Life-cycle cost–benefit analysis of extensive vegetated roof systems

Carter, Tim; Keeler, Andrew G.

doi:10.1016/j.jenvman.2007.01.024

Cited by 277 publications

(167 citation statements)

References 26 publications

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“…We used areas of complete coverage of the building database in San Francisco, Rio de Janeiro, Hong Kong, Prague, London, Atlanta, Cairo, Lillehammer, and Nagano to compute building area per Landscan pixel over a diverse set of development typologies. From these data we computed the following linear relationship between building area per square meter and population per square meter (n = 2856 pixels, R 2 = 0.678): (Carter & Keeler, 2008). MacRae et al (2010) report that 37% of roofs in Toronto, Canada are "suitable for greening of some form."…”

Section: Vacant Landmentioning

confidence: 99%

A Global Geospatial Ecosystem Services Estimate of Urban Agriculture

et al. 2018

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Though urban agriculture (UA), defined here as growing of crops in cities, is increasing in popularity and importance globally, little is known about the aggregate benefits of such natural capital in built‐up areas. Here, we introduce a quantitative framework to assess global aggregate ecosystem services from existing vegetation in cities and an intensive UA adoption scenario based on data‐driven estimates of urban morphology and vacant land. We analyzed global population, urban, meteorological, terrain, and Food and Agriculture Organization (FAO) datasets in Google Earth Engine to derive global scale estimates, aggregated by country, of services provided by UA. We estimate the value of four ecosystem services provided by existing vegetation in urban areas to be on the order of $33 billion annually. We project potential annual food production of 100–180 million tonnes, energy savings ranging from 14 to 15 billion kilowatt hours, nitrogen sequestration between 100,000 and 170,000 tonnes, and avoided storm water runoff between 45 and 57 billion cubic meters annually. In addition, we estimate that food production, nitrogen fixation, energy savings, pollination, climate regulation, soil formation and biological control of pests could be worth as much as $80–160 billion annually in a scenario of intense UA implementation. Our results demonstrate significant country‐to‐country variability in UA‐derived ecosystem services and reduction of food insecurity. These estimates represent the first effort to consistently quantify these incentives globally, and highlight the relative spatial importance of built environments to act as change agents that alleviate mounting concerns associated with global environmental change and unsustainable development.

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Section: Vacant Landmentioning

confidence: 99%

A Global Geospatial Ecosystem Services Estimate of Urban Agriculture

et al. 2018

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“…Retrofitting a conventional roof with the green roof brings higher economical and functional efficiency to the building itself and less negative effects to the surrounding landscape. Since the rooftop has very same area as the footprint of the building and also similar profile of precipitation and solar radiation, it serves as a useful space that can be turned into a substitute of lost original environmental amenity [10].…”

Section: Benefits Of Green Roofmentioning

confidence: 99%

“…The users can have expense saving by increasing the durability of building materials, tax reduction, energy saving and increasing property values from green roof installation [9] and [10]. In terms of the public, they can also gain economic benefits by turning environmental benefits such as reducing carbon dioxide emission, air pollutants, and stormwater retention into monetary values [9], [10] and [12]. As for the social benefits, vegetation on the green roof can reduce the stress for humans and outside noise level, resulting in the improvement of human health conditions.…”

Section: Benefits Of Green Roofmentioning

confidence: 99%

Green Roof Retrofitting: Potential Assessment in an Academic Campus

Naing¹,

Nitivattananon²,

Shipin³

2017

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Abstract. Retrofitting becomes the priority action for existing buildings under uncertain economic times and increasing environmental awareness. Before retrofitting, it is necessary to evaluate the potential and feasibility of the buildings to minimize the risks. The challenge is the evaluation with relevant criteria and assessment framework from sustainable perspective. Using Asian Institute of Technology (AIT) campus as study area, this paper aims to assess the potential of existing buildings for green roof retrofitting. Multicriteria analysis was applied in the potential assessment, where inputs were generated from questionnaires survey, visual inspection and literature records. The potential benefits were identified and estimated through systematic literature reviews and savings calculation. The results revealed that physical factors have the highest influence on the assessment where 47% of buildings in study area were found to be viable for retrofitting while 6% were not viable, and 47% as possibly viable. Free standing, concreteframed with flat roof and oriented to south buildings appeared to be more preferable for retrofitting. Approximately 2% of annual energy use could be saved from campus-wide retrofitting however mitigation of impacts related to urban heat island and air quality need a micro scale implementation to provide more effective results. The study contributes to the building industry by providing a way to conduct the potential assessment for green roof retrofits in terms of criteria and assessment framework not only at micro scale but also at a wider scale in the regional context.

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“…However, because there is no standard protocol for quantifying these urban heat island-related externalities, comparisons among these three roofing strategies are limited. To date there have been a number of published case studies that compare green roofs to black roofs [9][10][11][12][13] and white roofs to black roofs [14][15][16][17]. However, we could not find a comprehensive comparison of green and white roofs.…”

Section: Sproul Et Al (Version Dated 11/01/2013)mentioning

confidence: 95%

Economic comparison of white, green, and black flat roofs in the United States

Sproul

Wan

Mandel

et al. 2014

Energy and Buildings

164

104

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White and "green" (vegetated) roofs have begun replacing conventional black (dark-colored) roofs to mitigate the adverse environmental effects of dark and impervious urban surfaces. This paper presents an economic perspective on roof color choice, in particular the direct comparison of white and green roofs, by conducting a 50-year life-cycle cost analysis (LCCA). Using data collected from 22 flat roof projects in the U.S., we find that relative to black roofs, white roofs provide a 50-year net savings (NS) of $25/m 2 ($2.40/ft 2 ) and green roofs have a negative NS of $71/m 2 ($6.60/ft 2 ). An important implication is that green roofs never quite "pay." Despite lasting at least twice as long as white or black roofs and therefore requiring fewer replacements, green roofs cannot compensate for their sizable installation cost premium of $151/m 2 ($14/ft 2 ).However, while the 50-year NS of white roofs compared to green roofs is $96/m 2 ($8.90/ft 2 ), the annualized cost premium is just $3.20/m 2 -year ($0.30/ft 2 -year). This annual sum should not deter owners from reaping the environmental and aesthetic benefits of green roofs (such as enhanced biodiversity, greater carbon sequestration, and increased property value) that are not captured in this LCCA. Choosing between a white and green roof should therefore be based on the preferences of the building owner. If global warming is a priority, then an owner should choose white roofs, which are three times more effective than green roofs in cooling the globe. If local environmental benefits are favored, then an owner should choose green roofs, which offer builtin stormwater management and a "natural" urban landscape aesthetic. Although black roofs are more cost-effective than green roofs and even white roofs in rare cases, we strongly recommend building code policies that phases out dark-colored roofs in warm climates to protect against their adverse public health externalities.

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Life-cycle cost–benefit analysis of extensive vegetated roof systems

Cited by 277 publications

References 26 publications

A Global Geospatial Ecosystem Services Estimate of Urban Agriculture

A Global Geospatial Ecosystem Services Estimate of Urban Agriculture

Green Roof Retrofitting: Potential Assessment in an Academic Campus

Economic comparison of white, green, and black flat roofs in the United States

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