Scientific support of industrial high-temperature aquifer thermal energy storage (HT-ATES) planning has proven to be particularly valuable for enabling informed decision-making under uncertainty, integrating heterogeneous data sources into consistent conceptual and numerical frameworks, and guiding the stepwise refinement of site-specific models. This contribution presents an integrative modelling approach developed to support the planning of an HT-ATES in South-East of Berlin. Numerical modelling was employed from early stages to improve process understanding, and quantify uncertainty. To support the design of a multicomponent thermal push-pull test with tracers, the 1D advection–dispersion solver was integrated into a stochastic framework using Gaussian Process Emulator for parameter estimation under uncertainty, enabling calibration of thermal and solute dispersivities. To identify optimal well spacing under urban constraints, thermal criteria were evaluated using an ensemble of simplified spatial models, which informed a probabilistic classifier predicting thermal interference under natural and technical uncertainties. The results for the 6 month injection/withdrawal cycles allowed identifying the distance range of 130-180 m in a well doublet. The sensitivity analysis confirmed that the well placement, aquifer thickness, charging flowrate, charging temperature, permeability, and porosity are influencing the thermal interference. Finally, to represent the site heterogeneity and support planning on the large scale, a full-scale 3D hydrogeological model was built using geological and geophysical datasets and is designed for iterative updating as new drilling and field data become available. Together, these models form a flexible and scalable framework that bridges scientific analysis and applied engineering needs in the development of urban ATES.

Aquifer Thermal Energy Storage (ATES) is a promising technology for storing excess energy in urban environments. Despite its potential to support urban decarbonization, the planning, approval, and implementation of ATES systems in Germany remains limited, partly due to uncertainties regarding long-term performance and environmental impacts within the subsurface. In particular, mineral precipitation and biofilm formation may clog wells and aquifers, thus posing operational challenges.

To assess temperature-dependent biogeochemical processes, we performed sterile and non-sterile flow-through column and batch experiments at 20°C, 40°C, and 80°C. Column experiments were conducted using natural siliciclastic sediment, while analogous artificial sediment was applied in the batch experiments. All experiments were carried out under anoxic conditions using natural groundwater from a ~200 m deep saline aquifer in Berlin. While flow-through column experiments focused on dissolution and precipitation processes, (de-)sorption phenomena and the distinction between biotic and abiotic processes under an Ar/CO₂ atmosphere, batch experiments examined the change of microbial abundance, activity and community composition, under four distinct gas atmospheres: N₂/CO₂, H₂/CO₂, Ar, and air.

Characterizing the original groundwater microbial community revealed the potential for microbial-induced corrosion, biofouling, iron sulfide and gas formation. Preliminary results of the batch experiments showed that growth and activity of the microorganisms were stimulated under anoxic compared to oxic conditions at 20 to 40 °C, while 80°C appeared to be detrimental. The presence of microorganisms appeared to induce changes in iron mineralogy and iron speciation.

The results will help to understand and mitigate the mechanisms responsible for efficiency losses in ATES systems.

We study hybrid pressure and temperature storage using supercritical CO₂ in the "supercharged hybrid gas-based energy storage” (SH-GES) process, a novel concept for surplus energy storage and potential geothermal system recharging. In this study the effect of reservoir permeability on geomechanical integrity during is assessed. Five reservoir permeability scenarios (50 mD to 2000 mD) were investigated using thermo-hydro-mechanically coupled numerical simulations. The reservoir is vertically bounded by low-permeability formations and transected by a tight fault. Pressure and temperature dependent two-phase flow, poroelasticity, and thermoelasticity are considered. Fault and rock mass integrity are assessed using Mohr-Coulomb safety factors, and monitoring of the minimum principal stress (S3). In the given setup the fault remains stable, and no tensile failure is observed. Shear failure may occur in the reservoir and the over- and underburden. Thermoelastic and poroelastic effects lead to reservoir bulging and stress redistribution, spatially aligning with zones of potential shear failure in the over- and underburden. Reservoir permeability governs pressure and temperature distributions in the reservoir, creating opposing impacts on the Mohr-Coulomb stability of the over- and underlaying formations. We show that reservoir permeability affects not only the stability of the reservoir, but also of the surrounding strata. This should be included in geomechanical assessments of subsurface energy storage.

Diese Fallstudie untersucht die Erfahrungen von Asper Investment Management beim Aufbau des Fernwärmenetzes in Bradford (West Yorkshire, UK) und diskutiert die Übertragbarkeit der dabei erzielten Entwicklungs­geschwindigkeit auf andere Märkte, insbesondere Deutschland. Bradford bietet eine hohe Wärmedichte in einem post-industriellen Stadtgefüge sowie einen politisch stark engagierten Gemeinderat; eine staatliche Investitionsbeihilfe von etwa 25 % der Gesamt­investition erlaubte es, die Endkundentarife unter das regionale Erdgas-Benchmark zu senken.

Der Zeitplan gilt als außergewöhnlich kurz: Zwischen Förder­zusage (Frühjahr 2022) und Planfeststellung für das Energie­zentrum (Herbst 2023) lagen lediglich 18 Monate; bereits im Mai 2025 befanden sich Bauarbeiten und erste Anschlussnahmen im Regel­betrieb. Wesentliche Treiber dieses Tempos waren stringente Investorenanreize, eine schlanke Projekt­organisation beim Entwickler sowie eine modulare Netz­konfiguration.

Technisch basiert die Anfangsphase auf einer großskaligen Luftwärmepumpe, flankiert von langfristigen Lieferverträgen mit öffentlichen Ankerkunden; perspektivisch ist die Einbindung industrieller Abwärme geplant. Die modulare Ausgestaltung ermöglicht eine stufenweise Erweiterung bis mindestens 2030.

Vier übertragbare Erfolgsfaktoren lassen sich ableiten: (1) frühzeitige Sicherung von Zuschüssen als Preis­senkungsinstrument, (2) phasenweiser Ausbau zur Reduktion von Risiko und Kapitalkosten, (3) institutionelle Unterstützung durch Kommunen zur Beschleunigung regulatorischer Prozesse und (4) konsequente Ausrichtung aller Projektakteure auf Zeit- statt Renditemaximierung. Gerade Letzteres zeigt, dass in liberalisierten Fernwärme­märkten erhebliche Synergiegewinne erzielt werden können, wenn Kapitalgeber, Behörden und Bauunternehmen gemeinsame Beschleunigungsziele verfolgen. Für deutsche Kommunen, die vor ähnlichen Dekarbonisierungs­aufgaben stehen, bietet das Bradford-Beispiel wertvolle Hinweise darauf, wie hohe Entwicklungsgeschwindigkeiten ohne Qualitätseinbußen realisierbar sind.