Supply chains and energy security in a low carbon transition

This special edition to be published in Applied Energy brings together a range of papers that explore the complex, multi-dimensional and inter-related issues associated with the supply or value chains that make up energy systems and how a focus on them can bring new insights for energy security in a low carbon transition. Dealing with the trilemma of maintaining energy security, reducing greenhouse gas emissions and maintaining affordability for economies and end users are key issues for all countries, but there are synergies and trade-offs in simultaneously dealing with these different objectives. Currently, industrialised energy systems are dominated by supply chains based on fossil fuels and these, for the most part, have been effective in enabling energy security and affordability. However, they are increasingly struggling to do this, particularly in respect to efforts to tackle climate change, given that the energy sector is responsible for around two-thirds of the global greenhouse gas emissions [1]. A key challenge is therefore how to decarbonise energy systems, whilst also ensuring energy security and affordability. This special issue, through a focus on supply chains, particularly considers the interactions and relationships between energy security and decarbonisation. Energy security is a property of energy systems and their ability to withstand short-term shocks and longer-term stresses depends on other important system properties including resilience, robustness, flexibility and stability [2]. Energy systems are essentially a supply chain comprising of multiple and interrelated sub-chains based around different fuels, technologies, infrastructures, and actors, operating at different scales and locations – from extraction/imports and conversion through to end use [3]. These supply chains have become increasingly globalised and are influenced by the on-going shifts in global supply and demand. Thus the aim of this special issue is to explore and discuss how to enable the development of a secure and sustainable energy system through a better understanding of both existing and emerging low carbon energy supply chains as well as of new approaches to the design and management of energy systems. In part, because moving from a system dominated by fossil fuels to one based on low carbon creates a new set of risks and uncertainties for energy security as well as new opportunities. A large number of submissions from over 18 countries were received for this special edition and 16 papers were accepted after peer review. These address a variety of issues and we have chosen to discuss the findings under two key themes, although many of the papers cut across these: (1) Insights from, and for, supply chain analysis. (2) Insights for energy security and its management. We then provide in (3) a summary of insights and research gaps. Table 1 provides a snapshot of the areas covered by the papers showing: theme (s); empirical domains; and geographical coverage

Collective Action and Social Innovation in the Energy Sector: A Mobilization Model Perspective

This conceptual paper applies a mobilization model to Collective Action Initiatives (CAIs) in the energy sector. The goal is to synthesize aspects of sustainable transition theories with social movement theory to gain insights into how CAIs mobilize to bring about niche-regime change in the context of the sustainable energy transition. First, we demonstrate how energy communities, as a representation of CAIs, relate to social innovation. We then discuss how CAIs in the energy sector are understood within both sustainability transition theory and institutional dynamics theory. While these theories are adept at describing the role energy CAIs have in the energy transition, they do not yet offer much insight concerning the underlying social dimensions for the formation and upscaling of energy CAIs. Therefore, we adapt and apply a mobilization model to gain insight into the dimensions of mobilization and upscaling of CAIs in the energy sector. By doing so we show that the expanding role of CAIs in the energy sector is a function of their power acquisition through mobilization processes. We conclude with a look at future opportunities and challenges of CAIs in the energy transition.This research was conducted under the COMETS (Collective action Models for Energy Transition and Social Innovation) project, funded by the Horizon 2020 Framework Program of the European Commission, grant number 837722

Constraints on anomalous Higgs boson couplings using production and decay information in the four-lepton final state

A search is performed for anomalous interactions of the recently discovered Higgs boson using matrix element techniques with the information from its decay to four leptons and from associated Higgs boson production with two quark jets in either vector boson fusion or associated production with a vector boson. The data were recorded by the CMS experiment at the LHC at a center-of-mass energy of and correspond to an integrated luminosity of . They are combined with the data collected at center-of-mass energies of 7 and , corresponding to integrated luminosities of 5.1 and , respectively. All observations are consistent with the expectations for the standard model Higgs boson

Performance of a Tungsten-Cerium Fluoride Sampling Calorimeter in High-Energy Electron Beam Tests

A prototype for a sampling calorimeter made out of cerium fluoride crystals interleaved with tungsten plates, and read out by wavelength-shifting fibres, has been exposed to beams of electrons with energies between 20 and 150 GeV, produced by the CERN Super Proton Synchrotron accelerator complex. The performance of the prototype is presented and compared to that of a Geant4 simulation of the apparatus. Particular emphasis is given to the response uniformity across the channel front face, and to the prototype's energy resolution.Comment: 6 pages, 6 figures, Submitted to NIM

Measurement of transverse momentum relative to dijet systems in PbPb and pp collisions at sqrt(s_NN) = 2.76 TeV

An analysis of dijet events in PbPb and pp collisions is performed to explore the properties of energy loss by partons traveling in a quark-gluon plasma. Data are collected at a nucleon-nucleon center-of-mass energy of 2.76 TeV at the LHC. The distribution of transverse momentum (p T) surrounding dijet systems is measured by selecting charged particles in different ranges of p T and at different angular cones of pseudorapidity and azimuth. The measurement is performed as a function of centrality of the PbPb collisions, the p T asymmetry of the jets in the dijet pair, and the distance parameter R used in the anti-k T jet clustering algorithm. In events with unbalanced dijets, PbPb collisions show an enhanced multiplicity in the hemisphere of the subleading jet, with the p T imbalance compensated by an excess of low-p T particles at large angles from the jet axes

Search for supersymmetry in electroweak production with photons and large missing transverse energy in pp collisions at sqrt(s) = 8 TeV

Results are reported from a search for supersymmetry with gauge-mediated supersymmetry breaking in electroweak production. Final states with photons and large missing transverse energy ( View the MathML sourceETmiss) were examined. The data sample was collected in pp collisions at View the MathML sources=8TeV with the CMS detector at the LHC and corresponds to 7.4View the MathML sourcefb−1. The analysis focuses on scenarios in which the lightest neutralino has bino- or wino-like components, resulting in decays to photons and gravitinos, where the gravitinos escape undetected. The data were obtained using a specially designed trigger with dedicated low thresholds, providing good sensitivity to signatures with photons, View the MathML sourceETmiss, and low hadronic energy. No excess of events over the standard model expectation is observed. The results are interpreted using the model of general gauge mediation. With the wino mass fixed at 10View the MathML sourceGeV above that of the bino, wino masses below 710View the MathML sourceGeV are excluded at 95% confidence level. Constraints are also set in the context of two simplified models, for which the analysis sets the lowest cross section limits on the electroweak production of supersymmetric particles

Search for standard model production of four top quarks in the lepton + jets channel in pp collisions at sqrt(s) = 8 TeV

A search is presented for standard model (SM) production of four top quarks (tt\uaftt\uaf) in pp collisions in the lepton + jets channel. The data correspond to an integrated luminosity of 19.6 fb 121 recorded at a centre-of-mass energy of 8 TeV with the CMS detector at the CERN LHC. The expected cross section for SM tt\uaftt\uaf production is \u3c3SMtt\uaftt\uaf 481fb. A combination of kinematic reconstruction and multivariate techniques is used to distinguish between the small signal and large background. The data are consistent with expectations of the SM, and an upper limit of 32 fb is set at a 95% confidence level on the cross section for producing four top quarks in the SM, where a limit of 32 \ub1 17 fb is expected

Observation of top quark pairs produced in association with a vector boson in pp collisions at sqrt(s) = 8 TeV

Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8TeV pp collision data corresponding to an integrated luminosity of 19.5 fb1, collected by the CMS experiment at the LHC. Final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identied by matching reconstructed objects in the detector to specic nal state particles from ttW or ttZ decays. The ttW cross section is measured to be 382+117 102 fb with a signicance of 4.8 standard deviations from the background-only hypothesis. The ttZ cross section is measured to be 242+65 55 fb with a signicance of 6.4 standard deviations from the background-only hypothesis. These measurements are used to set bounds on ve anomalous dimension-six operators that would aect the ttW and ttZ cross sections