Special Report: GREENpass – unleash the power of GREEN

image1Bernhard Scharf explains how to unleash the power of GREEN with the world’s first planning and optimisation technology for urban green infrastructure

The necessity to adapt urban landscapes towards climate resilience is undisputed and the same is true of Nature-based solutions (NBSs). Apart from the European Green Infrastructure Strategy (2014) many different policies, for example the Paris licence to vegetate (City of Paris, 2016) or the Urban Heat Island strategy in Vienna (2015) and many others, have been passed throughout Europe to promote NBSs. It is widely acknowledged that NBS derives multi-beneficiary effects exceeding the scope of the term ‘green infrastructure’ (GI).

However, on the path towards sustainable urbanisation one key element was missing: the predictability of GI interventions in urban planning processes as a tool for planners and authorities to develop cost-effective, reliable, tailormade solutions at different planning levels (local to regional) and levels of detail (preliminary, concept and detailed design).

GREENpass technology
GREENpass technology addresses the need of real estate developers, planners and authorities to predict the effects and resource demand of GI in urban planning. The core of GREENpass technology is a powerful numeric simulation software named ENVI-met: the world’s leading microclimatic simulation software, used by more than 5,000 scientists. The software is able to simulate energetic and particle processes within a model up to 10ha in size in time steps of one-third of a second with a typical resolution of two metres. The material database includes all typical urban surfaces that are underlaid with physical properties such as heat flux, albedo etc. A speciality of ENVI-met is the unique capability to simulate the reaction of greenery on various climatic framework conditions, including water consumption, CO2 uptake, aerodynamics, leaf area index and so on.

In general, climate models (that integrate green infrastructure effects) can only lead to climate-friendly planning processes on a large scale if they are consistent with conventional planning instruments that are used day to day by architects and city planners.

But existing microclimatic simulation and planning models often have a very scientific approach and do not provide directly relevant planning information in a reliable way. In particular, they do not provide resource indicators, for example construction and maintenance costs, or area analytics. For this reason, we developed the GREENpass method.

The GREENpass method expands the world’s leading microclimatic simulation software tool ENVI-met in terms of effects of building-integrated greening and resource indicators. Additionally, and in co-operation with the ENVI-met team, we have created an interface called the ‘GREENpass editor’(GP.me), which allows users to convert conventionally used planning principles (by computer-aided design and drafting (CADD) or geographic information systems (GIS)) directly in a microclimate model and to evaluate according to the detailing level needed for the respective planning phase.

The GREENpass method thus allows a rapid assessment of construction projects in terms of the microclimatic effects of urban green infrastructure already in the planning stage. The integration into the planning process is thus not only possible, but desirable. In addition, a certificate was developed – similar to a Leadership in Energy and Environmental Design (LEED) or DGNB (Deutsche Gesellschaft für Nachahltiges Bauen) certificate – which allows for the climatic rating of a planned object or a whole city quarter at a glance.

The GREENpass methodology and our adjacent service allow tailormade planning of urban green infrastructure and a clear cost transparency.

Next to the central issue of energy and microclimate, our technology can do even more. We optimise districts and individual projects in development, as well as modernising existing buildings, by regarding additional factors such as storm water management, cost efficiency, building physics, fine particulate matter and CO2 savings.

How it works
The GREENpass methodology differentiates urban and object planning projects, which are supported by three different application options of the GREENpass technology, specially designed to be consistent with the information demand at different stages of the planning process. For every application, a transparent and standardised analysation method has been defined.

Vulnerability and adaptation analyses
The interdisciplinary GREENpass team developed urban standard typologies (USTs) based on five co-operative cities (Hong Kong, London, Cairo, Santiago de Chile and Vienna) that are in line with the Local Climate Zones (LCZs) of Stewart and Oke (2012). Additionally, every typology has been designed in three different scenarios concerning the proportion of greenery and permeable surfaces. These USTs can be applied quickly to any city (or district) worldwide based on, for example, sky view factors etc. A mesoclimatic numeric simulation tool allows for simulating the urban climate performance and identifies urban heat islands. The proportion of greenery can be increased or even the typology changed to provide information on the effects of these measures on the urban climatic performance. This application especially addresses city authorities when creating policies.

City pre-assessment
New city quarters or retrofitted districts affect the climatic processes of adjacent areas. The GREENpass pre-assessment method uses ENVI-met with a reduced set of simulation parameters and simulation time to support project developers and judging panels in the phase of concept design of competitions with profound information on the thermal performance, wind field and impact on the adjacent areas to submitted projects.

City full assessment
The GREENpass full assessment was designed to support the detailing and optimisation process of urban development projects. It includes high-resolution holistic simulation of the project area, multi-parametric area and structure analytic and resource demand calculation, including different cost indicators, air conditioning hours, water demand, CO2 uptake, run-off factor etc. The aim is to optimise the performance of the project towards effects and costs through step-by-step standardised analyses of simulation results, defining of optimisation measures and iteration of simulation.

The set of GREENpass applications at city level provides an unprecedented opportunity to optimise and evaluate the microclimatic performance of the urban planning process for both authorities and private real estate developers.

Analogous to urban planning processes, the GREENpass technology also provides tailormade evaluation and assessment solutions for objects planning projects as groups of buildings or parks.

Object pre-evaluation
GREENpass pre-evaluation supports projects at an early stage as the preliminary design. To provide a very rapid and inexpensive service – as needed in this phase – the pre-evaluation foregoes numerical simulations. Instead, it processes a complex area and structure analysis of the project and matches with the GREENpass databank of UST performances. As a result, a possible range of thermal performance of the proposed project is provided.

Object pre-assessment
As described above, the object pre-assessment delivers reliable information on the thermal performance of a planned object (at day and night), wind field and the impact on adjacent areas. It will support competition entries to succeed or judging panels to select the best conceptual design.

Object full assessment
The GREENpass full assessment supports the optimisation of effects and resource demand as mentioned above. At the end of the iterative process a certificate is handed over to the client.

GREENpass certificate
The GREENpass certificate is provided at the end of both city and object full assessment. It summarises the results for every criterion, category and thematic field (climate, water, resources and socioeconomic quality). With respect to the degree of fulfillment of every thematic field, the GREENpass Platinum, Gold, Silver or just certified is granted to a project. On top of that the certificate includes a handbook for users.

How it works for your project
The GREENpass team is currently transferring the described knowhow to licensed partners worldwide. If you want to find out more, we are happy to provide more detailed information.

Doris Schnepf
Green4Cities Ltd
+43 676 67 00 215