This rate typically stands at approximately 20% to 25% for conventional photovoltaic (PV) systems, dependent on several factors including location, technology, and environmental conditions. Many methods of estimating rooftop area have been developed, ranging from. . In the last decade, solar has grown with an average annual rate of 26 percent, reaching a capacity of over 138 gigawatts in 2023. Of the total solar capacity. . Solar rooftop potential for the entire country is the number of rooftops that would be suitable for solar power, depending on size, shading, direction, and location. . This analysis is part of a series from our new report, Technology and innovation pathways for zero-carbon-ready buildings by 2030, and provides the strategic vision of experts from the IEA Technology Collaboration Programmes (TCPs) on how to help achieve some of the most impactful short-term. . Solar energy can be harnessed two primary ways: photovoltaics (PVs) are semiconductors that generate electricity directly from sunlight, while solar thermal technologies use sunlight to heat water for domestic uses, to warm buildings, or heat fluids to drive electricity-generating turbines.