AI-powered tool used to map sustainable roofs globally

AI-powered tool used to map sustainable roofs worldwide

Graphic abstract. Credit: DOI: 10.116/j.landurbplan.2021.104167

As cities around the world continue to urbanize, there is a greater need to expand and optimize existing spaces. Cities have accelerated research into how underutilized rooftop spaces can contribute to climate action, food production and other purposes. Sustainable roofs, such as green roofs and photovoltaic panels, can contribute to the roadmap for reducing cities’ carbon footprints, but while studies have been done to measure their potential, few are tracking the actual performance of cities.

To address this, Dr. Filip Biljecki, Presidential Young Professor of the Department of Architecture at the National University of Singapore (NUS) School of Design and Environment, and NUS Master of Architecture, Mr. Abraham Noah Wu, developed an automated tool that uses satellite imagery to track how roofs around the world are adopting solar panels and/or vegetation. Known as Roofpedia, it uses a fully convolutional neural network (deep learning) that allows researchers and policymakers to study how cities around the world are greening their roofs and using them for photovoltaic installations.

This is a research project under the NUS Urban Analytics Lab, a multidisciplinary research group at the NUS School of Design and Environment. Their research has been published in the international journal Landscape and urban planning.

Tracking the adoption of solar and green roofs in 17 cities

With Roofpedia, the researchers created an open roof registry with data from 1 million roofs in 17 morphological and geographical cities, spread across Europe, North America, Australia and Asia. These cities are: Berlin, Copenhagen, Las Vegas, Los Angeles, Luxembourg, Melbourne, New York, Paris, Phoenix, Portland, San Diego, San Francisco, San Jose, Seattle, Singapore, Vancouver and Zurich.

Using this data, the researchers developed the Roofpedia Index, to benchmark the cities based on the degree of sustainable roof landscape in terms of solar energy penetration and green roofs. This is derived by considering both the surface coverage and the number of buildings with solar and green roofs in a city as a percentage value of the entire area.

Zurich received an index score of 100 due to its high scores for both area coverage and number of green roof buildings. The high green roof coverage is the result of efforts by the Zurich city government to make green roofs mandatory for all new buildings since 1991. Las Vegas topped the index with a score of 86. This may be due to the high solar potential of the geographical area.

“By collecting such data, Roofpedia makes it possible to measure how cities can further use their roofs to reduce CO2 emissions and how much untapped potential their roof landscape has. For example, users can supplement Roofpedia with other data sources to measure the effectiveness of government subsidies and Whether the climate promises of others have been fulfilled. In addition, by collecting current data from satellite images, users can also more accurately determine the current carbon offsetting capacity of cities,” shared Dr. Biljecki with me.

Roofpedia ranks Singapore third in solar roof coverage

Based on the Roofpedia Index, Singapore ranks third out of 17 cities, with a score of 75, for the application of solar energy on roofs, behind Las Vegas (score of 86) and Zurich (score of 81). The scores in the Index have normalized, and while Singapore ranks high in total area, it lags behind some other cities because relatively fewer buildings are equipped with solar panels.

Mr Wu said: “While Singapore has ambitious plans to significantly expand its solar deployment by 2030 as part of the SG Green Plan, rooftop solar deployment is largely driven by the government. As such Roofpedia points to a higher concentration of solar-powered buildings in core areas such as Woodlands, Jurong or Ang Mo Kio compared to other districts such as Pasir Panjang.Singapore’s relatively lower score for the number of buildings equipped with solar panels indicates that there is potential is to involve private residences and commercial buildings to maximize even more Singapore’s rooftops.”

Mr. Wu explained that the scoring system takes into account both the number of buildings and the total area of ​​the building, allowing users to study the degree of adoption by individual owners, as well as the overall expanse of solar and rooftop vegetation in other areas. towns.

The researchers emphasized that each city has its unique characteristics and that the exact benefit of having greenery or solar panels on roofs depends a lot on the urban shape and design. The city’s geolocation and macroclimate are also planning a part. For example, in drier areas, green roofs are more difficult to maintain, while solar roofs in rainy and dark areas make no economic sense. Taking these constraints into account, a city could still be ecologically progressive without a sustainable roofscape.

dr. Biljecki explains: “Vancouver may not rank well in the Index, but it is nevertheless consistently ranked as one of the most sustainable cities in the world with access to sufficient hydropower, which alone provides 25 percent of the city’s energy needs, and has plans to to get 100 percent of energy used from renewable sources by 2050. What the Roofpedia Index does is it can complement existing sustainability indices by adding a new dimension to the assessment of a city’s overall sustainability.”

The future of Roofpedia

The research team has made Roofpedia’s data from 1 million roofs openly accessible and hopes to encourage other scientists on board to work with them to expand the database by tracking more cities or incorporating other environmental indicators.

dr. Biljecki stated that the accuracy of Roofpedia’s results would depend on the quality and time period of the satellite images provided and whether the approach would differentiate other man-made features (such as skylights) from solar panels. However, when the data is aggregated on a city scale, Roofpedia can generally indicate how sustainable a city’s roofs are, allowing for comparative analysis across cities.

“Our project is designed to be open, as cities today are dynamic and quickly adopt sustainable tools. In addition, the design is modular, meaning new geographies, roof typologies and functions can be added. As such, our research group plans to develop a add a temporary feature so that users can study the evolution of sustainable measures on roofs over time and how many more cities can increase their roof landscape.We hope our work can help researchers, local authorities and the public to understand and promote the further use of roofs in achieving sustainable urban development for a climate neutral world,” said Dr. Biljecki.

Green roof or solar energy? Turns out both are best

More information:
Abraham Noah Wu et al, Roofpedia: Automatic mapping of green and solar roofs for an open roofscape registry and evaluation of urban sustainability, Landscape and urban planning (2021). DOI: 10.116/j.landurbplan.2021.104167

Provided by the National University of Singapore

Quote: AI-powered tool used to map sustainable roofs worldwide (2021, September 7) retrieved September 8, 2021 from globally.html

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