Estimating solar energy potential in Warsaw
Over 70% of the EU’s energy is consumed by cities. Having that in mind, the Cities on Power project intends to contribute to the European Union target of 20% production of renewable energy by 2020. The project promotes the use of renewable energy in urban areas by delivering an interactive tool to support citizens in the decision making on new ways of energy supply.
To reach this target it was intended to provide a fully interactive IT-toolbox with maps of solar potential, which allows citizens and decision makers to estimate how much energy they can derive in a specific point from solar panels, when their investment returns and how it influences the natural environment.
Simulations were based on simplified 3D model of buildings in Warsaw. Main part of the simulations was done using the „r.sun” module dedicated to GRASS-GIS 6.4. Such a solution makes it possible to run whole simulation on high performance GNU/Linux machines, to conduct whole process for area of over 517,000,000 m2.
To limit the final size of the database, results were clipped to surface of roofs only, using a binary data type (i.e. 0-shadow, 1-sunny) and synthetic atmospheric conditions (i.e. taking into account annual changes of sun declination, cloudiness, Linke atmospheric turbidity coefficient, etc.) as provided for engineering purposes by the Ministry of Transport, Construction and Maritime Economy. Such a solution allows following calculations: direct, diffuse and total solar radiation for every square meter of a building’s surface in Warsaw.