (http://www.enviromission.com.au/financial/2006_EVM_Annual_Report%20.pdf) the only employee expesense they had is $13k. Probably for the secretary. Out of their six directors there is only one engineer and he only has a background in semiconductor research. Two have a financial background. One is "non executive" and apparently only provides council. The most intersting one to me is the one with his law background in "white collar crime".

So who is doing the research and development? Apparently not them. What do they actually do? Provide money for the project? They claim they want to build and operate not only one but multiple towers. This page here quotes a price of 800 Million Dollar for a single tower: http://www.solarmissiontechnologies.com/project.htm. So who is going to pay for that? Their finacial report states cash reserves of $208(!) and
a total Equity of about $7 Million. So wtf are they doing? What is this? A joke?

I like the original idea, but probably there is a reason why there have been no follow ups in 25 years. Maybe I'll drop a line to Schlaich Bergerman just out of curiosity.