• Energy Research
• 7. Clean energy close
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Decarbonisation of energy systems requires deep structural change. The purpose of this research was to analyse the rates of change taking place in the energy systems of each Member State of the European Union (EU), and the EU in aggregate, in the light of the EU's climate change mitigation objectives. Trends on indicators such as sectoral activity levels and composition, energy intensity, and carbon intensity of energy were compared with decadal benchmarks derived from deep decarbonisation scenarios. The methodology applied provides a useful and informative approach to tracking decarbonisation of energy systems. The results show that while the EU has made significant progress in decarbonising its energy system. On a number of indicators assessed the results show that a significant acceleration from historical levels is required in order to reach the rates of change seen on the future benchmarks for deep decarbonisation. The methodology applied provides an example of how the research community and international organisations could complement the transparency mechanism developed by the Paris Agreement on climate change, to improve understanding of progress toward low-carbon energy systems.

Long-duration gamma-ray bursts (GRBs) release copious amounts of energy across the entire electromagnetic spectrum, and so provide a window into the process of black hole formation from the collapse of massive stars. Previous early optical observations of even the most exceptional GRBs (990123 and 030329) lacked both the temporal resolution to probe the optical flash in detail and the accuracy needed to trace the transition from the prompt emission within the outflow to external shocks caused by interaction with the progenitor environment. Here we report observations of the extraordinarily bright prompt optical and gamma-ray emission of GRB 080319B that provide diagnostics within seconds of its formation, followed by broadband observations of the afterglow decay that continued for weeks. We show that the prompt emission stems from a single physical region, implying an extremely relativistic outflow that propagates within the narrow inner core of a two-component jet.

Based on the results of previous studies, the efficiency of a Brayton/Hirn combined cycle fuelled with a clean syngas produced by means of biomass gasification and equipped with CO2 removal by chemical absorption reached 33.94%, considering also the separate CO2 compression process. The specific CO2 emission of the power plant was 178 kg/MW h. In comparison with values previously found for an integrated coal gasification combined cycle (ICGCC) with upstream CO2 chemical absorption (38–39% efficiency, 130 kg/MW h specific CO2 emissions), this configuration seems to be attractive because of the possibility of operating with a simplified scheme and because of the possibility of using biomass in a more efficient way with respect to conventional systems. In this paper, a life cycle assessment (LCA) was conducted with presenting the results on the basis of the Eco-Indicator 95 impact assessment methodology. Further, a comparison with the results previously obtained for the LCA of the ICGCC was performed in order to highlight the environmental impact of biomass production with fossil fuels utilisation. The LCA shows the important environmental advantages of biomass utilisation in terms of reduction of both greenhouse gas emissions and natural resource depletion, although an improved impact assessment methodology may better highlight the advantages due to the biomass utilisation.

Energy efficiency is the main concern of research community while designing routing protocols for wireless sensor networks (WSNs). This concern can be addressed by using energy-harvesting scheme in routing protocols. In this paper, we propose a secure routing protocol that is based on cross layer design and energy-harvesting mechanism. It uses a distributed cluster-based security mechanism. In the cross-layer design, parameters are exchanged between different layers to ensure efficient use of energy. Energy-harvesting system is used to extract and store energy, which is used to take decisions for the node state and thus for the routing issues. Simulation results show that our routing protocol can perform better in many scenarios and in hostile attack-prone environment.

Low carbon options for the chemical industry include switching from fossil to renewable energy, adopting new low-carbon production processes, along with retrofitting current plants with carbon capture for ulterior use (CCU technologies) or storage (CCS). In this paper, we combine a dynamic Life Cycle Assessment (d-LCA) with economic analysis to explore a potential transition to low-carbon manufacture of formic acid. We propose new methods to enable early technical, environmental and economic assessment of formic acid manufacture by electrochemical reduction of CO2 (CCU), and compare this production route to the conventional synthesis pathways and to storing CO2 in geological storage (CCS). Both CCU and CCS reduce carbon emissions in particular scenarios, although the uncertainty in results suggests that further research and scale-up validation are needed to clarify the relative emission reduction compared to conventional process pathways. There are trade-offs between resource security, cost and emissions between CCU and CCS systems. As expected, the CCS technology yields greater reductions in CO2 emissions than the CCU scenarios and the conventional processes. However, compared to CCS systems, CCU has better economic potential and lower fossil consumption, especially when powered by renewable electricity. The integration of renewable energy in the chemical industry has an important climate mitigation role, especially for processes with high electrical and thermal energy demands.

Phosphorene nanoribbons (PNRs) have been widely predicted to exhibit a range of superlative functional properties; however, because they have only recently been isolated, these properties are yet to be shown to translate to improved performance in any application. PNRs show particular promise for optoelectronics, given their predicted high exciton binding energies, tunable bandgaps, and ultrahigh hole mobilities. Here, we verify the theorized enhanced hole mobility in both solar cells and space-charge-limited-current devices, demonstrating the potential for PNRs improving hole extraction in universal optoelectronic applications. Specifically, PNRs are demonstrated to act as an effective charge-selective interlayer by enhancing hole extraction from polycrystalline methylammonium lead iodide (MAPbI3) perovskite to the poly(triarylamine) semiconductor. Introducing PNRs at the hole-transport/MAPbI3 interface achieves fill factors above 0.83 and efficiencies exceeding 21% for planar p-i-n (inverted) perovskite solar cells (PSCs). Such efficiencies are typically only reported for single-crystalline MAPbI3-based inverted PSCs. Methylammonium-free PSCs also benefit from a PNR interlayer, verifying applicability to architectures incorporating mixed perovskite absorber layers. Device photoluminescence and transient absorption spectroscopy are used to demonstrate that the presence of the PNRs drives more effective carrier extraction. Isolation of the PNRs in space-charge-limited-current hole-only devices improves both hole mobility and conductivity, demonstrating applicability beyond PSCs. This work provides primary experimental evidence that the predicted superlative functional properties of PNRs indeed translate to improved optoelectronic performance.