Alice Springs, Australia, with around 300 days of sunshine every year, is an ideal test location for solar power installations. The Desert Knowledge Australia (DKA) Solar Centre is a government-funded public showcase of solar installations, demonstrating a range of solar power technologies from many of the world's leading manufacturers.
Case Study: The Desert Knowledge Australia (DKA) Solar Centre
This collection of solar installations operating under the same environmental conditions since October 2008 allows meaningful comparisons of performance among various brands.
Desert Knowledge Australia Solar Centre is not a research facility, but rather a public installation to demonstrate solar power, with output data available to anyone. Kyocera's interpretation of data collected during a 24-month period and downloaded from DKA shows that Kyocera solar technology delivered more kilowatt hours per installed kilowatt than any other competing crystalline solar module operating for the same 24-month period at the DKA site.
Kyocera has three polycrystalline silicon solar installations at DKA: a fixed pole-mount system; a single-axis tracker that adjusts east-west orientation throughout the day; and a dual-axis tracker that adjusts the array's up-and-down tilt, allowing for variation in the sun's angle during the year as well as moving from east to west throughout the day.
Polycrystalline silicon array, fixed pole-mount
These fixed arrays have the same configuration as the single axis and dual axis pole mounted tracking arrays included in the Kyocera “Solar Forest” at the Solar Centre.
They are installed at the optimal orientation for a fixed array: due north and at a tilt close to Alice Spring’s angle of latitude. The output from these fixed arrays can be directly compared to the outputs from the single and dual axis tracking systems.
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Electricity produced (annual):
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8.76 MWh*
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System size:
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5 x 1.08 kW
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Array area:
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5 x 8.02 m²
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Number of panels:
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5 x 8
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Panel efficiency:
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13.4 %
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Panel type, peak power:
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Kyocera KD135GX-LP
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Panel rated output:
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135 W
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Inverter size, type:
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5 kW, SMA SMC 5000A
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Array orientation:
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True north, at 20º tilt
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Installation completed:
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30 September 2008
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*This figure is based on an assumption of 1.622 MWh annually, per kWp of installed solar panels. This may prove to be a conservative estimate for Alice Springs.
Polycrystalline silicon array, single axis trackers
Single axis trackers adjust the east-west orientation of an array, to increase its solar exposure through the day.
Solar panels are best able to generate electricity from light hitting their surface at a right angle. Adjusting their surface to follow the path of the sun will increase their electricity production.
These trackers are an “active” system, driven by motors according to a pre-programmed schedule. The arrays are returned to the east after sunset.
Using a program to angle the trackers will not necessarily always find the direction with the greatest amount of light like light sensitive trackers – however its single line of motion causes less wear on the motor. The tracker is powered from the array’s DC output.
Polycrystalline silicon array, single axis trackers
Single axis trackers adjust the east-west orientation of an array, to increase its solar exposure through the day.
Solar panels are best able to generate electricity from light hitting their surface at a right angle. Adjusting their surface to follow the path of the sun will increase their electricity production.
These trackers are an “active” system, driven by motors according to a pre-programmed schedule. The arrays are returned to the east after sunset.
Using a program to angle the trackers will not necessarily always find the direction with the greatest amount of light like light sensitive trackers – however its single line of motion causes less wear on the motor. The tracker is powered from the array’s DC output.
|
Electricity produced (annual):
|
10.95 MWh*
|
|
System size:
|
5 x 1.08 kW
|
|
Array area:
|
5 x 8.02 m²
|
|
Number of panels:
|
5 x 8
|
|
Panel efficiency:
|
13.4 %
|
|
Panel type:
|
Kyocera KD135GX-LP
|
|
Panel rated output:
|
135 W
|
|
Inverter size, type:
|
5 kW, SMA SMC 5000A
|
|
Type of tracker:
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BW Solar 5 Star Tracker
|
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Installation completed:
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30 September 2008
|
*This figure is based on an assumption of 1.622 MWh annually, per kWp of installed solar panels. This may prove to be a conservative estimate for Alice Springs. A gain of 25% has been assumed for the tracker.
*This figure is based on an assumption of 1.622 MWh annually, per kWp of installed solar panels. This may prove to be a conservative estimate for Alice Springs. A gain of 35% has been assumed for the tracker.
Polycrystalline silicon array, dual axis trackers
Dual axis tracking systems adjust the array’s tilt up and down, as well as moving from east and west through the day. This allows for the change in the sun’s height in the sky through the year.
Solar panels are best able to generate electricity from light hitting their surface directly. Adjusting their surface to follow the path of the sun increases their electricity production.
The cost of a dual axis tracking system should be weighed against the gain that it offers over a fixed array. The outputs from the Solar Centre's fixed pole-mount, single axis tracking and dual axis tracking arrays can quantify this advantage for an installation in central Australia.
These dual axis trackers respond to light sensors on the face of the array. The control system determines whether the available light is mostly direct or diffuse. In diffuse or cloudy conditions, the tracker will react with less sensitivity, to limit its readjustments through the day.
The touch screens at the Solar Centre's Interpretive Centre can be used to compare the input of this array with the fixed pole-mount and single axis arrays over the life of the system.
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Electricity produced (annual):
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11.83 MWh*
|
|
System size:
|
5 x 1.08 kW
|
|
Array area:
|
5 x 8.02 m²
|
|
Number of panels:
|
5 x 8
|
|
Panel efficiency:
|
13.4 %
|
|
Panel type:
|
Kyocera KD135GX-LP
|
|
Panel rated output:
|
135 W
|
|
Inverter size, type:
|
5 kW, SMA SMC 5000A
|
|
Type of tracker:
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WattSun, A2125
|
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Installation completed:
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30 September 2008
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In addition to its interpretive visitor center, which helps educate the public about the benefits and capabilities of solar power, DKA has a world's-first interactive website providing live data feeds from the Solar Centre and information on the operational performance of the different solar technologies. This information is available for viewing by the public — anyone, anywhere, can access it. It is important to look at the Normalised Output tab to view the actual "kilowatt hours generated" per kilowatt of modules installed. This allows comparisons between the different-sized systems.
Kyocera's interpretations contrast with the old belief that monocrystalline silicon solar cells, which are more expensive, may outperform polycrystalline.
"We believe there is an important difference between lab test conditions and real-world results," stated Michael Ludgate, Kyocera Solar, Inc.'s Director of Business Development and Marketing. "The live data feeds from the DKA Solar Centre provide the industry with long-term, system-level data that prove the reliability and performance of solar installations in real-world applications."
The dual-axis tracking system performed best among Kyocera's three installations. Since solar panels generate the most electricity when light hits their surface directly, adjusting the surface to follow the sun increases their electrical output. The dual-axis trackers respond to light sensors on the face of the array, and are powered by the sun.
Meaningful and accurate comparisons of solar technology performance at DKA will improve the knowledge base for solar initiatives globally, helping to create a more sustainable future. For more information, visit www.dkasolarcentre.com.au
The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag
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