You may have heard a LOT about solar energy lately, but is it worth it? We think so!
In fact, it’s been the mission at Shoals to steer away from reliance upon fossil fuels and shift to dependence on clean energy, which we've been doing, one step (or solar panel!) at a time.
A Day in the Sun
Recently, Gabby and Laurel, two of our 2018 Sustainable Engineering Interns (SEIs), went out in the field to tackle one of their summer projects which focuses on the solar arrays around the Appledore Island. They are looking to profile each array, meaning that they are checking each one over to verify its efficiency.
To calculate the efficiency of an array, they need to have a couple things: the tilt angle (which they measure with a compass), the temperature of the panels themselves (measured with an infrared thermometer), current (measured with an ammeter), voltage (measured with a voltmeter), and irradiance (measured with a pyranometer). Additionally, the duo performed some routine maintenance on the arrays by fastening the bolts that secure the panels in place with a torque wrench.
So, Gabby and Laurel worked their way across the island, checking solar rays and catching rays! But, what did they find?
The short answer: a lot of loose bolts but pretty good solar panel efficiency! Loose bolts might sound alarming at first, but with high winds and a surplus of gulls out here, it is easy for bolts to become loose! This is why it is always important to perform routine maintenance on panels, both on gull-packed islands and on your own home (if you've got solar panels).
As for the efficiency, our panels are doing well! Laurel and Gabby calculated that both our monocrystalline and polycrystalline solar panels are at the ideal tilt angle for where it should be for optimal efficiency!
The temperature has fluctuated between the ideal (77°F and below) as well as soaring to temperatures which are far hotter than the optimal temperature for maximum efficiency...but the island is actually producing an excess amount of clean energy than what is actually being used, so this minor escape in efficiency is not costing the island much.
The Scoop on Bird Poop
One of the largest problems we have regarding our solar panels on Appledore is the bird poop (and bird pellets; regurgitated material) that often gets caked on and prevents solar energy from being captured. Since our solar panels can't dodge the incoming bird strikes, our solar arrays, and the island, often get the crappiest outcome...efficiency is lost. (And this isn't just a Shoals problem! In fact, bird poop can be a problem on the mainland too.)
Since the gulls nest on the island, we have to come up with some innovative solutions to protect the panels while coexisting with this large colony of seabirds.
What are we doing about it? Last summer, the 2017 Sustainable Engineering Interns tried out a hydrophobic coating on some of the island's solar panels, but found that it had little to no effect on removing the bird droppings. Another idea included using a tall pole to attract birds to an alternative perch instead of the panels, but that also had little effect. While other techniques exist in the solar energy market for deterring birds from panels, Shoals is still searching for a more environmentally friendly solution to preventing this buildup.
In the meantime, Shoals staff clean the panels intermittently throughout the summer season to ensure that they are as clean as they can be, and of course, the rain helps...but isn't that ironic? To keep your solar panels clean and operating at maximum efficiency, you need clouds and rain!
Let's just hope for sun showers then!
Different Panels, Different Pros and Cons
As mentioned above, Shoals has two types of photovoltaic solar panels on Appledore: monocrystalline silicon solar panels and polycrystalline silicon solar panels. Shoals started with polycrystalline silicon solar panels but has since switched over to installing more efficient monocrystalline silicon solar panels. What other differences exist between the two types? See for yourself!
Still curious about solar? Watch Gabby and Laurel talk about the island's arrays!