Authors: Charikleia Karakosta, Zoi Mylona, Jason Papathanasiou & John Psarras
Published in: ICDSST 2023: Decision Support Systems XIII. Decision Support Systems in An Uncertain World: The Contribution of Digital Twins
Year of publication: 2023
Summary: Nowadays, boosting the implementation of energy efficiency measures in buildings and subsequently, mainstreaming energy efficiency financing is of paramount importance for the European Union towards achieving its goal of carbon-neutrality by 2050. Unfortunately, statistics have shown that a lot of effort is needed to achieve the Europe’s targets, since energy efficiency is not yet considered as an attractive investment by the financial sector. The lack of expertise and knowledge, as well as the different perspective of project developers and financing institutions are some indicative challenges that have to be overcome. Specific to energy efficiency in buildings this is reflected by the current insufficient trends observed in the renovation rates of buildings, which reveal the urgent need for action since this is the largest consumer of energy in Europe. Furthermore, a combination of public and private funding through innovative financing instruments is required to overcome current barriers that prevent mobilization of necessary investments. The aim of this paper is to set up a role-based methodological approach for the deployment of an integrated matchmaking mechanism on an ICT platform to boost energy efficiency investments in an easy-access and trust-worthy way. The methodology envisages to follow a multidisciplinary perspective which takes into account the interactions between various key factors, such as stakeholders and barriers, so as to facilitate the complex set of decision-making actions for building renovation. The core of concept centres around the definition of the roles of the potential users of a big data for buildings platform, their interdependency and requirements with the ultimate purpose of accelerating renovation rates.
Authors: Ioanna Andreoulaki, Aikaterini Papapostolou, Charikleia Karakosta, Filippos Dimitrios Mexis, and John Psarras
Published in: 9th International Symposium & 31st National Conference on Operational Research - Book of Proceedings
Year of publication: 2023
Summary: Although it is evident that the implementation of energy efficiency measures, upgrades of energy consuming systems and installation of sustainable technologies are effective ways of reducing energy needs and consumption in buildings, renovation rates in the EU remain quite low. A plethora of factors might hinder the application of retrofitting actions in the building sector, including technical issues, financial barriers, behavioral aspects, as well as risks related to the economy and energy market. With the aim of incentivising energy efficiency investments in buildings, an approach has been followed to identify, explore and categorise the most common financing instruments that promote retrofitting actions in the building sector. Towards this direction, a literature review of financing tools for renovation projects is conducted. Specific examples of renovation projects and financing schemes in European countries are presented, to validate the correlation between building and financing typologies. Current barriers and issues that need to be addressed to encourage energy efficiency financing and, thus, increase renovation rates are highlighted. The findings of the research provide useful insights for market actors interested in energy efficiency financing and stakeholders engaged in renovation projects. Moreover, the conclusions of the analysis can become a starting point for further research on the topic, setting a basis for standardising sustainable investments in the building sector by matching renovation projects with the appropriate financing methods.
Authors: Aikaterini Papapostolou, Ioanna Andreoulaki, Konstantinos Touloumis, Panagiotis Kapsalis, and John Psarras
Published in: 9th International Symposium & 31st National Conference on Operational Research - Book of Proceedings
Year of publication: 2023
Summary: Due to the severe consequences of the climate crisis, which is largely due to gas emissions ensued by energy consumption worldwide, reaching energy transition targets has become an important pillar of energy polices. A considerable percentage of total CO2 emissions is generated because of energy usage in buildings. However, the rate of renovations aiming to improve energy performance of the European building stock remains low. The ENERGATE project aims to encourage financing of retrofitting actions in buildings, by developing a web-based marketplace to provide a communication medium and offer renovation related services to various engaged parties. Thus, the supply side (building owners, asset managers etc.) needs to enter data relevant to the buildings to the ENERGATE platform, so that the products (i. e. buildings and corresponding retrofitting measures) can be matched with the demand side (investors, ESCOs etc.). In this paper, existing frameworks which aim to model data relevant to buildings are investigated and, by examining several datasets, potential variables which influence a building’s likelihood of being renovated, as well as retrofitting measures that could apply to it, are explored. The aim is to generate a Common Data Model, which could be used as a basis to develop the building profiles within the ENERGATE platform. Besides, the conducted research could provide useful insights for stakeholders engaging in retrofitting projects, by pointing out the most important elements of the building’s characteristics which should be examined in order to determine the most appropriate renovation strategies.
Authors: Panagiotis Kapsalis, Aikaterini Papapostolou, Konstantinos Touloumis, Ioanna Andreoulaki, Zoi Mylona, Haris Doukas
Published in: 14th International Conference on Information, Intelligence, Systems and Applications(IISA 2023)
Year of publication: 2023
Summary: Nowadays it becomes evident that there is a lack of Information Technology systems that decision making as the creation of financing schemes for the building sector. In this context an information system acting as a marketplace enables data driven components that will be exploited by end users to perform bids and offers for building investments. This work focuses on the functional description of the EU-funded project ENERGATE marketplace for energy efficiency investments. ENERGATE System Architecture fosters data sharing, interoperability and the integration of data driven techniques, underlying the design principles to be followed having alignment with existing EU standards and protocols.
Authors: Ioanna Andreoulaki; Daniela Stoian; Aikaterini Papapostolou; Andriana Stavrakaki; Vangelis Marinakis
Published in: Institute of Electrical and Electronics Engineers (IEEE)
Year of publication: 2024
Summary: Reducing buildings' energy consumption through energy efficiency interventions has become a key priority to mitigate climate change. To this end, stakeholders involved in the implementation and financing of energy efficiency projects in the building sector could benefit from the development of specific methodologies and user-friendly tools that can assist them by supporting them in managing large datasets and by simplifying decision making processes. In this context, the aim of this paper is to propose a decision-making tool for triggering investments in energy efficiency. The tool's workflow consists of three layers: project selection (layer 1) - narrowing down the list of potential energy efficiency projects according to investor preferences, aggregation (layer 2) - leveraging an optimisation algorithm to create clusters of similar projects, and finally, prioritisation (layer 3) - applying the TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method to rank the clusters. The tool brings significant added value to stakeholders involved in financing energy efficiency interventions, offering standardisation and automation of procedures.
Authors: Ioanna Andreoulaki; Aikaterini Papapostolou; Daniela Stoian; Konstantinos Kefalas; Vangelis Marinakis
Published in: Multidisciplinary Digital Publishing Institute (MDPI)
Year of publication: 2025
Summary: Nowadays, the increase in sustainable investments, especially when it comes to energy efficiency in buildings, has been recognised as an important pillar towards reductions in energy consumption. In this context, there is a need for efficient and user-friendly digital tools that can support decision-making procedures for all involved parties in the energy efficiency value chain. The scope of this paper is to present a high-level architecture and system design of the energy efficiency marketplace developed within the framework of the ENERGATE project, an EU-funded initiative aiming to assist Building Owners, Project Implementors, and Financial Institutions to collaborate and execute energy-efficient building renovations. To this end, structured data through predefined information entries will be collected. This will facilitate the interactions between heterogenous stakeholders and contribute to the standardisation of processes. The paper focuses on the functional description of the system design of the ENERGATE platform by defining the architecture, components, modules, interfaces, and structured data, as well as highlighting the requirements of potential platform users and design principles to meet the necessary requirements while ensuring security, reliability, and effectiveness.
Authors: Ioanna Andreoulaki; Aikaterini Papapostolou; Charikleia Karakosta; Vangelis Marinakis
Published in: International Journal of Decision Support Systems (IJDSS)
Year of publication: 2025
Summary: The European Commission highlights energy efficiency in buildings as a fundamental strategy to achieve the EU's climate objectives. In this context, the paper proposes a decision-making approach based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to support the financing of energy efficiency (EE) projects. By leveraging multi-criteria analysis with investor-focused evaluation criteria, the methodology helps financing bodies assess and prioritize energy renovation initiatives. The TOPSIS method is chosen for its capacity to efficiently process numerous alternatives and is applied to a dataset of 48 EE projects in Greece. Results suggest that certain types of renovation actions, particularly heating system upgrades, tend to be more appealing for investors than other interventions.
Authors: Ioanna Andreoulaki, Aiketerini Papapostolou, Vangelis Marinakis
Published in: 6th International Conference in Electronic Engineering & Information Technology (EEITE)
Year of publication: 2025
Summary: The reduction of the amount of energy consumed in buildings is considered essential for achieving carbon neutrality. As a result, energy-saving measures in the building sector are crucial for addressing the climate crisis. However, the high costs discourage building owners and managers from undertaking energy efficiency projects, despite the financial benefits resulting from the savings. Consequently, it is clear that investments in these projects can play a significant role in increasing energy savings, however, there are several risks that need to be considered. In this context, the aim of this paper is to identify and prioritise the most important risks of energy efficiency investments. 14 risks are identified, categorised and evaluated by experts using the Analytical Hierarchy Process for Group Decision Making. The decision makers represent the different market actors involved in the implementation and financing of energy efficiency projects. The results show that different types of stakeholders involved in the energy efficiency value chain have different perspectives in terms of the importance of each risk factor, however risks related to the credit quality of the end client and the volatility of energy prices are the most significant.
Authors: Daniela Stoian, Konstantinos Kefalas, Ioanna Andreoulaki, Katerina Papapostolou, Vangelis Marinakis
Published in: 6th International Conference in Electronic Engineering & Information Technology (EEITE)
Year of publication: 2025
Summary: With global energy consumption increasing and environmental problems worsening, the need for effective solutions to reduce energy consumption in buildings is urgent. Energy renovation plays a key role in achieving this objective, allowing the energy efficiency of buildings to be improved and their negative impact on the environment to be mitigated. However, stakeholders involved in the renovation process often struggle to select the most appropriate energy efficiency measures to be implemented in a building. This paper aims to promote energy efficiency retrofits by providing an ML-based decision support system for identifying the most suitable and impact-heavy renovation actions for a certain building. First, an analysis of the available data from energy efficiency projects that have been implemented in the past is carried out and the different energy efficiency measures are identified. Then, different machine learning algorithms are applied, and the algorithms with the highest degree of accuracy are identified and further optimized. The results estimate the most energy efficient measures, in addition to the CO2 savings achieved. These results show how different combinations of features and algorithms can influence the outputs, leading to the selection of the best combination of techniques, indicating that Random Forest and LightGBM algorithms outperform other models in predictive accuracy, making them suitable for large scale energy management applications. Moreover, the results emphasise the importance of machine learning in the field of energy efficiency and energy in general, since the potential of machine learning models to support stakeholders in decision-making procedures are highlighted, taking advantage of existing data, conducting systematic analysis of available information and providing useful insights and predictions of the impact of specific interventions.
Authors: Székely Miklós, Stoian Daniela, Andreoulaki Ioanna, Papapostolou Katerina
Published in: GAZDASÁG ÉS TÁRSADALOM (Journal of Economy & Society)
Year of publication: 2025
Summary: This study investigates the economic benefits of digital platforms in addressing market failures within the building energy renovation sector in Europe. While significant capital is available for sustainable investments, the market is characterized by profound information asymmetry and high transaction costs, which hinder the efficient allocation of green capital. Using the ENERGATE platform as a case study, this paper examines how an AI-driven matchmaking system can standardize and aggregate projects, reduce information gaps, and match project supply with investment demand. Our analysis suggests that such platforms can significantly lower search and transaction costs for financiers, thereby mobilizing capital that would otherwise remain untapped. The findings provide insights into how technological solutions can create a more liquid and efficient market for sustainable investments, accelerating the transition to a low-carbon economy.
Authors: Ioanna Andreoulaki, Aikaterini Papapostolou, Konstantinos Kefalas, Natalia Konti, John Psarras
Published in: HELORS 2025 - Book of Abstract
Year of publication: 2026
Summary: To address the climate crisis, the European Union (EU) has established specific targets related to the energy transition, emphasizing the urgent need to reduce energy consumption in the building sector. Based on the Energy Efficiency Directive (EED) and the Energy Performance of Buildings Directive (EPBD), increasing renovation rates are deemed necessary. The policies of EU Member States, including Greece, try to adopt and implement policies aligned with the targets and directives of the EU. However, the high costs discourage building owners and managers from implementing energy efficiency projects, despite the economic benefits arising from energy savings. At the same time, financiers face their own challenges, such as uncertainties about return on investment, lack of standardized risk assessment protocols, and limited awareness of long-term benefits, which further constrain the flow of capital into the sector. Therefore, it becomes evident that financial programs and investments in energy efficiency projects can play a very important role in increasing energy renovations. In this context, the scope of this paper is to conduct a market analysis, aiming to formulate and evaluate policy recommendations to increase investments in energy efficiency of the Greek building stock. Specifically, through PESTLE (Political, Economic, Sociological, Technological, Legal, and Environmental) and SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis, the factors of the internal and external environment influencing investments in energy efficiency in buildings are identified, along with the benefits, opportunities, potential weaknesses, and risk factors affecting this sector. At the same time, the current and desired state are assessed in order to propose improvements to national policies.
Authors: Ioanna Andreoulaki, Aikaterini Papapostolou, Vasilis Kotrogiannis, Daniela Stoian, John Psarras
Published in: IEEE
Year of publication: 2025
Summary: Improving the energy performance of the building stock is necessary to achieve carbon neutrality in the EU, since a big proportion of the overall energy demand is associated with the building sector. Therefore, energy efficiency projects in buildings can play a significant role in climate change mitigation. Nevertheless, the high upfront costs deter building owners, property managers, real estate developers and other stakeholders in the building sector, from deploying energysaving measures. Although there are numerous tools to finance those projects, such as loans, national programmes and EU funding mechanisms, it might be difficult for stakeholders to identify the most suitable financing tool for their case. In this context, the aim of this paper is to propose a decision support system that compares the preferences of the stakeholder with available data on existing financing tools, so as to provide recommendation, using cosine similarity as a comparison metric. The methodology is applied on examples applicable to the Greek market. The results show that the proposed approach can significantly assist stakeholders in navigating through different financing tools, but different approaches and data entries are needed depending on whether these tools are provided by private or public entities.
Authors: Aikaterini Papapostolou, Ioanna Andreoulaki, Vasilis Kotrogiannis, Vangelis Marinakis
Presented in: EURO 2024 Copenhagen
Year of Presentation: 2024
Summary: Using the ENERGATE project as a case study, it applies a stakeholder engagement approach involving stakeholder mapping, pilot input, workshops, surveys, and semi-structured interviews to identify market needs, barriers, priorities, and key performance indicators for energy efficiency investments. The findings show that building stakeholders and financiers evaluate projects differently, with concerns ranging from upfront costs, technical complexity, and access to finance to risk assessment, reliable data, and investment security. In response, the proposed ENERGATE platform supports project development, aggregation, matchmaking, funding exploration, and decision-making through filtering mechanisms, multicriteria analysis, machine learning techniques, and visualised benchmarks. Overall, the study highlights the potential of stakeholder-driven digital tools to reduce uncertainty, improve access to sustainable finance, and scale energy efficiency renovations across Europe.
Authors: Ioanna Andreoulaki, Aikaterini Papapostolou, Vasileios Kotrogiannis, Vangelis Marinakis
Presented in: EMCEI 2024
Year of Presentation: 2024
Summary: This presentation outlines a methodological framework for designing an online marketplace that promotes energy efficiency retrofitting projects in buildings by simplifying stakeholder interaction, standardising project information, and improving access to finance. Motivated by low renovation rates in the European Union and persistent barriers such as fragmented procedures, limited communication, and knowledge gaps between market actors, the study identifies three key user groups: building owners, implementers, and financiers. Drawing on input from ENERGATE project partners, it defines four marketplace use cases that connect these stakeholders according to their needs, such as finding technical partners, securing financing, preparing standardised project offers, and aggregating projects into attractive investment packages. The proposed marketplace uses predefined data entries, key performance indicators, machine learning predictions for energy and CO₂ savings, benchmarking, filtering, and multicriteria decision analysis to support project evaluation and matchmaking. Overall, the study shows that an ICT-enabled marketplace can accelerate early-stage project development, reduce complexity, improve investment prioritisation, and support broader deployment of sustainable building renovation projects.
