Energy Research Centre of the Netherlands

Ammonia, widely regarded as the “hydrogen carrier of the future,” offers high hydrogen content, ease of production, and a well-established infrastructure for handling and transportation globally. Meanwhile, ammonia cracking requires a heat supply at high temperatures, and induction heating provides efficient, precise, and rapid heating to conductive materials of different shapes and sizes. Therefore, this work presents a proof of concept for ammonia cracking using induction heating with three different reactor configurations: (1) a 3D metal workpiece; (2) a 3D metal workpiece and Ni/Al2O3 catalyst; and (3) only Ni/Al2O3 catalyst. The performance of the inductively heated reactor is also compared to an electric furnace. The results showed that the reactor with the workpiece and the catalyst required 97 W to reach 650 °C, being the most efficient in terms of power usage when compared to the workpiece alone and the electric tube furnace, which required 39% and 132% more, respectively; the least efficient configuration is with just the catalyst, needing 138 W to reach just 116 °C. Overall, the introduction of the 3D workpiece allowed for fast and uniform conversion and heating within the reactor, enabling efficient and dynamic process control when applying induction heating to chemical reactors.

Abstract Planetary flows are shaped by interactions at scales much smaller than the flows themselves, with mesoscale and sub–mesoscale eddies playing key roles in mixing, particle transport and tracer dispersion. To capture these effects, we introduce a stochastic formulation of the primitive equations within the Location Uncertainty (LU) framework. Derived from conservation principles via a stochastic Reynolds transport theorem, this approach decomposes velocity into a smooth–in–time large–scale component and a random–in–time field representing unresolved scales effects. To model the velocity noise term, we develop two data–driven methods based on Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) and extend this to hybrid approaches combining model– and data–driven constraints. Simulations show that the LU framework enhances gyre flow predictions, improving mixing, jet structure, and tracer transport while revealing the interplay between small– and large–scale dynamics.

Black Smoke (BS) served and still serves in several countries as official measure for Particulate Matter (PM) because of its easy determination via the blackness of filter samples. However, BS is a poor proxy for total PM but a rather good equivalency quantity for light absorbing "Elemental Carbon" deriving from diesel emissions (ten Brink et al., 2021). The latest WHO Report on Air Quality (WHO, 2021) recommends monitoring of Elemental Carbon (EC), but does not prescribe a specific measurement method, so using the BS method to obtain EC concentrations remains an inexpensive option in countries where BS is still measured and expensive direct EC measurements are not easily available. Yet there is a caveat: national regulations demand the use of the measurement protocol given in ISO-9835 (ISO, 1993), which prescribes optical reflectance measurements on filter samples. We analysed this report and found a series of critical issues. It only mentions a dimensionless "Black Smoke Index" (BSI), whereas in official legislation BS must be provided as mass concentration (in μg m-3). In addition ISO-9835 gives no reference for the conversion of the measured light absorbance to BSI; in fact the report does not even provide a proper definition of BS. Therefore we strongly argue to use the official EU-manual by Christolis et al. (1992) for BS determination when and where ever BS is still measured. This manual prescribes the conversion of light absorption as measured with the standard EEL 43 Smoke Stain Reflectometer for samples on the standard substrate of Whatman-1 cellulose fibre filters in monitoring networks. The BS concentrations obtained following this manual can then be provisionally converted to EC with the factor of 0.15±25% found by ten Brink et al. (2021) to obtain EC values as if measured according to the European reference EUSAAR2-TOT protocol (EN 16909:2017) in the countries still measuring BS until local equivalency is established with proper protocols.

The urgency to combat global climate change has prompted the implementation of many regional and national policies, with the European Green Deal standing out as one of the most significant initiatives. We use the recently developed TIMES-Europe energy system model to study the pivotal role of the residential sector in achieving the ambitious energy savings goal formulated by the EU in the broad framework of its Fit-for-55 policy package. We observe improved energy efficiency in households across a set of scenarios that differ in terms of climate policy ambition and level of collaboration between European countries. We find that, by 2030, residential buildings can realize up to 3000 PJ in overall energy savings. Cross-country collaboration may yield an additional 11% reduction in residential energy consumption, which could increase to 18% when combined with dwelling retrofitting subsidies. Our analysis of the transformation of the residential fuel mix, particularly the interplay between biomass and natural gas usage, reveals a trade-off between short-term energy efficiency gains and long-term CO2 reduction goals. In the short run, scenarios lacking stringent climate control measures exhibit higher energy savings in comparison to those embracing ambitious climate targets. This initial difference, however, diminishes over time: energy savings from climate-compliant scenarios nearly align with those in scenarios without strict climate compliance around 2040. Scenarios lacking effective climate policy result in significant delays in decarbonizing the European residential sector. Our findings underscore the critical role of ambitious climate targets and accelerated retrofitting rates, highlighting the necessity to imminently and proactively implement directed policy interventions.

Sorption-enhanced dimethyl ether synthesis (SEDMES) is a powerful technology to produce dimethyl ether (DME) from captured CO2 and renewable H2. In situ water by-product removal by zeolites shifts the thermodynamic equilibrium of the reaction towards product formation. Sorption enhancement proved to provide a single-pass CO2 conversion above 90%. This work presents a modelling study of the SEDMES process to optimize its performance under varying conditions. A universal cycle was designed to fulfil the requirement of continuous DME production as well as feed and purge flows. The cycle design is based on a state-of-the-art pilot plant commissioned by TNO in 2023, located in Petten, The Netherlands. Multiple Pareto fronts were generated to express the trade-offs between DME productivity and carbon selectivity in the SEDMES process for the first time. The impact of such process parameters as operating pressure, cycle duration, amount of inert gases, tube geometry and feed flow rate was analysed. A general trend of increased carbon selectivity and productivity at higher pressure was observed and analyzed under relevant cycle durations. However, this enhanced performance comes with the negative side effect of higher DME loss associated at elevated pressure operation. The SEDMES process proved to be tolerant to high concentrations of inert gases such as N2, reducing the need for extensive pretreatment steps. A lower feed flow rate was found to positively impact carbon selectivity to DME, which is promising for operation under intermittent conditions. Finally, even a minor increase in tube diameter reduced the Gas Hourly Space Velocity (GHSV), enhancing DME selectivity in a manner comparable to the effect of lower feed flow rates. Maximum productivity increases from 2.2 kg/h with 50.2% DME selectivity at 20 bar to 3.6 kg/h with 88.5% DME selectivity at 50 bar. The optimal cycle duration for these points also increased from 113 to 233 min, respectively.

Ground mounted solar parks lead to changes in the micro-climate under and between the PV tables. In particular, the vegetation on the soil is, in various degrees, shaded from direct sunlight and indirect, diffuse light. Also, the changes in precipitation distribution, air temperature and wind speed will affect the conditions. This leads to varying conditions for the vegetation affecting photosynthesis, which on the longer term influences the soil quality. To ensure sufficient light for photosynthesis, initial thresholds for irradiance have been drafted by TNO and Wageningen University and Research for the climate conditions in the Netherlands. Based on these rules, we present for the first time a method to evaluate the trade-off between soil irradiance and energy yield, related to table configuration and module choice, for utility-scale solar parks. Irradiance on the ground has either passed around the PV tables, passed through the gaps between panels or is transmitted between the solar cells in the panels. This leads to an optimisation of the module transparency and the size and relative position of the PV tables, when minimising the costs and at the same time complying with these irradiance criteria. To illustrate this optimisation, we have simulated the annual energy yield and ground irradiance and calculated the effect on the levelised cost of electricity. We present two solar park designs, that have the same ground irradiance distribution. One design is installed with partially transparent, bifacial modules, the other with gaps between the opaque, bifacial modules. Although the transparent bifacial modules have a somewhat lower module power, this system produces more kWh per hectare and has a lower levelised cost of electricity. The present paper shows that the partial transparency of bifacial modules is a key feature to maintain the soil ecology, and profitability, thus contributing to societal acceptance.

Abstract Chapters 1 and 2 laid out the framework and guiding principles of the European electricity market. In this chapter, the basics of capacity calculation are discussed, i.e. how to determine how much (cross-zonal) transmission capacity is available for commercial exchanges. The geographical organization of the European Union into capacity calculation regions (CCRs) is discussed, and the succession of timeframes over which capacity is calculated. The capacity calculation process is described in detail: the inputs required, actors involved, and the different methodologies of capacity calculation used/applied in Europe. Then, the day-ahead capacity calculation methodology applied in Core CCR is explained through several important steps and concepts: non-costly remedial action optimization, individual validations, allocation constraints, evolved flow-based, advanced hybrid coupling. Finally, the future evolution of capacity calculation in Europe is explored.