In various areas HafenCity is making big contributions to sustainability
Halting global warming, protecting biodiversity and tackling a host of other ecological challenges will only succeed if households and companies are in a position to shape lifestyles and commercial patterns in a sustainable way by creating suitable economic parameters and appropriate infrastructure. The development of cities is of particular importance in this context, as 77 percent of the population living in Germany is concentrated in conurbations. Since a large part of our cities has already been built and the existing stock can only adapt gradually, the importance of neighborhoods that are at the planning stage or under construction is that much higher.
It is not only urban development and infrastructure that contribute to the sustainability of HafenCity, but also each individual building. The financial amount of approximately €10 billion invested by developers alone, as opposed to approximately €3 billion spent by the public sector, demonstrates the crucial importance of the properties being built in terms of the ecological quality of the district, but also its social and cultural quality. Since an intelligent, advance purchase strategy for existing properties meant most of the land in the HafenCity area was owned by the city at the start of development, it has since been possible to use the allocation of land to developers as a central control mechanism via the process for awarding planning options and via concept tenders. This approach provides, among other things, for high architectural quality in HafenCity, street level space for retail and cultural uses, diversified housing offers with price differentiation, communal areas and the financial burden of neighborhood management. The focus will thus be on environmental sustainability aspects. These include the high building standard of the HafenCity Ecolabel and pilot projects going beyond it, a smart mobility concept and sustainable heating supply.
HafenCity’s first buildings meet the high statutory building standards in Germany and are already contributing to a much more sustainable building stock in Hamburg as a result. As global warming continues, however, this standard is no longer adequate for new neighborhoods. Newly built neighborhoods must not only compensate for existing neighborhoods, but also act as test beds for new technical possibilities. They must therefore also exceed the targets of the international Sustainable Development Goals or the Hamburg Climate Plan.
Since 2007, HafenCity Hamburg GmbH has been awarding the HafenCity Ecolabel, the first certification system in Germany for sustainable construction, which initially encouraged developers to build especially sustainable buildings on a voluntary basis. Certification was made a condition for the award of planning options on building plots in 2010, and since 2017 only buildings to the highest platinum standard have been planned in eastern HafenCity. So far 36 buildings in HafenCity have been certified or pre-certified with the Ecolabel. In 2017 the Ecolabel was thoroughly reworked. In terms of its aspiration and system, the HafenCity Ecolabel is similar to other certification systems introduced later – such as that of the German sustainable building council (DGNB), of which HafenCity Hamburg GmbH has been a member since its outset.
The most important substantive goal of certification is the reduction of CO2 consumption in the production, operation and deconstruction of the buildings. The focus is not only on reducing energy requirements, but also on the generation of energy from renewable sources by the building itself. Therefore, the requirements in the area of energy consumption fall short of the specifications in the 2016 German energy saving regulations (ENEV) only to the extent that they lead to a recognizable further reduction of CO2 emissions in the life cycle of the building. Since a considerable part of a building’s CO2 emissions is already generated during the manufacture of the building materials, reducing CO2 emissions during operation can lead to an increase in CO2 emissions during the building life cycle due to additional constructional effort.
In the Elbbrücken and Strandkai neighborhoods, several buildings will be constructed in the coming years that will take the lifecycle assessment of CO2 emissions well beyond the level of platinum certification. In particular, the aim is to reduce the so-called gray energy – i.e. the energy that has already been used in the production of the building materials. Buildings are being constructed from wood, from a mixture of wood and concrete, and with concrete-saving building methods. Recycled building materials and CO2-reduced steel are used. Due to the documentation of the materials used and the separability of composites, the materials of the new buildings themselves will also be recyclable. HafenCity Hamburg GmbH aims to set an example in its own newly planned office building and is designing a building that will have zero CO2 emissions over its life cycle. These highly innovative and ambitious requirements for ecological sustainability do not come at the expense of mixed use and the proportion of subsidized housing in any of the buildings. The projects play an absolutely pioneering role in terms of a comprehensive understanding of sustainability.
The Ecolabel therefore looks at more than just the energy balance. Comfort and convenience in the building play a role, as does the approach to public resources in the surrounding area. Participation in neighborhood-related mobility concepts such as the smart mobility concept for eastern HafenCity is also mandatory.
Green heating power
So that the high energy requirements for the buildings can also be met in terms of infrastructure, all the buildings in HafenCity must be connected to two district heating networks operated by private network operators. In western HafenCity, this is the Hamburg district heating network operated by Vattenfall, which is supplemented in HafenCity by solar thermal power (1,800 m² of solar thermal systems are installed on rooftops in western neighborhoods, providing 40 percent of hot water requirements there), as well as other CO2-reducing generating plants (such as the steam turbine in the HafenCity heating plant). Since 2002, this has enabled an efficient energy mix that, with CO2 emissions of 175 g/kWh, clearly outperforms the conventional environmental standards-compliant natural gas-based heat supply whose CO2 emissions average 240 g/kWh.
Thanks to its decentral, modular local heating supply network, eastern HafenCity can boast contractually guaranteed CO2 emission rates of only 70 g/kWh. Actual CO2 emission rates are considerably lower, at approx. 35 g/kWh under current plans. The concept is characterized largely by the use of emission-free industrial waste heat and renewable energy. The proportion of waste heat in consumption is around 90%. A modern combined heat and power plant in Oberhafen, operated with balanced biomethane, covers part of the remaining heat demand in efficient cogeneration - only the peak load is generated by conventional gas-fired boilers. Industrial waste heat comes from the nearby Aurubis copper refinery, where excess heat from gas scrubbing is now no longer discharged unused into the Elbe. A further energy center at Peute with buffer storage tanks and boilers ensures that the highly fluctuating waste heat can be drawn down evenly and securely. The primary energy factor is 0.17. In eastern HafenCity alone, this will save around 12,000 metric tons of CO2 per year compared with a natural gas-based heat supply when complete.
HafenCity’s mobility concept prioritizes walking, cycling and public transport (subway, rapid transit, buses and ferries) not only for ecological reasons but also to enhance the quality of the urban environment. This also includes the goal of substantially reducing car ownership in HafenCity. Firstly, this will reduce the construction costs of large underground garages and the need for parking spaces in public areas. Secondly, people who for various reasons are dependent on a car and own one will then use it for the vast majority of journeys. Since owning a private car entails high fixed costs, the distances traveled in the city do not have a significant cost impact. The purchase of a ticket, on the other hand, is perceived as an additional cost.
The smart mobility concept for eastern HafenCity therefore aims to enable residents and workers to dispense with a private vehicle and weigh up the options of cycling, public transport and car sharing according to the situation. In the underground garages of the private buildings, a cross-district station-based car sharing system is being set up as a dependable service for all residents and workers under the terms of the individual property purchase agreements. The system contributes to reducing both moving and stationary car traffic as well as improving the amenity value of public areas through reducing CO2 emissions and noise pollution.