Adela Marian

Research Institute for Sustainability (RIFS)

Superconducting cables have been proven in a variety of pilot projects and utility installations, demonstrating several of their advantages, including compact size and low energy losses, which can make the technology economically attractive for certain applications. It is clear though that different applications impose different requirements and ch...

The combination of liquid hydrogen and superconducting cables presents a unique opportunity to distribute both hydrogen and bulk electricity in the same infrastructure. In particular, liquid hydrogen around 20 K is ideally suited for cooling the MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</su...

In this policy brief we explore the views of stakeholders in South Africa, the EU’s largest trading partner in Africa, and consider measures necessary to ensure that the EU’s Carbon Border Adjustment Mechanism addresses issues of justice and sustainability. In particular we identify three key recommendations for European policymakers.

Solar technology diffuses across the globe as countries transition from fossil to renewable energy. Little solar-specific experience and capacity in newly adopting countries can result in technical failures and lower solar plant performance. This contributes to making the investment in solar plants in newcomer countries risky and may undermine poli...

This report presents a framework for the systematic monitoring of the global hydrogen economy, suggesting data sources and indicators to systematically survey the most important trends and developments. Monitoring based on this framework could provide an important knowledge base for the continuous review of policy measures related to the German and...

This policy brief outlines the potential benefits and challenges of including international quality standards as technical requirements in the design of public auctions, highlighting the crucial role of the Quality Infrastructure (QI) system in newcomer countries. Key lessons learnt are synthesised from international experiences with technical requ...

The purpose of this study is to examine if and how the EU CBAM influences the climate policy debate in Ukraine, one of the countries that is expected to be most affected due to its large share of carbon-intensive exports to the EU. The study seeks to find out how the EU CBAM can be made more instrumental in promoting an increase in the country's cl...

Since the EU Commission announced the introduction of a carbon border adjustment mechanism (CBAM) within the European Green Deal, debates intensified on its effectiveness for climate action, adhering to WTO regulations , and potential trade wars with China and the US. We argue that the implications of the EU CBAM for affected countries, especially...

This paper presents the main technological achievements of the first 3-gigawatt-class HVDC superconducting cable system, which was manufactured and successfully tested in the European project Best Paths. The technical focus is set on the cable conductor, the electrical insulation, and the high-voltage terminations. Furthermore, the implementation c...

In this article, we review the main impacts of the COVID-19 pandemic on the global energy sector and evaluate the implications of related policy responses on prospects for a transition to a climate-friendly energy system. In doing so, we differentiate between different types of countries and different dimensions of energy supply. Firstly, we assess...

Wenn die EU einen CO2-Grenzausgleich (Carbon Border Adjustment Mechanism, CBAM) einführt, könnten Länder, denen die Ressourcen für die Dekarbonisierung fehlen, schwerwiegende wirtschaftliche Folgen zu spüren bekommen. Die EU sollte daher mögliche politische Risiken berücksichtigen und Stakeholder aus Drittstaaten in die Gestaltung des CBAM einbezie...

The rising share of renewable energy in the European grid creates a demand for long-length, high-power transmission lines. Superconducting cables represent an attractive option for such connections, offering considerable savings in energy and space for installation. Due to its low cost, the MgB2 superconductor might be an interesting choice, but it...

Superconducting links are an innovative solution for bulk power transmission, distinguished by their compact dimensions, high efficiency and small environmental footprint. As with any new technology field, there is a large amount of design possibilities for such links, each of them having a profound impact on the system configuration. For instance,...

An EU Border Carbon Adjustment Mechanism (CBAM) may bring severe economic consequences to countries without the resources to adapt to a low-carbon paradigm. The EU should therefore consider possible policy risks and involve third-country stakeholders in CBAM policy design; use CBAM revenues to fund decarbonisation in at risk countries; and build em...

Grid integration remains one of the key challenges related to the worldwide expansion of distributed renewable energy systems. This paper presents innovative measures for increasing the hosting capacity of distribution grids with a focus on the medium-voltage grid, based on representative interviews with leading large-scale distribution system oper...

This IASS study takes an in-depth look at Covid-19's impacts on the global energy sector, and then zooms in to the country level to see individual country effects and responses. The case studies are compiled by energy researchers in Argentina, China, Germany, India, Israel, and the United States. Despite similar impacts of the corona crisis on ener...

High investment costs are a key impediment to the energetic refurbishment of residential buildings in Germany. A versatile consumer market for smart thermostat systems suggests that they might constitute a low-investment alternative that is also accessible for tenants. Here, we assess the cost-effectiveness of smart thermostat systems under differe...

Best Paths, the largest research project in the field of energy financed under the European Union's 7th Framework Programme for Research, Technological Development and Demonstration, explored new avenues for delivering reliable power in Europe through the large-scale integration of renewable energy. The project ended in September 2018, having unite...

This paper investigates the interplay between the German incentive regulation and renewable capacity integration. A comprehensive review of the current incentive regulation scheme and its 2016 amendment is first presented. Then, results of ten representative interviews with large-scale distribution system operators are analyzed. Firstly, all necess...

What are the prerequisites for employing superconducting links in the power grid of the future? This document assesses the main elements of a new 3-gigawatt-class superconducting cable. In addition to discussing the technical details of the cable conductor, electrical insulation, and grid connections, it outlines the environmental benefits and futu...

The integration of rooftop photovoltaic systems in the low-voltage distribution grids has become a major international trend, helped by the sinking prices for photovoltaics. One of the key questions revolves around the technical challenges brought about by the grid integration of these decentralized systems. This paper therefore analyzes the substa...

Superconducting power cables represent a recent innovative development for high-capacity underground transmission. They are set to join the portfolio of technologies that will be needed to accommodate the growing demands on electricity grids. These demands are brought about in particular by the rising amount of renewable energy and the increase in...

High-voltage direct-current superconducting cables are an attractive option for the high-capacity links of the future. Key elements of a 3-GW-class superconducting cable have been validated within the Best Paths European project.

BEST PATHS (acronym for “BEyond State-of-theart Technologies for rePowering Ac corridors and multi- Terminal HVDC Systems”) is a collaborative project of 40 leading European organizations from science and industry, supported by the 7th Research Framework Programme of the European Commission. The project investigates the feasibility of technological...

Der Ausbau von Photovoltaik-Aufdachanlagen ist international zu einem Megatrend geworden. Eine zentrale Frage bezieht sich dabei auf die technischen Herausforderungen bei der Integration in die Niederspannungsnetze. Daher analysieren wir in der vorliegenden Studie die umfangreichen Erfahrungen der deutschen Verteilnetzbetreiber, die eine Vorreiterr...

Superconducting transmission lines (SCTL) are an innovative option for the future electricity grid and in particular for high-capacity HVDC power transmission. The promise of superconducting electric lines lies principally in their small size, with potential advantages in terms of efficiency, environmental impact and public acceptance. Furthermore,...

Technological innovations are crucial for addressing the challenges of expanding and operating the electricity grid posed by the ongoing transformation of the energy system and the integration of renewable energy sources in particular. A multitude of technologies are already available, however reshaping the grid goes beyond technological developmen...

BEST PATHS (acronym for "BEyond State-of-the-art Technologies for rePowering Ac corridors and multi-Terminal HVDC Systems") is a collaborative project within the FP7 framework of the European Commission that includes an MgB2-based power transmission line among its five constituent demonstrators. Led by Nexans and bringing together transmission oper...

Despite the extensive research and development investments into superconducting science and technology, both at the fundamental and at the applied levels, many benefits of superconducting transmission lines (SCTL) remain unknown to the public and decision makers at large. This paper aims at informing about the progress in this important research fi...

In order to accommodate future demands on electricity grids, including increasing amounts of renewable energy, the current electricity grids will have to be modernised and expanded to enhance their flexibility and add new short-and long-distance links. The limitations of standard transmission technologies have spurred research and development in th...

Um künftige Anforderungen an Stromnetze zu erfüllen, auch bedingt durch wachsende Anteile erneuerbarer Energien, müssen die derzeitigen Stromnetze modernisiert und erweitert werden, um dadurch ihre Flexibilität zu erhöhen. Das erfordert neue Fernleitungen und lokale Verteilnetze. Da der herkömmlichen Übertragungstechnik Grenzen gesetzt sind, wurden...

Cables made of MgB2 superconductors are currently explored as a viable solution for transporting high electrical power in the AC regime. In order to be competitive against the DC solution, the cables need to have an acceptable level of AC losses. In this contribution, we discuss the main aspects relevant for designing a cable with a sufficiently lo...

There is universal agreement between the United Nations and governments from the richest to the poorest nations that humanity faces unprecedented global challenges relating to sustainable energy, clean water, low-emission transportation, coping with climate change and natural disasters, and reclaiming use of land. We have invited researchers from a...

A Sisyphean task: Laser cooling of molecules is difficult, mainly due to their rich vibrational structure, typically requiring dozens of repumping lasers. However, a proof-of-principle experiment to laser cool SrF molecules has been done (see picture), showing that laser cooling of some molecules is possible with just three lasers, as Highlighted h...

We have designed and implemented a new Stark decelerator based on wire electrodes, which is suitable for ultrahigh vacuum applications. The 100 deceleration stages are fashioned out of 0.6 mm diameter tantalum and the array's total length is 110 mm, approximately 10 times smaller than a conventional Stark decelerator with the same number of electro...

Maxwell’s demon has now been realized using laser light. The ability to let atoms pass one way but not the other through a light ‘gate’ could provide new means to cool atomic and molecular vapours.

We study the dynamic behavior of ultracold neutral atoms in a macroscopic ac electric trap. Confinement in such a trap is achieved by switching between two saddle-point configurations of the electric field. The gradual formation of a stably trapped cloud is observed and the trap performance is studied versus the switching frequency and the symmetry...

We demonstrate trapping of an ultracold gas of neutral atoms in a macroscopic ac electric trap. Three-dimensional confinement is obtained by switching between two saddle-point configurations of the electric field. Stable trapping is observed in a narrow range of switching frequencies around 60 Hz. The dynamic confinement of the atoms is directly vi...

We demonstrate high resolution coherent control of cold atomic rubidium utilizing spectral phase manipulation of a femtosecond optical frequency comb. Transient coherent accumulation is directly manifested by the enhancement of signal amplitude and spectral resolution via the pulse number. The combination of frequency comb technology and spectral p...

Optical spectroscopy and frequency metrology at the highest level of precision and resolution are being greatly facilitated by the use of ultracold atoms and phase stabilized light in the form of both cw and ultrashort pulses. It is now possible to pursue simultaneously coherent control of quantum dynamics in the time domain and high precision meas...

Phase control of wide-bandwidth optical frequency combs enables amazing capabilities in optical frequency measurement and synthesis, optical atomic clocks, united time-frequency spectroscopy, coherent pulse synthesis and manipulation, and deterministic studies in sub-cycle physics.

We take advantage of a phase-stable, wide-bandwidth femtosecond laser to bridge the fields of high-resolution spectroscopy and ultrafast science. Thus approach, which we call Direct Frequency Comb Spectroscopy (DFCS), involves using light from a comb of appropriate structure to directly interrogate atomic levels and to study time-dependent quantum...

A phase-stabilized femtosecond laser comb is directly used for high-resolution spectroscopy and absolute optical frequency measurements of one- and two-photon transitions in laser-cooled 87Rb atoms. Absolute atomic transition frequencies, such as the 5S1/2 F=2-->7S1/2 F"=2 two-photon resonance measured at 788,794 768,921 (44) kHz, are determined wi...

We implement a simple optical clock based on the F 2 2 P 7 , ν 3 optical transition in methane. A single femtosecond laser’s frequency comb undergoes difference frequency generation to provide an IR comb at 3.39 µ m with a null carrier-envelope offset. This IR comb provides a phase-coherent link between the 88-THz optical reference and the rf repet...

Two different schemes using femtosecond lasers for optical frequency metrology without the use of nonlinear fiber are experimentally demonstrated, allowing phase coherence between the microwave, visible, and infrared portions of the electromagnetic spectrum.

Ultrashort laser pulses have thus far been used in two distinct modes. In the time domain, the pulses have allowed probing and manipulation of dynamics on a subpicosecond time scale. More recently, phase stabilization has produced optical frequency combs with absolute frequency reference across a broad bandwidth. Here we combine these two applicati...

We employ cavity ring-down to perform absorption experiments of InGaAs/GaAs QDs. Integrating an AlAs/GaAs DBR incorporating InGaAs QD's into a Fabry-Perot cavity, we demonstrate this approach and its potential for sensitive measurements on semiconductor nanostructures.

We are using a phase-stabilized femtosecond laser comb to investigate two-photon transitions in laser cooled Rb atoms. The bandwidth associated with the femtosecond pulse is sufficiently wide to allow exploration of a large number of atomic states in a single pulse. The time delay between successive pulses is tuned so as to create an optical freque...

The carrier-envelope-phase-stabilization of femtosecond lasers has enabled new applications of ultrafast lasers. We will discuss our work on one such application: coherent locking of 1550-nm mode-locked sources to optical atomic clocks.

The authors have conducted detailed experimental investigations of the intensity-related dynamics of the pulse repetition and carrier-envelope offset frequencies of passively mode-locked Ti:sapphire lasers. Two different laser systems utilizing different intracavity dispersion compensation schemes are used in this study. Theoretical interpretations...

We have performed systematic studies of intensity-related dynamics of the pulse repetition and carrier-envelope offset frequencies in mode-locked Ti:sapphire lasers. We compared the results for two laser systems that have different intracavity dispersion-compensation schemes. We found that the carrier-envelope phase noise and its dynamic response d...

We are using a phase-coherent wide-bandwidth femtosecond laser comb to induce two-photon transitions in cold Rb atoms. The novel aspect of this type of precision spectroscopy is that all the relevant intermediate states are covered by the broad optical comb and thus can resonantly participate in the two-photon process. The two-photon transition rat...

A remarkable synergy has been formed between precision optical frequency metrology and ultrafast laser science. This has resulted in control of the frequency spectrum produced by mode-locked lasers, which consists of a regular "comb" of sharp lines. Such a controlled mode-locked laser is a "femtosecond optical frequency comb generator." For a suffi...

This is a report on behalf of the World Team of Stable Laser and Optical Frequency Measurement Enthusiasts, even if most detailed illustrations draw mainly from our work at JILA. Specifically we trace some of the key ideas that have led from the first stabilized lasers, to frequency measurement up to 88 THz using frequency chains, revision of the D...

A two-photon transition in cold Rb atoms will be probed with a phase-coherent wide bandwidth femtosecond laser comb. Frequency domain analysis yields a high-resolution picture where phase coherence among various transition pathways through different intermediate states produces interference effects on the resonantly enhanced transition probability....