Ambities voor de Nederlandse Basisindustrie in relatie tot een Systeemtransitie Klimaat

Input voor de discussie met de vaste Kamercommissie EZK op 19 januari 202

Modeling the sorption dynamics of NaH using a reactive force field

We have parametrized a reactive force field for NaH, ReaxFFNaH, against a training set of ab initio derived data. To ascertain that ReaxFFNaH is properly parametrized, a comparison between ab initio heats of formation of small representative NaH clusters with ReaxFFNaH was done. The results and trend of ReaxFFNaH are found to be consistent with ab initio values. Further validation includes comparing the equations of state of condensed phases of Na and NaH as calculated from ab initio and ReaxFFNaH. There is a good match between the two results, showing that ReaxFFNaH is correctly parametrized by the ab initio training set. ReaxFFNaH has been used to study the dynamics of hydrogen desorption in NaH particles. We find that ReaxFFNaH properly describes the surface molecular hydrogen charge transfer during the abstraction process. Results on heat of desorption versus cluster size shows that there is a strong dependence on the heat of desorption on the particle size, which implies that nanostructuring enhances desorption process. To gain more insight into the structural transformations of NaH during thermal decomposition, we performed a heating run in a molecular dynamics simulation. These runs exhibit a series of drops in potential energy, associated with cluster fragmentation and desorption of molecular hydrogen. This is consistent with experimental evidence that NaH dissociates at its melting point into smaller fragments

Predictions of melting, crystallization, and local atomic arrangements of aluminum clusters using a reactive force field

A parametrized reactive force field model for aluminum ReaxFFAl has been developed based on density functional theory (DFT) data. A comparison has been made between DFT and ReaxFFAl outputs to ascertain whether ReaxFFAl is properly parametrized and to check if the output of the latter has correlation with DFT results. Further checks include comparing the equations of state of condensed phases of Al as calculated from DFT and ReaxFFAl. There is a good match between the two results, again showing that ReaxFFAl is correctly parametrized as per the DFT input. Simulated annealing has been performed on aluminum clusters Aln using ReaxFFAl to find the stable isomers of the clusters. A plot of stability function versus cluster size shows the existence of highly stable clusters (magic clusters). Quantum mechanically these magic clusters arise due to the complete filling of the orbital shells. However, since force fields do not care about electrons but work on the assumption of validity of Born–Oppenheimer approximation, the magic clusters are therefore correlated with high structural symmetry. There is a rapid decline in surface energy contribution due to the triangulated nature of the surface atoms leading to higher coordination number. The bulk binding energy is computed to be 76.8 kcal/mol. This gives confidence in the suitability of ReaxFF for studying and understanding the underlying dynamics in aluminum clusters. In the quantification of the growth of cluster it is seen that as the size of the clusters increase there is preference for the coexistence of fcc/hcp orders at the expense of simple icosahedral ordering, although there is some contribution from distorted icosahedral ordering. It is found that even for aluminum clusters with 512 atoms distorted icosahedral ordering exists. For clusters with N≥256 atoms fcc ordering dominates, which implies that at this point we are already on the threshold of bulklike bonding

Parametrization of a reactive force field for aluminum hydride

A reactive force field, REAXFF, for aluminum hydride has been developed based on density functional theory (DFT) derived data. REAXFF_(AlH_3) is used to study the dynamics governing hydrogen desorption in AlH_3. During the abstraction process of surface molecular hydrogen charge transfer is found to be well described by REAXFF_(AlH_3). Results on heat of desorption versus cluster size show that there is a strong dependence of the heat of desorption on the particle size, which implies that nanostructuring enhances desorption process. In the gas phase, it was observed that small alane clusters agglomerated into a bigger cluster. After agglomeration molecular hydrogen was desorbed from the structure. This thermodynamically driven spontaneous agglomeration followed by desorption of molecular hydrogen provides a mechanism on how mobile alane clusters can facilitate the mass transport of aluminum atoms during the thermal decomposition of NaAlH_4

Institutional constellations and policy instruments for offshore wind power around the North Sea

This paper analyses how institutional constellations and their associated mode of risk allocation are reflected in the choice of policy instruments for the promotion of offshore wind power. Using the Varieties of Capitalism framework we expect that governments in Liberal Market Economies (LME) tend to use policy instruments that privatise investments and risk-taking, while those in Coordinated Market Economies (CME) use policy instruments that facilitate investments and shared risk-taking in the earlier, more riskful phase of technological development. We test our expectations through a longitudinal comparative analysis of the use of policy instruments and the deployment of offshore wind power in Denmark, the United Kingdom, Germany and the Netherlands between 1990 and 2020. Our results confirm the market oriented nature of policy instruments employed by the LME case of the United Kingdom throughout, while we witness initially lower levels of market orientation among the CME cases of Germany, Denmark and the Netherlands. Though the market orientation of Germany's policy instruments declined half way to build up domestic momentum, we generally see an increased use of market oriented policy instruments over time by the CME. Putting the trajectories together we witness an overall convergence in the use of policy instruments which we attribute to the liberalisation of the energy sector in the EU as well as to policy-learning effects. The results have generic relevance and can also be used to inform future national strategies and policies for deploying new low-carbon technologies, such as electrolysis for green hydrogen, which face similar risks and challenges

Integrated assessment on the implementation of sustainable heat technologies in the built environment in Harbin, China

Heating in built environments is an essential factor regarding energy consumption and CO2 emissions. Thus, the application of sustainable heating technologies is vital for reducing CO2 emissions. The literature indicates the requirement for a comprehensive assessment of the technical, economic, and environmental performances of various sustainable heating technologies and their implementation feasibility at the local level. Accordingly, this study presents a quantitative assessment relative to Harbin, a typical northern city with a coal-dominated heating system. Seven sustainable heating technologies were examined using current policy and future renewable scenarios. The results indicate that the examined heating technologies are technically feasible. Biomass heating saves costs and emissions (CO2 avoidance costs of 24–47 €/t), although fuel availability and storage management limit its implementation. Solar heating is a promising technology with reduced costs and low CO2 emissions (CO2 avoidance costs can decline by 50% from 2020 to 2050). However, its current resident acceptance is relatively low as lengthy investigations and periods for underground construction are required. Electric heating is preferable in terms of implementation feasibility; however, its economic competitiveness and environmental impact depend heavily on electricity prices and grid cleanliness (CO2 avoidance costs of 120–463 €/t). This study contributes to the existing literature on sustainable heat transition in China by providing informative local circumstances in Harbin and presenting assumption-making methods in detail when local data is not transparent. The integrated assessment provides solid evidence to facilitate decision-making in the clean heating transition in northern cities of China. The methods are applicable to other countries with similar heat-supply structures and climate conditions

Modeling of Hydrogen Storage Materials: A Reactive Force Field for NaH

Parameterization of a reactive force field for NaH is done using ab initio derived data. The parameterized force field(ReaxFFNaH) is used to study the dynamics governing hydrogen desorption in NaH. During the abstraction process of surface molecular hydrogen charge transfer is found to be well described by the parameterized force field. To gain more insight into the mechanism governing structural transformation of NaH during thermal decomposition a heating run in a molecular dynamics simulation is done. The result shows that a clear signature of hydrogen desorption is the fall in potential energy surface during heating

Multiscale modeling of interaction of alane clusters on Al(111) surfaces: A reactive force field and infrared absorption spectroscopy approach

We have used reactive force field (ReaxFF) to investigate the mechanism of interaction of alanes on Al(111) surface. Our simulations show that, on the Al(111) surface, alanes oligomerize into larger alanes. In addition, from our simulations, adsorption of atomic hydrogen on Al(111) surface leads to the formation of alanes via H-induced etching of aluminum atoms from the surface. The alanes then agglomerate at the step edges forming stringlike conformations. The identification of these stringlike intermediates as a precursor to the bulk hydride phase allows us to explain the loss of resolution in surface IR experiments with increasing hydrogen coverage on single crystal Al(111) surface. This is in excellent agreement with the experimental works of Go et al. [ E. Go, K. Thuermer, and J. E. Reutt-Robey, Surf. Sci. 437, 377 (1999) ]. The mobility of alanes molecules has been studied using molecular dynamics and it is found that the migration energy barrier of Al_(2)H_6 is 2.99 kcal/mol while the prefactor is D_0 = 2.82 × 10^(−3) cm^2/s. We further investigated the interaction between an alane and an aluminum vacancy using classical molecular dynamics simulations. We found that a vacancy acts as a trap for alane, and eventually fractionates/annihilates it. These results show that ReaxFF can be used, in conjunction with ab initio methods, to study complex reactions on surfaces at both ambient and elevated temperature conditions

Techno-economic-environmental analysis of seasonal thermal energy storage with solar heating for residential heating in China

Seasonal thermal energy storage (STES) of solar heat is an option of interest for clean heat transition, as residential heating is often fossil fuel-based. This study 1) proposes an integrated optimization criterion to examine how local context influences the optimal configuration planning, techno-economic-environmental performance, and feasibility of STES application; 2) identifies the position of STES in comparison to other sustainable heating options considering the local context; and 3) provides a comprehensive and transparent showcase highlighting the importance of the local context in determining the feasibility of STES in the clean heating transition. The TRNSYS modeling tool is adopted to analyze the performance, and Pareto optimization is applied to treat the multi-objective optimization. The solar fractions and storage efficiencies of the four case studies range between 58-67% and 57–69%, respectively. STES has significant potential to reduce CO2 emissions (52–72%) compared to conventional heating systems. However, the heating cost of the STES system (5.4–8.7 €-ct/kWh) is more than twice that of the conventional heating system. The CO2 avoidance cost of the four case studies ranges between 114 and 368 €/t. Properly reducing the borehole number in cold climate zones and increasing the solar collector area in warm climate zones help improve the system performance