Nature Based Solutions - Implementation Models Database

Implementation model

Green Roof Strategy in Hamburg

A short description of the NBS project

In response to climate change, one of Hamburg’s objectives is to become greener ‘in the city and on the roofs’. In this regard, Hamburg becomes the first German city to have developed a comprehensive Green Roof Strategy which goal is to plant a total of 100 hectares of green roof surface with plants and flowers in the metropolitan area by 2020. In particular, new residential constructions provide a 44 hectare green roof potential over 5 years and new business constructions provide an additional potential of 66 hectares. The city’s ambition is to have 20% of the green roofs on new buildings to be made available to residents or employees for recreation, in the form of sports fields and parks, or as gardens in shared use by the housing community. By promoting green roofs, the city aims to encourage space efficient leisure areas, improve the city’s rainwater retention capacity, increase 1 and reduce extreme temperature effects (i.e. reduction of the heat island effect). The strategy is characterized by a broad instrumental approach covering the range of instruments that are available to the public sector: creating (financial) incentives and providing good examples, communicating about the positive aspects of green roofs and stipulating the greening of rooftops where necessary. These instruments are encapsulated into four action points: 1. Promotion: with an incentive programme the city is providing subsidies until 2020 for each owner (private or public) voluntarily deciding for a green roof. The subsidy will be paid both for refurbishing the roof as well as green roofs in new buildings. 2. Communication and dialogue: the incentive programme is communicated strongly with a city-wide awareness campaign “On Your Roofs, Get Set, Green!”. Using posters, brochures, press articles and internet promotion, the green roof benefits are shared with Hamburg inhabitants and visitors. The greening of public roofs is an excellent promotional example. A full-time communication officer in the Hamburg Ministry of Environment and Energy is in charge of all communication actions. A dialogue is necessary with local politicians, authorities, architects, engineers and economists. 3. Policy and regulation: embed the Green Roof Strategy in urban landscape planning. The Strategy aims to incorporate or enhance green roofs into legally binding instruments such as the Hamburg Building law, the wastewater law, planting regulations on structural systems and land-use plans. 4. Scientific support: the HafenCity university is providing scientific support to the Green Roof Strategy. Scientists at the university are evaluating international findings on green roofs, developing their own recommendations for Hamburg’s green roof construction, and collecting data on water retention and the water management effectiveness of green roofs especially with severe cloudbursts (the latter to convince sceptics that question the green roof’s water retention capacities of large roofs). In fact, the city of Hamburg and the HafenCity university want to develop guidance for the promotion of green roofs which other cities can then use to create their own measures for climate change adaptation. The scientific work is partly funded by the federal government of Germany as a part of the “Measures to Adapt to Climate Change” project.

NBS Implementation context
Location Germany, Hamburg (Germany)
Latitude
Longitude
Status Ongoing (since 2012)
Dates
Description of the NBS
NBS Scale object (building, etc.)
NBS Impacts scale • Object (building) • Neighbourhood • City
Urban density/ Soil consumption High (dense city center, etc.)
Combined with other(s) environmental friendly solution(s)?
if other
NBS Typology
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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
Waste
Recycling
Other 0
Public health and well-being Acustic
Quality of life
Health
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
Other
Stakeholder and Governance
Who Started this initiative? Governments • Local government/municipality (Hamburg municipality)
Contracting Authority
Project manager (leader and main partners): entities names, and know-how involved
Who (else) was involved in the project ? (Inhabitants, local association, etc.)
More detail on the process and the role of the different stakeholders (How did it happen?)
OPTIONAL Considering the actual impacts, who are the primary beneficiaries of the project.
Cluster Governance Model Description
cluster5_network_governanceCollaborative_governanceGreen roofs are an investment with clear future returns: a green roof can create a more pleasant building climate and help to save on heating or cooling costs; it insulates in winter and cools in summer resulting in energy savings varying from 2-44% depending on roof insulation measures separate from the green roof; it also protects the roof water proofing from weathering effects so that green roofs last up to twice as long as conventional flat roofs; plants and substrate on green roofs retain a large amount of rain water, which results in additional savings of 50% on rain water fees for the owner in Hamburg. Hamburg’s Ministry for Environment and Energy invests. €500.000 of its own resources for the implementation of the overall Green Roof Strategy, including efforts in all four areas of activity: promotion/support, dialogue and communication, scientific support, and policy/regulation. It also includes a full-time employee based at the Ministry. In addition, Hamburg’s Ministry for Environment and Energy and the Harbour City University receive €300.000 in federal grants on expenditure basis from the German Ministry of the Environment under a funding programme supporting local activities for the adaptation to climate change. This federal grant on an expenditure basis is used to pay a full time communications officer and a part-time HafenCity researcher for 2-3 years. The Green Roof Strategy’s incentive programme has € 3 million at its disposal until the end of 2019. This amount includes the total remuneration to be provided under the financial incentive programme implemented via Hamburg’s investment and development bank (IFB), which handles all applications and transactions for the Green Roof incentives programme. Of the total € 3 million, € 2 million are sourced from the ‘implementation and service’ budget line of the Ministry responsible for city development and environment; the other € 1 million stems from the innovation fund of the Senate Office. The general approach taken is that financial incentives are available to those that voluntarily decide for a green roof before 2020. After that date Hamburg plans to have green roofs are compulsory by law. In particular, until 2020 building owners can receive subsidies to cover up to 30-60% of construction costs for the greening of their roofs. The multi-functionality of green roofs is reflected in the subsidy system supporting the Green Roof Strategy. A basic subsidy creates incentives to build a basic green roof while additional funding encourages more specialized, sustainable measures. Optional additional subsidies are then provided for: constructing high quality rooftops (root penetration protection and improving load bearing capacity for existing roofs), sustainable urban develop (inner city roofs, a green roof in combination with solar energy generation, and/or space utilization area) and an extra flood prevention by reducing rainwater discharge (improving run-off delay). Private owners with a 20-100sqm green roof who live themselves in the building receive a 40% subsidy on the total construction cost, including materials and contractor, and even up to 60% on material cost if the constructors are trained (professionals) either in architecture, roofing, landscaping or gardening thus ensuring high quality in construction. For all other owners with a >20sqm green roof - commercial, private, public - an owner receives a basic financial incentive ranging from € 14/sqm meters (on 8cm substrate soil thickness) to € 56/sqm (on 50cm substrate soil thickness) net vegetation area (maximum can be achieved via additional subsidy of € 1/sqm of net vegetation area per additional centimetre substrate soil thickness (rooting layer thickness)).
Financing
Global Estimated cost of the project 1M€- 5M€
Cluster cluster2_financial_institution
FM • Municipal Green Bonds
Description of the financing mechanism Green roofs are an investment with clear future returns: a green roof can create a more pleasant building climate and help to save on heating or cooling costs; it insulates in winter and cools in summer resulting in energy savings varying from 2-44% depending on roof insulation measures separate from the green roof; it also protects the roof water proofing from weathering effects so that green roofs last up to twice as long as conventional flat roofs; plants and substrate on green roofs retain a large amount of rain water, which results in additional savings of 50% on rain water fees for the owner in Hamburg. Hamburg’s Ministry for Environment and Energy invests. €500.000 of its own resources for the implementation of the overall Green Roof Strategy, including efforts in all four areas of activity: promotion/support, dialogue and communication, scientific support, and policy/regulation. It also includes a full-time employee based at the Ministry. In addition, Hamburg’s Ministry for Environment and Energy and the Harbour City University receive €300.000 in federal grants on expenditure basis from the German Ministry of the Environment under a funding programme supporting local activities for the adaptation to climate change. This federal grant on an expenditure basis is used to pay a full time communications officer and a part-time HafenCity researcher for 2-3 years. The Green Roof Strategy’s incentive programme has € 3 million at its disposal until the end of 2019. This amount includes the total remuneration to be provided under the financial incentive programme implemented via Hamburg’s investment and development bank (IFB), which handles all applications and transactions for the Green Roof incentives programme. Of the total € 3 million, € 2 million are sourced from the ‘implementation and service’ budget line of the Ministry responsible for city development and environment; the other € 1 million stems from the innovation fund of the Senate Office. The general approach taken is that financial incentives are available to those that voluntarily decide for a green roof before 2020. After that date Hamburg plans to have green roofs are compulsory by law. In particular, until 2020 building owners can receive subsidies to cover up to 30-60% of construction costs for the greening of their roofs. The multi-functionality of green roofs is reflected in the subsidy system supporting the Green Roof Strategy. A basic subsidy creates incentives to build a basic green roof while additional funding encourages more specialized, sustainable measures. Optional additional subsidies are then provided for: constructing high quality rooftops (root penetration protection and improving load bearing capacity for existing roofs), sustainable urban develop (inner city roofs, a green roof in combination with solar energy generation, and/or space utilization area) and an extra flood prevention by reducing rainwater discharge (improving run-off delay). Private owners with a 20-100sqm green roof who live themselves in the building receive a 40% subsidy on the total construction cost, including materials and contractor, and even up to 60% on material cost if the constructors are trained (professionals) either in architecture, roofing, landscaping or gardening thus ensuring high quality in construction. For all other owners with a >20sqm green roof - commercial, private, public - an owner receives a basic financial incentive ranging from € 14/sqm meters (on 8cm substrate soil thickness) to € 56/sqm (on 50cm substrate soil thickness) net vegetation area (maximum can be achieved via additional subsidy of € 1/sqm of net vegetation area per additional centimetre substrate soil thickness (rooting layer thickness)).
Business Model
Class Type Description
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Temporal Factor
Expected time for the NBS to be fully effective after its implementation
Expected life time of the intervention
Already feedbacks on the project? In case, the project has already been adapted to new requisites, please explain the modifications brought
Success and limiting factors
Process Enablers
Class Subclass Type Description
Knowledge_driversGeneration of evidence Awareness • Research on benefits • Research on cost effectiveness; Information accessibility and sharing • Knowledge platforms; • Climate Change The Green Roof Strategy fits within Hamburg’s aim to be a growing, yet climate-friendly and resilient, compact city. For this purpose green rooftops provide a financially beneficial and multifunctional solution. In addition to reducing of climate change threats, they highly improve green quality space in the city. Investing in green roofs for adaptation to increase stormwater management and flooding risk is financially beneficial and minimizing the cost of upgrading the current sewage system. The German Federal Ministry for the Environment, Nature, Building and Reactor Safety supports Hamburg’s Green Roof Strategy as a pilot project within their programme “Measures for adaptation to climate change”, providing financial support, networking and transfer of knowledge. Promotion and communication of the Green Roof Strategy are a top priority and several hurdles still have to be taken. For example, it has been questioned whether green roofs indeed provide the needed water retention capacities especially with a heavy storm water event. The concern is that support for this only stems from small scale experimental settings and that real and large roofs would not provide adequate retention service. To solve the matter HafenCity University is currently researching this question. Further, when initiating the Green Roof Strategy it was challenged whether Hamburg was having sufficient flat roofs to be able to succeed with the strategy. GIS-based research solved this question, showing that over 40% of the cities roofs are flat and suitable for greening. Another particular challenge requiring strong communication efforts on the positive benefits of green roofs has been the appearance of specific animals on the green roofs. On one of the industry flat roofs a sea gull colony of >5000 individuals has found a new home, putting off other businesses to also install green roofs. Similarly, green roofs attract insects which may result in people deciding to not choose for a green roof. Communication and research for Hamburg therefore have shown to be a crucial component for succeeding with the Green Roof Strategy.
Governance_driversCo-creation and participation • Involvement of urban government • Tools to build a common vision
Economy_driversDe-risking Government support • Public de-risking strategies; • Provisioning of incentives to attract private investment
Process Inhibitors
Class Subclass Type Description
Knowledge_driversUncertainty • Operational unknown • Performance unknown
Governance_driversParticipation and awareness • Perception • Lack of participation
Economy_driversRisk perception
What makes this project a pioneer?
Field
Criteria
Brief description of the innovativeness
Has the project received a prize, an award?
Has the project received a media coverage? (in reviews, in press, etc.)
IM Keywords
References