Understanding how solar radiation works in relation to landscape dynamics is probably one of the most interesting phenomena where the power of GIS can be effectively demonstrated. In this exercise, different tools in ArcGIS Pro were used to calculate the amount of incoming solar radiation for a given area. In particular, a solar cadaster for the town of Hallein was created, as well as some metrics relating to the potential of deriving energy from the sun were generated.
Solar radiation analysis requires a high-resolution Digital Surface Model (DSM) to accurately model the amount of insolation received from the sun. Variations in different aspects of topography heavily affect the amount of energy received in a particular area on the Earth's surface.
With this, a 1-meter resolution DSM was used covering the area south of Salzburg. Since the process is quite resource-intensive, a subset of the area was used covering the town of Hallein.
Different scenarios are presented in the succeeding sections.
To calculate the amount of solar radiation in the study area, the Area Solar Radiation tool in ArcGIS Pro was used. This tool provides a number of output raster files including one raster representing the duration of direct incoming solar radiation. The amount of solar radiation was calculated in two different times corresponding to the days when the maximum (Summer Solstice) and minimum (Winter Solstice) amount of sunlight can be possibly experienced assuming that there the sky is clear and there are fewer obstructions (ex. clouds) in the atmosphere. Also, the amount of solar energy during the summer season (July-September) was calculated.
Usually, to measure the viability of solar panels in an area, the term peak sun hour is used. This refers to an hour in which your solar panels produce a certain amount of energy. The question is, how many peak sun hour (PSH) does a solar panel usually need?
1000 Wh/sq.m = 1 PSH
In the US, any location that gets around 4 PSH (daily) is considered a good location to produce useful amounts of solar energy. Although you can still use solar power to supplement your power, this might be not as cost-effective.
With this, we can see that the PSH in Hallein during winter is way below the minimum amount required.
A solar cadaster provides orientation, angle, irradiation, and the potential of solar production for each rooftop.
Zonal Statistics (Mean) was used to create this using the building footprint data downloaded from OSM. For this, the mean value was used instead of the maximum mainly because there might be areas where the maximum value only covers a very small portion of the building which may not even be enough for a standard size of a solar panel.
The building polygons with the Peak Sun Hour attribute were converted into points so we can easily visualize the Top 20 buildings with the highest energy yield in the time periods used. The size of the circles corresponds to the amount of energy yield.
A web mapping application was also created to provide a more interactive way to visualize the results of the solar radiation analysis in Hallein. A Swipe widget was added to dynamically compare the layers within the web app.
