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Solar Photovoltaic vs Wind

by Laurent GUERBY Wed Aug 15th, 2007 at 09:16:20 AM EST

DeAnander Lazy Quote Diary: Mark Jones on Capitalist Entropy diary sparked a discussion on solar photovoltaic electricity production.

Let's compare published data for Jerome latest wind farm and a being built solar photovoltaic plant.
(More below)

From the diaries ~ whataboutbob


Jerome offshore windfarm article provides us with the following data: cost of 378 millions euros  (514 millions USD at fx=1.36) for 120 MW peak, offshore wind has 40% of peak load efficiency (from Jerome comment in the discussion), it will produce 420 480 MWh per year. that makes it to 10.7 USD per installed effective watt for offshore wind.

The Solar power station in Victoria is planned to cost 420 million AUD (349 millions USD at fx=0.83) and produce 270 000 MWh per year. Watt-peak is 154 MW, so from the MWh number we deduce that load efficiency is 20% of peak (doesn't work at night, clouds, etc...). That makes it to 11.3 USD per installed effective watt for solar PV.

Price of installed effective watt (as defined above) does not take into account financing and maintenance.

So we still have to compare maintenance cost over the next N years of an on-shore field of mirrors and off-shore wind farm. And also to compare photovoltaic expected lifetime vs offshore windfarm lifetime. Some solar cells have already lasted more than 20 years and lost only 10% of their efficiency.

Does that make 11.3-10.7=0.6 USD per installed effective watt (5.6% difference)?  I'd say likely.

So all in all I'd say according to published numbers concentrated solar PV can already be cheaper than wind (unless I did misundertand something :).

Of course we should do both, but there's no reason to dismiss photovoltaics. There are also other ways to harness solar power.

How will those costs move in the future?

We're comparing first of its kind solar PV plant vs quite mature offshore wind farm technology. As Pierre mentions in the diary discussion:

PV using dedicated silicon wafers is starting about now. These wafers will have way more impurities than VLSI grade wafers, and the PV will go down a bit in yield, but the panels should be much cheaper after a couple of years (like 2-3 times per peak watt I expect). Also, they will be decoupled from VLSI economic cycles (by which production of PV basically stopped whenever their was an expansion of the microchip business, every 3 years or so)

So it's likely future prices will fall more on the solar side than for offshore wind side. Of course the Victoria project can have cost overruns and/or not deliver as planned.

From wikipedia the efficiency of PV cells is also notably rising:

Latest achievement is 40.7% in 2006 so the trend is continuing.

The wikipedia article mentions energy payback (energy cost to make solar cell vs their expected total produced energy over their lifetime), all studies show it's a myth (see also the article cited by Bruno-ken). Just like windfarm slaughtering birds.

As a side note the wikipedia timeline of solar cells article has many interesting information:

# 1984 - 30,000 SF Building-Integrated Photovoltaic [BI-PV] Roof completed for the Intercultural Center of Georgetown University. At the time of the 20th Anniversary Journey by Horseback for Peace and Photovoltais in 2004 it was still generating an average of one MWh daily as it has for twenty years in the dense urban environment of Washington, DC.

Probably in the worst place (pollution, etc...) old technology PV are still working after 23 years.

   # 1984 - Amoco Oil pulled factory loan to make brutal and unwelcome takeover of Solarex Corporation factory in Frederick, Maryland.
    # 1988-1991 AMOCO/Enron used Solarex patents to sue ARCO Solar out of the business of a-Si, see Solarex Corp.(Enron/Amoco)v.Arco Solar, Inc.Ddel, 805 Fsupp 252 Fed Digest.

As with batteries and electric cars, intellectual property is used to gain a few decades of big oil profits and other pro global warning activities.

   Section 8. The Congress shall have power [...] To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries;

Promote progress indeed.

Display:
I note you are comparing a rather optimistic projection for a version of one future technology (concentrated PV) with a real-world example for a version of another technology in its infacy (off-shore wind).

Still, PV technology is maturing. And spreading. Last year in Germany, it fed about 2 TWh into the grid.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Wed Aug 15th, 2007 at 06:52:53 AM EST
Yes as I mentionned it's "first" of its kind.

The Victoria project FAQ mentions they're building plants to produce needed pieces first so there are still risks.

On the other side the PV cell itself is coming from Spectrolab who has been in the business (for space use in decade length missions) for 50 years and still making progress. The rest is sun tracking mirrors which are not really new either. And if I believe this press release (cited on wikipedia) the CS500 model has been running commercially since 2003 (with a less efficient PV cell but the rest look identical).

BTW I didn't notice but BNP Paribas is also listed as member of the financing team for Jerome wind farm.

http://www.q7wind.nl/en/windpark.asp

Annual power production:     435 GWh

So that's slightly above (3.5%) the 420.5 GWh I computed so it puts the price per installed effective watt at 10.3 USD for wind (vs 10.7).

by Laurent GUERBY on Wed Aug 15th, 2007 at 08:12:10 AM EST
[ Parent ]
The thing is, this optimistic price projection reminds me of optimistic price projections for off-shore wind ten years ago, or indeed solar thermal and concentrated solar 15 years ago. They may represent a real potential once the technology is well understood and mass-produced, but I think they wager too much. It's also that this isn't the sole concentrated solar power plant project currently pursued, but seems to claim the lowest price.

On wind, I again emphasize that your example is valid for off-shore wind, which is not much more out of its infacy than concentrated PV. On-shore parks may produce only 60%, but a MW installed costs a third than for Q7.

But, again, these are quibbles, not fundamental doubt in the technology.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Wed Aug 15th, 2007 at 10:21:41 AM EST
[ Parent ]
The wikipedia article mentions energy payback (energy cost to make solar cell vs their expected total produced energy over their lifetime), all studies show it's a myth (see also the article cited by Bruno-ken).

Having read the link, I'd say it's not a complete myth, but something valid just for big centralised solar plants(!): the energy cost of concrete poured in them and labour of specialised staff.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Wed Aug 15th, 2007 at 07:05:34 AM EST
To make a complete opinion, also read the wikipedia article which points to:

* http://www.nrel.gov/docs/fy05osti/37322.pdf
page 2: after reevaluation the current cost and use of concrete/aluminium adds 3-5 monthes to payback time

* http://jupiter.clarion.edu/~jpearce/Papers/netenergy.pdf
there are difference in favour of roof mounted against centralized plants but they're small in time to payback

* http://www.csudh.edu/oliver/smt310-handouts/solarpan/pvpayback.htm
Interesting data on solar cells reusing waste product of chip production, and solar cell only silicon being 10 times less energy intensive than chip silicon.

All in all I still think it's just a myth: payback time is greater for PV than wind but it's not significant.

And I wouldn't be surprised if the average payback times for installed PV drop below wind in the coming years.

by Laurent GUERBY on Wed Aug 15th, 2007 at 07:49:50 AM EST
[ Parent ]
Interesting. I clearly remember a time when efficiency was 20% and that was "as good as it would ever get."


-----
sapere aude
by Number 6 on Wed Aug 15th, 2007 at 07:39:42 AM EST
Yes going from 9% to 40% in 30 years is not bad :).

For payback time, I see that no study looks at concentrated solar PV (as used for the Victoria project) energy cost. The PV cell itself is very small (but likely more hazardous components) the rest is mirror and tubes.

by Laurent GUERBY on Wed Aug 15th, 2007 at 08:18:46 AM EST
[ Parent ]
Some studies do look at concentrated PV, check the article bruno-ken linked.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Wed Aug 15th, 2007 at 10:22:35 AM EST
[ Parent ]
I couldn't find the text of the study referenced by Bruno-ken so I don't know if it's the same kind of PV concentrator than the one used at Victoria. The payback cited is under 0.7 to 1.3 year according to the table anyway.

Two other papers on the topic:

* http://socrates.berkeley.edu/~kammen/C226/8r.pdf
transporation can account of up to 19% of installation energy cost, so on site or near site production of component should matter (as market expands production site should pop up in more places).

* http://www.concentrixsolar.de/cms/upload/pdf/SCC_3_Lerchenmueller_2005_04_27_Paper.pdf
they conclude that 1.5 euros per watt-peak is within reach in case of mass production, assuming 20% load and fx=1.36 that gives 10.20 USD per installed efficient watt, not far from the data I computed.

by Laurent GUERBY on Wed Aug 15th, 2007 at 10:38:45 AM EST
[ Parent ]
More papers:

* http://socrates.berkeley.edu/~kammen/C226/10r.pdf
cost per kwh estimates for various solar projects

* http://www.greenhouse.gov.au/renewable/recp/pubs/booklet.pdf
energy in Australia

by Laurent GUERBY on Wed Aug 15th, 2007 at 11:07:37 AM EST
[ Parent ]
A nice blog showing progress for onshore wind turbine (with monthly production updates):

http://www.biofuels.coop/windblog/

An interesting analysis of wind-only reliance here:

http://www.biofuels.coop/windblog/?p=143

including negawatts as "to be done first".

by Laurent GUERBY on Wed Aug 15th, 2007 at 08:26:06 AM EST
The numbers seem a bit optimistic, but not wildly so.

And, well, there are real (positive) developments coming down the pike for CSP (both PV and steam).

Finally, this is a great discussion ... in that isn't it a great question to be asking: which is the cheapest way to add new power, solar or wind.  With both being competitive with fossil-fuel electricity, even without considering "external" costs.

And, of course, what we want the answer to be:  both. Let's drive the utilization up and costs down in both arenas.

Thank you.


Blogging regularly at Get Energy Smart. NOW!!!

by a siegel (siegeadATgmailIGNORETHISdotPLEASEcom) on Wed Aug 15th, 2007 at 09:52:03 AM EST
Interesting, but even $10/W is still too expensive for anything other than large industrial use.

Current retail prices in the UK are around £6/W for PVs vs 30p/W for solar hot water.

So a £5k PV system will only produce around a third of the household electricity and take around 15-20 years to pay back - longer if batteries need to be replaced.

As I said, prices need to drop substantially - i.e. by at least 75% - before a majority of people start taking PVs seriously as a grid alternative.

The political problem is that the energy companies have no interest in watching 30-80% of their market disappear. And since they have a more powerful lobby group than PV retailers do, I think we're unlikely to see any political support for PVs or solar any time soon.

Which is why the biggest driver of change is going to have to be a huge price drop and increased efficiency.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Aug 15th, 2007 at 09:53:30 AM EST
Or prices of competing power has to go up...

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by A swedish kind of death on Wed Aug 15th, 2007 at 10:50:01 AM EST
[ Parent ]
Indeed retail is a different market I don't directly talk about here. And price drop is equivalent of price rise in other technologies, eg if we start counting all real costs of oil/gas/coil :).

But one interesting thing is that the Victoria project is using a large number - 19250 - of relatively small CS 500 Heliostat dishes to produce the advertized 154 MW peak, so that's 8 kW peak per dish, so about 1.6 kW assuming 20% load (average price per dish of the plant is 18130 USD).

These numbers for one dish are not far from home consumption so this has great potential as a very distributed system.

by Laurent GUERBY on Wed Aug 15th, 2007 at 11:07:10 AM EST
[ Parent ]
Ooops I misunderstood the documentation (and forgot to look at the drawings :), 19250 is the number of mirrors ("heliostats") on ground. It looks like there will be 246 small towers with each 256 PV cells (total 62976) and agregating around 78 mirrors light.


 Plant components:
    Heliostats - 19,250
    Receivers - 246
    PV Modules - 62,976
by Laurent GUERBY on Wed Aug 15th, 2007 at 01:18:30 PM EST
[ Parent ]
Jerome offshore windfarm article provides us with the following data: cost of 378 millions euros  (514 millions USD at fx=1.36) for 120 MW peak, offshore wind has 40% of peak load efficiency (from Jerome comment in the discussion), it will produce 420 480 MWh per year. that makes it to 10.7 USD per installed effective watt for offshore wind.

The Solar power station in Victoria is planned to cost 420 million AUD (349 millions USD at fx=0.83) and produce 270 000 MWh per year. Watt-peak is 154 MW, so from the MWh number we deduce that load efficiency is 20% of peak (doesn't work at night, clouds, etc...). That makes it to 11.3 USD per installed effective watt for solar PV.

I figured it interesting to check how thermal solar power stands in comparision, so I picked Andasol 1 in Spain. I picked it just because it was the first plant I came to think about, so no particular selection process. I do not know how it stands versus other solar thermal plants.

From the factsheet:
Cost: 310 million euros (421,6 millions USD at fx=1.36)
Capacity: 50 MW
Production: 179 000 MWh
Gives:
Efficiency: 41% (179 000 / (50*365*24))
Installed effective watt: 20 MW (50*41%)
USD/Installed effective watt: 21 (421,6/20)

However, this cost also includes a liquid salt heat storage system to allow for electricity generation up till 7,5 hours after sundown. How much this is worth depends a lot on what other power sources and what consumption patterns you have.

Afaik, thermal and pv competes on equal terms in spain when it comes to benefits, indicating that at least in Spain PV is more expensive then the cost estimated for Victoria.

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by A swedish kind of death on Wed Aug 15th, 2007 at 11:45:55 AM EST
Thanks for doing the computation!

wikipedia: http://en.wikipedia.org/wiki/Andasol_1_solar_power_station

Storage of energy is a nice feature for this plant, and it is certainly worth something.

Some information for energy storage technologies:

The last one has price per Wh data:

In one of the largest contracts for an energy storage system in the wind power industry, VRB Power Systems Inc. has contracted to supply a 1.5 MW x 8 hour Vanadium redox battery system. This will be driven from phase 2 of the wind farm and will enable surplus electricity to be generated when demand is low, and will improve consistency or supply to the electricity network

http://www.leonardo-energy.org/drupal/node/959

says the cost of the battery system is $6.3 millions.

French 2006 average grid power use is 55GW (peak use was 87GW), so 1.3TWh per average day.

Cost of storing one average day of France electricity use by this system is thus 682 billions USD (37% of 2006 France GDP). Of course we don't have to store all of it in batteries but this gives a reference number :).

That's 1.5*8=12Mwh for 6.3 millions USD so 525 USD per battery stored kWh.

I couldn't find wh figures for andasol, assuming the "6 hours" cited means a quarter of a day production, daily production being 490 Mwh that makes it to 122 Mwh of energy stored, which is worth 64 millions USD by the battery price above. That's 15% of the plant price so overall not a big difference if my computations hold.

More on energy storage here:

http://thefraserdomain.typepad.com/energy/energy_storage/index.html

The vanadium stuff is mentionned and many more.

by Laurent GUERBY on Wed Aug 15th, 2007 at 12:28:19 PM EST
[ Parent ]
A solar thermal project in Spain:

http://thefraserdomain.typepad.com/energy/2007/04/11_mw_solar_tow.html

11 MW peak, 24.3 GWh per year for 47 millions USD so 2.7 MW installed effective MW so 17 USD per installed effective watt.

by Laurent GUERBY on Wed Aug 15th, 2007 at 01:38:06 PM EST
[ Parent ]
This is a case of comparing things that are not really comparable, and it brings out some highly doubtful numbers.

First of all, the notion of a price per MW is atrocious. The only relevant price is that of $/kWh, i.e. per energy output. Prices per capacity can have relevance for intra-industry comparisons (i.e. comparing the cost of one wind farm vs another) but not to compare different technologies. Prices per kWh include the initial investment cost (and the financing cost), the operating cost and the fuel cost. The comparison made appears to focus only on initial investment costs

Second, the comparison of an actual project with an advertisement for a project that does not exist is, similarly, a debatable venture.

Thirdly, presenting offshore wind as a mature technology is also a bit misleading. You can still count on your fingers the number of operating industrial offshore wind farms. PV technology can, conversely, be described as having a 30-year history and it might be more useful to compare recently built PV plants (ther's a number of them) to recently built offshore wind plants.

I won't comment on the Australian project, other than to say that public promotional material made available several years before construction starts is unlikely  to provide much useful information.

On the Dutch project, I'll bring up the following tidbits, to enlighten readers:

  • this is, in many ways, an experimental project. It is the first one to have been built so far from shore (more than 25km), and the first one to be built in such deep waters (20+meters depth). As such, it benefitted from specific public support to get it done, reflecting the extra cost there technical parameters entail;

  • this project was the first one to be project financed by banks. As such, the numbers that were made public reflect the pretty conservative assumptions of the banks with respect to both project costs (including contingencies) and project revenues (taking into account, for instance, lower wind levels than commercially expected). The headline number also reflects the presence of reserve accounts, i.e. money set aside in the budget just in case but that will return to investors once debt is repaid;

  • finally, the Dutch support framework for wind energy is based on a much shorter support mechanism than in other countries - 10 years instead of 15 or 20. This in turn requires financings to be shorter, and thus repaid faster, which increases the apparent financing cost (but not the real cost taken over 20 years, the usual life span of wind turbines);

  • a separate, additional point is that the project has been structured such that the upfront investment costs actually include operating expenses for a number of years, which will thus not need to be added when calculating rea lcosts per kWh.

Thus, the calculation is overtly conservative for offshore wind, and likely very optimistic for the (potential) solar project.

From our portfolio of existing projects, prices for wind are in the 4-7c/kWh range, for offshore wind in the 7-10c/kWh range, and for solar around 15-20c/kWh. Don't ask me to convert these to USD/MW, because I can't.


In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Wed Aug 15th, 2007 at 12:11:16 PM EST
I was also going to comment on costs, but thankfully, you beat me to the punch.  I would like to add some thoughts.

In no sense is offshore windpower mature, and while the long-term prognosis is exceptional, the technology can not truly be considered commercial.  Q7 pushes the frontier in both financing and water depth for a large project, but it uses quite conventional turbines.

The first real offshore turbines are still being tested at onshore prototype sites, including REpower 5M (4WTs), Multibrid 5MW (2 WTs, one with a tripod foundation), and the Enercon 6MW (evolved from a number of turbines beginning at 4.5 MW).  I've visited all these turbines, but won't climb until next month.

Several other smaller turbines have offshore versions, including one Nordex N90 about a 100 or so meters offshore in Rostock harbor.  The German offshore test station is planned to begin construction next year.

REpower has installed one 5M turbine near the Beatrice oil rig at depths around 45 meters, so while this is not a "large commercial" project, it is the state of the art currently.  A second 5M was intended to be installed last year, but was pushed back to this summer as the rig was not available.  I don't know if the second WT is already installed.

The real state of the art will be floating foundations, as the rest of the world does not look the pool table equivilent of the North Sea.  Floating foundations will allow projects to be sited far enough from coasts to obviate conflicting use and visual effects, which in most parts of the world have depths up to 200 meters.

Except in the North Sea, it makes no sense to go offshore until high value onshore wind sites are operational.  Onshore remains the focus of any chance we have to meet necessary renewable targets worldwide, but even including the remaining sites in northern Europe.

"Life shrinks or expands in proportion to one's courage." - Anaïs Nin

by Crazy Horse on Wed Aug 15th, 2007 at 12:39:33 PM EST
[ Parent ]
First of all, the notion of a price per MW is atrocious. The only relevant price is that of $/kWh, i.e. per energy output. Prices per capacity can have relevance for intra-industry comparisons (i.e. comparing the cost of one wind farm vs another) but not to compare different technologies. Prices per kWh include the initial investment cost (and the financing cost), the operating cost and the fuel cost.

Laurent has chosen USD/installed effective watt as benchmark, which is just installation cost (in $) / output (Wh) * the number of hours in a year (365*24). Perhaps not the measurement I would have chosen, but nothing wrong with it per se as long as you want to compare installation costs. I guess the assumption is that the differences in financing and operating cost is small. Fuel cost is the same, zero.

solar around 15-20c/kWh

Thermal, PV or both?

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by A swedish kind of death on Wed Aug 15th, 2007 at 12:58:26 PM EST
[ Parent ]
are only part of the cost. Financing and operating costs are not irrelevant, in fact financing costs are the single biggest driver of relevant costs for renewable energy. And using a figure that requires the fule cost to be zero is extremely dangerous as it makes all renwables look really bad compared to fossile fuel-based sources.

As far as I know, both thermal and PV are in that price range.

In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Wed Aug 15th, 2007 at 01:26:18 PM EST
[ Parent ]
First of all, the notion of a price per MW is atrocious. The only relevant price is that of $/kWh, i.e. per energy output.

If you read my post carefully you see that I quote only output figures, I just divide them by 365*24.

Why do I do this division and post in installed efficient MW and not USD/kWh "retail price"?

Because I don't have data for financing, maintenance and lifetime of the power plants which is needed to provide the retail price per kWh. Financing being equal we have to guess the relative value of other parameters if we want to get the kWh retail price.

several years before construction starts

My understanding is that the CS500 solar dish model is in production since 2003 at the Umuwa site according to the company document I cited, but it has only 10 dishes (at a price of 207 500 USD per 22kW peak dish, probably first prototypes :).

google map of the Umuwa plant:

http://maps.google.com/maps?q=http%3A%2F%2Fbbs.keyhole.com%2Fubb%2Fdownload.php%3FNumber%3D893511&am p;t=k&om=1&ie=UTF8&ll=-26.473512,132.01476&spn=0.002295,0.003616&z=18

Here is an Oil Drum post with a nice photo of Umuwa dishes:

http://europe.theoildrum.com/node/2583

The 22kW peak dishes at Umuwa have a diameter of 13.7 meter, height of 14.5 meters:

http://www.bcse.org.au/docs/Project%20Profiles/Anangu%20Pitjantjatjara%20Solar%20Station.pdf

I don't know if the dish will be the same or different at the Victoria plant.

Of course all projects carry risk, overestimates are floating around but that's life :).

by Laurent GUERBY on Wed Aug 15th, 2007 at 01:12:54 PM EST
[ Parent ]
well, as pointed out above, energy and "net" capacity may be partially linked for renewable sources, but they are certainly not for other energy sources and thus provide highly misleading numbers, which the coal and gas industry will certainly love you for, as it will paint them in a highly flattering light (their investment costs are in the 1 USD/kWe - less for gas, a bit more more for coal)

USD/kWh is not a retail price, it's the price of energy. It can be retail or wholesale. Using USD/MW is like quoting the price of water with respect to the diameter of the pipe - it makes little sense.


Because I don't have data for financing, maintenance and lifetime of the power plants which is needed to provide the retail price per kWh.

Well, my point is precisely that the items you don't have are very relevant and do drive the actual price of electricity for the various technologies. In one case they are included (and even oversized), and in the other they are ignored, or at least unknown.

In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Wed Aug 15th, 2007 at 01:34:44 PM EST
[ Parent ]
(please read my post again for the water/pipe)

Well, my point is precisely that the items you don't have are very relevant and do drive the actual price of electricity for the various technologies. In one case they are included (and even oversized), and in the other they are ignored, or at least unknown.

That's why there's more to the diary than just the first two paragraphs :).

If you look risk and maintenance by small window of the scale of physical parameters in the plant:

  • Wind: normal temperature, large physical forces/motors, no hasardous material
  • Solar thermal: high temperatures, moderate to large physical forces (stirling engine or other), may be hasardous materials (to move heat)
  • Solar PV: normal to moderate temperatures (they cool the PV cell if I understand correctly), no physical forces (just moving small mirrors on ground), no hasardous material.

I can't quantify the induced risk and maintenance overhead of course, but I'd say solar PV will likely have the lower of the three.
by Laurent GUERBY on Wed Aug 15th, 2007 at 01:50:01 PM EST
[ Parent ]
This 189 pages PDF has many info:

http://www.azcommerce.com/doclib/energy/az_solar_electric_roadmap_study_full_report.pdf

page 88-90 it gives 2006 cost per installed effective Watt at 21.7 USD. It notes than if more than 10 MW/year are installed this cost would likely go down to 13 USD.

But the interesting line is their "Non-Fuel Fixed O&M" if you look at the tables you see that CPV are low compared to other solar tech (and projections for the future are even lower).

Amonix technical paper for 2006 has a section on maintenance of their CPV systems for the past years.

by Laurent GUERBY on Wed Aug 15th, 2007 at 02:22:54 PM EST
[ Parent ]
Fortunately I have someone (a very close friend) doing first line research in soalr cells for the  last ten years.. she is a great researcher coming from the great unviersity suystem of spain (Barceloan too) .. in phsyics.. and of course after spending a lot of money in her education the spanish state is using her by.. well... suffice to say she is now working in research for an europeaa company..at least european.. but of course.. not in Spain..

She has told me a lot of times that efficiency is not really a problem... silice cost is the problem.. the same efficiency but with any kind of cheaper material and the future is all solar.. the problem is that this new material is not there yet..

So they are coming with cheaper ways to process it..soa s to spend less enrgy int he proces of creating it (first roadblock) and with ways to put less silice without losing the 10% efficieny  (that's all it is needed she says.. 10%.. more than enough.. acutally 5% would be fine with most of the elements you can find in the market...)

So... what to do... research on new materials.. and ways to recude the silice requirements of the cell.

On the good side.. she also projects huge growth in the sector because there have been very important discoveries in the last ten-fifteen years... and now these technologies will move mainstream and reduce the price heavily.. especially on the energy requirements of the production (deposition).

That was for the last part of this great diary.. regarding the comparison with wind.. I just sit and listen to the experts discuss (jerome, you.. and the rest....) I just learn.

A pleasure

I therefore claim to show, not how men think in myths, but how myths operate in men's minds without their being aware of the fact. Levi-Strauss, Claude

by kcurie on Wed Aug 15th, 2007 at 04:58:51 PM EST
From my googling around USA Amonix and Spain's Guascor have a joint venture to build a plant producing PV in Spain. I've seen German business operating in or for Spain too.

There seem to be a lot of solar power plants of various kind being built in Spain right now, plus their supporting part plants, with EU/state/region providing part of the funding which is quite encouraging.

I don't search through spanish well so I had some trouble finding what's going on after the initial in english press release :).

If you have links to pages in spanish about those projects I'm interested: I'm able to grok them but finding them via google is harder for me.

by Laurent GUERBY on Wed Aug 15th, 2007 at 06:06:50 PM EST
[ Parent ]
Latest achievement is 40.7% in 2006 so the trend is continuing.

That would be 42.8% :-)

The solar vs. wind thing is silly since we need both (we can't do only wind). Photovoltaics are still a long way from being competitive, but as the costs are going down all the time, this is all the more reason to support them in all ways (from funding research to subsidising construction and operation).

by nanne (zwaerdenmaecker@gmail.com) on Thu Aug 16th, 2007 at 10:49:15 AM EST
Thanks! Solar vs wind is just the catchy title :). I wrote:

So all in all I'd say according to published numbers concentrated solar PV can already be cheaper than wind (unless I did misundertand something :).

Of course we should do both, but there's no reason to dismiss photovoltaics.

This post was about updating the "we're not there yet on solar PV techno for plants on a cost basis" line to the latest developments.

Now, from the link you provided:

July 30, 2007

From 40.7 to 42.8 % Solar Cell Efficiency

University of Delaware-led team sets solar cell record, joins DuPont on $100 million project.
Newark, Delaware [RenewableEnergyAccess.com]

Using a novel technology that adds multiple innovations to a very high-performance crystalline silicon solar cell platform, a consortium led by the University of Delaware (UD) has achieved a record-breaking combined solar cell efficiency of 42.8 percent. The current record of 40.7 percent was attained in December 2006 by Boeing's Spectrolab, Inc.

[...]
Barnett and Honsberg said that reaching the 42.8 percent mark is a significant advance in solar cell efficiency, particularly given the unique small and portable architecture being used by the consortium and the short time--21 months--in which it was developed.

Honsberg said the previous best of 40.7 percent efficiency was achieved with a high concentration device that requires sophisticated tracking optics and features a concentrating lens the size of a table and more than 30 centimeters, or about 1 foot, thick. The UD consortium's devices are potentially far thinner at less than 1 centimeter.

"This is a major step toward our goal of 50 percent efficiency," Barnett said. "The percentage is a record under any circumstance, but it's particularly noteworthy because it's at low concentration, approximately 20 times magnification. The low profile and lack of moving parts translates into portability, which means these devices easily could go on a laptop computer or a rooftop."

[...]

In November 2005, the UD-led consortium received approximately $13 million in funding for the initial phases of the DARPA Very High Efficiency Solar Cell (VHESC) program to develop affordable portable solar cell battery chargers.

[...]

So they pushed from 37% efficiency in 2005 (end of wikipedia table) to 42.8% in less than three years on 13 millions USD funding (aka peanuts), plus the stuff need far less sun concentration which means less temperatures and other issues.

ThatBritGuy should send them a postcard :).

by Laurent GUERBY on Thu Aug 16th, 2007 at 01:40:10 PM EST
[ Parent ]
From the same site:

http://www.renewableenergyaccess.com/rea/news/reinsider/story?id=49617

Kenya, not a place that comes readily to mind as a PV leader is, in fact, just that. With roughly 30,000 small (truly small, 20-100 watts, not kilowatts, per household) systems sold per year, has the world's highest household solar ownership rate.

Interesting!

by Laurent GUERBY on Thu Aug 16th, 2007 at 01:56:04 PM EST
[ Parent ]
Regarding the efficiency of renewable energy production systems, a result known as Betz'law:

http://en.wikipedia.org/wiki/Betz%27_law

http://www.windpower.org/en/tour/wres/betz.htm

states that it is not possible to capture more than 16/27 -which is roughly equal to 59.3%- of the wind blowing through a wind turbine kinetic energy.

I have read in

http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0471489972.html

that modern wind turbines do achieve peak efficiency rates higher than 50-53%, close to the limit fixed by physics.
Does anyone know of a similar physical ceiling for solar-derived energy?

by Imad Srairi on Fri Aug 17th, 2007 at 05:48:21 AM EST
[ Parent ]
http://www.iop.org/EJ/abstract/0957-4484/11/4/342

Prospects for photovoltaic efficiency enhancement using low-dimensional structures

Martin A Green 2000 Nanotechnology 11 401-405   doi:10.1088/0957-4484/11/4/342

Abstract. The use of photovoltaic solar cells provides an elegant way of converting sunlight to electricity. The photovoltaic industry is currently growing very rapidly, at a compounded rate of about 30% each year. Energy conversion efficiency is a key parameter with this technology since it directly impacts both material and deployment costs. The performance of the traditional bulk semiconductor solar cell is limited to about 33% while thermodynamic limits on the conversion of sunlight to electricity are much higher, at 93%. Low-dimensional structures appear capable of allowing much of this gap to be bridged. These structures allow increased flexibility with traditional efficiency enhancement approaches such as those based on `stacked' or tandem cells, which double efficiency limits to 68%. Perhaps more interestingly, they offer scope for completely new device concepts such as those relying on excitations between multiple energy bands and improved `hot-carrier' cells, that offer scope for similarly high performance.

google on "limits to photovoltaic efficiency" has many links. There are mentions of a "Shockley Queisser" framework for maximum efficiency.

by Laurent GUERBY on Fri Aug 17th, 2007 at 07:28:46 AM EST
[ Parent ]


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