The importance of facades for the solar PV potential of a Mediterranean city using LiDAR data

- Calculation of solar potential of roofs and facades of a city.
- Comparison with estimated local electricity demand.
- Facades significantly contribute to overall solar potential.
- Facades help adjusting PV generation to the load diagram.

The aim of this work is to discuss the potential of facades and other vertical features for the photovoltaic potential of the cityscape. The photovoltaic potential in two representative case studies in the city of Lisbon, Portugal, is computed using a digital surface model determined from LiDAR (Light Detection And Ranging) measurements and local typical meteorological year time series. Results are compared with estimated local electricity demand derived from the population distribution.The annual analysis shows that roof and facade PV potential exceeds the local non-baseload demand and can contribute to 50-75% of the total electricity demand. Hourly breakdown shows peak PV power can only achieve winter mid-day electricity demand if the solar potential of facades is also taken into account. Its added value for off-peak PV supply is less significant in winter since non-south facades are not particularly exposed. In summer, however, facades can satisfy non-baseload morning and afternoon demand. A conservative economic analysis shows payback times below 10 years can only be achieved with PV on roofs while a 50/50 mix would lead to payback times of 15 years.