Reviewed by Lexie CornerJul 17 2024
A novel machine learning framework designed by IIASA researchers to estimate global rooftop area growth from 2020 to 2050 can help plan sustainable energy systems, urban development, and climate change mitigation, and it has the potential to provide significant benefits in developing economies. This research was published in Scientific Data.
Global rooftop area layer results for different regions. Each panel uses colors to show the amount of rooftop area per grid cell (small area). Rooftop area growth is visible in East China, West Africa, and Central Europe. Image Credit: Joshi et al. (2024)
In 2019, buildings worldwide utilized approximately 18 % of total annual power generation and created 21 % of greenhouse gases emitted into the atmosphere, considerably contributing to climate change. As the world's population rises, we will require more structures, increasing demand for power and construction materials.
The global rooftop area is the total gross surface area of all roofs of buildings worldwide. This measurement is useful for various applications, including installing roof-mounted solar panels for sustainable energy, planning cities, and researching environmental implications.
Understanding the worldwide rooftop area and its projected rise over the next 30 years will allow everyone to better plan for sustainable energy systems, improve urban development, and limit buildings’ impacts on climate change and biodiversity loss.
To assist with this, IIASA researchers created a machine-learning framework that utilizes big data from around 700 million building footprints, worldwide land cover, global roads, and population statistics. Their approach forecasts rooftop area increases from 2020 to 2050 using five possible future scenarios. The data pertains to nearly 3.5 million small areas globally.
Using the framework, the researchers calculated that by 2020, the total rooftop area worldwide will be 0.25 million square km, out of a total human-made built-up surface area of 1.46 million square km. Asia had the highest share (0.12 million square km), followed by Europe (0.47 million), North America (0.39 million), and Africa (0.02 million).
By 2050, the worldwide rooftop area will grow to between 0.3 and 0.38 million square km, a 20-52 % increase over 2020. Africa is expected to have the most growth, perhaps doubling its rooftop area.
The team’s study is the first high-resolution worldwide estimate of rooftop area increase based on several socioeconomic pathway narratives. It highlights how massive geographic datasets and machine learning can help with sustainable development and climate action.
The main point is that rooftop solar power has enormous potential in emerging nations. With significant rooftop area expansion, these locations may use their manufacturing capabilities, high solar potential, low-cost labor, and entrepreneurial spirit to achieve long-term development and prosperity.
The implications of this research for policy and the public are significant. Our dataset can aid in more realistic planning of decentralized solar energy systems, thereby promoting sustainable energy solutions. Estimating the potential of rooftop solar technology in achieving climate policies, especially in emerging economies, can help these policies be more effective and affordable, in line with the Sustainable Development Goals for clean energy, sustainable cities, climate action, and life on land.
Siddharth Joshi, Study Lead Author and Research Scholar, Integrated Assessment and Climate Change Research Group, IIASA Energy
Joshi began working on the framework's conceptualization, development, and analysis while participating in the 2021 IIASA Young Scientists Summer Program. He got the Mikhalevich Award for his efforts in this field.
Journal Reference:
Joshi, S., et al. (2024) Global high-resolution growth projections dataset for rooftop area consistent with the shared socioeconomic pathways, 2020–2050. Scientific Data. doi:10.1038/s41597-024-03378-x.