Analysis of the potential of urban surfaces for energy use by applying solar energy or green roofs

Renewable energy is rapidly increasing in importance in the energy mix in many countries worlwide. They are a key part of the energy transition to more sustainable energy systems.Green roofs are multi-layered systems covered with plants, grasses or turf that are placed on terraces and roofs of different types. Energy savings and reduced urban heat-island effects are among the most notable benefits of green roofs.Traditionally, green roofs and photovoltaic (PV) or solar-thermal installations have been competing systems, but several studies and actual installations have shown that synergistic effects predominate. For example, vegetation has a cooling effect on green roofs that can increase the electricity production of PV panels and reduce the energy demand of the building. Additionally, solar panels can increase the diversity of flora and fauna inhabiting the green roof.This paper presents a scalable and adaptable model to estimate which roofs are suitable for energy use. These energy uses can include the placement of photovoltaic panels to produce electricity, the installation of solar-thermal panels to produce heat or the use of green roofs for planting vegetation directly to improve energy savings. The purpose is to quantify the potential for renewable electrical and thermal installed capacity and to estimate the electrical output, heat output or energy savings for a given roof, a neighborhood, or entire city.