FLEXor – The development of simulation and optimization models for energy-flexible operation in the built environment

Energy flexibility refers to the ability of a building or neighbourhood to activate its on-site flexibility sources (building’s thermal mass, heat storage tanks, batteries, EV charging) while safeguarding user needs and comfort. FLEXor is an optimization tool for flexible energy use, storage and generation in buildings, that generates optimal load profiles in response to grid signals, such as dynamic energy prices, thus facilitating energy planning and optimal system dimensioning and control It comprises interconnected models that handle user inputs, activate sub-models, and define system topology. These include component models (building envelope, hot water tank, heat sources, EV charging, PV systems and electric batteries), functional models (energy costs, fixed energy demand), and a model for typical demand profiles It is implemented in Python and uses the Pyomo software package for formulating, solving and analyzing optimization models.The tool is available in a backend solution, run on a SINTEF server, while their frontend is accessible in two ways: via a Web App, and via API (Application Programming Interface) for more advanced users and for use by other software. FLEXor is a three-level model. The top model reads the user input, collects and organizes the input parameters and input data, sets up and activates the second- and third-level models, and collects and organizes the results. This model is not interchangeable. The second-level model sets up the system topology in the building used to define the connections between the energy components in the building. This model is interchangeable. The third-level models have several different purposes. These include component models, such as the building envelope, domestic hot water (DHW) tanks, electric batteries, heat sources (e.g. direct electric heaters, district heating, and heat pumps), electric vehicle charging, and onsite PV systems; functional models to calculate energy costs, fixed energy demand, the Linear Time-Invariant (LTI) model structure; and a model to calculate energy demand profiles via PROFet. The starting point is given by typical (non-flexible) energy demand load profiles taken from PROFet, based on a statistical analysis of hourly measurements from several buildings classified in different categories. The flexibility sources are modelled as internal variables (the model’s states) such as indoor temperature, tank temperature, battery state of charge, and are subject to boundary conditions and constraints that represent user comfort and user needs, such as a comfort band for indoor temperature, a lower bound for the hot water tank's temperature, and the charging of electric vehicles within the connection time and capacity. All the component models (third-level) in FLEXor are designed to be self-standing. Thus, they are self-contained, and do not include the control and/or optimization of other components. The models are designed to be i) linear, ii) in state space form (when applicable), and iii) transparent. This allows the high-level model to be fast, lean, relatively simple, and able to leave a component out of the optimization process if necessary.publishedVersio

Samfunnsøkonomisk verdi av flomdemping fra vannkraftregulering – Oppsummering av prosjekt SamVann

publishedVersio

Safe delivery of goods and services with smart door locks: Unlocking potential use

The purpose of this paper is to identify the potential of using smart door locks in unattended home delivery of goods, and at home services (unattended and attended) by producing new knowledge on Potential adopters and Non-adopters. Survey data on Potential adopters and Non-adopters were statistically analysed to identify their 1) characteristics (sociodemographic, interpersonal trust and technological literacy), 2) stated demand for unattended home delivery of goods and 3) attitudes regarding in-home services using smart door-locks. Results suggest that potential users are resourceful and more sociable than non-adopters. Furthermore, they have a higher problem perception. Potential adopters are more positive to let in cleaners, craftsmen, healthcare personnel, service personnel, in-fridge delivery services and pet sitters into their home unattended using smart door locks. Regarding goods, they are more positive towards delivery of sports equipment and furniture and appliances. Due to the differentiated needs of Potential adopters and Non-adopters, we propose a typology based on three dimensions (Technological trust, Social trust and Life management needs). Increased understanding of potential users’ delivery preferences can be used in the smart door lock market development. The proposed typology can e.g. be used in the upscaling of smart door locks for home delivery of goods and services by diversifying strategies to meet varying adopter needs. A successful unattended delivery system behind closed door can reduce the number of failed deliveries, porch piracy, and unnecessary trips to let in service providers, and might enhance perceived flexibility and convenience of consumerspublishedVersio

Developing a framework to assess water smartness and sustainability of circular economy solutions in the water sector

The transition to a circular economy in the water sector is challenged by the lack of comprehensive tools to assess and compare the performance of innovative solutions across multiple sustainability dimensions. This study aims to develop a structured framework of indicators to support such assessments and guide the sector toward achieving the United Nations Sustainable Development Goals (SDGs). The framework was co-developed with stakeholders and encompasses technical, social, environmental, economic, and governance dimensions. It is organized into four hierarchical layers: dimensions, objectives, criteria, and indicators. Objectives were designed to be broadly applicable, while criteria and indicators were formulated to assess alignment with these objectives and capture the multifaceted nature of “water smartness.” The framework was tested and validated through workshops and structured engagement activities across six demonstration cases. Results from exploratory data analysis confirmed the framework's relevance for decision-making, highlighting its capacity to compare alternatives under diverse scenarios and its alignment with the SDGs. Additionally, the testing process pointed out the differentiated responsibilities of involved stakeholders, offering practical insights for advancing full-scale implementation of circular economy models in the water sector.publishedVersio

A Case Study of System Reliability and Availability of Blue Hydrogen Production

The transition toward a low-carbon future has positioned hydrogen as a critical energy carrier, with blue hydrogen emerging as a bridge between conventional fossil fuels and cleaner alternatives. Blue hydrogen is produced by reforming natural gas with carbon capture and storage (CCS) to reduce CO2 emissions, representing an intermediary solution between grey and green hydrogen. However, ensuring the reliability of the complex systems (e.g. the hydrogen production systems) is critical for economic feasibility, operational safety, and environmental sustain-ability. This paper analyses the system reliability of blue hydrogen production technologies, evaluating the challenges in reliability modelling and assessment specific to these systems. It addresses key issues such as the integration of multiple technologies, data limitations, operational risks, and the performance of critical equipment. Through this analysis, the study highlights the importance of robust reliability engineering frameworks towards the challenges of blue hydrogen systems.A Case Study of System Reliability and Availability of Blue Hydrogen ProductionpublishedVersio

Flooded with potential: urban drainage science as seen by early-career researchers

This opinion paper reflects on the current challenges facing urban drainage systems (UDS) research, along with solutions for fostering sustainable development. Over the course of a year-long project involving 92 participants aged 24–38, including PhD candidates, post-doctoral researchers, and early-career academics, we identified critical challenges and opportunities for the sustainable development of UDS. Our exploration highlights four key challenges: limited public visibility leading to resource constraints, insufficient collaboration across subfields, issues with data scarcity and data sharing, and geographical specificities. We emphasise the importance of raising public and political awareness regarding UDS's vital role in climate adaptation and urban resilience, advocating for blue-green infrastructure and open data practices. Additionally, we address systemic academic barriers that hinder innovative research. We call for a shift away from metrics that prioritise quantity over quality. We recommend establishing stable career pathways that empower early-career researchers. This paper aims to catalyse a broader community dialogue about the future of UDS research, uniting voices from various career stages. By presenting actionable recommendations, we aim to inspire fundamental changes in research conduct, evaluation, and sustainability, ensuring the field of UDS is prepared to meet pressing urban water management challenges worldwide.publishedVersio

Significance of pyrolysis in the circular economy: An integrative review of technologies, potential chemicals, and separation techniques

publishedVersio

Thermal performance estimation for cryogenic storage tanks: Application to liquid hydrogen

The design of cryogenic liquid storage solutions requires accurate methods for estimating heat ingress, from the material level to the tank level. For insulation materials, thermal performance is usually measured using ambient conditions and liquid nitrogen at 77 K as boundary temperatures. A key question is how much heat ingress increases when storing liquid hydrogen (LH2) at 20 K. We address this by introducing the Concavity Hypothesis, namely that heat ingress is a concave function of the cold boundary temperature, and show that the increase in heat ingress is below 26 %. Additionally, we demonstrate that heat ingress is much more sensitive to the warm boundary temperature than the cold boundary temperature. At the tank level, we compare two methods for assessing the steady-state thermal performance of cryogenic tanks: thermal network models and the heat equation solved with the finite element method. The latter offers high accuracy and adaptability for complex geometries, while thermal network models benefit from simplicity, speed and robustness. We apply both approaches to a self-supported 40 000 m LH2 tank concept for maritime transport that operates at constant pressure, and analyze sensitivity to structural support thickness, warm boundary temperature, and choice of insulation material. The thermal network model can estimate heat ingress with -1% error and the cold-spot temperature with error less than 1 K.Thermal performance estimation for cryogenic storage tanks: Application to liquid hydrogenpublishedVersio

Long‑term phase changes in cathodically protected marine reinforced concrete bridge

The application of cathodic protection (CP) gains increasing interest for maintaining the structural integrity of coastal concrete bridges facing premature degradation due to reinforcement corrosion. The present investigation was undertaken to obtain field experience on the long-term performance of impressed current cathodic protection (ICCP) installed on a Norwegian marine concrete bridge. Cores with and without anode ribbons from five protection zones were extracted 16–17 years after installation of ICCP. The cores were investigated by visual inspection and using µ-XRF for elemental distribution. µ-XRF measurements showed decreased intensities for calcium and sulfur around anode ribbons in some samples. Chloride accumulation at anode ribbons was observed in three of five cores, leading to lower ingress depth in the concrete but also a higher maximum chloride content near the anode compared to the cores without anode ribbons. The anode ribbons appeared intact. Phase changes around the anode ribbon were investigated with XRD, TGA and pH measurement. The ICCP had induced neutralization (pH 7) of the overlay mortar in the vicinity of some of the anode ribbons, resulting in the decomposition of hydration products like portlandite and the formation of gypsum, leading to a weaker material.publishedVersio

Logistics of the Hydrogen Industry in Northern Europe

Hydrogen is seen as an important element in the near future energy systems. However, challenges exist on its exact role, financing, and policy. In this document, we present a preliminary analysis of potential value chains for hydrogen in Northern Europe. We employ an optimisation model, BROMo, to perform this analysis. BROMo has been used in the past to model value chains in the context of bioresource management, and recycling. In this work, we model the hydrogen value chain and its related value chains in the context of production and demand logistics in Northern Europe. This puts hydrogen in the same context as other industrials sectors of the economy, as opposed to being solely a component of the energy system. Initial findings from this study reveal that a simplified model of hydrogen sources can serve as a foundation for more intricate analyses. This approach allows for varied scenario assumptions concerning the significance of hydrogen value chains in the future.publishedVersio