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.
Titanium-based lithium adsorbents such as protonated titanate (H2TiO3, HTO) are promising materials for direct lithium extraction, but their long-term use is limited by titanium dissolution during acidic regeneration. In this work, the role of regeneration chemistry in controlling lithium recovery and HTO stability was investigated using porous HTO/PVC composite beads. Li2TiO3 was shaped into spherical beads by solvent–antisolvent granulation with polyvinyl chloride as binder and subsequently converted to HTO by acid-induced proton exchange. Lithium adsorption and desorption were evaluated through batch experiments, kinetic studies, multi-cycle stability tests, and recirculating packed-bed operation using hydrochloric and sulfuric acid solutions with and without ammonium acetate buffering.The HTO/PVC beads achieved lithium uptake capacities of approximately 20–22 mg g−1 without loss of intrinsic HTO adsorption capacity after shaping. Unbuffered acidic regeneration caused significant Ti dissolution and progressive capacity loss, particularly under strongly acidic and sulfate-containing conditions. In contrast, buffering the regenerant to pH ≥ 3 suppressed Ti dissolution while maintaining efficient lithium desorption. The results are consistent with titanium speciation, where buffering prevents pH excursions into the Ti-solubilization domain without limiting proton-driven Li+/H+ exchange. Repeated batch cycling and packed-bed experiments confirmed that buffered regeneration preserves sorbent performance and enables lithium enrichment during regenerant reuse. These findings show that regeneration chemistry, rather than sorbent composition alone, governs the durability of HTO-based adsorbents and provides a practical route to improve their process relevance for direct lithium extraction.
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.
