The buildings in Stockholm Royal Seaport have been designed with a high performance building envelope and has through these passive measures achieved a good energy performance.
To achieve a high energy performance there must be well insulated facades, ceilings, floors, and windows, as well as energy efficient installations. In addition to a high-performance building envelope renewable energy will be produced locally on the roof of the buildings.
Energy calculations have been submitted during the buildings’ different design stages, the energy calculations are required to be updated and submitted for each phase. Once the building has been in operation for two years, metered energy consumption will be submitted, and the results can then be compared with the calculated values. Also, construction site sheds must be energy efficient, and all electricity used during construction has to be eco-labelled. Embodied emissions of built-in material should be minimized.
All figures relate to the kWh/m² Atemp year, and include energy for heating, domestic hot water, property energy, and cooling. Supplements for air circulation in miscellaneous rooms may be made in accordance with the Swedish National Board of Housing, Building and Planning instructions.
The results of the developers vary, but many of them achieved good results. Energy performance has gradually improved as the project progresses.
Energy performance has gradually improved, at the same time, the requirements of the Swedish building code regulations, have tightened. However, only the purchased energy is reported.
In Norra 1 and Västra, the energy commitments were voluntary, and the developers’ data has not been reviewed by the city of Stockholm.
Diagram 3.4 Average energy performance per phase, kWh/m2 Atemp and year
Norra 2 was the first phase that imposed strict energy requirements, with a weighting factor 2 for electric heating. All developments are connected to district heating and have a ventilation heat recovery system (air-handlings unit). Form factors, high-performance building envelope, and the proportion of windows/glassed surfaces vary between buildings.
Conditions that were less beneficial could be partially compensated by using technical components like solar panels, solar cells, and waste water heat exchangers. In this phase, it was possible to compensate with all self-generated energy. Differences of estimations of hot water due to a new Sveby-version (Swedish industry standard for energy) – 25 kWh/m2 Atemp – resulted in the need of compensating additional 5 kWh/m2 Atemp and year.
Measued energy performance have been submitted by more than half of the developers. The city of Stockholm have reviewed the results, and it has been noticed that so far, no developer comply with the requirements. All developers report problems with metres and commissioning of systems, as well as heat losses, which, were not detected until the warranty inspection. Fine-tunings and adjustments of the systems are in progress, a reassessment will take place in a year.
6 of 9 developers have, two years after occupation, reported metered energy performance values. So far, none of the properties comply with the requirements, and deviations have occurred because of measurement errors, and heating system problems (ventilation, thermal bridges, losses from warm water circulation, etc). Troubleshooting, measures, and adjustments will continue into 2019.
The change of requirements since Norra 2 means that it is no longer possible to compensate with self-generated energy in the energy calculation. In this development phase, a special land allocation competition for a plus energy building i.e. a house that produces more energy than it uses over the year, has been organized.
The estimation for hot water use increased by 5 kWh/m2, year. Some developers chose to ensure their compliance with the requirements using a geothermal heat pump and/or installation of waste water heat exchangers, instead of optimizing the building envelope; despite a weighting factor 2 for electric heating. Greater focus has been put on hot water circulation and other system losses, and thermal bridges that have proven to be a very important part of the energy balance. Some developers have geo-heat recovery, with a preheating of the incoming air in the heat recovery. Half of Brofästet’s developers have an energy system combining geothermal heat pump, with district heating.
Gasverket has several existing buildings with high cultural-historical values. The challenge has been to balance the historic values with energy efficiency measures. To reach the requirements, buildings are renovated with well insulated floor joists and roofs, as well as energy efficient windows and ventilation systems. New buildings are equipped with well-insulated building envelopes with heat recovery, and district heating.
Gasklockan 4 is designed with efficient geothermal heat pumps, district heating, and free cooling from the geothermal system. To minimize ventilation losses, each home will have on-demand ventilation The average u-value is under investigation, but it is uncertain whether it meets the requirement or not.
In Södra Värtan even more strict energy requirements are imposed.
A land allocation competition has been organized and one of the selections criteria’s was to embrace lower energy performance, like 45 and 40 kWh/m2 Atemp net energy. Calculated design values are generally below the requirement levels, but these developments are still in early design stages. In Södra Värtan the focus will be efficient hot water circulation and minimizing other system losses.
The requirements in Västra are based on voluntary agreements, the metered energy was reviewed by the city two years after move-in. The results are, by a wide margin, below the Swedish building code regulations, and are based on values corrected according to normal years.
The requirements in Norra 1 are based on voluntary agreements, and the metered energy performance was reviewed by the city two years after move-in. The results are, by a wide margin, below the Swedish building code regulations, and are based on values corrected according to normal years.
All requirements are for kWh/m2 Atemp and year.
All property developers from phase Norra 2 and onwards have installed roof mounted solar to locally generate electricity or heat. Solar PV produce electricity and solar collectors produce heat. Most the property developers chose to install solar PV.
All new properties have installed solar and produce local renewable energy. Buildings in Norra 2 exceeded the solar requirements, the likely reason for this is that the developers were credited for this in the energy balance calculation. At later stages, the results are close to the requirements, except for the plus energy building of Stockholmshem in Brofästet, this building is exceeding the requirement.
All developers achieved or exceeded the set requirement.
There are no solar panels on existing buildings in Gasverket, due to the historical value of the buildings. The solar electricity that SISAB’s school produce covers both new and already existing buildings.
Requirements in Västra are based on voluntary agreements. Four of the eleven properties have on-site solar power. HSB is the only developer in the stage that has reported a production of 2,5 kWh/m2 Atemp.
The requirements in Norra 1 are based on voluntary agreements. One developer, Reinhold Gustavsson, has local energy production, through a “ground heating system” on the roof.
In the Stockholm Royal Seaport, the simplified model for life cycle analysis (LCA) developed by IVL has been tested by the developers. The city’s aim is to create an industry awareness of materials with high carbon footprints, and as to learn about comparability and, eventually, be able to specify requirements with key figures.
The vacuum waste collection system has been streamlined, energy efficient site sheds have been used. Eco-labelled electricity has been used for construction sites and site sheds. The embodied carbon calculations have been performed in order for the climate impact to be minimized at a later stage.
Energy use in the vacuum waste collection station has been minimized by 30%, by optimizing the ventilation system. Energy use per ton of waste does not yet meet target levels, as the system is not fully developed yet, see table 3.1 below.
In 2017 and 2018, target levels for energy use for plastics and newspapers have declined. Energy use for residual waste has slightly increased because of leaking valves in the system. This issue has been resolved, and energy use should be reduced in the coming years. The leak affected the electricity use of the residual waste the most, since this is the largest waste fraction.
|Target level / turn-out||Residual waste||Plastic||Newspapers|
|Target level/ turn-out||Residual waste||Plastic||Paper|
|Target level, kWh/ton||95³||300||110|
|Turn-out 2018, kWh/ton||140||349||249|
|Turn-out 2017 kWh/ton||113||401||250|
Stockholm City Environmental requirements regarding fuels, vehicles, machinery, management of chemical products, as well as materials and goods are implemented in the Royal Seaport.
The energy used in construction work is a small part of the total lifecycle energy. Fuel largely come from fossil fuel sources. All electricity is 100% renewable, and all diesels are of environmental class 1.
|Etapp||Norra 2||Norra 2||Brofästet||Brofästet||Gasverket||Gasverket||Gasklocka 3 och 4||Gasklocka 3 och 4||Västra||Västra||Norra 1||Norra 1||Jackproppen||Jackproppen||Ängsbotten||Ängsbotten||Totalt|
|Norra 2||Norra 2||Brofästet||Brofästet||Gasverket västra||Gasverket västra||Gasklocka 3 och 4||Gasklocka 3 och 4||Västra||Västra||Norra 1||Norra 1||Jackproppen||Jackproppen||Ängsbotten||Ängsbotten||Totalt|
|Temporary site-access roads||1,5||0,7||4,7||1,6||N/A||N/A||N/A||N/A||55,5||0||IU||IU||N/A||N/A||73,2||12,7||149,9|
|Completion of public open space||4,3||0,8h||N/A||N/A||N/A||N/A||N/A||N/A||5,7||0,6||8,3||1,5||N/A||N/A||N/A||N/A||21,2|
To assess the embodied carbon from material and construction choices between the different stages, the city compiled the main material types and quantities, see the table below.
Soil conditions in Västra were unfavourable, and therefore required that piled decks were constructed. A piled deck consists of concrete and steel, which have a high impact on the climate.
|Aspect||Amount, unit||Norra 1||Västra||Norra 2|
|Aspect||Amount, unit||Norra 1||Västra||Norra 2|
|Amount of material||Concrete, tonnes||15 200||47 356||2 705|
|Steel, tonnes||1 096||5 837||358|
|Asphalt, tonnes||3 300||4 394||3 347|
|Totalt, tonnes||19 596||57 587||6 410|
|Climate impact (tonnes CO2)||Concrete, tonnes||1 430||4 455||254|
|Steel, tonnes||320||1 704||105|
|Totalt, tonnes||1 865||6 313||476|