A method for predicting the economic potential of (building-integrated) photovoltaics in urban areas based on hourly Radiance simulations Karoline Fath a,b,⇑ , Julian Stengel a , Wendelin Sprenger b , Helen Rose Wilson b , Frank Schultmann a , Tilmann E. Kuhn b a Institute for Industrial Production (IIP), Karlsruhe Institute of Technology (KIT), Hertzstraße 16, 76131 Karlsruhe, Germany b Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstraße 2, 79110 Freiburg im Breisgau, Germany Received 17 November 2014; received in revised form 2 March 2015; accepted 11 March 2015 Communicated by: Associate Editor Hans-Martin Henning Abstract This study presents and demonstrates a methodology for calculating the economic potential of photovoltaic installations in urban areas including the previously often disregarded potential on building fac ¸ades. The analysis of a 2 km 2 urban area has shown that build- ing fac ¸ades there provide almost triple the area of building roofs. However due to non-optimal inclination and orientation, they receive only 41% of the total irradiation. From this, the economic potential under present market conditions was calculated, resulting in 17% of all analyzed building surfaces, i.e. 0.3 km 2 of roof surfaces being economically exploitable for photovoltaic installations already now which corresponds to an installed capacity of 47 MW p . Considering further a material substitution from the building integration of the photovoltaic installations, an economic potential of up to 56 MW p or 0.4 km 2 results, of which up to 6 MW p or 0.04 km 2 are eco- nomically installable on building fac ¸ades. Fac ¸ade-mounted installations would then account for 13% of the economic potential. The calculation of an economic potential and additionally considering the material substitution from building integration both con- stitute an extension to many existing renewable energy potential studies just focusing on the technical potential. However, only the eco- nomic potential allows forecasts of the future diffusion of this technology. Ó 2015 Elsevier Ltd. All rights reserved. Keywords: Photovoltaics; 3D city model; Radiance; Technical and economic potential 1. Introduction In Germany the price for electricity generated by photo- voltaic plants dropped below the average electricity tariff of 0.25 €/kWh for private households at the beginning of 2012 (Wirth, 2014; Bundesministerium fu ¨r Wirtschaft und Energie, 2013), making them a profitable investment for households with a high share of self-consumption even without public subsidies. With the levelized cost of electric- ity (LCOE) ranging from 0.078 €/kWh to 0.142 €/kWh in November 2013 (Kost et al., 2013), the installation of a photovoltaic plant for electricity generation and as insurance against further increasing electricity tariffs is an attractive solution even for commercial enterprises with an average electricity tariff of 0.15 €/kWh in 2013 (Bundesministerium fu ¨r Wirtschaft und Energie, 2013). Consequently, new potential assessments for this now mature renewable energy technology are necessary. These assessments should no longer consider only a technical http://dx.doi.org/10.1016/j.solener.2015.03.023 0038-092X/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Institute for Industrial Production (IIP), Karlsruhe Institute of Technology (KIT), Hertzstraße 16, 76131 Karl- sruhe, Germany. Tel.: +49 721 608 44455; fax: +49 721 608 44682. E-mail address: Karoline.Fath@gmail.com (K. Fath). www.elsevier.com/locate/solener Available online at www.sciencedirect.com ScienceDirect Solar Energy 116 (2015) 357–370