Search

The global energy system is in transition. It is attempting to reach net‐zero greenhouse gas emissions by 2050. The systemic changes mean that the role of bioenergy will change. The potential of bioenergy to make a flexible contribution to the energy system is key for the achievement of global emission reduction ambitions and the functioning of the low‐carbon energy system and economy. As the volume of sustainably available biomass resources is limited, defining the contributions from bioenergy to a low‐carbon energy system and finding balances – and ideally synergies – between the different possible energy and climate system services that biomass can provide will be very important. The recognized system services include, among others, the flexible operation of bioenergy plants to integrate variable renewable energy sources and to provide negative carbon dioxide (CO2) emissions. Interest in flexible operation of bioenergy value chains, bioenergy with carbon capture and utilization as well as synergies with renewable hydrogen‐based value chains has increased recently. The objective of this paper is to present a holistic definition of flexible bioenergy as a system service based on the work conducted in International Energy Agency (IEA) Bioenergy Technology Collaboration Programme's Task 44 Flexible Bioenergy and System Integration, and to provide some practical examples. The paper also presents the different bioenergy system services and considers their definitions and interactions, as this is important in energy system design. The definition of flexible bioenergy shows that the flexibility provision from bioenergy goes far beyond the traditional definition of providing short‐term flexibility in the power sector. Indicators to demonstrate the value of services as well as further quantitative assessment of synergies and trade‐offs are needed to valorize the different services from bioenergy and create viable business cases. [ABSTRACT FROM AUTHOR]

Time series of radiative cooling of the upper mesosphere and lower thermosphere (UMLT) by carbon dioxide (CO2) are examined for evidence of trends over 20 years. Radiative cooling rates in K day−1 provided by the SABER instrument are converted to time series of infrared power radiated from three distinct layers between 0.1 hPa and 0.0001 hPa (65–105 km). Linear regression against time and a predictor for solar variability provides estimates of the trend in exiting longwave radiation (ELR) from these layers. Trends in ELR are not significantly different from zero at 95% or 99% confidence in each layer. These results demonstrate energy conservation in the UMLT on decadal time scales and show that the UMLT continues to radiate the same amount of energy it receives despite cooling and contracting over two decades. These results are enabled by the long‐term stability of the SABER instrument calibration. Plain Language Summary: The Earth's upper mesosphere and lower thermosphere (UMLT) is the region between approximately 65 and 105 km in altitude. Infrared radiation emitted by CO2 is a fundamental component of the energy budget of the UMLT. Carbon dioxide (CO2) is increasing in this region. The amount of infrared energy emitted by CO2, over time, must balance the amount of energy from sunlight that is absorbed in the UMLT. Observations from orbiting satellites over the past two decades have shown that the temperature in the UMLT is decreasing due to the increasing CO2. A decreasing temperature implies a decrease in infrared energy emitted by an object. Energy conservation, however, requires that the amount of infrared energy radiated from the UMLT balance the amount of energy received, regardless of the temperature. In this paper we show that there is no significant long‐term change with time (i.e., zero trend) in the infrared energy emitted from the UMLT even though the UMLT temperature has been decreasing for the last 20 years (and longer) due to increasing CO2. This result confirms that energy is conserved in a cooling and contracting UMLT. Key Points: Time series of infrared power (W) radiated by CO2 from the upper mesosphere & lower thermosphere (UMLT) are developedTrends in radiated power are not different from zero at 95% or 99% confidence in the three layers examined between 0.1 and 0.0001 hPaIncreasing CO2 reduces the UMLT temperature while radiating the same amount of energy over time, thus conserving energy [ABSTRACT FROM AUTHOR]

A carbon paper‐based gas diffusion electrode (GDE) is used with a bismuth(III) subcarbonate active catalyst phase for the electrochemical reduction of CO2 in a gas/electrolyte flow‐by configuration electrolyser at high current density. It is demonstrated that in this configuration, the gas and catholyte phases recombine to form K2CO3/KHCO3 precipitates to an extent that after electrolyses, vast amount of K+ ions is found by EDX mapping in the entire GDE structure. The fact that the entirety of the GDE gets wetted during electrolysis should, however, not be interpreted as a sign of flooding of the catalyst layer, since electrolyte perspiring through the GDE can largely be removed with the outflow gas, and the efficiency of electrolysis (toward the selective production of formate) can thus be maintained high for several hours. For a full spatial scale quantitative monitoring of electrolyte penetration into the GDE, (relying on K+ ions as tracer) the method of inductively coupled plasma–mass spectrometry (ICP–MS) assisted energy dispersive X‐ray (EDX) tomography is introduced. This new, cheap and robust tomography of non‐uniform aspect ratio has a large planar span that comprises the entire GDE surface area and a submicrometer depth resolution, hence it can provide quantitative information about the amount and distribution of K+ remnants inside the GDE structure, in three dimensions. [ABSTRACT FROM AUTHOR]

As carbon monoxide has a broad spectrum of biological activities, its production by plasma is a significant advantage in medicine. This paper presents a comparative study of the CO production of two plasma jets: a MHz‐jet and a kHz‐jet. Both were fed with a helium gas with CO2 ${\text{CO}}_{2}$ admixture (0%–1%). CO was produced by CO2 ${\text{CO}}_{2}$ dissociation and its maximal concentration was hundreds of parts per million, which is safe for clinical applications. For the same specific energy input, the CO production was more efficient for the kHz‐jet than the MHz‐jet. Both had antibacterial properties on Escherichia coli, and the addition of CO2 ${\text{CO}}_{2}$ improved them for the MHz‐jet, while it reduced them for the kHz‐jet. [ABSTRACT FROM AUTHOR]

Across Europe, countries are reducing CO2 emissions and energy demand by lowering the temperature in public office buildings. These measures affect men and women unequally because the latter prefer and, indeed, perform better under higher temperatures than the standard temperature. Lowering the temperature thus further increases an already existing inequality. We show that the philosophical literature on discrimination provides an interesting theoretical approach to understanding such measures. On prominent understandings of what discrimination is, the policy would be considered direct discrimination against women if it could be shown to reflect a broader inattentiveness to the needs of women in society. Alternatively, and more straightforwardly, the policies can be considered indirect discrimination because of their disparate effects on men and women. The final part of the paper shows that the policies are also wrong for the reasons it is often argued that discrimination is wrong—to wit, that it harms or disrespects those who are discriminated against. The final section suggests a range of measures to offset the discriminatory aspects of the policy. [ABSTRACT FROM AUTHOR]

Multiphysics inversion exploits different types of geophysical data that often complement each other and aims to improve overall imaging resolution and reduce uncertainties in geophysical interpretation. Despite the advantages, traditional multiphysics inversion is challenging because it requires a large amount of computational time and intensive human interactions for preprocessing data and finding trade‐off parameters. These issues make it nearly impossible for traditional multiphysics inversion to be applied as a real‐time monitoring tool for geological carbon storage. In this paper, we present a deep learning (DL) multiphysics network for imaging CO2 saturation in real time. The multiphysics network consists of three encoders for analysing seismic, electromagnetic and gravity data and shares one decoder for combining imaging capabilities of the different geophysical data for better predicting CO2 saturation. The network is trained on pairs of CO2 label models and multiphysics data so that it can directly image CO2 saturation. We use the bootstrap aggregating method to enhance the imaging accuracy and estimate uncertainties associated with CO2 saturation images. Using realistic CO2 label models and multiphysics data derived from the Kimberlina CO2 storage model, we evaluate the performance of the deep learning multiphysics network and compare its imaging results to those from the deep learning single‐physics networks. Our modelling experiments show that the deep learning multiphysics network for seismic, electromagnetic, and gravity data not only improves the imaging accuracy but also reduces uncertainties associated with CO2 saturation images. Our results also suggest that the deep learning multiphysics network for the non‐seismic data (i.e., electromagnetic and gravity) can be used as an effective low‐cost monitoring tool in between regular seismic monitoring. [ABSTRACT FROM AUTHOR]

This document is a response to concerns raised by Reershemius and Suhrhoff regarding a study conducted by Kantola et al. The authors of the response acknowledge that Reershemius and Suhrhoff did not find any faults with the derivation in the paper, which they state are factually true. They also mention that Reershemius and Suhrhoff arrived at a similar result in their own unpublished work. The response addresses specific implementation details raised by Reershemius and Suhrhoff and argues that these concerns lack merit. The authors appreciate the constructive engagement and transparency of data. [Extracted from the article]