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► Consistently tap alternative heat sources such as wastewater heat
► Convert public buildings to renewable heat and form district heating networks
Ambitious energy-efficient refurbishment, even in areas protected by the Milieu, so that warm rents remain affordable
BMBF project "Urban Heat Turnaround" by the Institute for Ecological Economy Research, law firm Becker Büttner Held and Berliner Wasserbetriebe presents recommendations

The advancing climate crisis, the war in Ukraine, the associated uncertainties and price increases - there are many reasons to get out of oil and natural gas as quickly as possible when it comes to heating. In order for the heat transition in cities to progress faster and more effectively, energy experts of the project "Urban Heat Transition" recommend a mix of measures: cities should develop a spatial heat planning and tap all sustainable heat potentials such as wastewater heat. In addition, they should expand district heating, create neighbourhood heating networks - especially around public buildings - and support fair energy refurbishments in protected areas. Funded by the Federal Ministry of Education and Research (BMBF), the Institute for Ecological Economy Research (IÖW) developed recommendations for states, cities, municipalities and neighbourhood managers together with the law firm Becker Büttner Held (BBH) and the Berliner Wasserbetriebe as well as representatives of the Berlin Senate and district administration.
Using Berlin as an example, the research project investigated central aspects of a climate-neutral heat supply. So far, the capital still depends on natural gas for two-thirds of its heating, heating oil for 17 per cent and coal for five per cent. "Berlin is facing challenges in the heat transition that other cities are also familiar with: Rising rents fuel fears of expensive renovation projects, the change has not yet reached the neighbourhoods despite funding pots and technologies such as the use of wastewater heat are only slowly being implemented," explains project manager Dr Elisa Dunkelberg from the IÖW. "In two and a half years of practice-oriented research, we have compiled solution strategies that should not be missing from any urban heat planning."

Higher thermal insulation standards also in areas protected by urban development law

The next heating bill will show tenants how expensive it is to depend on fossil fuels. Even if the markets calm down, the CO2 price will rise. That's why energy-efficient renovation that goes beyond the legal minimum standards can also be worthwhile from the tenants' point of view: If landlords use subsidies and allocate the modernisation costs fairly, the warm rent remains stable or can even decrease, as the researchers have calculated.

Especially in areas of social preservation, municipalities should allow more ambitious refurbishments: "In Berlin's 70 or so social preservation areas, ambitious energy refurbishments have rarely been approved so far. The same applies to a change from gas floor heating to renewable energies or district heating," says Charlotta Maiworm from BBH. "In order to keep rents affordable in the long term, these projects should be approved - but only under certain conditions or stipulations, such as that the costs for tenants may not be higher than the measures according to the regulatory minimum standard." The research team summarises in a guideline what municipalities and neighbourhood managers should pay attention to.

Alternative heat sources: Wastewater heat & Co.

In order to use resources efficiently and minimise energy imports, local heat sources must be used extensively. While some cities have great potential in individual areas, such as Munich with geothermal energy and Hamburg with industrial waste heat, other cities such as Berlin must exploit all potential and aim for a broad mix of environmental heat pumps, commercial waste heat, direct electricity use and biomass.

One heat source that is available all year round in all cities and only needs to be "tapped" is wastewater heat: it could be an important building block in the future energy mix and, for example, cover up to five per cent of the heat demand in Berlin in the future. "For their municipal heat planning, cities need information about where and to what extent wastewater heat is available and how it could be used," says Michel Gunkel from Berliner Wasserbetriebe. "In the 'Urban Heat Turnaround' project, we have therefore prepared this data in a geo-based tool - the wastewater heat atlas - which we are currently testing in an internal test phase."

Heat planning and district heating networks

The information from the wastewater heat atlas must be merged with other data, such as heat demand, for heat planning. The goal of heat planning is to find out where climate neutrality can best and most cost-efficiently be achieved with which future heat supply. District heating makes sense where renewable heat and waste heat potentials exceed the demand of individual buildings. "To shoot for local heat sources, public buildings play a central role," Elisa Dunkelberg emphasises. "If a large wastewater heat pump is installed there, for example, it can also supply surrounding houses via a neighbourhood heat network." Whenever public buildings are due for heating changes or renovations, it should therefore be checked whether a district heating system is possible. Sample calculations show that with the planned federal subsidy for efficient heating networks, neighbourhood heating can be offered at competitive prices. The researchers also propose measures to facilitate implementation - such as model contracts and criteria catalogues.

At the conference "Urban heat transition - How cities can supply themselves with climate-neutral heat" at the end of March, more than 300 administrative staff and neighbourhood managers from various cities learned about the current state of research on the urban heat transition. Guides, infographics, publications and materials on the conference: www.urbane-waermewende.de.

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More information

Guide: Energy-efficient refurbishment in Berlin's protected neighbourhoods: How tenant and climate protection go together (www.urbane-waermewende.de/publikationen-1)
Research report: Dunkelberg et al. (2022): Public buildings as nuclei for climate-neutral district heating (ibid.)
► Infographics of the project: www.urbane-waermewende.de/publikationen/infografiken

About the project

The Urban Heat Turnaround project was coordinated by the Institute for Ecological Economy Research (IÖW). The joint partners were Berliner Wasserbetriebe and the commercial law firm Becker Büttner Held (BBH). The Senate Department for the Environment, Mobility, Consumer and Climate Protection, the district of Charlottenburg-Wilmersdorf and the district of Neukölln were involved as municipal partners. The project was funded by the Federal Ministry of Education and Research (BMBF) in the funding initiative "Sustainable Transformation of Urban Spaces" of the Social-Ecological Research (SÖF) funding priority.

www.urbane-waermewende.de

Source: IÖW-PM of 26 April 2022

Keywords:
DE-News, Renewable, Climate protection, Communities, New books and studies, Quarters, Solar thermal, Thermal insulation