February 10, 2010
IBM Uses Cheap Materials For Solar Cells
Decent efficiency photovoltaic (PV) solar cells made from cheap copper, zinc, tin, and sulfur but rarer selenium. The efficiency is close to that of commercial thin film PV.
Researchers at IBM have increased the efficiency of a novel type of solar cell made largely from cheap and abundant materials by over 40 percent. According to an article published this week in the journal Advanced Materials, the new efficiency is 9.6 percent, up from the previous record of 6.7 percent for this type of solar cell, and near the level needed for commercial solar panels. The IBM solar cells also have the advantage of being made with an inexpensive ink-based process.
Even with selenium this type of cell has materials cost advantages over existing commercial thin films from First Solar made of cadmium and telluride. Also, this cell has advantages over the CIGS (copper indium gallium selenide) cells of the newer thin film manufacturers since indium and gallium cost more and CIGS also uses selenium.
But currently capital costs are more important than materials cost - at least among the thin film makers. The thin film makers are managing to find ways to cut their costs without switching to cheaper elements. Some CIGS PV makers expect to get their costs down to 50 cents per watt in 2010 versus current low cost leader First Solar's 85 cents a watt in 2009. Also, silicon polycrystal prices have fallen so far and have the potential to fall even farther so that silicon PV makers shouldn't be counted out of the race to lower costs..
Price declines in PV, bigger incentives by state and federal governments, and state requirements for more power from renewables are combining to cause a possible doubling in the amount of PV installed in the United States in 2010 as compared to 2009.
Selenium was $23/lb. in 2009. A thin film module will use tens of milligrams of the element per peak watt, so the price of selenium could rise many times before it became a problem.
Selenium occurs in fairly high concentration in coal (2 orders of magnitude higher than in the copper ores from which it is currently obtained as a byproduct), so large amounts could be extracted from coal ash if prices increased enough.
I did a similar cost calculation for CIGS once, and found material costs were about 2% of overall costs. The thing is, those layers really are very, very thin.
2 other thoughts:
The wide variety of PV chemistries insulates the overall industry from commodity shortages, and
The EIA counts very few of the 500-600MW of PV installations mentioned in the NYT article in their electrical generation stats, because they're mostly on the customer side!
I looked into the training classes ("green jobs") my local community college offers and they were all filled. I was very disappointed because I saw that as a way to start my own business and it only takes about 2 years to get certified. Now I'm seeing the prices on PV falling and the ease of installation increasing.
I'm probably missing some info (I am NOT a know-it-all on this subject) but I don't think anyone needs a 2 year college education to unroll PV roofing materials and glue them to a roof. Am I missing something here? Are all of those folks getting certified wasting their time and everyone else's money or what? Granted you have to have DC-AC converters etc. but that work can be (and probably should be) done by an electrician after Joe Public glues his PV shingles to his own roof right?
Any input would be appreciated.
Mark A - It sounds like a certification racket to me. AFAIK the main thing that's special about solar is the controller electronics and the grid interconnection. Beyond that would be a bit of knowledge about the effect of shading on solar arrays (it can be much worse than one might think, depending on the configuration), and a few things like that.
I'd bet most of what is taught in the cert courses will be obsolete in a few years anyway. OTOH, solar has bubble characteristics, and what looks like a good job now might turn out to be one with little demand in a few years. It all depends on government tax policies and oil prices - both very volatile.
As a homeowner I would be very wary of 'solar shingles' (as opposed to roof mounted panels).
Why, although it sounds like a no-brainer?
How about fixing leaks in between &underneath?
Can you walk on the shingles around the problem area, or do you have to remove a bunch of them to make a pathway to it?
Solar, once its cheap enough, is a nice supplement, as is wind power, but as a mainstay?
With solar, what do you do with several cold *and* cloudy days back to back?
With wind, what do you do with several hot as hell, no wind in sight, days back to back?
It fails when you may need it most.
From what I've read:
Most roofs are not built to bear the weight of mounted solar panels and fastening them to the roof has potential drawbacks too (leaks, rot) plus they're relatively expensive in comparison to PV shingles. And if there's a leak to fix then my (total shot in the dark) guess is that it wouldn't be prohibitively more expensive to fix; a few hundred $ maybe.
I'm struggling to get my head around the science of these photovoltaic cells.
Slightly off-topic but my main question is how does the metal 'Silver' fit into all of this?
Silver bugs often point out that demand for silver for use in solar energy (as well as in general electronics) is set to take-off. Given that silver has the best conductivity of all metals and is currently used in a lot of electronic products (although in tiny amounts these soon add up) this made some sense to me. Clearly if cheap substitutes which are almost as good are available that will put a brake on any price explosion for silver.
What are peoples thoughts?
Buying silver when the price crashes way down (a la end of 2008) appears to make a lot of sense to me. You get a) a China growth play (through increased industrial demand), a 'peak silver' play (the concept that as a non-renewable resource supplies will at some point become harder/more expense to get), as well as the general precious metal play (silver returning to its historic role as an inflation hedge/wealth preserver/tangible asset in world of fiat currency/derivatives).
A global deflationary depression would hit you. But if that happens most people will have bigger problems than the price of silver.
Mark A- Another reason that the two years is required, is that most of these systems run at about 400VDC. As you can imagine that has quite the potential for destruction. Most states require two years of on the job training or an equivilent degree to work with high voltage, which is usually defined as anything at or above 400V.
The cost of the cells isn't any longer a problem - it is the cost of the inverters and, to a lesser extent, the installation costs which kill solar in most cases. Hey you could sell cells at $0.20 per watt and it still won't work if your grid-tie inverters remain around the prices they are.
Besides the potential manufacturing cost savings, an ink-based process permits the fabrication of shapes and configurations difficult and costly to achieve otherwise. Novel shapes of PV devices are necessary to reach the desirable steep drops in installation costs.
Anyone know how long the grid tie inverters last?