The application of vertical greening systems (VGS) onto building envelopes constitutes an innovative way to implement more green in the living environment. Especially in dense urban areas, where only limited space is available to integrate more horizontal greening at ground level, VGS have the potential to contribute towards creating a greener, healthier, more nature-inclusive and climate resilient urban environment. This by facilitating and contributing to natural ecosystem functioning, hence providing ecosystem services and through those, benefits for society. These benefits include among others an enhanced microclimate, biodiversity and aesthetic appeal, as well as improved physical and mental health, thermal performance, energy efficiency and air quality, and reduction of urban heat island effect and noise disturbance.
In order to substantiate the total set of costs and benefits associated with VGS implementation and enhance rational decision-making, in present research the development of a standardised framework and interactive economic valuation tool is proposed.
In the end, an economic valuation framework and tool were developed which can support the decision-making process regarding VGS application. The framework is based on Life Cycle Cost Analysis (LCCA) and Social Cost Benefit Analysis (SCBA). These analyses relate to real estate investors and society (resident focus) respectively. To assess and report on the values of the costs and benefits of these innovative systems, distinct themes were established. The cost themes entail financial costs, environmental costs and potential Ecosystem Disservices. Benefits are distributed over the themes health & well-being, climate adaptation & mitigation, real estate, social & recreational & commercial and biodiversity.
The current version of the tool is able to perform quantification and monetisation for financial costs, large parts of the environmental costs, reduction of airborne PM10, increased rental incomes (investors) and rental costs (residents), reduced energy usage for heating and MIA & Vamil tax incentives. Based on implemented valuation methods, the case study delivers project specific results. Though, it is explicitly noted that these results do not yet provide a complete representation of all costs and benefits, due to a limited number of (benefit) indicators that are monetised. Hence, this version of the tool should be regarded as initial impetus for further development. This in order to ultimately obtain an all-encompassing VGS Valuation Tool, fit for project specific economic valuation of costs and benefits of VGS.
The result dashboard visualises the valuation outcomes and results in clear tables and graphs, generating insights into the contribution of different themes towards the total costs and benefits of VGS. This can initiate further recommendations for a research agenda into distinct aspects of certain VGS.
Hence, the VGS Valuation tool could become a conversational mechanism or steering instrument, to stimulate or justify choices for specific types of VGS at given locations. The test panel of anticipated end users was enthusiastic about the comprehensiveness and user experience of the tool and acknowledged its future practical value.