The tool helps citizens determine how much electricity can be produced on their rooftop from a solar photovoltaic (PV) system, what system may work best, and estimate their system cost and payback time.
Sanborn designed a fully automated, time-saving workflow that efficiently extracted 3-D building wireframes by auto-filtering the city's LiDAR point cloud in the ground, building and vegetation classes. Sanborn then tested and fine-tuned the parametersdepending on the land-cover and type of terrainand the points in the building class were used to derive 2-D building polygons.
Finally, the 2-D polygons were used to create bounding boxes to extract the 3-D wireframes. Altogether, Sanborn extracted wireframes for more than 40,000 buildings with this approach. The data was found to be more than 90 percent accurate, far surpassing the city's requirement of 80 percent accuracy.
"For many community members, Boulder's Rooftop Solar Tool will spark the conversation about what is possible in terms of personaland community-widepower generation. For others, it will provide the information they need to take the next step toward going solar," says David Driskell, the city's executive director of community planning and sustainability. "This exciting development represents a key step on our community's path to clean, local power."
The project has identified 553 Megawatts of potential high-yield photovoltaic capacity capable of delivering 740,000 Megawatt-hours per year. This is enough clean, renewable energy to power 70,000 American households, create more than $2 billion in local business, and offset carbon emissions equivalent to planting more than 11 million trees.
