Ice music

I forgot to mention today about hearing the ice sing while skating. Beautiful (and loud). Here's an analysis by an acoustical engineer, Gunnar Lundmark, relating tone frequency to ice thickness. I guessed - with my less than perfect ear - that today's tone was A4. According to wikipedia that's 440 Hz which would correspond to about 7.5 cm of ice. The ice was reported to be 9 cm which should have produced something closer to a G4. Amply within my margin of error.

From Gunnar Lundmark's site you can link to sounds of ice music. Try the sound of thin ice and the sound of too thin ice.

We've got ice!!

The clear, cold days started well before Christmas and the temperature has been sinking steadily: -10C today at midday. We (Alessandro, Ariana - a Czech friend - and I) went to a lake a 20 minute drive east of Uppsala where today's ice report indicated 9 cm thick ice. With the cold temps and no snow at all, the whole lake was skateable. The white stuff is ice crystals which didn't interfere with skating although it was easier skating in the clear, dark streaks that criss cross the lake. The streaks are where the ice cracked and refroze.

The skating equipment is designed for long distance trips such as going around the islands of the archipelago. A basic set consists of long blades attached to cross country ski shoes (although this can get more or less specialized). Poles are used much in the same manner as for skiing. The orange ice picks are essential safety epuipment and are worn aroung the neck for easy access should you fall through the ice and would like to climb out again. A soft pad for breaks is a nice luxury item I like to have, too.

Burnt goat

Looks like they torched Gävle's goat last night. This is what it became about 12 hours after I took its picture for yesterday's blog post . The story's in the Local.

Gävle Julbock

The large straw goat in the town of Gävle made the news on Christmas day. Not because something happened to it, but simply because it was still in place, untouched and unharmed. The 13 meter high Christmas symbol has been torched more often than not since it first made its appearance in Gävle in 1966. Various strategies to ensure that Gävle still would have its goat have been tried including employing guards, making a spare goat and, in recent years, drenching it in flame retardant. The flame retardant worked but took all the yellow luster out of the goat. This year's method is different: no guards, no flame retardant, no spare. It burns up - it's gone. This realization seems to be sufficient to get the bonfire-happy Swedes to leave their goat alone. So far, anyway.

While in Gävle today, I bought a little wooden goat to decorate the Christmas tree. If you're wondering why the tree doesn't have needles, it's because I converted my potted ficus plant into a Christmas tree this year.

The other pic is just a classic tourist shot of the houses in Gävle's old town.

Correction: Apparently there are guards at night, and a torching attempted had been successfully thwarted by a passerby who used one of the available extinguishers. I don't see it in my pic, but there's supposed to be a burned patch on one leg.

New blog

I've finally decided to separate my CIGS ramblings from my personal ones even though the two often overlap. The plan is to move over all CIGS related stuff from this blog to the new one, Sunny Side Up - a CIGS adventure. Apparently my last post on quantum eficiency had a tad too much detail for some friends and family. This way I can feel free to talk about band gaps, Fermi levels and activation energies along with the usual nuts and bolts of the CIGS world somewhere else. Not that I will - there's a risk of severe ignorance exposure. But at least the possibility's there. I hope to get some CIGS-savvy guest bloggers over at the new blog, too, starting with my co-workers at Uppsala University. We'll see if this goes anywhere. It'll be a couple of weeks before I actually move the CIGS stuff.

I still plan on expounding on my usual inanities here.

The black hole in the milky way

Zoom in to the center of the milky way in this film from ESO, the European Organisation for Astronomical Research in the Southern Hemisphere. Got this from Lunken's blog.

How does a CIGS solar cell respond to sunlight?

Well, hopefully the solar cell will act like a battery when the sun shines on it. But, of course, I want to go into a bit more detail than that. I've already written a fair number of posts regarding the making and workings of CIGS solar cells. You'll find them by clicking on the "CIGS" label at the bottom of this post. If you're new to the CIGS world, I suggest you start there first.

By now, you must be tremendously curious about the wonderful graph my colleague Sebastian put together for me, my own computer skills being somewhat limited in this regard. First off, you probably can't read the labeling on the graph very well because it's too small. This is easily remedied by a single click on the graph itself to see it full size - a handy trick that's useful for websites in general. So go take a closer look now and I'll explain what you're seeing.

First off, I've actually got two graphs for the price of one. I'm "allowed" to put them together because they have a meeting ground in their shared x-axis, the one labelled wavelength. This refers to the wavelength of light. The units are nanometers, nm (1 nm = 0.0000001 centimeters - does that help?).

One graph is the solar irradiance aka solar spectrum. I'm pleased to display the visible part of the solar spectrum in the pretty colors. The y-axis on the left is for irradiance of the solar spectrum in units of watts per square meter per nanometer. The "square meter" part refers to sun power falling on a square meter of surface pointed directly at the sun. The "nanometer" part refers to the color or wavelength interval of incoming light so that you can see the relative power contribution by the various colors. To get the total solar power you'd have to integrate or add up all the individual contributions by wavelength interval over the entire spectrum including the wavelengths that lie outside the regions of my graph. Understandably a bit confusing, but I'm trying.

The graph of the solar spectrum is labelled very scientifically as "AM 1.5 global solar irradiance at sea level". This is a bit more information than I had intended to discuss, but, well, Sebastian is very much a scientist (I'm more of an engineer). Anyway, here goes. This spectrum is what's referred to as a "standard sun" for the purpose of comparing the performance of solar cells with each other under the same sunlight conditions. AM 1.5 stands for air mass 1.5 and refers to the sun when its zenith angle (the angle from vertical) is 48.2 degrees. This corresponds to sunlight that travels through an atmosphere that's "1.5 atmospheres thick". AM 1 would, of course, refer to a sun that's directly overhead with sunlight travelling through an atmosphere that's 1 atmosphere thick. The "global" part of the label refers to the fact that both direct and diffuse light are included. The diffuse light is the sunlight available to you when standing shaded from direct sunlight.

I think the spectrum must be what you might get in some fairly pristine environment and it's not the same as you would get where there are high pollutant levels. Humidity will also affect the spectrum. In fact, much of the "choppiness" in the spectrum is due to absorption by water molecules. In any case, the sun tends to be at some angle in the sky other than the zenith angle of 48.2 degrees. However, when you see a power rating of a solar module, it will have been calculated using this AM 1.5 spectrum. So a module rated at a certain power output will rarely produce that particular power. It's just a means of comparing solar module A to solar module B. Nevertheless, this particular spectrum has been chosen because it's a good indication of average solar power per square meter arriving at the earth's surface.

Now that I've gone through that lengthy discussion I might as well tell you how much sun power arrives at the earth's surface for the AM 1.5 spectrum. It's, conveniently, 1000 watts per square meter. Just out of curiosity, I went and read what the max sun power was according to our sensor (pyranometer) on the roof at the lab. Three days ago we had full sun and the power was impressively over 450 W for an hour or two. Being near the winter solstice, the sun rises only 6 degrees above the horizon.

Ok, onto the other part of the graph labelled quantum efficiency. The y-axis for this graph is on the right and its measure is percent. Quantum efficiency is also called spectral response, the former term being preferred by solar scientists. It's a measure of how well a solar cell can produce electric current from the incoming sunlight color by color, wavelength by wavelength. For scientists, the sunlight is "quantized" into photons, the minimum energy packets by which light can give its energy up. The quantum efficiency measures the percentage of incoming photons that will result in an electron coming out of the solar cell. For the units of incoming sun power, I could have replaced the "watts" with "photons per second".

You'll see that the top and relatively flat part of the quantum efficiency curve lies at about 90%. So if you shine pure red light, say, onto the solar cell 90% will be converted to electricity. If the quantum efficiency were 90% over all wavelengths, then you'd have a 90% efficient solar cell. But it isn't, and you don't. The reasons? Some light is reflected away and never even makes it into the cell. Some light produces overly energetic electrons that shrug off the extra energy as heat. That's not good when you'd rather just have electricity. And some light never frees up an electron at all, it just produces heat directly. And then, some freed electrons get trapped before making it out. They're forced to give up their energy and wait around for another photon to come by for another chance at freedom. The result is as you see in the graph. A solar cell has a fairly limited working range.

The particular solar cell in the graph is a pretty good one. It's a CIGS cell I made and measured and this one is my best ever at 18.5% efficient. In the graph you can see that where the sun is producing most of its power the cell is also at its most efficient, that is 90%. Going to the violet and ultraviolet there is less sun power available (thanks in part to ozone, but I digress) and what little there is is used poorly by the solar cell. For any CIGS savvy readers, you'll also notice that the characteristic absorption by the cadmium sulfide layer isn't there and you'd guess rightly that this cell is cadmium free. Going to the infrared part of the spectrum at longer wavlengths, again the sun power falls off, choppily and a bit more slowly. At a wavelength a bit over 1000 nm there's less than half the max sun power available while at the same time the quantum efficiency is down to about 50%. Half of a half is only a quarter as much power produced than at the max part of both curves (very approximately). Beyond 1200 nm, the solar cell is totally useless. Whatever sun power it picks up will only go as heat.

The information in the two graphs is sufficient to calculate the electrical current that a solar cell will (not just "can") produce, at least when the sun is looking like the AM 1.5 spectrum. Since the quantum efficiency curve is a real measurement of the current produced at each wavelength, this is considered a real measurement of maximum current output of the solar cell when the external circuit is in short circuit mode. Just take the incoming photons per second at each wavelength, multiply this by the quantum efficiency at each wavelength to get some reduced number, add up or integrate the contributions from all the wavelengths and there you have a measure of the short circuit current. This is considered a better measure of current than that measured under a solar simulator, because the simulator uses a light bulb whose spectral output differs from the sun's. The quantum efficiency method gives a wavelength by wavelength breakdown of the picture with soooo much more info.

Ok, so what's my point, anyway? Bit by bit, I'm hoping to explain why solar cells aren't better than they are. Why couldn't they be 80% efficient, or how about 60? 40% maybe? But not even 20?? That will be for another time. I'll try and make future posts much shorter than this one.

Hopefully my new blog contributors, Per-Oskar and Sebastian, will soon be spouting lots of CIGS wisdom of their own.

The dead can warm the living

I can't help but admire Swedish creativity and the desire to particate in developing new energy sources. Or maybe it's just that Swedes abhor wastefulness. The cemetary administration in the Swedish town of Halmstad has plans to connect their crematorium's output - the heat, not the ashes - to the local district heating system: I saw this in the Local. While the burning fuel does produce CO2 and presumeably particulates, at least it's from a renewable energy source. Halmstad would be following the examples of the already operating crematorium heating systems in Lund, Skövde and Östersund.

Hello World

You may have already noticed the appearence of two new names on the sidebar<-- And as one of the new contributors to this sporadically solar energy oriented blog, I thought I'd begin with a Hello and a brief introduction. Right now I am in the cleanroom, which is quite different from just any ordinary clean room. The cleanroom is a particle-controlled (and temperature/humidity they claim) environment common to most who work in microelectronics or thin film processing. Essentially, it's just very very clean. I am a phd student, and I do most of my work in this clean room. That takes up about half of my day; the other being spent sifting through articles or my own data for something of value. Like the originator of the blog, I am working with CIGS solar cells at the Ångstrom Solar Center, a research group within the division of Solid State Electronics, a part of the department of Engineering Sciences of the University of Uppsala. You see? It's all a big mess, at least when you try ordering anything by mail. 4 out of 5 packages end up at the division of Electricity research, or maybe Solid State physics or.. (wow, I am digressing rapidly..).
As a phd student I am working on any and most aspects regarding solar modules, or solar panels; i.e. the medium-to-large scale arrangement of solar cells for electricity production. By any and most I refer to such things as: interconnection of cells, patterning of thin films, isolation and edge deletion, encapsulation, long-term stability, climate testing and stability, etc. etc. At some point these things may be adressed and explained on this blog.
I also work part-time as a development engineer for a (ok, I'm gonna introduce another word here: Photovoltaic, which is the word I prefer to use for our type of electricity generating solar cells and modules, since the word means just this; electricity from light. The word is often abbreviated PV) PV startup company called Solibro. This puts me in touch with reality in a welcome and interesting way, as I get insight in what different challenges need to be adressed when you go from making a few sqare cm's of cells in a week, to making 1000 squar m's a day.
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The rest of my time is divided between The Girl, Photography, Tv-series, Music and Videogames. Roughly. I try to squeeze in things like eating and drinking as often as I can but you know how it is. I've been an occasional blogger for a while now, sometimes writing journal entries and sometimes just spitting out quotes that I like or uploading pictures. The ambition here is to write about PV and energy in a relaxed but interesting way, and hopefully in a way that is accessible to most people who are interested. If any readers have questions, I'd be happy to try my best at answering.
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So, Hello everybody!
/Per-Oskar

Lucia

"Lucia" is part of the winter and advent celebrations in Sweden. Named after a third century Italian saint who was tortured and killed for her faith, the celebrations on Dec 13th are now a deeply traditional part of Swedish culture. I guess this would be Sweden's equivalent of a beauty pageant in which one girl (never a boy!) is selected to bear the candles in her hair. A must in all the schools. The boys are allowed secondary roles by wearing the pointed hats with stars and white robes.

At work on Friday we celebrated with our Luciafest - a traditional Christmas dinner. Lots of varieties of marinated herring, potato gratin with fresh herring, herring-beet sallad, smoked salmon, ham and mustard, Swedish meatballs and little hot dogs (I don't like those). True to tradition, green vegetables are not part of the meal. Imported vegetables have only become popular in the last few decades, I believe, and are most definitely untraditional.

Brännvin and beer accompanied the herring, of course. And we sang the usual drinking songs interspersed with the Lucia song and a Christmas song.

I want to get thumbthing straight

In a few hours I'll be off to the hospital for a "thumb straightening". With both hands on my lap, the right thumb points towards the ceiling, the joint at the base of the thumb looking like it's been popped out of place. The remedy is to shorten a ligament such that the thumb gets pulled to where it should be. Sounds like a dubious fix which doc #4 is proposing, but I don't see any good alternatives. It's been 9 months since the injury - there were more moguls on a steep ski slope than I had accounted for - and my attempts to exercise the thumb back into position have failed. I still can't turn a key in a lock or change gears on my bicycle, but if I concentrate, I can just manage to remove the cap off of a beer bottle. Not that I need to. My colleagues at Friday beer usually give me a hand with that.

I should be home tomorrow evening in time to see what the Nobel prize winners are having for dinner and also get a look at the gowns the princesses will be wearing.

Grocery shopping

I decided to follow up on yesterday's investigation into eco/health logos by inspecting the groceries I bought today.

Unpeeled potato chips with sunflower oil - no mark
Economy corn flakes - no mark
3 personal care products - none had marks
Grana Padano Italian cheese - it had a stamp to show it was "genuine", but no eco-logo

Hmmm... I've emptied the first of my two bags and haven't found a single mark! Moving on to the rest of the groceries:

Coffee beans - Fair Trade. I wouldn't have bought the beans without the mark, but I had to pay 20% more than I would have for the "unfair" beans.
Liquid laundry detergent - Bra Miljöval (good environmental choice). This was a surprise, since I had grabbed what I thought was some economy brand.
Milk - Svenskt Sigill (Swedish environment). Again a surprise, since I'd picked up the most "common" milk.
Oranges - two marks, the keyhole because they're healthy and the European ecological. I had purposely looked for ecological, which I tend to when buying fresh produce. I also decided not to look at the price.
Liquid acacia honey from Hungary - no mark. I bought it because it was cheap.
White flour - no mark. It was the most common brand.
Oats - two marks, the keyhole and the European ecological. I had deliberately chosen ecological at a 20% higher price.

I'm not sure how I did, but it was well enough to feel a certain amount of smug satisfaction. Of course, I don't really know how much better humanity is for the choices I made this evening.

My dinner tonight consisted of split pea soup left over from the weekend, several glasses of water and some of the potato chips. Well, actually about half the 200g bag of chips. A dubiously healthy portion of self-indulgence to accompany the smug satisfaction.

Sweden: How food is marked

While I believe the intentions are good, there are so many different ways in which foods are labelled that I thought I'd write this post for myself to see if I can figure it out a bit. Trying to sift through all the logos is confusing. I thought I'd list them here not in order of importance, but in order of my own familiarity and those that I look for when food shopping. The first three, nyckelhål, KRAV and fair trade, are the ones I look for regularly. The others I note and they will often influence my purchase.

Nyckelhål (keyhole): Healthy food. Low in fats, sugar and salt, rich in fiber. Natural products such as fruit, fish and vegetables are included.


KRAV: the main ecological mark in Sweden. Protection of waters, no chemical pesticides, no GMO (gene modified food), no artificial fertilizers, good animal care with feed grown by same producer as much as possible. Working conditions must be adequate and there are requirements involving health and social responsibility. Upcoming requirements will include limits on greenhouse gas emissions in production and food transport. Individual controls to ensure that participating producers are actually following the rules.

Fair Trade - Rättvisemärkt: Guarantees producers and workers adequate compensation, especially in third world countries. Products are bought directly from the producer with long term contracts. This is one of my favorite labels that I look for, even if I only see it on a handful of different foods.



Svensk sigill: This one's for food produced in Sweden and involves environment, animal care, safe products and care of Sweden's open landscapes.




Svanen: Ecology and environment. Not just for food, now you can make sure the chairs you buy are also ecological. This mark is for a huge variety of ecological products including cleaning agents, fuels, envelopes, restaurants... it's a very long list.



EU ecological: 95% of the food must be ecologically produced. I don't see this label much. It's apparently less stringent than KRAV.







Bra miljöval: An environmental label regulating such things as household chemicals. I don't see it on foods very often.




I've already presented quite a list and yet I've skipped a bunch. There's a label just for sugar to indicate that it's 100% pure. Also a "Rainforest Alliance" which I've never come across that controls agriculture in rainforest areas. There's a symbol to indicate foods that have been subjected to ionizing radiation. There's a European version of the Swedish bra miljöval (good environmental choice) caled the European flower that I've never seen. There's one for asthma and allergies, another for gluten-free foods.

I found much of the info above in Sweden's National Food Administration's site - http://www.livsmedelssverige.org/markning/symbolguide.htm.

Clearing snow in Uppsala

Last week's snow caused the usual snow clearing problems. It seems that the first heavy snow of the season comes as a surprise and is totally unexpected - this happens every year, of course. Mostly, however, I think Uppsala's snow clearing has been well planned and executed in the past, although I noted with consternation that the glacial roads in my neighboor were inadequately sanded this time despite treacherous walking conditions. The municipality has a snow clearing contract with a private company, Asfab, which does no more and no less than the contract stipulates.

Snow clearing is according to priority: clearing within 4 hours on main roads, bus routes, main bicycle paths, main walkways, schools, steps and squares; clearing within 6-8 hours according to subcategories of lower priority roads, bike paths and walkways. There is a similar prioritizing for slipperiness sanding (sorry for not taking the time to find better English words). Salt is used only for emergencies since it's an environmental contaminant.

In addition, there are a number of places around town for homeowners to pick up sand for free - limit: 100 buckets per homeowner. I have some empty paint buckts that I plan on filling with sand. A bit late, I guess. My driveway is semi-glacial already. But, honestly, I had no idea it was going to snow and then rain on top of it! Really, this was so unexpected!

Bicycling on ice

Since Tuesday we've had crisp cold winter days. At midday under a bright sun temps were -5, one of my favorite temperatures (the other one is 28). A sheet of ice covered sidewalks and roads. For 3 days I was too chicken to bicycle on the ice despite the studded snow tires and chose to go to work by bus, instead. But, finally, on Friday I got the bike out. Once I got out of the neighborhood - that was the tricky part - the bike paths were well sanded and it was quite straightforward. I've resolved not to fall off the bike this winter. I make this resolution every year and every year I've fallen off.

Friday evening we had our usual Friday beer in the kitchen at work at the end of the day. Afterwards we headed into town, all of us on bicycles, of course, to a pub for dinner and another beer. It had started snowing beautifully and a few centimeters had already hidden the ice on the bike paths. But the snow gives the tires something to grip and it usually gets easier. Until hitting a patch of hidden slick ice, that is. 3 beers and one tandoori chicken later it was time to go home. As I applied the brakes to stop at a crossing, sure enough, the bike did a neat sideways skid and I hit the ground. Good thing I was well padded with winter clothes and the snow was nice and soft. I didn't even get a bruise. Considering the lack of evidence, I've decided not to count it as a "real" fall.

Sweden: world's best at recycling

The logo to the left is placed on packaging to indicate that recycling costs have been prepaid. The symbol made its debut in Germany in the early 90's and is now used in 24 European countries (Do you know how many countries there are in Europe? No? Me either...)

When I buy a washing machine, for example, the cost of disposing the packaging is included in the purchase price. To get rid of all the cardboard, plastic and styrofoam etc, I still have to take it to the dump. But no money is ever collected at a dump for disposal. When the washing machine itself has reached the end of its life, the same thing applies: haul it to the dump. The recycling has been prepaid.

Sweden proudly touts the world's highest recycling rates. Here are some recycling statistics for Sweden year 2007 from REPA. REPA is Sweden's register for producer's responsibility and collects producer's fees for recycling packaging.

Amount recycled plastic, 65%. Sweden's goal: 70%
Amount recycled paper packaging, 73%. Sweden's goal: 65%
Amount recycled metal packaging, 67%. Sweden's goal: 70%
Amount recycled glass, 95%. Sweden's goal: 70%
Amount recycled newspaper, 85%. Sweden's goal: 75%

This is what I write about on a dark, rainy November evening in front of the fire. I lit the fire with some wadded up newspaper. I estimate that 85% of the newspapers I get go to recycling and the rest goes up in smoke.

The war in Iraq was all about oil...

...according to Issam al-Chalabi who was Iraq's oil minister under Saddam Hussein from 1987 until the invasion of Kuwait in 1990. While I might speculate on the kind of person who had such close ties to Saddam, I did find today's 2 hour seminar at the Ångström Lab (my place of employment) interesting. The talk was entitled "Past and Future Oil Production in Iraq" and was given to a full lecture hall. It was organized by Kjell Aleklett, president of ASPO, Association for the Study of Peak Oil and Gas, and physics professor down at the other end of the building. al-Chalabi was a great speaker with his London-trained English who also spoke passionately from his heart about Iraq and its future. Iraq's modern history and future go hand in hand with oil. This talk is highly actual because the global rights to Iraqi oil are being decided upon with the major discussions having occurred in the last three weeks.

I have six pages of notes, so it will be hard to try and keep this short. Prof. Aleklett showed numerous graphs on oil reserves and production to give the overview. Essentially, peak production was attained in July of this year due, surprisingly, to Chinese demand in their preparations for the Olympics. This will likely not be repeated again, ever. The giant oil fields are dwindling. While much of Iraq is, surprisingly again, unexplored, the new oil that will be discovered will be more costly to extract. The international oil companies need these reserves if production is to be maintained. The projected stakes: 57 billion barrels of oil produced from now until 2050 with an estimated price of $60/barrel = $3420 billion.

al-Chalabi presented the history of Iraqi oil and indeed a brief history of the great civilizations of Mesopotamia and Babylon. Clearly al-Chalabi is extremely proud of his heritage and of being Iraqi. So here's his story as best as I can re-tell it:

After the fall of the Ottoman Empire, the French and British drew up the maps of the Middle East of which Iraq was the "crown jewel". They didn't bother to take into account the various ethnic groups and their religions. Along with the Dutch, the oil was divided amongst themselves. Then, as now, the oil companies involved were Shell, BP, Chevron/Exxon/Mobil. In 1958 Iraq proclaimed itself a republic. In 1961 land was confiscated from the oil companies. Oil was nationalized in 1972 and the oil companies sued Iraq for "taking their land". The oil boom of 1973 caused the US to start getting involved. The biggest "elephants" (oil term for a giant oil field) had yet to be produced. The country prospered until Saddam Hussein came to power in 1979. War with Iran started in 1980 and lasted 8 years. Facilities were destroyed and oil production dropped from 4 million barrels/day to 600,000. By 1990, production returned to 3.5 million a day, but not the hoped for 6. Then Kuwait was invaded and the US placed an embargo on oil that lasted until 2003.

Today, production is at 2 million barrels of which 1.5 is for export. Iraq remains an occupied country with 150,000 troops, almost entirely American. What about the oil? Was it all about the oil? Here al-Chalabi cites statements by various prominent people. Alan Greenspan: "I'm sorry to acknowledge it was all about oil". Colin Powell and General Sanchez also make similar statements. Wolfowitz, the mastermind of the invasion: "Nothing to do with oil. It was all Rumsfeld". But the Pentagon had been studying how to privatize oil before the invasion began. Here al-Chalabi got a bit worked up as he talked about how lies led to murder. The arbitrary division of Iraq by the US along religious sectarian lines promote the current climate of violence necessary for foreign oil to regain its control. 5000 scientists and engineers have either been assassinated or have emigrated. The US is "unable" to solve the murders. The Kurds in the north are now separatists, further undermining Iraq's ability for national oil control.

Back in 1967, Iraq exploited oil under national efforts. Iraqi oil laws were in place and foreign involvement required separate laws. Saddam broke sanctions in 1997 by signing contracts with Russia and China. As of the last few weeks, an attempt to amend the contract with China is underway such that the Iraqi parliament can be bypassed so as to benefit Shell Oil. But any new contracts that don't go through parliament would be illegal. Right now, service contracts for 25+ years are being awarded "illegally" resulting in foreign control of 95 out of 115 oil fields. Today, Iraqis must queue for hours sometimes to get gasoline.

At the end of the talk, al-Chalabi fielded questions. Here are some responses: The era of cheap oil is gone. There will be no more big discoveries, but there will be continued availability of oil, although mostly in the "troubled" Middle East. Iraq's destiny has been and will continue to be decided by oil. In 1973 it was determined that oil reserves would be consumed within 25 years (Prof. Aleklett disagreed, but I myself remember the news around this. Not coincidentally, I became a photovoltaic researcher in 1981.) Iraq's oil should be developed centrally with regional involvement to ensure Iraqi control such that the Iraqi people may also benefit. Obama is naïve to state that the US will become independant of foreign oil. In addition, it is not likely that he can oppose the wishes of global oil companies with regards to Iraq. Oil is priced in US dollars rather than euros because of US influence.

Issam al-Chalabi has been living in Jordan since 1991.

I wanted to write this today before tomorrow's news articles distorted my view. I'm so susceptible to what's written in the media...

Winter tires

Last week temps had sunk below freezing during the nights. There was frost on the grass and ice on the roads in the mornings. I decided to quit bicycling and start going to work by bus. But after a week of this I've become anxious to get back on my bicycle, so this past weekend I removed the summer tires and put on my studded winter ones.

With darkness now arriving at 4pm, I've learned that the only real way to fight Swedish winter depression is to get out into it no matter what kind of weather it is or how grey it might be.

This week warmer weather has returned with lots of rain. Tonight I bicycled home in a relatively balmy 4C under a steady drizzle. I was happy to get home, light the fire and sit here and write this post, of course.

Weather iPhone app

My friend Graham Dawson from Australia has just launched his first iPhone app to provide detailed weather information in Australia. It's got a wonderful layout with timed radar screens and a locator - a fun thing to look at on a rainy day. It instantly became one of iPhone's best selling apps. His brother Ross Dawson wrote about it in his blog and has included a video demo, so I'll say no more here.

It will be interesting to see what Graham does next!

Unusually political thoughts

It's hard not to get caught up in the euphoria of a victory for Obama. I had doubted that he could actually win in present day America. Still fresh for me is Bush's victory four years ago where his deceipt regarding the Twin Towers tragedy and the Irak war were already apparent at the time he was re-elected president. I became ashamed to be American and did everything to conceal this about myself here in Sweden.

It's hard to describe, then, the hope that I now feel. Maybe, just maybe, America is made up of more than just self-righteous power-hungry people steamrolling uncontrolled across the world leaving a path of environmental destruction and displaying a marked disdain for peoples too different from themselves (read Muslims). While the perception of an arrogant America holding the rest of the world in contempt may not fade quickly, the hope for change as promised by Obama is very real.

At the same time, I fear a repeat of Carter's legacy: a man of ideals and integrity who turned out to be hopelessly incapable in the political world, so much so that I couldn't bring myself to vote for him in 1980. I ended up not voting at all that year since I couldn't stomach the idea of voting for Reagan. I hope that Obama will prove to be a faster political learner than Carter was.

Otherwise, I'd have to go back to 1972 to find an election that has moved me as much as this one. Back then I was a teenager too young to vote, but not too young to be an avid McGovern supporter. My dear friend Sue Gochenaur and I would insolently sing "bye, bye miss American Pie" whenever we heard the national anthem in an attempt to distance ourselves from a Nixon-supporting United States. A feeling not unlike the present one for Bush. Past meets present.

And now for a sombering thought. The president of the United States is not actually Obama. It's George W. Bush. And while the celebrations of Obama's victory are going on, Bush is continuing on his path of inflicting as much damage on the environment as possible before making his exit. A set of new regulations is being pushed through to ease restrictions on pollutants among other things as I gleaned from the Washington Post. A better world will just have to wait.

Florence

I finally spent a few days with Alessandro in Florence. Schoolwork took up a fair amount of time even during my visit. He has two large stacks of schoolbooks for his 10 subjects: Latin, philosophy, history, art history, Italian, French, English, math, physics and biology. School at the Liceo (high school) "Leonardo da Vinci" is six days a week and Alessandro studies hard as he tries to learn in a new language and a new culture. Alessandro took me to see his school - at the time, it was "occupied" by students, meaning that they were protesting new governmental changes in public schooling and they were preventing access to the school if the purpose was education.

Otherwise we walked around town a lot. The Duomo is within easy walking distance from Alessandro's home. We ate decent, simple Italian meals in out-of-the-way trattorie and got gelato a couple of times, despite the rain. I had fresh fig ice cream - yum! No museums, though. I'll probably feel more like playing tourist on my next visit. Hopefully it won't rain so much the next time.

Still, I did take a bunch of tourist pictures. I decided to put them in a Picasa album so as not to take up so much space in the blog.

When I came back home to Sweden, the house temperature had dropped to 6C. Much as I enjoy the wood stove, it doesn't heat very well if I'm not there to feed the fire.

Climate tidbits

I took at look at a one page report from the NOAA (National Oceanic and Atmospheric Administration) about global climate indicators for September, 2008. Here are a few of their findings:

-The combined global land and ocean surface average temperature for September 2008 tied with September 2001 as the ninth warmest since records began in 1880

-Arctic sea ice coverage during September was at its second lowest extent since satellite records began in 1979.

-With just 0.47 inch of rain, Melbourne, Australia had its driest September since records began in 1855

Also in the report are the month's major hurricanes, typhoons, fires and rains, plus more detail on the above.

The report ends with their modest statement: "NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources."

Here are some more findings from July, 2008 from the Netherlands Arctic Station in the world's northernmost village on Svalbard:

-The North Pole is warming 1,5 degrees faster than the rest of the world. Ice and snow melt faster and the sun warms the dark surface of ocean and earth. More insects are emerging on Spitsbergen.

-The polar bear is endangered. Population has declined 20% because the sea ice has been melting more. Now there are only 25.000 polar bears left.

And lastly:

-The arctic ocean is a potential gold mine for oil and gas. Yesterday, an USA-report stated that 20% of all reserves of the world are located in the Arctic. With the melting of the pole, these reserves become available. Many countries want to take part in the discussion on the future of the poles. Also The Netherlands.

Whoopee, more oil! Maybe I'll go and buy myself a car after all, just as soon as the last of the ice melts.

Fun with setbacks

Be forewarned - this is a boring post about my latest difficulties with CIGS.

The CIGS evaporator is down again, this time for a corroded thermocouple (a temperature measuring device) that's needed to regulate the copper evaporation source. I haven't been permitted to keep a spare heater on hand due to the 13000 euro price tag, which means that a replacement can't be bought until failure occurs. Delivery time for the new source: 3 months.

However, far from putting an early end to my CIGS activities at the Ångström Lab, the missing source gives me a wonderful opportunity to get really creative in making solar cells. The heaters for the three metals, copper, indium and gallium, are namely interchangeable (not selenium because it evaporates at a relatively low temperature). The crystal structure for CIGS requires about 50% selenium, 25% copper and 25% indium and/or gallium. Indium and gallium are, in fact, interchangeable in the crystal. It's thus possible to make CIS (copper indium diselenide) or CGS (copper gallium diselenide) or something in between known as CIGS with varying electronic properties that are still useable for solar cells. Copper, however, is a must and so is selenium. So, I can either ditch the gallium source and use its heater for copper to make CIS, or ditch the indium source and make CGS.

But wait, there are more possibilities. What if I keep both gallium and indium and figure out a new way of getting copper where it's needed? To refresh your memory on how CIGS is made I'll refer you to an earlier post entitled The making of a CIGS solar cell. What if I start with glass and its molybdenum coating and also precoat it with all the copper I think I'll need? Then when indium, gallium and selenium come along, these four materials will all mix together anyway and still come out with the right crystal structure. I think, anyway. Molybdenum doesn't mix in but keeps itself safely separate for its future function as metallic contact.

Problem is, I don't have any good method of precoating with copper. Sputtering would be my first choice - then I could sputter copper on right after sputtering molybdenum onto the glass. But, drat it, I don't have a copper "target" that would be needed. There is, though, a small evaporator that can handle copper. Too bad it can coat only one substrate at a time and at best it could do two in a day. Ideally I would like to have a couple dozen. But I can still have some fun doing some preliminary tests with just a few.

And who knows? Maybe it'll work so well that CIGS solar maufacturers will all end up using this method. A more likely scenario is that it won't work very well. But at least I get to have fun playing with this stuff.

Now if I could just get equally creative with setbacks in my personal life.

Politics - please skip this post

It's not often I'll throw myself into the political world long enough to comment, but I've been entertained more than usual by the candidates for the upcoming U.S. presidential election. I think Pallin was a great choice for McCain - I was afraid he'd pick some exerienced politician with lots of savvy, but luckily he chose a bimbo. It means that the dark horse might even win this race even if he is a bit darker than many Americans can accept. My absentee ballot arrived in the mail yesterday and I sent it in a few hours ago. I even got one of those ballots with Obama's name spelled with a "b" and not an "s", so there's hope yet for American style democracy.

Meanwhile, here in socialist land, I'm enjoying the health care benefits that will get my hand and thumb bones repostitioned and the strings tuned such that I may even end up playing the fiddle by next year even if the hand ends up with the palm facing out rather than in. Just kidding. Of course.

Patent application

It appears that an interest has been taken in a patent application that Uwe, Per-Oskar and I wrote up a couple of years ago about being able to streamline CIGS module fabrication using some new technology. But at the time neither the university nor Solibro, the solar spin-off that's now partially owned by Q-Cells in Germany, was interested in the costs involved in securing the patent. It was given back to us to apply for a patent on our own, if we wished. We didn't, being the cash-strapped researchers that we are. The idea we were trying to patent was going to take quite a bit of development. In the past 2 years, Per-Oskar has been working on it with Uwe's help and has made significant headway. As for me, I haven't done anything except throw the initial idea to Uwe and P-O to implement.

Too bad that we're not going to get rich off of it - we merely get a one-time insignificantly small sum to keep us happy. There'll probably be a celebratory cake at some point too, I expect.

Is it coincidence that Uwe and P-O also happen to be fellow carpoolers?

Cambridge

Thumbthings REALLY never end

I had presumed that yesterday's visit to the doc would be my last - he would have told me what the status of my thumb and wrist was and essentially would have told me to live with whatever it was. But no. The first comment was about how the thumb is pointing int the wrong direction and that it would have to be operated if I'm ever to regain proper use of it. The second was that the bones in my hand should be repositioned so that they would stop grinding into each other. In other words, operation. This from the doc who has left me once on the operating table when I was already out cold because he decided at the last second not to operate. Due to a waiting list, the operation won't be until December. The thumb should be able to regain its strength, but the wrist will lose mobility. The idea with the wrist fix is that it will prevent almost certain arthritis due to heavy damage decades ago. This is disappointing since even now the wrist won't bend enough to allow for comfortable bicycling. After the operation I get to start over from the beginning with a cast and rehabilitation etc. Possibly I'll recover enough strength to finally be able to change gears while bicycling. Just so long as I don't try to hold onto the handlebar.

The making of a CIGS solar cell

Finally the nitty gritty of how to make thin film CIGS solar cells. Let's see, where to start?
The beginning comes to mind. "Substrate" in thin film lingo means the base upon which the solar cell will be formed. I'm using glass, ordinary window glass. Actually, I'm already cheating because the glass I use has a low iron content so it's not quite ordinary. Iron is a no-no for CIGS.

Step 1: Wash the glass. A hot ultrasonic soap bath and lots of rinses in purified water does it for me. Ends with a spin dry.

Step 2 is to coat the glass with a metal. Not just any metal. Molybdenum. In the pic you can see 4 pieces of the glass I use, 12.5 x 12.5 centimeters which has just been coated with molybdenum by a method called "sputtering". Since I'm going to focus on the CIGS layer, I won't describe what that means at this time (ok, briefly it means that highly energetic argon gas bombards a molybdenum "target" to knock off atomic chunks of the metal which conveniently land and stick to the glass substrate that's been placed nearby).

Step 3 is the fun part. CIGS, that is. Copper-indium-gallium-diselenide. As you may guess from the name, it's made up of four elements: three metals, copper, indium and gallium and one semi-metal, selenium. In a vacuum chamber where all the air has been pumped out, these metals get "evaporated". Literally. I have three pots for copper, indium and gallium. I heat these up way beyond melting. They get heated so much that they vaporize. Just for curiosity, the temperatures required are over 1000 degrees centigrade and about 1500C just for the copper. There's also a pyrex container with selenium that's vaporized, too, at a relatively measly 300C. These four vapors get mixed together in the vacuum. I then send the molybdenum-coated glass on a trip through this metal-selenide vapor and out it comes with a fine grey-black coating. If it happens that I get just the right amounts of all the elements and they coalesce at just the right temperature to form just the right crystal structure then I can get amazingly efficient solar cells, almost 20% efficient. But, really, it often seems like black magic to get it all just right like that. And therein lies the make-it or break-it future of CIGS. I, myself, have been able to make world record CIGS solar cells, but have been hardly reliable. Mostly I'm fixing corroded heating elements and trying to get this CIGS stuff to form in the right way. I think of it as making the world's best pizza with the tricky part being to make the world's best every single time I make a pizza. By the way, for those of you into character analysis, a lot of my analogies have to do with food.

Step 4 is the buffer layer. To refresh your memory on all the coatings involved I'll refer you to an earlier post about a CIGS solar cell. The standard buffer is a cadmium sulfide layer which involves a wet chemical dip in a mixture that turns intensely yellow and leaves a thin coating on the glass. I consider this process to be entirely disgusting and also a nuisance in that the used solutions contain cadmium and need to be treated as toxic waste. Good thing that alternatives to CdS exist. Even better that I use a non-toxic alternative myself, a zinc oxide - zinc sulfide mix which I deposit using another vacuum process. The process this time is called atomic layer deposition. It involves letting various gases flow over the substrate in turn, each leaving an atomic coating on the glass.

Step 5 is actually made up of two different zinc oxide layers. It's another sputtering process and is, in fact, carried out in the same vacuum chamber where the initial molybdenum was deposited. The first layer is pure zinc oxide. It's actually an insulator, but the layer is so extremely thin that charge carriers are able to cross it anyway by means of what physicists call "tunneling". The second layer is also zinc oxide, but it's mixed with 2% aluminum to make it conductive. It's a relatively thick layer because it needs to carry all the solar cell's current while minimizing resistive losses.

The last step is to deposit a metal grid on top. This layer is deposited by evaporating aluminum through a template in the pattern that you can see in the pic with the finished cells. It forms a convenient contact pad and the metal fingers help collect the generated current, thus providing some current carrying relief to the underlying ZnO:Al.

I typically carry out all of these steps on my own. From start to finish it could go as fast as a couple of days, but I'll usually spread it out over a week. Once the cells are made, they need to be characterized under sunlight and otherwise evaluated. Very often the CdS buffer will be replaced by some experimental layer. The CIGS evaporation system can make 24 substrates at a time, so it's quite time consuming to process and evaluate them all. I end up making a CIGS "run" only 2 or 3 times a month. Which is good, since it takes 12 or 13 hours to run the CIGS machine.

And in between, there are the endless repairs.

Spikning och disputation

Hardly anyone managed to get work done in our department yesterday. For one student, Olof Bengtsson, it was the day of his dissertation defense. His examiner - "opponent" as he is called - is an invited expert in the field. The defense involves short presentations by both the defendant and the opponent, after which the opponent and a judging board of three others may ask questions of the defendant based on the written thesis. This process takes 2 and half to three hours. In Olof's case, he started at 10am and was out a bit before 1pm. The judging board retreats for discussion while champagne and snacks are prepared for the expected outcome. If anyone ever fails the defense, I've never heard of it. Olof passed, of course, and we drank champagne and congratulated him in the meeting room. A formal dinner at one of the student "nations" was held that night with the usual toasts, brännvin and singing. I was seated with international students invited from the university in Gävle where Olof conducted much of his work. The students were from various countries - Lebanon, Pakistan, Peru, Sudan, India and I think a couple more. There were also a few Swedes. It made for a fun and interesting evening.

But there was more happening yesterday. Another student, Ulf Malm from our solar cell group will also be defending his thesis in three weeks. It's a requirement that the thesis be made public at least three weeks prior to the defense. Not unexpectedly, this event is also steeped in tradition (and alcohol). A copy of the thesis is quite literally nailed to a wall in a place for this purpose. Our department simply uses a board which can easily be taken down and moved. Ulf successfully nailed his thesis on the second attempt, having first bent his carefully selected spike from the 1930's to an unuseable shape. Afterwards, beer (spiköl) and chips were served while Ulf signed the copies with which we were personally presented. This event was conveniently scheduled at 4pm, suitably distant from both the 1pm champagne and the evening's brännvin.

I didn't even think of making a solar cell all day.

John Ellis and the Large Hadron Collider

One of the advantages of working in a place like Ångström is the access to the numerous interesting seminars given by distinguished scientists. Some are traditional annual events of which the most notable are the invited talks by the Nobel prize winners in physics. But throughout the year there will be invited speakers who are at the leading edge of scientific knowledge in their fields.

Todays' seminar was given by John Ellis, a key scientist at the forefront of supersymmetry theory at CERN. The subject of the talk was, of course, the Large Hadron Collider and the talk was entitled "What the Future May Hold". Of course, it's not always possible to know beforehand how many equations are likely to appear during the talk. I was somewhat apprehensive about having to sit through an hour of calculations designed to demonstrate why the proposed Higgs boson that's so sought afer should have precisely the mass that theory predicts. But this talk was clearly intended for a lesser informed audience and was very enjoyable for me.

Dr. Ellis' enthusiasm for the subject was infectious. Here we are at the brink of a deepening understanding of our world and universe. Not only are we not the center of our Copernican solar system, we may be, as Dr. Ellis phrased it, mere pond scum on the surface of a universe made up of matter that we can experience despite an overwhelming existence of something called antimatter. The large hadron collider will take us on a journey into realms where Newtonian physics is ludicrous and quantum mechanics merely fails, where 3 spatial dimensions are quaint and Einsteinian warping of spacetime old hat.

The collider will likely lead to insight into compelling questions about the origins of mass and where all the antimatter has gone. But I suspect the most likely result will be the generation of new questions that no one knew to ask.

A CIGS day

Last week I was finally able to make decent solar cells after some failed experiments and lots of equipment downtime. 16% conversion efficiency is what I expect out of M. Pilote, the name of my CIGS layer machine and that's what I got. Today I decided on a new experiment to see how much current the devices lose if I make the CIGS layer with only half the usual thickness - 1 micrometer instead of 2. The idea with CIGS is all about how to make solar cells good, fast and cheap. To make the devices thin, I decided for a first approach to run my carousel with the substrates on it at twice the usual speed cutting the deposition time in half. I was delighted that this also cut an hour off my work day, which ended up being 12 hours today anyway since I decided to continue with the rest of the layers that make up solar cells. It takes a long time for the warm-up, stabilization and cool-down phases of CIGS depostion. I realize that I have yet to properly describe this process - I'll have to do something about that! I should have finished devices by tomorrow, so I'll find out how today's run went.

It was already 9:30 pm when I left. I decided to take the carpool car home - too lazy to bicycle. As an excuse I used the car to pick up some gasoline for the lawn mower in the hopes of cutting the lawn one last time before winter. Since it's too late for a fire tonight, the house remains a cold 15C. I'm sitting here under blankets as I type.

Wish the house had insulation.

Cool weather

The temperature's dropped to 15C - inside the house, that is. Yesterday's nighttime low outside was 3C. Today I lit the living room fire for the first time after summer. I've already been using the small kitchen woodstove for the past several weeks. It certainly feels like it's an "in-between" season, part summer and part fall. I'm still picking apples from the tree and also the last blackberies went into my muesli and yogurt this morning. But I wished I had mittens when I bicycled home from work yesterday evening.

Dreams

It's been a year now that I've been contemplating finding a new job somewhere and moving. Even though I nearly have a job offer in Zurich, I don't actually have it yet. I suspect it's been the reason for the dreams I've been having where the recurring theme is trains and planes and me running to catch them but typically ending up taking them in the wrong direction while forgetting in the meantime what my destination was. On waking I'm usually tired and confused.
Last night's dream was fairly typical, but with an unusual twist. While running to catch the tram that would take me to the airport, the large travel bag I was carrying broke its zipper. Out popped multitudes of miniature penguins. The more I scooped them up and put them back, the more they popped out again and I was losing precious time. The dream finished as usual: I got to the airport but ultimately missed the flight because I couldn't remember which flight I was supposed to be on.

Cambridge: planning

Daniele will soon be off to Cambridge for his year as an exchange student from Uppsala University. After a busy summer involving lots of travel with the European Youth Parliament and a month of work at the Ångström lab, he's finally getting ready for his year abroad. Upon discovering the need to ship several boxes of books and other things, we've decided on an alternative method of transport for his things - I will go there myself and bring them. The finances for the decision were straightforward: 1600 crowns to ship a couple of boxes vs 570 crowns for me to fly roundtrip and bring them myself. Of course, the actual cost with public transport and lodging for 3 nights comes to a total of 1700 crowns - pretty darn good, especially considering that I view the trip as a mini vacation. This evening has been spent in all my train/plane/lodgings bookings. Exciting for both me and Daniele!

Apple and wood, part 2

The end of summer

Every year in August there's another of those numerous Swedish traditional occurrences: the kräftskiva or crayfish party. Since I enjoy the crayfish, I've never missed eating them in August. But unlike the earlier years - I've been in Sweden since 1998 - I no longer attend parties in which large quantities of brännvin or aquavit are consumed and the requisite drinking songs are sung. Mostly now I just down a kilo of crayfish with a friend or two.

Since crayfish eating happens at the end of August, it also signifies the end of summer. However, there are still the apples and pears to pick from the trees and the blackberries are ripe now, so it's not quite over yet. Tomas and Ariana will be over this weekend to help put the Åkerö apples in the food cellar. They should store well there and be edible until Christmas. Good thing it's loaded with spiders to keep the flies away.

I've also been watching the weather to see if it's time to transfer my 16 cubic meters of wood to the wood shed. When it's time, I'll have have a few people over for a wood stacking party. If it's anything like previous years, my friends do all the wood stacking and I make the food, an arrangement that seems to have been fairly satisfactory in past years.

And then, brrrr, darkness and cold settle in to stay.

Badger in garden

Camping at Fjällnora