Green roof subsidy programme - Hamburg

The green roof subsidy programme in Hamburg, Germany started in 2014 and offers financial support for the voluntary creation of green roofs and green facades to the sum of 3,5 million Euro until the end of 2024. Private and public building owners can receive subsidies to cover up to 60% of installation costs, including materials and labor. The subsidy programme is based on the thickness and surface area of the green roof rather than the water retention capacity alone. The programme is part of Hamburg's green roof strategy and the overall strategy for sustainable rainwater management.

Overview

Type of instrument:

Economic and fiscal instruments›Payments as rewards/for ecosystem services, subsidies, incentives

Challenges addressed

Water management (e.g. reuse)
Green space management (e.g. accessibility)
Drought and fire risk
Flood risk: pluvial and fluvial / soil permeability
Heat stress and heat island effect
Human health, comfort and well-being

Consideration of nature-based solutions:

Multifunctional green roofs are a nature-based solution that can provide diverse social, economic and environmental benefits. It is planned that 20% of the newly greened areas are to be used by residents or employees as open spaces. The roofs are also expected to contribute to a higher quality of life, better appearance of the city, improved energy balance of the buildings, greater biodiversity and increased retention of an average of 60% of rainwater, thus contributing to adaptation to climate impacts and cost savings.

Targeted (peri-)urban areas:

Green areas for water management

External building greens

Urban green space connected to grey infrastructure

Good practice characteristics:

Effective

Locally appropriate

Potential to be replicated / upscaled

Governance

Government body/bodies

Initiating body:

City of Hamburg, Ministry for Environment, Climate, Energy, and Agriculture

Instrument design:

Details about how the instrument was designed:

Hamburg involved other cities in a search for good practices and solicited feedback on draft versions of the incentive programme. A stakeholder group including housing estate companies, constructors, landscape architects and urban planners was involved in defining the incentive programme. Additional stakeholder groups have been set up to work on specific themes, such as fire protection of green facades in the long term and cost assessment of green roofs (construction costs, life cycle costs, saving costs opportunities).

Involvement of non-governmental actors:

Private sector, corporate, business

Researchers, university

Type of actor involvement:

Co-planning or co-design of instrument (e.g. boards, advisory role)

Instrument implementation:

Type of involvement:

In addition to the city implementing demonstrative green roofs on its own buildings, private and other public building owners can apply for funding to create green roofs and facades (since 2020) via the dedicated green roof subsidy programme.

Type of non-governmental actors involved:

Implementation of NBS (e.g. with government funds)

Targeted actors:

Public sector institution (e.g. school or hospital)

Private: household, real estate developer, business , financial

Financing

Sources of funding:

Public local authority’s budget

Budget:

1 000 000€ - 5 000 000€

Details about instrument financing:

Of the total 3,5 million Euro, 2 million are sourced from the ‘implementation and service’ budget line of the Ministry responsible for city development and environment; the other 1 million Euro stems from the innovation fund of the Senate Office (the Federal state’s government of Hamburg). Since 1st June 2020 the subsidy system also includes financial and practical support for green facades, with an overall funding of 0,5 million Euro. The subsify programme is implemented via the Hamburg’s Investment and Development Bank (IFB), which handles all applications and transactions for the Green Roof incentives programme. A number of minimum standard criteria must be fulfilled for the subsidy to be granted for green roofs (e.g. minimum 20 m2 net vegetation area, maximum 30° roof slope, minimum 8-12 cm soil thickness, depending on the type of the building). Subsidy amounts vary depending on the size of the measure, location (inner or outer city), combinations with rooftop solar arrays and several other aspects. If additional measures, such as increasing the substrate thickness, the use of open space or combination with solar energy generation, are planned for a green roof beyond the requirements of building law or nature conservation law, funding can also be granted.

Monitoring, evaluation and impacts

Is a monitoring framework in place?:

Yes

Scientific monitoring is conducted on rainwater run-off and micro-climate (HafenCity University) and on biodiversity (by the University Hamburg and Zurich University of Applied Sciences Wädenswil).

Did an evaluation take place?:

Yes

Evaluation - as part of the scientific monitoring - is carried out by the HafenCity Universität Hamburg, summarising results of the water management effectiveness of the green roofs as well as the replicability of the established instruments /strategy, financing programme, awareness raising, combination with other legal instruments). The city of Hamburg also regularly reviews its green roof legislation in particular with regards to the ecological quality standards for the roofs.

Achieved outcomes and impacts:

The implementation of the programme started in 2014. Between February 2015 and June 2019, 186 applications for funding were submitted and 136 approved. At least 13.5 million Euro have been invested in green roofs in Hamburg until 2020, of which 1.5 million Euro is public funding coming from the green roof subsdy programme.This allowed for creation of ca. 5.3 hectares of new vegetation area. In February 2019 the subsidy programme was extended by a further five years. The extended programme includes also subsidies for constructing green facades. The green roofs contribute to improve rainwater management, increase urban green space and biodiversity, reducing financial costs for urban management and enhancing human well-being.

Success factors and lessons learned:

The green roof financial support programme is - in combination with public relations and dialogue - the most important instrument in creating awareness about the benefits of green roofs. There is still a strong need to gather evidence of effectiveness, e.g. for water retention and temperature reduction and gather further evidence. Hamburg is working across departments and in cooperation with the housing industry to make green roofs and façades a legal requirement for all suitable buildings. However, the aim to create affordable housing is seen by the housing industry as contradictory to green roofs, although it has been scientifically proven that life cycle costs do not increase. Experienced disservices of green roofs – e.g. case of 2,500 seagull pairs breeding on 7 ha green roof during spring, or the emergence of more insects – necessitate further open and transparent dialogue, awareness raising and communication efforts. 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.

Sources and further information

References

List of references:

Naumann, S., Davis, M., Iwaszuk, E., Freundt, M., Mederake, L., 2020: Addressing climate change in cities – Policy instruments to promote urban nature-based solutions. Ecologic Institute, the Sendzimir Foundation: Berlin, Krakow. https://www.ecologic.eu/sites/default/files/publication/2020/3205-Addressing-climate-change-in-cities-2.pdf

IFB Hamburg, 2020. Hamburger Gründachförderung - Förderrichtlinie für die Herstellung von Dach- und Fassadenbegrünungen. http://www.ifbhh.de/api/services/document/696

Further documents

Weblinks:

https://una.city/nbs/hamburg/green-roofs-hamburg

https://oppla.eu/casestudy/21219

https://climate-adapt.eea.europa.eu/metadata/case-studies/four-pillars-to-hambur…

https://www.hamburg.de/foerderung/4364756/gruendachfoerderung/

https://www.ifbhh.de/foerderprogramm/hamburger-gruendachfoerderung

Photos

@Jochen Spieker en Flickr (CC BY-SA 2.0)