Abstract

This paper explores the challenges of local flexibility markets in Sweden, with a case study of “sthlmflex,” a local flexibility market in Stockholm. Local flexibility markets are emerging as important tools for managing local grid congestion, supporting the integration of renewable energy sources, and enhancing the resilience of the electricity grid. The study examines the drivers and barriers faced by market participants, especially aggregators and flexibility service providers. Through qualitative research, the study highlights the operational and challenging dynamics of local flexibility markets. The results show strong interest among actors to learn more about new concepts in the energy sector and to contribute to society. However, the findings also stress the importance of transparent and trustworthy governance, with the distribution system operator not overseeing the market. It is likely that both sellers and buyers would benefit from integrating the ancillary market with the local flexibility market, which should be governed by the transmission system operator.

Abstract

The pulp and paper industry accounts for ~6% of global industrial energy use and ~2% of direct COâ‚‚ emissions. This study develops a process-level energy and emissions model for an integrated Swedish kraft mill. Thermal and electrical demands were quantified using benchmark-specific energy consumption values, refined with first-principles models for drying, evaporation, and cooking. Emissions covered biogenic and fossil COâ‚‚ from combustion and indirect electricity use. Drying (38%), evaporation (24%), and cooking (18%) dominated thermal demand, with recovery and bark boilers supplying most steam and contributing >50% of total COâ‚‚ emissions. Three electrification pathways were assessed: electric boilers (EB), high-temperature heat pumps (HTHP), and mechanical vapour recompression (MVR). MVR reduced evaporator demand by ~92%, while complete substitution with low-carbon electricity cut mill emissions by up to 90%, depending on grid intensity. The framework integrates energy balances with technoeconomic indicators, supporting process-level prioritization and cost-effective decarbonization.

Abstract

As the Swedish energy system is experiencing capacity shortage challenges brought on by an overburdened grid in an increasingly electrified society, more solutions are needed for its optimization. One proposed solution is the increase of energy flexibility by encouraging public and private actors to enter the so-called local flexibility energy markets. This paper reports on the findings from a qualitative study in which we aimed to articulate how different industry actors conceptualise flexibility. Towards this goal, we employed the theoretical concept of boundary objects to illustrate the different meanings attributed to the same concept. Results show that although a generic definition of flexibility is existent across the different actors, the concept is also understood in accordance with their a)practices and needs, and b)engagement with large actors with significant decision-making power.

Abstract

One potential alternative for reducing CO2 emissions from the steel industry involves replacing the traditional coal-based steelmaking route with hydrogen-based steelmaking technologies. From a chemical and energetic point of view, this would mean replacing coal as source of energy and carbon for the iron ore reduction process with hydrogen as reductant and electricity as the main energy input. As a highly energy-intensive industry, the sourcing of energy for its needs greatly affects its overall environmental impacts and its role in a wider energy system. This paper evaluates a possible evolution of energy and material demands in different development stages of a steel plant transitioning towards hydrogen-based steelmaking technologies using a long-term mathematical optimization model. Moving to iron ore reduction by hydrogen from electrolysis with electricity from wind turbines would shift the raw material requirements from large amounts of mined coking coal to smaller amounts of diverse materials for the wind turbines and electrolyzers, including rare earth elements, as well as an increased need for natural gas and recycled steel scrap. While the total quantity of required materials will inarguably be reduced, the impacts of construction of and reliance on increased electricity generation will need to be considered.

Abstract

Under the background of deep peak-shaving in coal-fired power plants, the flexible control of the CO₂ capture process is of great significance for achieving efficiency decarbonization under wide-load range conditions. In this paper, an intelligent control method based on machine learning is proposed to maintain the flue gas capture rate requirements while keeping the energy consumption at a low level across a wide-load range. First, a thermodynamic model for the typical CO2 capture process with 30 wt.% monoethanolamine (MEA) solution is established. Second, considering the key operating parameters of the CO2 capture process, a machine learning model is trained to achieve accurate predictions of the capture rate and specific regeneration energy. Finally, an intelligent control method is proposed to minimize energy consumption while maintaining the required CO2 capture rate across wide-load range. The results show that the energy consumption of CO2 capture can be maintained near the minimum range using the intelligent control method, while maintaining a CO2 capture rate with a relative error of less than 5%, achieving the flexibility, high efficiency and low carbon of the coal-fired power plant.

Abstract

Enhancing energy efficiency in the building sector is vital for climate change mitigation. Phase change materials (PCM), known for their high latent heat storage capacity during phase transitions, offer promising potential in regulating indoor temperatures and reducing dependence on HVAC systems. This study presents a preliminary experimental investigation into the thermal performance of wallboards enhanced with PCM under subarctic conditions in Umeå, Sweden. Four types of wallboards were tested: a conventional gypsum board, a commercial PCM board (cPCM), and two lab-fabricated boards with 60% and 82% microencapsulated PCM by mass (mPCM60 and mPCM82). Thermal properties of the PCM were characterized using Differential Scanning Calorimetry (DSC), confirming high latent heat capacity and thermal stability. In a field setup, surface temperatures were monitored to assess thermal buffering capacity. Results show lower temperature fluctuations in the mPCM82 and mPCM60 wallboards, indicating enhanced thermal performance of the envelope compared to the gypsum board. However, the thermal performance of cPCM was even worse than gypsum, which could be attributed to the observed material settlement. These findings suggest the potential of PCM-enhanced wallboards to improve indoor thermal comfort and energy performance, while also emphasizing the importance of material selection and design in practical applications.