Several sources of flexibility in transmission and, especially, distribution networks are being unlocked by advances in information and communication technologies, aggregators, and new flexibility markets. However, maximizing benefits for both transmission and distribution system operators in a coordinated way requires new algorithms, modeling tools, and modernization of regulatory frameworks. Such approaches must account for uncertainties, the physical and operational constraints of flexibility providers and the grid itself, constraints on information exchange, and scalability, including computational requirements and time constraints. Given the diverse contexts and jurisdictions around the world, there is no single recipe for achieving coordination, but important trends and shared challenges are emerging. This paper surveys the complexities of coordination from technical, market, and technological perspectives, and outlines current practices, proposed approaches, and future research directions to effectively manage, coordinate, model, and leverage flexibility across voltage levels.
Every three years, the European Commission publishes a list of critical raw materials (CRMs) based on economic importance and supply risk. Boosting recovery rates is a strategy for criticality mitigation, but not equally relevant for all CRMs. This study develops a pragmatic, demand-driven framework to prioritise CRMs for recycling. The approach integrates four dimensions: criticality, relative availability, industrial demand, and recovery systems effectiveness. Industrial demand introduces a market-pull perspective, linking recycling to existing value chains and economic viability. The framework relies on publicly available data and avoids product-level modelling. Applied at the EU level and for Belgium and Germany, it demonstrates varying priorities across geographic contexts. Results position materials within a two-dimensional matrix that enables a structured diagnosis of where policy intervention is most likely to generate systemic impact. This approach translates criticality assessments into actionable recycling priorities for policymakers, aligned with industrial demand and regional specificities.
In order to overcome the problem that oil and gas boilers in existing buildings are typically replaced again by fossil fuel boilers, leading cantons in Switzerland have started to implement more targeted decarbonisation policies. The objective of the present paper is to critically discuss the experience made with policy measures for the decarbonisation of building-related heating systems in these cantons. For this purpose, semi-structured interviews were conducted as primary method. Early evidence indicates that the policies are effective by ensuring the transition to renewable heating technologies (primarily heat pumps). The implemented policy packages include coercive elements (mandatory renewable energy shares), subsidies as well as information and communication measures, resulting in a quasi-ban of fossil fuel boilers. Avoiding outright bans of fossil fuel use seems both effective to increase acceptance among building owners and reasonable to account for particularly demanding cases of boiler replacement (for which there is no technically or financially viable, fully renewable solution). Considering the very low carbon footprint of its electricity supply, Switzerland is a particularly convincing case for the transition from fossil fuel boilers to electric heat pumps. This is shown by means of an analysis of the CO2 emissions of heat pumps in comparison to gas and oil boilers across several European countries. We then compare the levelised cost of heat pumps for different subsidy levels. For a typical subsidy for the heat pump (equivalent to 11% of the investment cost), its levelised cost remains in an acceptable range compared to a gas boiler (7% more expensive). A sensitivity analysis shows the importance of high gas to electricity price ratios for financial viability. Evidence from leading cantons in Switzerland indicates that the chosen policy measures are effective, affordable and accepted and that they can be recommended to other countries.
High-phosphorus iron ore (HPIO) is a refractory ore due to its high phosphorus content and complex mineral phase structure. Hydrogen reduction has emerged as a promising technology for its superior performance. In this study, using hematite as a reference, the reduction kinetics and reaction mechanisms of HPIO under a hydrogen atmosphere were investigated via non-isothermal kinetics, with a particular focus on the influence of gangue minerals on the reduction behavior. The results indicated that the reduction process of HPIO differed significantly from hematite due to carbonate gangue decomposition and oolitic structure. Based on conversion rate (α) analysis, the reduction process of HPIO was reclassified into four distinct stages, whereas hematite reduction occurred in three stages. In the first three stages of HPIO, the most likely reaction kinetic mechanisms were the 1.5th-order reaction model (F1.5), the 3rd-order reaction model (F3), and the three-dimensional Jander diffusion model (D3), with corresponding activation energies of 67.05 kJ/mol, 70.36 kJ/mol, and 122.27 kJ/mol, respectively. Correspondingly, the rate-limiting step transitioned from the surface-to-interior gradient reduction process to intraparticle hydrogen diffusion. This transition was collectively driven by oolitic gangue phases, densification of the surface iron layer, and CO2 generated from carbonate decomposition, which synergistically hindered hydrogen diffusion within the particles.
This study explores the role of two lignocellulosic pathways, REDIFUEL and lignocellulose-to-naphtha, within the Belgian energy transition by integrating prospective life cycle assessment (LCA) with an energy system optimization model. The results show that system performance is primarily driven by resource imports rather than individual technology choices. Advanced biofuels may contribute cost-effectively to the energy transition by 2030, whereas biobased chemicals only become significant by 2050. However, their deployment increases reliance on wood and renewable hydrogen, leading to higher environmental impacts in several impact categories and a decline in the energy return on investment (EROI). More broadly, scenarios relying on imported renewable hydrogen are associated with increased upstream impacts, particularly for water depletion and land use, and lower EROI at the point of use. These results highlight a shift from local emission reductions to upstream, resource-related impacts occurring largely outside Belgium. Overall, the findings highlight that system-level assessments can yield different conclusions from product-level studies and are essential for capturing resource competition, cross-sector interactions, and burden-shifting effects.
