Summer 2010 Newsletter
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September 14, 2010

Thin Film Technology The good the bad and the untold.

For those keeping track of new developments in solar power technology, thin film cells have grabbed a lot of the spot light, mainly because its production is less costly . According to SolarBuzz.com, crystalline silicon wafers cost about 40-50% more so that production costs for thin film cells is markedly lower. The other advantage, notes SolarBuzz�, is that the materials in thin film are all strong light absorbers and can be easily spread over large areas such as coated glass or stainless steel sheets. SolarBuzz notes that thin film production technology will eventually lower manufacture costs and deliver the highest efficiencies and process yields.

However, there’s a minus side of thin film cells that takes some of the sheen off its performance. SolarBuzz points out that although thin film cells are potentially cheaper, they are less efficient, with production modules ranging from 5 to 8%. Compare this to a mono crystalline module with 10-17% efficiency. Over time, says the SolarBuzz article, some thin film cells have shown degradation of performance with stabilized efficiencies that can be 15 – 35% lower than initial values.

But don’t discount thin film cells. There’s a lot of progress being made in solar companies and in research labs. About 20 years have gone into thin film technology and it’s still evolving. Thin film technology production is making significant inroads to grid markets, particularly in Germany.

An August 20, 2010, article in Focus.com News noted, “Norway’s EnSol AS is developing a solar thin-film technology to be used on windows with a potential to reach over 20% efficiency and be commercially available by 2016.” The article goes on to describe the possibilities of a thin film composed of nanoparticles. The company states that this next-generation PV cell technology has tremendous potential for industrial scale, low environment impact, and cost effective production via spray on technologies.

There’s also plenty of research going on in universities around the globe. An April 20, 2010, Science Daily article states that “Researchers have made an important breakthrough in the use of continuous flow microreactors to produce thin film absorbers for solar cells – an innovative technology that could significantly reduce the cost of solar energy devices and reduce material waste.” Engineers in Oregon State University and Yeungnam University in Korea have demonstrated that this technology “could be used to continuously and rapidly deposit thin film absorbers for solar cells….” The lower costs are the result of chemical bath deposition deposit nanostructure films on various surfaces in a continuous flow. According to the article, this process makes thin film more commercially practical. We’ll have to wait a while for further developments, as it’s still in the patent application stage.

So don’t discount the promise that thin film cell technology holds for solar power users. It looks like there are some exciting advances that will surface in the near future. Keep tuned.

               
                  Websites to Check Out

A cool new website to check out is http://roofray.com/

With this web site you can pull up your roof on Google Maps and figure out how much solar power you could produce.

In addition you can see other roof arrays in your area and do a cost analysis. It’s a good tool for those that want to see what it would take to put solar on there home.
 

Helpful Tips and Stuff We’ve Learned Living Off Grid

For us old-timers in the solar world, search mode on your inverter was a must have feature and was used to reduce power consumption. Nowadays it’s hardly ever used. So lets take a look at what search mode is and when to use it.

First off, only off grid inverters have this feature and its purpose is to reduce the power consumption of the inverter when it’s not under load. As we know all electrical equipment uses energy. With that said even an inverter that has no load on it, is using between 12 and 30 watts. On early off grid systems this continuous load would be a factor. Let’s say you have a small 1000-watt array and it’s installed in Rochester, NY. Your average sun hours are 3.3 for the year. That’s 3300-watt hours per day produced from your array. If your inverter is using 25 watts per hour just sitting there when all your loads are off, you’re still burning 600 watts per day. That’s 18% of your daily power production going to just powering the inverter. So the inverter folks came up with search mode. In essence search mode puts your inverter to sleep when it doesn’t see a load. With the same example this would drop the daily watts to 150. Big difference. In this search or standby mode the inverter is not producing output voltage and as such any small loads like an electric clock or refrigerator would not receive power. In smaller systems with propane refrigerators and no need for small electric full time loads, this works just fine. While in search mode the inverter sends out a pulse of current looking for a load. When it senses a load the inverter starts up and away you go. So as you can see if you have loads that need continuous power then search mode is really useless but for the smaller systems it does help with system efficiency.
 

Spotlight On New Products

The LED light bulb has arrived. All you holdouts who are using incandescent bulbs can jump the CFL gap and go right to the most efficient bulb on the market. I’m spotlighting the LED’s because I feel they have reached the point where everyone should consider them as equal to the standard bulb in cost, quality and ease of use. Home Depot now sells an LED bulb from Eco Smart that fits in a standard light socket and looks pretty good.

Let’s look at the facts. A standard GE double life 40-watt incandescent bulb is rated to last 3,000 hours and costs $4 bucks for two. The Eco Smart bulb produces a 40-watt equivalent light but uses 8.6 watts. It has a five year warranty and is rated for 50,000 hours. It costs $20 bucks for one. If you figure that with two incandescent you have 6000 hours of use and divide that into the one LED lights rated at 50,000 hours that leaves you with 8 times the life span. Eight times $4 is $32, so you see, not only do you have to replace that incandescent bulb a bunch more, but right off the top you’re saving money. As for your electric bill you can see a drop of 5-15% in power consumption using LED, which of course saves you even more money. No brainer on this one.
 

An Off Grid Perspective

In our off grid perspective I thought we would reproduce an article from Home Power magazine that we really liked. Home Power gave us the permission to reprint this article so here it is in its entirety.  Please click here to read Clearing The Air: Home Power Dispels The Top Renewable Energy Myths.

Please feel free to make comments and suggestions for upcoming newsletters to farrel@apxsolar.com

Please feel free to make comments and suggestions for upcoming newsletters to farrel@apxsolar.com

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