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Beschreibung

 

Improving energy efficiency of the building stock in a city needs strategic and long-term thinking. Complex ownership structures, market barriers, diversity of building typologies, consumer preferences and multiple stakeholders involved in the construction and retrofitting of a building makes energy efficient buildings a challenge even with the advanced technological developments. However, to realise positive energy districts and reach the ambitious climate goals set forward by cities, zero and positive energy buildings play a critical role.

A variety of initiatives worldwide have proven that while a complex challenge, Energy Efficient Retrofitting of buildings is possible and has huge impact towards greener and more resilient cities.

Problems to be solved

Energy loss in buildings

Use of Inadequate materials

Energy poverty

Transition from fossil fuels

Make technologies affordable

Energy demand in buildings

Nutzen

Contribute to reach globally greenhouse gas emission goals for climate protection. Decarbonize the existing building stock. Increase energetic efficiency in buildings. Reduce holistically energy consumption.

Funktionen

Funktionen helfen Ihnen zu verstehen, was die Produkte für Sie tun können und welche Ihnen dabei helfen, Ihre Ziele zu erreichen.
Jede Lösung hat mindestens eine obligatorische Funktion, die erforderlich ist, um den grundlegenden Zweck der Lösung zu erreichen, und mehrere zusätzliche Funktionen. Diese Funktionen können hinzugefügt werden, um zusätzliche Vorteile zu bieten.

Obligatorische Funktionen
    Reduce building energy demand
    Improve living comfort
Mögliche Funktionen
    Maximize use of local renewable energy generated
    Increase local renewable energy generation
    Maintain good Indoor Air Quality
    Encourage energy efficient user behaviour

Varianten

From the technical perspective, the possible retrofitting measures are vast and can vary according to budget and intended goal. They include, but are not limited to, insulation of the thermal envelope, change of windows and installation in insulation levels, partial or total refurbishment of the heating and hot water systems, and installation of PV panels.

However, from the perspective of the stakeholders, there are some important differences in the decision-making process and engagement initiatives needed to be considered in the city level, when considering a refurbishment programme. Different categories of building refurbishment are presented in the following section.

Once defined which kind of building shall be refurbished, the following technical structures have considerable influence in the energy consumptions of the buildings. Different technologies are available for each of those:

  1. Building Envelopes: building envelopes and deployed insulation are key factors for the energetic behaviour of a building. Higher insulation levels lead usually to a higher energy efficiency of buildings i.e., a lower heat demand.
  2. Ventilation Systems: Ventilation in a building plays an important role for ensuring the wellbeing of its residents. Ventilation systems can be separated into active systems (e.g. mechanical ventilation such as fans) and passive systems (e.g. using the chimney effect). While active systems are using additional energy to move air, some passive systems might require the supply of minimal energy (e.g. for opening/closing windows). Higher insulated buildings cannot only rely on natural ventilation but usually require additional ventilation systems.
  3. Heating and Cooling Technologies: The new building regulations adopted by the EU encourages design of buildings such that it requires little energy for space heating and cooling. While several new technological developments minimise the need for space heating and cooling, the majority of the buildings do need active systems for ensuring comfort and health of the occupants (Heat pumps, district heating/cooling, solar thermal systems, CHP Plants, Absorption refrigerators, Vapour Compression Refrigeration Systems).
  4. Energy Management Systems/Smart Home Systems: Smart homes and energy management systems are key technologies for the implementation of sustainable technologies and the transition of buildings towards an eco-friendly state. The term “smart homes” describes buildings (mostly for residential purposes) that use digital technologies/Internet of Things to offer additional services such as the monitoring of systems, the control of appliances and the optimisation of the operation of appliances (e.g. maximising the usage of onsite-PV generation). While smart homes describe the functionalities on the level of a single residential building, energy management systems (EMS) conduct the operational management of larger energy systems that usually incorporate a multipurpose building or a multitude of buildings and appliances.
  5. Renewable energy generation: Reducing existing building energy consumption consists of two synergistic approaches: (i) to reduce the need for energy through implementation of energy efficiency measures and (ii) to offset the remaining building energy needs through use of renewable energy systems, as Illustrated in Figure 1(Sheila J. Hayter, 2011).

Figure 1 - Demonstration of how combining energy efficiency and renewable energy strategies significantly reduce total building conventional energy use. Source: National Renewable Energy Laboratory

As stated by (Sheila J. Hayter, 2011): “Renewable energy resources commonly used for building applications include solar, wind, geothermal, and biomass. Before selecting an appropriate renewable energy technology to apply to an existing building retrofit project, it is important to first consider a number of factors. Examples of these factors include:

•Available renewable energy resource at or near the building site,

•Available area for siting of the renewable energy technology,

•Cost of energy purchased versus investment for in sitio generation,

•Local regulations affecting renewable energy systems,

•Desire to preserve or not alter existing architectural features,

•Characteristics of the energy profiles to be offset by the renewable energy installation, etc…”

Beschreibung

Cities own, manage, or lease several buildings such as city halls, government offices, hospitals, schools, libraries, museums, social housing, etc. The city council has a high degree of control over such buildings. Ambitious energy efficiency programmes in these buildings can serve as a model for private buildings and inspire citizens to act.

Rahmenbedingungen des Stadtumfeldes

The business model used is an ESCO model, where a local Natural Gas provider acts as an energy services company. In this model the end customer will have a single interlocutor, which manages and coordinates all the agents needed to execute the energy rehabilitation. This company has been offering Energy Services contracts to commercial and industrial customers for several years, including several sports centres in Barcelona, making this project highly replicable in further clients.

Anwendungsfälle

Energieeffiziente Sanierung von tertiären Wohngebäuden in Valla Torg, Stockholm

Im Rahmen des GrowSmarter-Projekts hat die Stadt Stockholm ab 1961 in Valla Torg mehrere energetische Sanierungsmaßnahmen in 6 tertiären Gebäuden durchgeführt, um den Energieverbrauch um 60% zu senken, den Innenraumkomfort zu verbessern und auch die Lebensdauer der Gebäude zu verlängern.

Energieeffiziente Sanierung eines Wohngebäudes - Brf Årstakrönet

Im Rahmen des Projekts GrowSmarter konzentriert sich diese Maßnahme auf die energieeffiziente Sanierung eines Wohngebäudes aus dem Jahr 2007: Brf Årstakrönet, mit 56 privaten Eigentumswohnungen.

Energieeffiziente Sanierung des Gebäudes - Bildungszentrum Escola Sert

Gas Natural Fenosa hat die energetische Sanierung eines Bildungszentrums Escola Sert durchgeführt. Ziel ist es, die technische und wirtschaftliche Machbarkeit der Ergänzung eines tertiären Gebäudes um erneuerbare Energieerzeugung in Form von gebäudeintegrierter Photovoltaik (BIPVs) zum Eigenverbrauch zu validieren.

Energieeffiziente Sanierung von tertiären Gebäuden durch die Stadt Stockholm

Die Stadt Stockholm hat Maßnahmen zur energetischen Sanierung von 2 tertiären Gebäuden durchgeführt: einem kulturellen Zentrum und einem offiziellen Komplex. Beide Gebäude werden als kulturhistorisch bezeichnet.

Energieeffiziente Sanierung von tertiären Gebäuden durch die Gemeinde Barcelona

Die Gemeinde Barcelona hat zwei alte Textilfabriken nachgerüstet, die kürzlich aufgegeben oder als Lagerhaus genutzt wurden. Die Gebäude wurden in eine neue öffentliche Bibliothek (Library Les Corts) und ein Forschungs- und Entwicklungszentrum für Smart Cities umgewandelt, in dem sowohl öffentliche

Energieeffiziente Sanierung des Gebäudes - Sportzentrum CEM Claror Cartagena

Naturgy hat in Barcelona Nachrüstmaßnahmen durchgeführt, um den Energieverbrauch auf über 12.500 m2 Tertiärfläche zu senken. Drei Gebäude mit sehr unterschiedlichen Nutzungen wurden nachgerüstet, eines davon ist ein Sportzentrum, CEM Claror Cartagena.

Energieeffiziente Gebäudesanierung - Hotel H10 Catedral

Im Rahmen des GrowSmarter-Projekts hat Gas Natural Fenosa die energetische Sanierung von drei Gebäuden mit sehr unterschiedlichen Nutzungen durchgeführt, darunter ein Hotel H10 Catedral. Ziel ist es, die technische und wirtschaftliche Machbarkeit einer energetischen Sanierung eines tertiären Gebäudes zu überprüfen.

Energieeffiziente Sanierung von Wohngebäuden durch Naturgy

Naturgy hat Nachrüstmaßnahmen durchgeführt, um den Energieverbrauch von Gebäuden in fast 20.000 m2 Wohnfläche in Barcelona zu senken: Canyelles, Ter, Lope de Vega und Melon District.

Energieeffiziente Sanierung eines Wohngebäudes - Passeig Santa Coloma

Die Gemeinde Barcelona hat die energetische Sanierung eines Sozialwohngebäudes in Passeig Santa Coloma mit 207 Wohnungen und über 14.000 m2 gefördert.

Energieeffizienz in Gebäuden - Norwegische Erfahrung für Gabrovo

Gabrovo hat mehrere Energieeffizienzmaßnahmen durchgeführt, um die ökologische Umwelt und die Lebensqualität in der Stadt zu verbessern.

'Living' Energy Efficient Apartment Complex in Torino

In response to worsening heatwaves in Torino, Italy, the 25 Verde building was built incorporating over 150 trees and plants along with energy efficiency measures to create a unique living space that both addresses climate change adaptation needs and represent mitigation potential.

Energy Efficiency & CO2 saving at City of Antwerp

The City of Antwerp used a power quality improvement system, called E-Power, to improve energy efficiency and reduce consumption in eight of its buildings, with potentially more to come.

Nachrüstung alter sowjetischer Wohngebäude in Tartu

Im Rahmen des SmartEnCity-Projekts ist es das Ziel der Nachrüstung, den Energieverbrauch der Gebäude der alten Sowjetzeit, hrustsovkas, um rund 70% zu senken. Um dieses Ziel zu erreichen, wurden mehrere Energiesparmaßnahmen ergriffen.

Gebäudesanierung

Mailand will die energetische Sanierung des öffentlichen und privaten Wohngebäudes angehen, um bis zu 60-70% des Energieverbrauchs einzusparen und den Wohnkomfort zu verbessern.

Distrikt-Retrofit auf Eskişehir

Mit dem Ziel, durch eine tiefgreifende Nachrüstung einen nachhaltigen Stadtteil in Tepebasi zu erreichen, wurden die Verbesserungen in den Entwürfen der Gebäudehülle umgesetzt. Die Minimierung der Wärmeübertragung durch die Gebäudehülle ist entscheidend, um den Bedarf an Raumheizung und -kühlung zu

Bezirksumbau in Valladolid

Mit dem Ziel, einen Near Zero Energy District in Valladolid zu erreichen, wurde eine Reihe von Maßnahmen konzipiert, die sich auf die Verbesserung der Nachhaltigkeit der 19 Wohngebäude des FASA-Viertels, die Steigerung der Energieeffizienz und die Reduzierung der CO2-Emissionen seiner Gebäude konzen

Energy Retrofitting Through Public Procurement in Nottingham

A UK council housing estate with a high density of fuel poverty has benefited from an energy makeover which bundles technology, aesthetics and a novel approach to public procurement.

Energy Efficient District Heating and DHW retrofitting

Renovation of the whole district heating system (i.e. boilers room, district heating network, heat exchange substations and dwelling interventions)

Public Art Gallery on Retrofitted Apartments in Tartu

Tartu organized an international art competition to make its pilot area for turning Khrushchev-era buildings into modern energy efficient homes into an attractive and unique urban environment for its citizens to enjoy.

Beschreibung

Social housing is owned and managed by public authorities or non-profit organisations or a combination of two with the aim of providing affordable housing to the citizens. In addition to alleviating fuel poverty, retrofitting social housing may also improve public health. The main goal in this case should be to improve comfort while maintaining or reducing costs.

Rahmenbedingungen des Stadtumfeldes

The project Lorystraße 54-60 is a medium-size housing block with 95 flats, completed in 1966 and owned by ‘Wiener Wohnen’ the city-owned social housing operator. The thermal refurbishment reduced the heat energy demand by more than 80 percent. Additionally, a 9 kWp PV-System was installed.

Anwendungsfälle

Refurbishment of a Municipal Housing Estate in Vienna (Social Housing Lorystraße 54-60)

The project Lorystraße 54-60 is a medium-size housing block with 95 flats, completed in 1966 and owned by ‘Wiener Wohnen’ the city-owned social housing operator. The thermal refurbishment reduced the heat energy demand by more than 80 percent. Additionally, a 9 kWp PV-System was installed.

Refurbishment of a Municipal Housing Estate in Vienna (Social Housing Herbortgasse 43)

The municipal housing estate in Herbortgasse 43 was built in 1929 and is under heritage protection. The thermal refurbishment of the façade reduce the heat energy demand by about 75 percent, from 118 kWh/m²yr to approximately 28 kWh/m²yr. 8 additional flats are constructed in a rooftop extension.

Refurbishment of a Rental Social Housing in Vienna

The project ‘Hauffgasse 37-47’, completed in 1987, is a large housing block with 485 flats. It is supplied by a micro-district-heating-grid and currently fired with natural gas. The objectives were mainly focusing on the reduction of energy demand and the integration of renewable energy sources.

Beschreibung

Public authorities own and operate a small share of the buildings in the city. As such, to reach ambitious energy and climate goals, it is essential to encourage residents and commercial organisations to undertake energy retrofitting projects. There is a need to create awareness about the suitable policy measures and financial incentives among the final decision makers: the residents and commercial organisations. For most individuals and organizations, undertaking energy efficiency refurbishment is a big and important decision considering the high and long-term investment.

Rahmenbedingungen des Stadtumfeldes

In the Piemonte region in Italy, where Torino is located, maximum temperatures have risen by 2°C in the last 60 years, with extreme heatwaves projected to continue to increase in the coming century due to global climate change. Buildings, therefore, need to be more resilient to heat, while decreasing their contributions to fossil fuel emissions and urban heat island effect. The project was awarded a 20% discount on construction taxes due to the environmental benefits it provides.

Anwendungsfälle

'Living' Energy Efficient Apartment Complex in Torino

In response to worsening heatwaves in Torino, Italy, the 25 Verde building was built incorporating over 150 trees and plants along with energy efficiency measures to create a unique living space that both addresses climate change adaptation needs and represent mitigation potential.

Wertemodell

Benefits

Name of benefit

Economic

Reduce energy bills due to less energy loses

Generate income due to positive energy balancing

Creation of new jobs for local economy

Increased real estate value

Lower exposure to energy price fluctuation

Environmental

Reduction of greenhouse gas emissions

Support the transition from fossil fuels

Reduction in air pollution

Resources

Reduction of natural resources consume

Transition from fossil fuels towards renewable sources

Social

Include less privileged population in refurbishment programmes

Improved comfort in popular housing

Increase of quality of life due to energy bills reduction

Digital

Enhance energy consumption data

Evidence-based decision making

Enhance user awareness to improve efficiency

Optimize energy consumption due to constant monitoring

Rechtliche Anforderungen

The importance and necessity to deal with the energy efficiency of buildings is enormous. The EU also recognizes this and there are several standards on the energy efficiency of buildings at EU level. Several legislative initiatives have been introduced for building renovation, the most important ones can be mentioned:

  • Energy Performance in Buildings Directive (EPBD, Directive 2010/31/EU amended by Directive 2018/844/EU)
  • Energy Efficiency Directive (EED, Directive 2012/27/EU amended by Directive 2018/2002/EU)
  • Directive of 16 December 2002 on the energy performance of buildings
  • Directive of 6 July 2005 establishing a framework for the setting of eco-design requirements for energy-using products
  • Directive of 5 April 2006 on energy end-use efficiency and energy services
  • Directive of 23 April 2009 on the promotion of the use of energy from renewable sources providing for the promotion of energy efficiency
  • Directive of 21 October 2009 establishing framework for setting of the Eco-design requirements for energy-related products
  • Directive of 19 May 2010 on the indication of energy efficiency labelling and standard product information of the consumption of energy and other resources by energy-related products
  • Directive of 19 May 2010 on the energy performance of buildings

Since the member states had to integrate this directive into national law, there are many standards regarding energy efficiency in the EU on the national level differing from country to country. Some examples of regulations and standards regarding energy efficiency are listed below (United Nations Economic Comission for Europe, Mapping of Existing Energy Efficiency Standards and Technologies in Buildings in the UNECE Region, 2018):

  • France: sets minimum standards for existing buildings and defines the necessary renovations for them.
  • Switzerland: renovated building must not exceed 125 percent of the new building energy limit.
  • Denmark: Solar heating systems must be provided when the expected hot water consumption exceeds 2,000l per day and able to meet 95 percent of demand
  • Greece: 60% of domestic hot water from solar energy

Further standards of various countries can be found in the countries’ information sheets of the report of UNECE. Some regulations already mentioned from North America:

  • Energy Policy Act of 2005
  • ASHRAE9 90.1.2007
  • ICC Energy Conservation 2000-201510
  • Vancouver’s step-by-step plan

Betriebsmodelle

Energy retrofit call for huge initial capital investment with long pay back periods. To accelerate retrofitting, favourable financing and market mechanisms, as well as innovative business models are crucial. The policy interventions highlighted in the previous section have the potential to improve access to financing, de-risk investment and reduce barriers while increasing attractiveness of buildings sector investments. 

While local and national governments can promote specific supporting policies, public resources can cover only a limited amount of total investments. To obtain substantial results, it is necessary to involve private sector in financing energy efficient refurbishments. However, financial institutions face several challenges while in approaching the energy efficiency market. These include the small size, fragmentation of investments, lack of project standardisation which cumulatively result in higher risks.

There are a variety of financing mechanisms available to and being explored by local and state governments including energy service performance contracts (ESPCs), revolving loan funds, leasing, on bill financing, and more. Some of these are explained below:

  1. Revolving Loan Funds: Revolving loan funds (RLFs) are capital pools set aside by the local or national government from which loans can be made for energy retrofit projects. As the loans are repaid, the capital is then reloaned for another project. Assuming that defaults remain low, RLFs can be "evergreen" sources of capital that are recycled over and over again to fund projects well into the future.
  2. On Bill Financing: OBF is a type of loan, introduced first in the USA, that uses the utility bill as repayment vehicle. It helps reduce barriers like high upfront costs in retrofitting and is a possible solution for the owner tenant dilemma. The loan is paid back over time through the monetary savings on the reduced utility bill. The property owner pays the same bill before and after the renovations and the difference due to savings goes to the investor.
  3. Energy Performance Contracting: Energy Performance Contracting (EPC) is a form of financing for capital improvement which enables funding of energy upgrades from cost savings. Under an EPC arrangement an external organisation (ESCO) implements a project to deliver energy efficiency, or a renewable energy project, and uses the stream of income from the cost savings, or the renewable energy produced, to repay the costs of the project, including the costs of the investment (European Commission, 2020).

A key component of successful green retrofit finance programs is the concept of the “cash positive” financial model. This refers to having financial mechanisms which reduce the risk and burden from property owners by ensuring savings right from the first month. The financial arrangements should have interest rates that ensure that the monthly utility bill is reduced by an amount greater than or equal to the monthly repayment instalments providing immediate and steady returns. It has to be noted that legal aspects and underpinnings of various financial models vary greatly across state and local governments. It is essential to conduct rigorous due diligence to clearly understand what types of financing models can be deployed in your community.

Kostenstruktur

Fixed Costs

Variable Costs

ManpowerMaterial
Administrative costsTransportation
Tenant engagement activitiesEquipment
CommunicationUtilities (Energy & Water)
 Fees & Taxes

 

Marktpotenzial

The previous chapters “City Context” and “Supporting Factors” presented the enormous potential of the market when stated that 75% of the building stock in Europe is energetic inefficient. Worldwide this number might be even worse, generating an interesting gap to cover with refurbishment initiatives.

Stakeholder-Zuordnung

Initiativen der Regierung

Local and national governments need to make clear commitments to ensure long-term market signals towards energy efficient technologies. The accelerated uptake of energy efficient technologies will require a push and pull policy approach. On one hand, mandatory performance targets that push building owners to adopt energy efficient technologies. On the other hand, upfront incentives such as consumer rebates, which reduce barriers such as high upfront costs and higher cost of energy efficient products.

The following list provides examples of some policy measures that can be adopted:

Legislative

  • Design building codes and standards that encourage the delivery of deep renovation and regularly strengthen them in response to new technological developments. Strive for near-zero emissions in new construction.
  • Set Minimum Energy Performance Standards for energy use equipment.
  • Introduce quality standards/certification systems for installers and products.
  • Identify restrictive tenancy laws which disincentivise or inhibit energy performance improvement and update those laws to support sustainable transition.
  • Set minimum on-site renewable energy production limits in order to promote the local implementation of renewable energy sources and to utilize the existing local sustainable energy potential (e.g. legislative action to use at least a certain share of the roof area for PV:  Example 1 ;  Example 2.
  • Streamline the design of sustainable energy concepts by starting the process at the beginning of the planning phase of the transition process. Thereby, the district development process can be influenced by the energy concepts towards positive energy districts and energy saving and self-sufficiency potentials can be utilized more easily (avoiding disadvantageous path-dependencies in the planning process).

Technical

  • Ensure minimal or no addition and lock-in of inefficient and carbon-intensive technologies in all new constructions during the planning approval phase (e.g. Prioritising connection to district heating/cooling network).
  • Simplify and enable deployment of high-efficiency, low carbon technologies such as electric heat pumps and solar thermal units.
  • Promote use of advanced controls, such as energy management systems and smart home technologies for energy efficient behaviour.
  • Address challenges concerning local deployment of low/zero carbon technologies.
  • Ban energy intensive and polluting technologies that are reliable on fossil fuels (e.g. incandescent and halogen light bulbs, electric resistance heaters, oil boilers etc.).
  • Mandate the usage of waste heat from large scale plants for on-site or district systems. 
  • Promote the development of integrated energy concepts that incorporate various building types, sectors and energy demand to maximize the utilization of (energetic) synergies

Financial

  • Develop funding vehicles tailored to specific market segments that provide simple and commercially attractive source of finance for deep renovation.
  • Develop mechanisms to encourage deep renovation via third party financing e.g. ESCOs and EPCs
  • Strengthen carbon pricing mechanisms to provide the right economic signals.
  • Incentivise deep energy retrofitting of existing building shells (e.g. reduce property tax for high energy performing buildings).
  • Incentivise adoption of renewable energy and energy efficient technologies.

Worldwide there have been interesting movements happening towards increasing buildings efficiency. The European Union seems to be in the vanguard of the movement, with several directives published aiming climate neutrality. Among them are specific directives for Energy Performance of buildings, frameworks for setting requirements for materials and design, for promotion of renewables and so on.

While in the United States, the Energy Policy Act of 20058 covers almost every aspect of energy generation, distribution, and consumption, along with guidelines on energy efficiency. In 2012, 31 USA states, by adopting either ASHRAE9 90.1.2007 or the ICC Energy Conservation 2000-201510, implemented model codes for residential and commercial buildings, in Canada there is the Vancouver’s step-by-step plan to promote the uptake of highly energy efficient buildings by removing barriers to Passive House is linked to Vancouver’s Greenest City Action Plan   (UNECE, 2019).

In countries like Serbia, Kazakhstan, Belarus, Russia and some other, the governance structure is such that building codes are made at the federal level, without an option for regional governments to choose whether to adopt the codes or not. In such cases, regions are able to prepare and submit additional design and construction norms or procurement procedures requirements, which will reflect the regional specifics, but will not contradict the federal level law. This situation does not allow the codes to be updated more frequently considering the technological developments in the building sector. The regulatory bodies of these countries acting at the federal level are currently focusing on the implementation of performance-based building codes with minimum energy standards rather than prescriptive building codes. This will give building contractors and owners the flexibility to choose the best technological option to reduce energy consumption (UNECE, 2019).

Unterstützende Faktoren

Figure 3 - Percentage share of Buildings in the EU in different EPC classes

To achieve carbon neutrality , it is essential to consider both, the future buildings being built as well as the existing building stock, which constitutes a majority of the buildings we live in today and onwards. As already mentioned, approximately 75% of the European building stock is considered as not energy efficient, not reaching, at least, EPC class C. This is illustrated in Figure 3, while Figure 4 gives this distribution on a country base.

Figure 4 - Distribution of the building stock in the EU per EPC class. Source: (Buildings Performance Institute Europe, 2017)

The lifetime of European buildings ranges from 40 – 120 years. To reach the ambitious climate and energy goals set by the European Union and demanded for mitigating climate change, the majority of the building stock in the EU needs to be at least nearly zero-energy (Dorizas, Groote, & Fabbr, 2019). Consequently, renovating buildings is a crucial aspect of meeting the European energy efficiency and CO2 emission reduction targets. Aiming the decarbonisation of the building sector, three central pillars are recommended by the International Energy Agency (IEA, 2020):

  1. Sufficiency: This deals with interventions in design stage. Energy demand in buildings should be minimized while providing same or improved level of comfort. This will focus on reducing energy need using innovative design, materials and other similar measures that lead to passive buildings.
  2. Efficiency: Improving performance of building technologies through facilitation adoption of energy-efficient solutions through policy and market frameworks. This would also include investing and promoting research and innovation in highly energy efficient technologies.
  3. Decarbonisation: Once the energy demand for building is minimized by using sufficiency and efficiency measures, the remaining low energy demand should be satisfied with high performance, low carbon solutions.

Stadt-Kontext

It is estimated that people spend on average 85-90% of their time indoors either in their home, in school, at work or during leisure time. To ensure a high level of comfort, buildings across the globe are fitted with different technologies to heat or cool space, provide clean and hot water, fresh air and electricity to power appliances that simplify human life.

As per the International Energy Agency (IEA), buildings and building construction sectors combined are responsible for one-third of global final energy consumption and almost 40% of total direct and indirect CO2 emissions and hence are a source of enormous untapped efficiency potential (IEA, 2020).

Figure 2 - Global Urban Primary energy use and CO2 emissions

According to European Commission estimations, almost 75% of Europe’s building stock is currently energetically inefficient, and the annual renovation rate ranges from just 0.4 to 1.2%, depending on the country. The inefficiency of buildings in terms of energy and resource use constitutes a large societal challenge in connection to our total consumption and CO₂ footprint. This adds pressure on the total integrated energy and city system (State of Green, 2020). Thus, building efficiency plays a decisive role in supporting cities to achieve their carbon neutrality targets. Buildings generate direct CO2 emissions through fuels that are burned (e.g. oil, natural gas) and indirect emissions through the use of fossil fuel powered electricity that is used in the buildings (IEA, 2019). Figure 2 shows the share of buildings in urban energy use and CO2 emissions globally.

Kostenstruktur

Costs: Use Cases used as reference

A good reference to be used for costs is the mentioned Use Case from Vienna. The initial investments for interventions in 95 flats over 50 years old, was about 4,3 Mio. Euros, which accounts for €680 per m² of useable surface and contained the costs for thermal refurbishment works, maintenance works und works to increase housing comfort.

The thermal refurbishment of the façade reduced the heat energy demand by more than 80 percent, from 130 kWh/m²yr to approximately 23 kWh/m²yr. Additionally, a 50 m² large PV-System with 9 kWp was installed at the roof.

The total costs of € 4,3 million are reduced by direct grants and annuity grant and the annual rent-income of currently € 2.55 million (for 6.330 m² useable surface = € 3,35 per m² and month) is used for the payback of the investment (BABLE, 2019).

 

Daten und Normen

  • Energiesprong: This Dutch initiative is a good example, which started with several social housing providers coming together aggregating demand. The scale motivated the construction sector to adopt innovative methods to become more competitive and offer advanced renovation solutions. The initiative promises a complete make over to net zero energy homes in less than 10 days by using prefabricated facades, insulated rooftops with solar panels, smart heating and ventilation and cooling installations. The residents do not need to leave the home, reducing inconvenience.  The whole operation is cost neutral, at worst, for the tenants who get a 30-year performance warranty on indoor climate and energy performance. The residents get a fully renovated, much better looking, warm and comfortable home at the same cost. The costs for refurbishment are paid via reduced energy bills without affecting the bill for the residents. Energiesprong has now expanded to several countries across the world.
  • REMOURBAN: A sustainable urban regeneration model leveraging the convergence of energy, mobility and ICT to transform European cities into Smart Cities. REMOURBAN will implement large scale interventions and intense dissemination initiatives to demonstrate the potential of the urban regeneration model in different areas, such as energy. The REMOURBAN project aims to achieve sustainable districts in Tepebasi and Valladolid through deep retrofitting and renewable energy generation technologies. With the aim of achieving a Near Zero Energy Districts, a series of interventions have been designed focusing on improving the sustainability of residential buildings, increasing its energy efficiency and reducing the CO2 emissions of its buildings.
  • Smarter Together: an initiative funded by the EU and implemented in the three cities of Vienna, Lyon and Munich. Together with the citizens and private partners, the cities are developing smart city solutions. The focus is on the areas of building renovation, energy, mobility and logistics as well as information and communication technology. An emphasis is made on dialogue, where the human dimension of the Smart City is the focus of attention. The aim is to create an innovative, liveable and environmentally friendly areas.

Die Erstellung dieser Lösung wurde durch EU-Finanzierung unterstützt

Anwendungsfälle

Nachrüstung alter sowjetischer Wohngebäude in Tartu

Im Rahmen des SmartEnCity-Projekts ist es das Ziel der Nachrüstung, den Energieverbrauch der Gebäude der alten Sowjetzeit, hrustsovkas, um rund 70% zu senken. Um dieses Ziel zu erreichen, wurden mehrere Energiesparmaßnahmen ergriffen.

Gebäudesanierung

Mailand will die energetische Sanierung des öffentlichen und privaten Wohngebäudes angehen, um bis zu 60-70% des Energieverbrauchs einzusparen und den Wohnkomfort zu verbessern.

Distrikt-Retrofit auf Eskişehir

Mit dem Ziel, durch eine tiefgreifende Nachrüstung einen nachhaltigen Stadtteil in Tepebasi zu erreichen, wurden die Verbesserungen in den Entwürfen der Gebäudehülle umgesetzt. Die Minimierung der Wärmeübertragung durch die Gebäudehülle ist entscheidend, um den Bedarf an Raumheizung und -kühlung zu

Bezirksumbau in Valladolid

Mit dem Ziel, einen Near Zero Energy District in Valladolid zu erreichen, wurde eine Reihe von Maßnahmen konzipiert, die sich auf die Verbesserung der Nachhaltigkeit der 19 Wohngebäude des FASA-Viertels, die Steigerung der Energieeffizienz und die Reduzierung der CO2-Emissionen seiner Gebäude konzen

Energy Retrofitting Through Public Procurement in Nottingham

A UK council housing estate with a high density of fuel poverty has benefited from an energy makeover which bundles technology, aesthetics and a novel approach to public procurement.

Energy Efficient District Heating and DHW retrofitting

Renovation of the whole district heating system (i.e. boilers room, district heating network, heat exchange substations and dwelling interventions)

Public Art Gallery on Retrofitted Apartments in Tartu

Tartu organized an international art competition to make its pilot area for turning Khrushchev-era buildings into modern energy efficient homes into an attractive and unique urban environment for its citizens to enjoy.

Intelligente Steuerung einzelner Räume in bestehenden Gebäuden

Mit dem Ziel, den Energieverbrauch in den bestehenden Bürogebäuden in Strijp-S um 20% zu senken, wurde ein innovatives Konzept zur Optimierung des Energieverbrauchs bei gleichzeitigem Komfort entwickelt. Das System ermöglicht die interaktive Überwachung und Steuerung des HLK-Systems über eine mobile

Energieeffiziente Sanierung von tertiären Wohngebäuden in Valla Torg, Stockholm

Im Rahmen des GrowSmarter-Projekts hat die Stadt Stockholm ab 1961 in Valla Torg mehrere energetische Sanierungsmaßnahmen in 6 tertiären Gebäuden durchgeführt, um den Energieverbrauch um 60% zu senken, den Innenraumkomfort zu verbessern und auch die Lebensdauer der Gebäude zu verlängern.

Energieeffiziente Sanierung von tertiären Gebäuden durch die Stadt Stockholm

Die Stadt Stockholm hat Maßnahmen zur energetischen Sanierung von 2 tertiären Gebäuden durchgeführt: einem kulturellen Zentrum und einem offiziellen Komplex. Beide Gebäude werden als kulturhistorisch bezeichnet.

Energieeffiziente Sanierung eines Wohngebäudes - Brf Årstakrönet

Im Rahmen des Projekts GrowSmarter konzentriert sich diese Maßnahme auf die energieeffiziente Sanierung eines Wohngebäudes aus dem Jahr 2007: Brf Årstakrönet, mit 56 privaten Eigentumswohnungen.

Energieeffiziente Sanierung von tertiären Gebäuden durch die Gemeinde Barcelona

Die Gemeinde Barcelona hat zwei alte Textilfabriken nachgerüstet, die kürzlich aufgegeben oder als Lagerhaus genutzt wurden. Die Gebäude wurden in eine neue öffentliche Bibliothek (Library Les Corts) und ein Forschungs- und Entwicklungszentrum für Smart Cities umgewandelt, in dem sowohl öffentliche

Energieeffiziente Sanierung des Gebäudes - Bildungszentrum Escola Sert

Gas Natural Fenosa hat die energetische Sanierung eines Bildungszentrums Escola Sert durchgeführt. Ziel ist es, die technische und wirtschaftliche Machbarkeit der Ergänzung eines tertiären Gebäudes um erneuerbare Energieerzeugung in Form von gebäudeintegrierter Photovoltaik (BIPVs) zum Eigenverbrauch zu validieren.

Intelligente Gebäudesanierung in Köln

Um die Energieeffizienz bestehender Wohngebäude im Rahmen des EU Horizon 2020 GrowSmarter Project um 70% zu verbessern, wurden Renovierungsmaßnahmen durchgeführt. Dazu gehören die Isolierung der Gebäudehülle, hocheffiziente Fenster, Treppenhausbeleuchtung, Aufzug und Heizungsanlage.

Energieeffiziente Gebäudesanierung - Hotel H10 Catedral

Im Rahmen des GrowSmarter-Projekts hat Gas Natural Fenosa die energetische Sanierung von drei Gebäuden mit sehr unterschiedlichen Nutzungen durchgeführt, darunter ein Hotel H10 Catedral. Ziel ist es, die technische und wirtschaftliche Machbarkeit einer energetischen Sanierung eines tertiären Gebäudes zu überprüfen.

Energieeffiziente Sanierung des Gebäudes - Sportzentrum CEM Claror Cartagena

Naturgy hat in Barcelona Nachrüstmaßnahmen durchgeführt, um den Energieverbrauch auf über 12.500 m2 Tertiärfläche zu senken. Drei Gebäude mit sehr unterschiedlichen Nutzungen wurden nachgerüstet, eines davon ist ein Sportzentrum, CEM Claror Cartagena.

Energieeffiziente Sanierung von Wohngebäuden durch Naturgy

Naturgy hat Nachrüstmaßnahmen durchgeführt, um den Energieverbrauch von Gebäuden in fast 20.000 m2 Wohnfläche in Barcelona zu senken: Canyelles, Ter, Lope de Vega und Melon District.

Energieeffiziente Sanierung eines Wohngebäudes - Passeig Santa Coloma

Die Gemeinde Barcelona hat die energetische Sanierung eines Sozialwohngebäudes in Passeig Santa Coloma mit 207 Wohnungen und über 14.000 m2 gefördert.

Refurbishment of a Rental Social Housing in Vienna

The project ‘Hauffgasse 37-47’, completed in 1987, is a large housing block with 485 flats. It is supplied by a micro-district-heating-grid and currently fired with natural gas. The objectives were mainly focusing on the reduction of energy demand and the integration of renewable energy sources.

Refurbishment of a Municipal Housing Estate in Vienna (Social Housing Lorystraße 54-60)

The project Lorystraße 54-60 is a medium-size housing block with 95 flats, completed in 1966 and owned by ‘Wiener Wohnen’ the city-owned social housing operator. The thermal refurbishment reduced the heat energy demand by more than 80 percent. Additionally, a 9 kWp PV-System was installed.

Refurbishment of a Municipal Housing Estate in Vienna (Social Housing Herbortgasse 43)

The municipal housing estate in Herbortgasse 43 was built in 1929 and is under heritage protection. The thermal refurbishment of the façade reduce the heat energy demand by about 75 percent, from 118 kWh/m²yr to approximately 28 kWh/m²yr. 8 additional flats are constructed in a rooftop extension.

Refurbishment of secondary schools and a public gym into zero-energy

The refurbishment of a public gym and the addition of 16 class rooms to the schools serves as a testbed for the use of new energy solutions. It is a pilot project testing climate friendly smart city solutions. The current energy performance of 104 kWh/m2 is reduced to 27 kWh/m2.

Verwandte Lösungen

Energiemanagement-System für Gebäude

Der größte Teil der öffentlichen Mittel für die Energieeffizienz in der EU wird für den Gebäudesektor vorgeschlagen. Die Bundesmittel in diesem Bereich belaufen sich 2014 auf 5,4 Milliarden Euro. Eine Möglichkeit, die Energieeffizienz von Gebäuden zu erhöhen, ist die Implementierung eines Gebäudeenergiemanagementsystems (BEMS).

Smart Home System

Der größte Teil der öffentlichen Mittel für die Energieeffizienz in der EU wird für den Gebäudesektor vorgeschlagen. Die Bundesmittel in diesem Bereich belaufen sich 2014 auf 5,4 Milliarden Euro. Ein intelligentes Heimsystem ist eine Möglichkeit, die Energieeffizienz von Wohnungen zu verbessern.

Lokales Energiesystem

Etwa ein Viertel des Energiepreises entfällt auf den Transport der Energie. Die Implementierung eines lokalen Energiesystems kann die Energieerzeugung von einem zentralen System auf ein dezentrales System verlagern.

Intelligenter und vernetzter öffentlicher Raum

Ein intelligenter und vernetzter öffentlicher Raum sammelt Daten im öffentlichen Bereich und zeigt oder reagiert auf die Daten. Die Daten können sicher über Wi-Fi oder andere ähnliche Technologien übertragen werden, d.h. in Kombination mit einem zentralen System.