Published on September 29th, 2008 | by Michelle Bennett76
A Thin Film Solar Installation Revisited
A season has passed since we covered the installation of Magco Inc.’s new thin film solar panel installation. The previous article generated a lot of interest and questions, so it’s time to get back on the roof and report on some real-world figures.
If you need a refresher on thin film solar technology, check out two of our previous posts. The important thing to remember here is that thin film solar is lighter than silicon panels, and uses different wavelengths of light.
In May of 2008, Magco Inc. installed 27kW of Unisolar‘s triple-junction laminate panels. That’s 4,900 sq ft of thin film goodness. The building contains a warehouse and offices, and it has a metal roof. The solar panels were literally glued to the roof.
Total installation cost: US$215,000 (including inverter and hiring a master electrician)
Energy produced each month provides about 1/3 of Magco’s total needs. That may not seem like a lot, but recall that this includes a warehouse with associated heating/cooling, machinery and equipment. Magco anticipates producing about US$9,000 each year from the panels. So let’s do the math:
If Magco earns $9,000/year, they’ll regain their investment in almost 24 years. That’s about US$43.88 per square foot on this installation. If you only calculate the installation cost and optimal energy production, the price per watt comes out around $8/watt.
Keep in mind that these are pre-rebate figures. State and national renewable energy programs can go a long way towards reducing these costs. Maryland does have a solar energy rebate program. More on that as the information becomes available.
Solar panels typically come with a twenty-year warranty, and they’re built to last; the wires connecting the panels will probably wear out first. These panels actually protect the roof because they’re glued right on top of it, extending its lifetime and potentially reducing maintenance costs. The panels themselves do not require any maintenance. Also, because thin film is light weight, the building did not require any extra structural support. For a large building, that’s an important feature.
Want to keep track of Magco’s solar panels? Click here for daily and monthly information and trends. As of this writing (Sept. 2008), the panels have produced 15,191kW of renewable energy.
Readers also asked important questions. Do rooftop heat islands affect performance? What about performance on sunny vs. cloudy days? Both answers relate to the qualities of thin film technology. Thin film solar panels perform well in high temperatures because of the chemicals involved. Most solar technologies (except of course solar thermal) lose efficiency at high temperatures, but the changes in performance should not be significant, unless you stick your panels in an oven.
As for sunny vs. cloudy days, the wavelengths of light that thin film solar absorbs are also the wavelengths that pass through clouds. Typically thin film solar performs better in cloudy conditions than silicon solar, but silicon panels are more efficient in direct sunlight. That’s currently the trade-off between these technologies, and it’s important to consider your local climate when choosing solar panels. Germany, for example, gets a lot of cloud cover, but that hasn’t stopped them from leading the charge to deploy solar technology.
We’ll keep our eye on Magco’s roof and report back if there are any new developments. I should also mention that Magco has other green technologies in its commercial repertoire. The same building boasts a small green roof, solar tubes, and rain barrels – oh my! Magco installed these products on their building to “go green” and better understand the real-world commercial applications of these technologies.
Have any more comments or questions? Leave a message below.
Many thanks to Patrick Bollinger and Magco Inc. for their valuable time and information!