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Miguel Ángel Pascual | María Fernández Boneta |
PhD, CEO at Efinovatic, Spain | Research Project Manager at CENER (National Renewable Energy Centre), Spain |
The global goal of zero net emissions by 2050 requires improvements in energy efficiency, electrification of energy services and increased penetration of renewable energy generation. The revised Renewable Energy Directive (RED) [1] adopted in 2023, raises the EU’s binding renewable energy target for 2030 to a minimum of 42.5%. But then, the intermittency of renewable energy and the increasing use of these distributed energy resources will put additional pressure on existing grids. In this scenario, the building sector becomes a critical element in addressing today’s challenges. With the ability to produce, consume, store, sell and buy energy, buildings become active participants in the buildings-to-grid ecosystem. Building-to-Grid (B2G) practices, based on digitalisation and ICT technologies, create an opportunity for buildings to generate new value streams with energy services. Emerging technologies such as IoT, artificial intelligence, big data, blockchain and 5G enable new approaches such as distributed resources including demand response, distributed generation, storage, and renewable generation, which enable consumers to provide energy flexibility.
The revised Energy Performance of Buildings Directive (EPBD) [2], emphasises the use of smart technologies and control systems (BACS) to improve the energy performance of buildings, including a common general framework in its Article 15 and Annex IV (Smart readiness of buildings).
In this scenario, the current intelligence of existing buildings needs to be assessed and building professionals and end users need methodologies and tools to carry out this assessment, diagnosis and proposal of the most appropriate measures to improve such indicators and then upgrade the intelligence of buildings according to market needs.
The Smart Readiness Indicator (SRI) is a common EU methodology that rates the smart readiness of buildings (or building units) for their capability to perform three key functionalities: (KF1) ‘optimisation of energy performance and operation’, (KF2) ‘response to the needs of the occupants’, and (KF3) ‘adaptation of operation to provide energy flexibility’, including the ability of the building or building unit to enable participation in demand response. The SRI was introduced in the EPBD as a way to emphasize the role of smart building technologies – such as technologies for building automation, control and monitoring of equipment operation – in improving the energy efficiency of buildings and their capability to be active components of the future EU energy system.
The SRI scheme incorporates a calculation framework defined in the SRI delegated Regulation, which includes the assessment of smart technologies present in a building, classified into nine technical domains: heating, cooling, domestic hot water, ventilation, lighting, dynamic building envelope, electricity, electric vehicle charging, and monitoring and control. Each service (e.g., heating emission) is rated according to its ability to impact on seven different impact criteria: energy efficiency, maintenance and fault prediction, comfort, convenience, health, wellbeing and accessibility, occupant information, and energy flexibility and storage.
Each service included in a National Service Catalogue (i.e., at Member State level) contains a list of functionality levels, from least to most smart, to cover the associated service. Each functionality level is described as an individual functionality, which in practice is associated with a physical installation that may include sensors, actuators, other control hardware, software and visual interfaces.
Finally, the calculation framework includes the weighted sum of all scores to provide a final SRI score, as well as aggregated scores per impact, domain and key functionality.
The SRI is based on a self-referencing system, which means that the indicator expressed as a percentage (%) is the score relative to the same building with the highest possible score.
The SRI2MARKET project aims to support Member States in successfully planning the introduction of SRI into their national regulations and markets. In particular, SRI2MARKET is working on specific Member States and with general objectives that are differentiated; Austria, France, Portugal, Spain, Croatia, Greece and Cyprus (Figure 1).
Figure 1. Focus countries of the SRI2Market project.
The SRI2MARKET project has developed online learning and assessment tools based on the SRI calculation methodology. In particular, the SRI2MARKET e-learning programme (available in seven languages at https://learning.sri2market.eu) establishes a graded learning system to ensure proper training of building professionals and other interested end-users, while at the same time enabling a quality control system to curate the SRI2MARKET database.
The learning path is made up of three stages or levels, closely linked to access to the assessment platform, which is protected by login details: Level 1 - SRI User, Level 2 - SRI Beginner and Level 3 - SRI Expert. In order to achieve each level, it is mandatory to complete specific tasks as shown in Figure 2 below and at the same time, each level grants different access to the assessment platform. Specifically, the achievement of "Level 2" will automatically provide access to the assessment platform (https://sri2market.eu) and the achievement of "Level 3" will differentiate the user account and classify the corresponding projects according to these criteria, making them valid for advanced monitoring of SRI scores.
Figure 2. SRI2MARKET training programme.
The above structure ensures that the SRI2Market database is populated with high quality and trustworthy input data in order to extrapolate aggregated and consolidated conclusions regarding the SRI test phases.
The SRI training platform is currently being used by more than 800 trainees with the aim of becoming ‘SRI experts’ (i.e. achieving level 3 SRI expertise). Most of them (around 600) are currently taking the SRI course in Spain as part of the Spanish test phase.
The SRI2Market database, which can be consulted at https://sri2market.eu/sri/powerBi/, includes 172 EU buildings assessed so far, 80 from these located in Spain. This tool offers the possibility to display results with different segmentations: user level, building type, building size or construction year.
The database will continue to be populated during the rest of year 2024 and most of 2025, when the advanced benchmarking provided by the project database and visualisation interface will be used to submit the corresponding report to the European Commission at the end of the official SRI test phases such as the Spanish test phase.
Some preliminary results of the advanced benchmarking and monitoring tools based on the current sample of buildings are shown in the following figures. These figures can answer a first list of questions that are useful for defining roadmaps and supporting policy decisions.
Figure 3 shows a comparison of the current state scores and the scores for the improvement proposals, for Spain and the European Union. It can be seen that the Spanish results follow the same tendency as the rest of the European Union, with most of the cases in the bin for SRI scores between 0% and 10% with a mean SRI score of 20%.
The histogram for the cases with improvement proposals shows that most of the cases are in the bin for SRI scores between 30% and 40%, with an average total SRI score of 39.5%.
In the right column of the Figure 3 we have the results for the main functionalities. As can be seen, the least present functionality in the existing building stock is energy flexibility.
Figure 3. Left column: histogram with SRI distribution (for EU and Spain). Right column: Key functionalities scores. First row: current state assessments. Second row: improvement proposal assessments.
Figure 4 shows the mean overall SRI for each EPC class. The EPC class is not a mandatory input in the platform, so it is not known for all assessments. The results of this graph are inconclusive due to the small sample size so far, but there is a slight tendency for better SRI scores to be associated with better EPC labels.
Figure 4. Mean SRI score versus EPC class.
Figure 5 analyses the correlation between the three key functionalities. Each point is an SRI assessment, placed on the graph with the coordinates of the corresponding key functionality scores. There is a clear correlation between energy performance (KF1) and responsiveness to occupant needs (KF2). This can be interpreted as BACS improving energy efficiency will also improve occupant comfort.
On the other hand, Key Functionality 3 (i.e. energy flexibility) is not related to the other two.
Figure 5. Key Functionality scores correlations.
Figure 6 shows the overall SRI score related to the year of construction of the building. There is no clear trend, but it seems that modern buildings can achieve a higher SRI.
Figure 6. SRI versus year of construction.
Figure 7 shows several graphs representing the results obtained with both catalogues (i.e. the simplified catalogue for Method A and the detailed catalogue for Method B). Almost half of the buildings have been assessed using each catalogue. So far, the simplified Catalogue for Method A has achieved a better score, especially for key functionality 3 (energy flexibility).
Figure 7. SRI scores according to both default catalogues (A and B).
The SRI2MARKET assessment platform includes an ISO 52120 assessment approach. Figure 8 shows that most cases fall into the D class, with an average SRI score of 24. Those that reach the B class have an average score of 39 and those that reach the A class have an average score of 43.
Figure 8. Relationship between ISO 52120 and SRI score.
The sample size is not large enough to be highly representative, so no conclusions can be drawn. However, the following trends can be identified:
· The expected total SRI score for the existing building stock is between 0 and 20%.
· The key functionality that is less present in the existing building stock is KF3 - Energy Flexibility.
· There is a slight correlation between the energy certification class and the SRI score.
· The functionalities KF1 - Energy Efficiency and KF2 - Response to Occupants are highly correlated.
· It is found that buildings assessed with the simplified Catalogue A achieve a higher average SRI score than those assessed with the detailed Catalogue B.
· Most of the buildings assessed will fall into the D category of ISO 52120.
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