SolarCity is a web-based simulator application created to help households, businesses and municipal authorities evaluate their prospects for generating electricity using rooftop-mounted solar photovoltaic (PV) systems.
For homes and businesses, the simulator provides the means to calculate likely savings from rooftop solar PV compared to other power sources and based on a cash flow financing model.
For municipal authorities, the simulator supports assessments of different policy incentives – such as generation or capital subsidies – on each city’s rooftop solar PV market.
The SolarCity simulator combines ultra-high-resolution three-dimensional building footprints with solar irradiation data, computed at one metre (m) grid cells. It is one of a series of web applications developed by the International Renewable Energy Agency (IRENA) as part of the Global Atlas for Renewable Energy.
What is the SolarCity simulator?
SolarCity is a web application provided by IRENA to enable households, businesses and municipal authorities to evaluate the prospects for electricity generation using rooftop-mounted solar PV installations.
Is SolarCity a global solution?
The methodology of the SolarCity simulator can be deployed worldwide, including in locations where solar potential is high but not yet fully evaluated. The first implementations of the simulator were in the districts of Kasese in Uganda and Chongli in Zhangjiakou, China. SolarCity is one of a series of web applications developed by IRENA as part of the Global Atlas for Renewable Energy.
To what extent is shading on rooftops considered in the solar irradiation simulation?
The solar irradiation simulation for SolarCity is very accurate. To correctly estimate the effects of shading, rooftops are captured in three dimensions, with the respective tilt and azimuths of each rooftop section determined before the shading simulations are applied (see methodology).
What is the spatial resolution for the simulated solar irradiation and PV module production calculations?
The calculations have been made using a base resolution of one metre – the same as the source imagery.
Which solar module was used to estimate the production potential of each different rooftop? Is there an option to compare different panel types?
We estimated the amount of energy (in kWh) that can be produced from sunlight based on the size of the system (in kW) per year. In this case, the user can use any conversion efficiency that corresponds to the technology of interest to calculate the yield.
What is the level of uncertainty in the solar PV performance calculations?
The combined uncertainty in the models used to perform these calculations (irradiation and performance) is estimated to be typically around 5% when fed with accurate input data. However, as this is the first implementation with rooftop attributes that have been calculated from satellite-sourced imagery at 1 m resolution, the precise uncertainty estimate will be updated after the release of the platform.
Does the simulator provide seasonal generation profiles?
No. The PV performance modelled in the SolarCity simulator, although calculated on an hourly time stamp over a typical meteorological year, has been aggregated to provide annual average results to simplify the calculations and visuals.
Does the simulator account for storage capacity?
Yes. The option to configure storage has been included in the simulator to allow users to assess how to live off the grid and be energy self-sufficient when excess solar energy cannot be fed into the electricity grid.
Does the simulator account for net metering?
The general architecture of the SolarCity simulator contains a module for empirical and business assessments of net metering, feed-in tariffs and storage capabilities.
What is the source for default investment and operating costs?
For investment and operating costs, the default values are obtained from either IRENA’s Costing Database or IRENA’s focal points in the country; users can edit these values.
How can I request a simulator for my city?
The current version of the SolarCity simulator has been built for demonstration in Kasese, Uganda and Zhangjiakou, China. With careful consideration on a case by case basis, IRENA may work with its Members to develop versions of the simulator for selected cities in their countries. For more information, please contact IRENA’s Resource Assessment unit at: GlobalAtlasServices@irena.org.
Can IRENA perform a detailed analysis of a city?
On a case by case basis, IRENA may decide to use the capabilities of SolarCity to conduct specific studies requested by its Members. The outcome of such studies could be in the form of a published report and may not include interactive software online. Please contact IRENA for more information at: GlobalAtlasServices@irena.org.
Where can I find more details about how the SolarCity simulator works?
You may download the SolarCity methodology report here.