Detailed guide to sustainable residential development
ESG in other Skanska divisions
The Skanska Group's climate goal
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ESG
Environmental
Social
Governance
Skanska’s Scandinavian roots form the basis of our commitment to the environment, corporate social responsibility, and governance. We took the experience, knowledge and values developed in Scandinavia and adapted them to the specific conditions of Central Europe and the Czech Republic.
Detailed guide to sustainable
residential development
In our Climate Plan for Skanska Residential Development in Central Europe we address all aspects of decreasing greenhouse gas emissions.
We analyze the emissions we produce in three key areas
Direct emissions caused by the operation of company vehicles and the consumption of natural gas
Indirect emissions from purchased electricity for our offices
Emissions arising within the life cycle of apartment buildings and emissions associated with used materials, including business trips
We set ambitious targets
by 2045
-70 %
by 2030
Become carbon neutral
Cut direct emissions by 70% by 2030
Cut emissions caused by the life cycle of residential buildings by 50% by 2030
We regularly update our action plans and set our own high targets, which also meet Skanska’s global target. Since we’ve been focusing on sustainable development for over a decade, we’ve got a bit of a head start. The Financial Times regularly puts us with the European leaders in reducing carbon footprint. We also present our results and examples of our work each year in our annual Sustainability report.
[E] Environmental sustainability
[S] Social responsibility
[G] Governance
[E] Environmental sustainability
We use clean energy and recycled materials
We focus on increasing buildings’ energy efficiency and the recyclability of the materials used.
The energy for heating, lighting and controlled ventilation over the lifetime (50 years) of our residential buildings accounts for more than half of all emissions, which we are continually striving to reduce. Manufacturing the embedded materials accounts for another third. That’s why we make active use of renewable energy sources and recycled and recyclable materials, and we design our residential projects to be as energy efficient as possible. As a result, from an energy standpoint the projects we design approach the passive standard. In the future we plan to develop passive, zero energy and positive energy buildings.
PED values for individual projects are affected by a combination of large energy saving systems, construction processes, new technologies, and even simple solutions that have an impact on the construction and use of the residential building during the course of its 50-year life cycle. In this case, lower values on the curve mean a more energy-saving and sustainable residential project.
We track our success over time on the PED (Primary Energy Demand)
This refers to primary energy from renewable resources where the total energy necessary for building operations (heating, cooling, lighting, ventilation, air humidity adjustment, preparing hot water) is multiplied by the primary energy coefficient for that type of energy (e.g. natural gas, electricity, heating oil, district heating).
Classification label
The walls of our residential buildings hide a whole complex of technologies and systems providing comfort and savings to residents. We present all these solutions simply as a Classification label. It contains information about the building’s energy consumption, installed technologies, savings and sustainability for each phase of the project. It compares our parameters with the current legislative requirements, allowing users to easily compare individual components such as building performance and sustainability.
PENB results show that all our current projects are more energy efficient (by 35% on average) than the legislative requirements at the time their approval process was completed.
The energy consumption and sustainability assessment is available on the website for each residential project in the section Apartments – “Search for actual savings”.
Building Energy Performance Certificate
A key reference in the energy balance is the PENB (Building Energy Performance Certificate). Under Act No. 406/2000 every new construction project is required to prepare this document. Its primary benefit lies in providing a unified methodology for classifying the energy needs of real property. It calculates the consumption of all energy entering the building for heating, cooling, preparing hot water, lighting and ventilation. The PENB takes into account the efficiency of all technical systems as well as the auxiliary energy needed to operate the auxiliary technical systems such as pumps or systems management. It does not, however, assess the energy connected to direct consumption by individuals, i.e. electricity consumption from electrical appliances such as dishwashers, washing machines, or freezers. The PENB score makes it possible to compare selected buildings to each other and make an objective choice. For each project we openly publish the full version of the Building Energy Performance Certificate.
Věděli jste, že 75 % nově dokončených bytových domů v České republice za rok 2022 spadá do kategorie energetické náročnosti PENB – B a pouze 6,2 % do mimořádně úsporné kategorie PENB – A? Data vychází z evidence ČSÚ.
Comparisons should consider most of all the energy performance category the selected building falls under. The best residential projects are found in section A (very efficient) and the worst in section G (very inefficient). After that one should take a look at the percentage comparison with the “reference building”, the legislative standard valid at the time the building’s approval process was completed. To take phase two of the Modřanský cukrovar project as an example, we can see that it holds a PENB rating of A (very efficient) and comes in at 44% more efficient than the 2022 legislative standard in total energy. That is an excellent result, and from an energy balance standpoint this residential project approaches the passive standard.
Another important indicator is the specific heat demand. It shows the amount of heat that must be supplied to the building to achieve the required temperature regardless of the heating system or heat source. The main factors affecting this demand are the building construction and its thermal insulation properties. According to the results of an investigation by the Czech Statistical Office for 2021, 80% of all energy in households goes to heating and hot water, with the rest going to lighting, cooking, cooling and other end uses.
The most important aspect, however, is the total energy supplied, which combines the total energy demand into one and acts as the sum of all energy components (heating, hot water, lighting, ventilation, cooling) entering the building. The PENB gives the calculated values for ordinary behavior and not including outlet consumption, so it cannot be taken as final energy consumption. The PENB can only act as a rough guide if you want to determine what your operational costs would be.
The real consumption will always differ from the calculation, partly because the PENB values do not include outlet consumption and partly because each apartment has a different number of users with different habits regarding appliance use, level of heating, and intensity of lighting.
To compare the needs of individual buildings see the auxiliary graphs in the PENB showing the share by energy carrier.
Please keep in mind that the building and apartment are only as energy-saving as their occupants.
Other building parameters
The classification label also gives detailed parameters showing factors such as the average heat transfer coefficient, total energy demand for forced ventilation, and total energy demand for hot water. All data comes from the PENB (Building Energy Performance Certificate), which is prepared by an independent energy specialist and made available for download on the residential project website.
Water savings
At Skanska we see water as a precious commodity, and so we try to manage it as efficiently as possible in all our projects, from rainwater to utility or recycled (grey) water. We equip all apartments with energy-saving fittings (faucets, shower heads) and a water recycling system that reuses drinking water to flush the toilet and wash clothes in the washing machine. We try to use as much rainwater onsite as possible to avoid wasting drinking water. Water management represents an important part of the classification label, which includes the anticipated savings of the selected building.
Taking the second phase of the Modřanský cukrovar project as an example, we can see a carefully designed drinking water management system that meets the LID concept (Low Impact Development) to conserve water on location. In addition to toilet flushing, recycled (grey) water can also be used for washing machines, not even a drop of rainwater ends up in the sewer system, and every faucet has a water-saving fitting. Overall, this amounts to a reduction in drinking water consumption of about 59%, i.e. 64.4 L of water per day per resident.
This is the anticipated saving based on a comparison of the data for average daily drinking water consumption per person for various activities in Prague households. The average daily amount is listed on the Pražské vodovody a kanalizace (Prague water supply and sewer system) website (111 liters of drinking water per day in 2022) as well as a more detailed data breakdown (e.g. for the toilet, personal hygiene, watering plants, drinking). In the calculation we also compare ordinary water fittings with the water-saving fittings we install in our residential projects. In buildings with the recycled (grey) water management system we anticipate 100% use of that water for toilet flushes and washing machines. The water saved via flushing toilets using recycled (grey) water is also compared to the data from residential projects already completed.
Based on the average daily consumption from Pražan we divided the estimated 40 L (personal hygiene + showers) in a 25/75% split, with 30 L falling to showers. For the calculation without water-saving measures we consider water flow of 13.5 L/min, while for the calculation with water-saving measures we consider water flow based on the shower sets installed at each individual project.
Energy-saving technologies
No residential building can meet the parameters for sustainable and energy-saving buildings as fully as possible today without modern technologies. They bring significant savings for apartment and building owners. In order to keep them as efficient as possible, it is important to give them the necessary care and regular maintenance over the long term.
Solar power
Taking the second phase of the Modřany sugar refinery as an example once again, we have 90 solar panels on a total area of 233 m2 with an installed capacity of 49.5 kWp, which is the maximum possible capacity under the current legislation for residential buildings that does not require a license from the Energy Regulatory Office. In order to calculate the approximate savings, we need to know how many MWh a solar panel with a capacity of 1 kWp can generate, considering that the conditions in the Czech Republic indicate that this is approximately 0.95 MWh of electricity. This brings us to approximately 47 MWh of electricity savings per year. According to data from ČEZ, the largest electricity distributor in the Czech Republic, one household in the Czech Republic consumes an average of 3 MWh of electricity per year. Since the second phase of the Modřany sugar refinery project offers 126 apartments, the savings amount to an average of 0.37 MWh of electricity per apartment per year. Each apartment thus achieves approximately the same emissions savings as an average gas car traveling to Croatia and back (approximately 1650 km). Pretty impressive, right? Multiply that by 126 apartments and you have a noticeable contribution to the environment from just one apartment building in Prague.
Solar thermal system
Returning to the second phase of the Modřany sugar refinery again, we have 63 solar collectors with a planned gain of 434.1 kWh/m2 per year on a total area of 153 m2. Photothermal panels use solar power to heat water and significantly decrease gas consumption as well as the building’s carbon footprint. The photothermal system works on different principles than photovoltaic panels, so they should be kept distinct from each other.
We have been installing photothermal panels in Skanska residential projects since 2012, so we have a great deal of data about their efficiency. Our calculations show that solar energy provides an average of 33% of the energy needed to heat hot water.
For the second phase of the Modřany sugar refinery the annual savings from photothermal panels represents approximately 66.4 MWh of energy, which amounts to about 10% of the planned needs for heating hot water in the building.
If we divide to find the results for one average apartment, the annual savings come to approximately 0.53 MWh. The photothermal system alone makes each apartment save as much in emissions as about 24 full-grown trees per year. This makes the whole apartment building equivalent to a forest.
Recovery units
Recovery is a simple system that pre-heats the fresh air being brought in using the waste heat during ventilation. In addition to ensuring good air quality inside the building, this system also saves energy consumption for heating, leading to lower CO2 and operating costs. The recovery unit also has a positive effect on residents’ health, as it captures particles of just thousandths of a millimeter and prevents the intrusion of dust particles, allergens, etc.
Recovery of waste heat from grey water
This new technology makes use of the heat from waste water drained from baths, showers and washing machines at a relatively high temperature. That heat can then be transferred through a heat-exchange surface (like a pipe) to cooler water in a neighboring pipe, heating the cooler water. This results in efficient energy savings, cutting gas consumption an average of 6.7% for preheating non-drinking water.
External shading
External shading in the form of outdoor blinds or shutters is intended to provide shade for the greatest possible area in the summer and a smaller area in winter, when the sun’s rays fall at more of an angle and the sun is lower in the sky. In summer, well-designed external blinds naturally lower the temperature in the apartment by 5-7°C, partially removing the need for air conditioning. In winter they act as an added layer of insulation, again making a positive difference in lower energy consumption and lower CO2 emissions.
Water-saving fittings
Choosing the right fittings depends on the type of building and the needs of its future users. We also consider BREEAM sustainability criteria when developing our projects. To reduce water flow we use equipment such as aerators, pressure-reducing valves, and adjustable nozzles that can be installed on shower heads, bathroom sinks and kitchen sinks. These fittings form an important part of our efforts to conserve drinking water and help apartment residents lower their water consumption by up to 32% without any reduction in their comfort.
Adaptation and mitigation measures
Blue-green infrastructure
In the context of residential construction, blue-green infrastructure has to do with planning and implementing environmental components into the urban environment and residential areas. The term “blue-green” refers to the combination of water-based, green and sustainable components that have a positive influence on the environment and quality of life. Typically, this involves green roofs with a retention layer, swales and permeable surfaces, accumulation tanks, retention tanks and other measures that can retain all rainwater on location and help it to gradually evaporate and absorb. This lowers the impact of heat islands in the city. Today blue-green infrastructure is the standard for public areas at all Skanska residential projects.
Green roofs
Green roofs have an ecological, economic and social benefit, and they look great as well. Vegetation cover on roofs acts as an added layer of heat insulation and can lower the temperature on the roof by nearly 50%. In summer green roofs reduce air conditioning costs for apartments on the top floor, while in winter they prevent heat loss. They also improve sound insulation by up to 6 dB. From an economic standpoint, another major benefit is the increased lifespan of the roof, which vegetation cover extends to up to double the original lifespan. Green roofs capture CO2 emissions from the atmosphere, reduce the heat island effect in cities, and promote local biodiversity. Skanska projects have been making use of green roofs on residential projects for over 15 years. A more recent trend is combining green roofs with solar panels, known as biosolar roofs.
Biodiversity
It sounds like a buzzword, but it’s actually incredibly important. We incorporate elements for creating biotopes in our projects: birdhouses, feeders, lizard walls, and refuges for insects and pollinators. We plant nectar-bearing plants and trees because they attract pollinators and have a positive impact on the local microclimate.
Biowaste
Our projects include not only recycling bins, but also biowaste and compost bins. The compost is then available for anyone interested in gardening in the shared plots or in their balcony flowerbeds.
Charging stations for electric cars
The average Czech citizen produces two tons of CO2 per year in modes of transport alone. In order to improve this number, we equip our apartment buildings with charging stations for electric cars and stands for shared bicycles. We take care to abide by current legislation, construction rules, and fire regulations.
Recycling water and materials
Recycled (grey) water
The Czech Republic has the fourth lowest water supply in Europe, meaning water conservation is one of our top priorities. One of our most effective tools is a grey water management system allowing residents of our buildings to recycle drinking water and save about a fourth of their drinking water.
We send water from baths, showers and bathroom faucets to a utility room in the basement of the building, where it undergoes cleaning in a four-chamber system and is then sent back to toilet tanks. The extremely thorough cleaning process, which includes mechanical, biological and chemical cleaning, results in high-quality recycled water. Our measurements show that grey water can replace up to 25% of drinking water, leading to savings on water and sewage fees. We first put this new technology to work in the Czech Republic in the Botanica apartment buildings in Jinonice, Prague, which have saved over 10 million liters of drinking water in four years.
The system is easy to operate, highly efficient and requires minimal operating costs. With this positive experience using the system, we plan to deploy it for washing machines in the Modřany sugar refinery, again for the first time in the Czech Republic. This can reduce daily drinking water consumption by an additional 6%. The heat from grey water can also help recovery units pre-heat utility water in the building.
Rebetong
Rebetong, an alternative concrete developed by ERC-Tech and Skanska, uses up to 100% processed construction rubble instead of natural stone. We can even make it using brick rubble, a recyclable that has been underutilized in construction until now. Compared to standard concrete, Rebetong saves approximately 8% of CO2, and we have been using it for our residential projects since 2019. At the Modřany sugar refinery Rebetong serves not only in the load-bearing structures for the building, but also as an uncovered element in the entryways and on the facades of the apartment buildings. We use Rebetong in our projects for up to 20% of concrete structures, saving approximately 1,750 kg of construction aggregate for each m3 of concrete.
3D printing in construction
An important element of sustainable construction involves looking for alternative construction methods, which is why we recently tested 3D printing at Modřany. This new technology is not yet widely used in construction, but it may offer a number of benefits. In this project, a robotic 3D printer printed an atypical room for a shared terrace in the apartment building, all in just two hours on a construction site in full operation. We wanted to test the potential of 3D printing for potential use at a greater scale, since we think it may improve efficiency, safety and especially sustainability. In the future we are considering using this technology for building structures that are usually prefabricated, such as balconies. We also want to make 3D printed facade panels out of recycled concrete onsite in upcoming phases of the Modřany sugar refinery.
Wood as the material of the future
Wood in construction represents another way forward. We are putting it to use for the first time in the apartment building Dřevák in the D.O.K. project in Radlice, Prague. Wood offers countless benefits, key among them reducing carbon footprint, faster construction and greater efficiency in the circular economy. We will be using CLT panels to replace almost half the total volume of concrete, reducing the carbon footprint by up to 560 tons of CO2, 28% less than conventional construction methods. Another advantage of this procedure is the fact that the apartment building will retain another 1400 tons of CO2 in the wood over the course of its lifetime, approximately equivalent to the emissions produced by 345 gas cars per year.
We also prioritize producing energy from renewable resources in all our projects and all our construction sites, applying water-conserving methods and new recycling methods as well. Modern digital tools help us continually improve our internal processes.
[S] Social responsibility
In addition to environmental concerns and transparent governance, we also take social responsibility extremely seriously. We are aware of our role in society and we contribute to making it a better place. Social responsibility allows us to actively support society at large and help solve challenges on a global and local level.
Komunitní centrum Cukrkandl v pražských Modřanech
Supporting communities and residents
in Prague
We take public opinion into account in our work, getting neighbors and residents of the affected districts involved in planning our projects through public participation via in-depth interviews and discussions.
We operate the established Cukrkandl community center in Modřany, Prague, and we provided the facilities for the Colben Center in Prague 9. Our plots intended for future construction serve temporarily as a space for local residents to gather in coffeeshops, sports areas or community gardens. This represents an active contribution to building local communities and promoting integration.
Support for disadvantaged communities
We work to support the most vulnerable among us. The Strom splněných přání project (the Tree of Fulfilled Wishes) connects employees with children, families and senior citizens in care facilities and shelters. Employees have the opportunity to grant specific wishes and give Christmas joy to those who need it.
We respond to current threats. We put together five mobile houses for communities in Moravia affected by tornado and provided them for residents who had lost their homes overnight to use free of charge.
In Libčice nad Vltavou, where we built an apartment building, we contributed to adding community areas by the football field.
Educational activities
We actively raise awareness of climate measures within our organization and among the non-professional public as well. We develop educational programs for our employees and make use of the available communication channels for raising awareness among our clients, partners and the general public.
We partner with organizations that help us pass on our practical experience and knowledge on sustainable topics to other companies and the younger generation. This includes Změna k lepšímu, CZGBC, Nordic Chamber of Commerce, H2Ospodář, UCEEB and many more.
Working with experts helps us get better
We design our residential projects with the help of established experts as well as new voices: innovators, school staff and artists.
If you are one of the above and would like to offer us your ideas, technologies or know-how, please get in touch.
[G] Governance
Building sustainability assessment
and certificate
In order to consider sustainability from other angles – not just energy consumption, but also responsible development, construction, and creation of public outdoor spaces – we began using BREEAM (the Building Research Establishment Environmental Assessment Method) in 2016. We were the first in the Czech Republic to commit to designing and building sustainable housing from the standpoint of the environmental, social and economic sustainability of the project. An independent committee reviews buildings to ensure a decreased carbon footprint, efficient land use, careful conservation of water or use of water-saving technologies, and innovations installed. With this certification, potential residents can also be certain that their chosen Skanska project has premium quality, healthful and sustainable materials with EPS, FSC and PEFC certificates.
The final certificates for Skanska residential projects received the assessment Excellent or Very Good; the Botanica project in Prague 5 holds the top place at present due to careful planning and implementation of modern technologies and sustainable solutions. The BREEAM certificate is issued by an independent auditor who assesses the quality of the residential project based on the project documentation and other materials for assessment. An interim certificate is issued based on the design before construction begins, and then a second audit is carried out after construction is complete to verify the application of all attributes from the project documentation and issue a final certificate.
ISO Certifications
ISO 45001
We hold ISO 45001 certification, confirming our established and maintained system for managing occupational health and safety for developing residential projects, acquisitions, project management, documentation, apartment sales, and customer care.
ISO 14001
We hold ISO 14001 certification, confirming that the system we have established for environmental management for developing residential projects, acquisitions, project management, documentation, apartment sales, and customer care is compliant with current legislation.
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