solar cities

How does urban morphology affect the solar potential of cities?

Temperate cities like Singapore or Hong Kong are well suited for expanded applications of solar energy. With developments in semi-transparent photovoltaic-cells, we may soon see glass building façades transformed into harvesters of solar energy while simultaneously providing passive shading.

Focusing on previously under-explored factors such as the albedo (reflectivity) of the urban landscape, we propose a model to more fully assess the spatiotemporal variation in the solar potential of cities: from the roof-tops and facades down to the street-level.

Solar Cities investigates the solar potential of cities in three dimensions, below and beyond the rooftop.

Ten cities arranged in order of the annual solar irradiation maintained by their urban surfaces, with a breakdown showing ground-, façade- and roof-level contributions (all values are /yr):
New York
1.94 MWh/m2
Manhattan
Bar chart - New York Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.4 MWh/m 2 Façade 1.4 MWh/m 2 Ground 0.1 MWh/m 2
Singapore
1.84 MWh/m2
Singapore
Bar chart - Singapore Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.2 MWh/m 2 Façade 0.8 MWh/m 2 Ground 0.9 MWh/m 2
Mandalay
1.54 MWh/m2
Mandalay
Bar chart - Mandalay Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.6 MWh/m 2 Façade 0.5 MWh/m 2 Ground 0.5 MWh/m 2
Honolulu
1.50 MWh/m2
Honolulu
Bar chart - Honolulu Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.4 MWh/m 2 Façade 0.5 MWh/m 2 Ground 0.6 MWh/m 2
L.A.
1.49 MWh/m2
Los Angeles
Bar chart - Los Angeles Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.4 MWh/m 2 Façade 0.7 MWh/m 2 Ground 0.4 MWh/m 2
Athens
1.44 MWh/m2
Athens
Bar chart - Athens Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.6 MWh/m 2 Façade 0.6 MWh/m 2 Ground 0.2 MWh/m 2
Lisbon
1.30 MWh/m2
Lisbon
Bar chart - Lisbon Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.4 MWh/m 2 Façade 0.5 MWh/m 2 Ground 0.4 MWh/m 2
Toronto
1.30 MWh/m2
Toronto
Bar chart - Toronto Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.2 MWh/m 2 Façade 0.9 MWh/m 2 Ground 0.1 MWh/m 2
Hong Kong
1.22 MWh/m2
Hong Kong
Bar chart - Hong Kong Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.2 MWh/m 2 Façade 0.3 MWh/m 2 Ground 0.7 MWh/m 2
Paris
0.97 MWh/m2
Paris
Bar chart - Paris Roof-top, facade and ground-level breakdown 0% 50% 100% Roof 0.2 MWh/m 2 Façade 0.6 MWh/m 2 Ground 0.2 MWh/m 2

The results suggest that cities with high densities of tall buildings and erratic fluctuations in height, such as New York and Singapore, possess large degrees of un-tapped solar potential.

The model can support local governments in strategizing urban developments and provide decision making support for energy harvesting initiatives.