Which Data Source Is Best For My Solar Project?
Key takeaway: Satellite, LiDAR, and aerial imagery make it easy to draft preliminary solar designs for sales conversations; drone imagery confirms measurements and automatically constructs a photogrammetry-based 3D model to create final PV layouts with accuracy for engineering documents and install plans that never have a revision.
In solar, getting a quick preliminary proposal to a customer could be the difference between winning and losing a deal. That means the prelim design must be accurate enough to communicate production estimates, offset, and obstructions or shading implications with customers; at the same time, you have to build the plan quickly and in a cost-efficient manner.
That’s where different data sources matter. Whether satellite, LiDAR, aerial, or on-site drone imagery, you need to choose the right source for the right step in your process.
This article explains about the core data you need and how different data sources stack up.
The data you need for an accurate solar plan
A lot of data is required for a full, comprehensive plan set. However, you can often get away with slightly less accuracy and comprehensiveness, for the sake of speed, when doing a preliminary design. Here’s what you need for each stage:
1. Sales conversations: Estimated roof measurements (width, length, and pitch) and a general understanding of obstructions that might cause shade or stop you from placing a panel in a certain location.
2. Immediately before contract signing: Fully accurate roof measurements (width, length, pitch, and azimuth) with all obstructions and shade analysis noted so you can accurately place panels and estimate production.
3. Engineering documents and installation plan sets: Precise measurements with placements noted for roof racks, exact panel placement, and a fully accurate shading analysis leading to an accurate production estimate.
Understanding the four main data sources in rooftop solar
Here’s how the main data sources in solar stack up in terms of speed, accuracy, and cost.
| Satellite | Aerial | LiDAR | Drones | |
|---|---|---|---|---|
| Strengths | Quick, inexpensive, and easy to integrate into preliminary design platforms. | More accurate than satellite data and provides a clearer image in most cases. | Makes it easier to estimate heights of buildings (including roof pitches) plus the size of shade causing obstructions. | The most accurate and recent data source available; it also keeps on-site Surveyors safer since they do not need to climb roofs. |
| Weaknesses | Grainy images that make roof obstructions and shade-causing items difficult to notice. | Databases are limited (and expensive to access). If you need to plan your own custom flight, the cost can become astronomical. | Not photorealistic; the map shows rough structures at best. | Requires time to schedule a truck roll on-site. |
| Use Case | Preliminary designs when the roof is fairly flat or uncomplicated. | Complex sites where satellite imagery doesn’t exist and drones are not feasible or allowed by regulation. | As an additional layer on top of satellite imagery to get a better sense of the height of on-site items. | 1. If you’re already on-site during the sales process. 2. To confirm measurements after closing the deal. |
Use the layering strategy for maximum accuracy and efficiency
Giving up a little bit of accuracy can make sense in the preliminary stages of a deal. First, remote data sources are easy to pull from, speeding up your proposal process. Second, many customers may not want someone coming to their property until they’ve made a decision. Third, you save time and money on deals that may not close anyway.
But you should only sacrifice the minimum amount of accuracy for the sake of speed and/or customer experience.
Rather than solely relying on one data source for preliminary designs, you should follow a data-layering strategy:
Start with satellite: Whether Google Maps, Bing, Nearmap, or another data source, quickly get the lay of the land for the general roof pitch, property type, and obvious obstructions like trees.
Layer on LiDAR: Add a LiDAR layer to the preliminary design, ensuring you have a more complete picture of object height on site.
Confirm any small issues: In a grainy satellite image, you might see something that looks like an obstruction. See if you can confirm that with other publicly available data sources, for example, if you were using Nearmap, try looking at Bing or Google Earth to see if they have a more recent or slightly clearer image.
This three-step layering strategy will help ensure you have the most accurate preliminary design possible without sacrificing speed, efficiency, or customer experience. From there, you can confirm measurements with a drone on-site when it makes sense for your sales process.
Choose the right data for the right step
Solar projects require a lot of data; some sources are more critical at each step than others. While you can work quickly in the preliminary stages, you need fully accurate measurements to inform production estimates, procurement, engineering docs, and installation planning. With each successive stage, the need for accurate data increases in order to maintain a quality build process.
