Volume 92, Issue 9-10 - Special Issue: Sensoren und Messtechnik für die Energiewende/Sensors and measurement technology for the energy transition; Guest Editor: Annette Röttger

Hydrogen is an energy gas that is used commercially in a variety of applications that include fuel cells. Before utilization, hydrogen must meet certain quality characteristics. ISO 14687 specifies the limit values of impurities in H 2 . Carbon monoxide is an impurity that must be accurately measured in commercial H 2 and its limit value as specified in ISO 14687 is 200 nmol/mol. In this work, we present a new laser spectrometric method for traceable CO impurity measurements in H 2 . The method is based on Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS). We demonstrate the applicability of the method by measuring CO amount fractions in H 2 in the range of 0.05–20 μmol/mol. The traceability of the results to the SI units is addressed and uncertainties are evaluated following the GUM (Guide to the expression of uncertainty in measurement) principles. For the CO amount fraction measurement range of 0.05–20 μmol/mol, the relative combined uncertainty of the results is in the 1.5 % range, k = 1.

Nitrous oxide (N 2 O) is gaining interest in maritime applications for several reasons, primarily related to engine performance enhancement, emissions reduction, and auxiliary power supply. While N 2 O can enhance combustion efficiency and reduce certain emissions, uncontrolled use could result in increased NO x formation and other pollutants. Effective N 2 O monitoring is critical in maritime applications for ensuring operational safety, regulatory compliance, and optimal performance. We introduce an innovative first-principles N 2 O spectrometer designed specifically for maritime applications, such as monitoring emissions during and after combustion processes. This TDLAS based spectrometer targets the P29e line at 4.55 µm spectral band and provides direct absolute mole fraction measurements, eliminating the necessity for prior or routine calibration.

For the setup of wideband power calibration systems at PTB and at INMETRO, two wideband multi-range voltage dividers that integrate (remotely) selectable voltage ranges from 60 V to 480 V, have been build up. The design is based on a phase-compensated, buffered, resistive voltage divider, in which the effect of stray capacitances within the high voltage arm has been minimised. The basic errors at 50 Hz show that all ranges are within ±60 ppm and ±5 µrad. The frequency-dependent amplitude errors in all four voltage ranges up to 100 kHz are practically identical and below 500 ppm. The phase errors up to 100 kHz follow a simple and almost linear phase characteristic with frequency, described by time constants with values within ±5 ns for each range. It could be shown that the frequency responses do not change with the applied input voltage. Self-heating effects, observable in the ratio error have been minimised by a fan to be smaller than 10 ppm at 480 V.

Radon ( 222 Rn) is a radioactive noble gas that is formed in the decay of the primordial 238 U decay chain, with an average abundance of 3 parts per million (3 g ⋅ t −1 ) in the earth’s crust. Since radon is the only noble gas in the decay chain, it has with its half live T 1 2 ${T}_{\frac{1}{2}}$ = 3.8232(8) d, the ability to emanate from the ground or building materials and to interfere with the biosphere. Taking into account Directive 2013/59/Euratom, the EURAMET EPM project RadonNET was founded to find a trade-off between energy efficiency and health effects by means of measurements with small uncertainties. With this in mind, an pulse ionization chamber for the time-resolved measurement of radon activity at low concentrations is described here. The solution shown is characterized by low sensitivity to room and impact noise. Experimental investigations show the properties of the pulse ionization chamber under various conditions, particularly with regard to its use in sensor networks in larger buildings or future cities.

The measurement and control of temperature plays a key role in achieving the European Green Deal targets for a low carbon energy system. Fibre-optic thermometry is an emerging technology that can improve temperature measurement in extreme environments for energy providers and industry due to its distributed sensing and immunity to electromagnetic fields. Various applications for optimisation and monitoring in the energy sector are described, covering the whole range from energy generation to transmission and consumption. However, fibre-optic thermometers have cross sensitivities to other quantities (e.g., strain and humidity) and ageing effects that need to be investigated, quantified and minimised to obtain traceable and reliable measurements. This is particularly important so that applications in critical infrastructure can benefit from future measurements that are not possible with conventional sensors. The European INFOTherm project aims to overcome the limitations that currently prevent the widespread use of fibre-optic thermometry by creating a dedicated European metrology infrastructure for research, development and calibration. First results on measurement uncertainty, improvement of measurement techniques and practical field tests are presented.

Zusammenfassung Der geplante Hochlauf von Infrastrukturen für nachhaltigen Wasserstoff entlang der Wertschöpfungskette erfordert einen gleichzeitigen Aufbau der nötigen Qualitätsinfrastruktur, um Sicherheit, Qualität und Abrechnungsgerechtigkeit zu gewährleisten. Von der Erzeugung erneuerbarer Energien, über die Produktion und den Transport von Wasserstoff und seinen Derivaten, bis hin zum Verbrauch werden an vielen Stellen Messungen verschiedener Messgrößen durchgeführt. Das stellt die Akteure der Qualitätsinfrastruktur vor neue Herausforderungen. Hierzu unterstützt die PTB andere Nationale Metrologie-Institute und Partner, z. B. in Tunesien und Namibia.

The paper highlights the global dimension of the energy transition and the crucial role of quality infrastructure. With a growing global population and rising energy consumption, the demand for electricity worldwide could almost double by 2050. This requires a fundamental shift from fossil energy systems to more sustainable and environmentally friendly alternatives. The energy transition involves not only technological but also societal transformations that enable the shift to renewable energy sources. A key facilitating and driving factor is quality infrastructure: it encompasses metrology, standardization, accreditation, conformity assessment, and market surveillance, enhancing the quality, safety, and environmental compatibility of products, services, and processes. The projects of the Physikalisch-Technische Bundesanstalt (PTB) International Cooperation contribute significantly to the development of a robust and reliable quality infrastructure that promotes international trust in products and services. Through close cooperation with global partners, internationally recognized cross-sector standards and good measurement and testing practices, for example, are developed to sustain free and fair trade while boosting safety and quality. This collaboration enables partner countries to establish their own national quality infrastructure, thus strengthening their position in global value chains and advancing the global energy transition. These complex interrelations are illustrated by examples from Vietnam and Tunisia.

The digital transformation of the quality infrastructure (QI) and the energy transition are two interrelated system changes. The energy transition and the overall increasing importance of sustainability requires the QI to more comprehensively assess products (e.g., batteries and electronics). In addition, the QI must provide trust and reliability to emerging technologies that are new or not fully established in the market (e.g., for the hydrogen economy). These requirements can only be met by a QI that reimagines its processes and incorporates digital solutions. The text presents concrete developments by the QI institutions and assesses their correlation with parallel developments in industry and the circular economy.

In the context of future cities and smart campuses, sustainability is a key challenge for future developments. The Smart Metrology Campus (SMC) data infrastructure, implemented as a lambda architecture, supports the collection of both sensor data and metrological metadata for electric energy meters. A Digital Twin for energy-aware High-Performance Computing can use the data to optimize the energy usage. This paper presents two possible integrations of the SMC data with the Digital Twin: using the collector agent of the Digital Twin and the serving layer of the SMC data infrastructure, and a direct integration of the speed layer into the Digital Twin database. Both methods are evaluated based on data access latency, historic data availability, and system complexity. The integration of the SMC lambda architecture with the Digital Twin offers benefits in terms of reduced maintenance, improved data flow stability, and easier extension for additional sensors or metadata.