Nature Based Solutions - Implementation Models Database

Green roofs, Urban green spaces management

Photovoltaic Roof Garden

A short description of the NSB

As part of EU Biosolarroofs concept, the project Photovoltaic Roofgardens combines previously separated disciplines as green roof construction, building-integrated photovoltaic systems and roof design. Producing renewable energy, offsetting increasing soil sealing, improving the micro-climate, storing CO2 and rain water and extending the life of the roof membrane – a combined roof system should do all this and much more. The aim of the project is to combine these concepts to develop one holistic system. Synergies will be found between areas that have until now competed with each other. For the development of such a holistic concept, the following comprehensive analysis was carried out: understanding of users and users’ needs, coordination of appropriate vegetation systems in combination with PV shading, effects of shading patterns on people, integration and coordination with the architecture, landscape planning, construction and irrigation concepts as well as cost and revenue. These concepts have been tested using demo simulations. The research project’s initial results were presented at BOKU Wien: the plant-filled roof terrace creates a pleasant, comfortable environment. The photovoltaic pergola with semi-transparent glass-glass modules provides shade and produces green energy. The wooden test facility at BOKU does not yet represent the final architectural design. But it is already clear how the solution works: the previously underutilised terrace has become an attractive recreational and meeting place with a noticeable three to five degree temperature difference. In the test garden, five tons of CO2 are saved every year thanks purely to the photovoltaic system, without taking account of the CO2 retention properties of the plants and soil. The plants also act as a fine dust filter. The final design of the photovoltaic roof garden consists of a green roof structure, a pergola made of wood or steel and a canopy with photovoltaic glass-glass modules. A photovoltaic roof garden unit measures around 56sqm and can be endlessly multiplied. It provides about 5.500 kilowatt hours of green energy a year, or enough to supply one to two households. The costs including plants, steel girder construction and photovoltaic system are around €79.500. At €1.400 per square metre, the photovoltaic roof garden costs roughly the same as a conservatory. But for the same price, it provides both green energy and pleasant, green surroundings.

NBS Implementation context
Location Wien (Austria)
Status (from - to) Project delivered (2013-2015)
NBS Scale Object (building)
NBS Impacts scale Object (building) Neighbourhood City
Urban density/ Soil consumption High (dense city center)
NBS Typology

NBS Uban Challenges
Climate Issues Climate mitigation
Climate adaptation
Other 0
Urban water management and quality Urban water management and quality
Flood management
Other 0
Air Quality Air quality at district/city scale
Air quality locally
Other 0
Urban Space and Biodiversity Biodiversity
Urban space design
Urban space management
Other 0
Urban Regeneration and Soil Air quality at district/city scale
Other 0
Resource efficiency Food, energy and water
Raw materials
Other 0
Public health and well-being Acustic
Quality of life
Other 0
Environmental justice and social cohesion Environmental Justice: Recognition
Environmental Justice: Procedural Justice
Environmental Justice: Distributional Justice
Environmental Justice: Capabilities
Environmental Justice: Responsibility
Social Cohesion
Other 0
Urban planning and governance Urban planning and form
Governance in planning
Other 0
People Security Control of crimes
Control of extraordinary events
Other 0
Green economy Circular economy
Bioeconomy activities
Direct economic value of NBS
Other 0
NBS Stakeholders & Governance

Project partners are about some research institutions, semi government organizations/institutions and private sector: tatwort Nachhaltige Projekte, Institut für Ingenieurbiologie und Landschaftsbau der BOKU Wien (IBLB), Fricke, Raintime, Ertex Solar, Institut für Konstruktiven Ingenieurbau, AG Ressourcenorientiertes Bauen der BOKU Wien (IKI), Treberspurg und Partner, ATB Becker, voestalpine Krems, CES clean energy solutions, Wien Süd, BUWOG.

Initial actors (Leaders) Community Research institutions
Involved actors Governments Semi-government organizations / institutions, Community Research institutions ,Market Private sector
Ecological scale Local scale green area
Governance model CLUSTER 5: Network Governance Collaborative governance
NBS Financial aspects

This project is funded by the Federal Ministry for Science, Research and Economics and the Austrian Research Promotion Agency. The costs including plants, steel girder construction and photovoltaic system are around €79.500 (€1.400 per square metre).

Global (estimated) cost of the project 50k€ - 200k€ (€79.500)
Financing mechanism CLUSTER 1: Public financing
NBS Business Models Archetype
Technological Substitute with renewables and natural processes
Social Non applicable
Organisational Develop scale-up solutions
NBS Success and limiting factors
Process enablers
Knowledge Generation of evidence Lesson learnt through implemented projects, Collaboration Networks, Awareness Climate Change
Governance Process efficiencies Collaboration, Co-creation and participation Co-production
Economy Create conditions for new business models and finance schemes
Process inibitors
Knowledge Uncertainty Performance unknown
Governance Institutional barriers Lack of flexibility of decision making structures
Economy Perception of the benefits Short term vision
IM Keywords
  • Collaborative governance

  • Local scale green area

  • Public financing

  • Substitute with renewables and natural processes

  • Develop scale-up solutions