LiDar: The Future of Home Evaluations for Solar

How Lidar Technology Can Change Your Perspective on Solar Readiness

In many regards, solar works the way one would expect: the sun shines on the solar panels, the panels produce electricity, which means your home needs to be facing the right direction (south) without anything blocking the Sun’s access. But what exactly is the “right” direction? And how much solar access is enough solar access? LiDar has helped us change the answers to these questions. So, What is LiDar?

The Past

For a long time, basic tools were needed to measuring solar readiness for a home: a tape measure to measure available roof space and obstructions, a compass to determine a home’s orientation to south, and a tilt meter to determine roof pitch. With the creation of the SolMetric SunEye, these hard measurements were combined with panoramic photographs of the sky to factor in shading from trees for a complete solar analysis.  

However, these methods had their drawbacks, requiring evaluators to climb on the roof and capture data from all possible areas. This means steep, tall,  dormered and generally human-unfriendly roofs would have to settle for the site evaluator’s best estimate, often prefaced with” you could go solar but…”

Until LiDAR.

The Present: LiDAR

LiDar stands for Light Detection and Ranging Technology, and is, according to the National Oceanic and Atmospheric Administration (NOAA), a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth. In layman’s terms, LiDAR uses a series of lasers and scanners to obtain measurements by shining or “pulsing” infrared beams at an object. The scanners and lasers then measure the reflection of light from the targeted object, and calculates the distance between the object and point of reflection or the “range”. This allows for increased measurement accuracy in areas where it is not feasible or practical to measure by hand.

lidar

 

LiDAR has been used to obtain measurements since the 1960’s.  Commercial aviation has allowed for the use of LiDAR in air crafts to combine light measurements with terrain maps to create accurate topographical maps with laser precision (pun intended).  In 2013, NASA (a major user of LiDAR) combined their existing LiDAR technology with thermal imaging to create a system that would not only accurately measure land surfaces, but would also simultaneously measure the levels of heat they are exposed to.

Now I know what you’re thinking- “What does all of this have to do with solar?” Well, the sun shines on rooftops, heating as it illuminates. So, by measuring the distribution of heat on a roof it is possible to accurately measure the given amount of sun exposure that roof has. In this way, each area where the sun hits the roof can be mapped and measured.  This is head and shoulders above the Solmetric SunEye, which is limited to capturing sun exposure to only where the pictures are taken. LiDAR measurements are so accurate, in fact, that shade reports that include them (such as Aurora’s shading analysis) is accepted by the Massachusetts Clean Energy Center (MassCEC) as a valid proof of a home’s solar access when providing funding.

Your Home

The LiDar allows solar evaluators to measure the hard to reach spots on a roof as well. It accurately measures the amount and effect of shade created by obstructions such as trees and chimneys. For many homes, the effect of a tree’s shadow on the far, east side of a southeast facing roof is too hard to judge with the naked eye.  Dormers, while they can be shade causing, deepening on their placement, there still might be enough sunlight to suit the electricity needs of a home owner. And while you can’t necessarily change the orientation of an east-west facing house, you’d be surprised the amount of sunlight a home facing due east receives!

The Future: Solar For Your Home

Though the seasons change seemingly unexpectedly in the northeast, one thing is for sure; they will change and change again. Likewise solar still works the way you expect it: the solar panels collect sunlight, the sunlight collected is converted to electricity, and the created electricity can help offset your electric utility needs.   With that said, certain homes may still be better suited for solar than others due to factors they can’t change. However, just as every New Englander knows to carry an umbrella even when the sun is out, even though it seems “obvious” that your home may have some challenges for solar, LiDAR has helped reveal the potential of otherwise disqualified homes. It never hurts to take a second look.

 

References

  1. “What is Lidar” – US Department of Commerce, National Oceanic and Atmospheric Administration. (2012, October 01). What is LIDAR. Retrieved September 08, 2017, from https://oceanservice.noaa.gov/facts/lidar.html

 

 

 

Article Written By Lumyr D. – Installation Team – Rayah Solar

 

 

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