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The atmosphere concentration of CO2 is steadily increasing and causing climate change. To achieve the Paris 1.5 or 2 oC target, negative emissions technologies must be deployed in addition to reducing carbon emissions. The ocean is a large carbon sink but the potential of marine primary producers to contribute to carbon neutrality remains unclear. Here we review the alterations to carbon capture and sequestration of marine primary producers (including traditional ‘blue carbon’ plants, microalgae, and macroalgae) in the Anthropocene, and, for the first time, assess and compare the potential of various marine primary producers to carbon neutrality and climate change mitigation via biogeoengineering approaches. The contributions of marine primary producers to carbon sequestration have been decreasing in the Anthropocene due to the decrease in biomass driven by direct anthropogenic activities and climate change. The potential of blue carbon plants (mangroves, saltmarshes, and seagrasses) is limited by the available areas for their revegetation. Microalgae appear to have a large potential due to their ubiquity but how to enhance their carbon sequestration efficiency is very complex and uncertain. On the other hand, macroalgae can play an essential role in mitigating climate change through extensive offshore cultivation due to higher carbon sequestration capacity and substantial available areas. This approach seems both technically and economically feasible due to the development of offshore aquaculture and a well-established market for macroalgal products. Synthesis and applications: This paper provides new insights and suggests promising directions for utilizing marine primary producers to achieve the Paris temperature target. We propose that macroalgae cultivation can play an essential role in attaining carbon neutrality and climate change mitigation, although its ecological impacts need to be assessed further. To calculate the parameters presented in Table 1, the relevant keywords "mangroves, salt marshes, macroalgae, microalgae, global area, net primary productivity, CO2 sequestration" were searched through the ISI Web of Science and Google Scholar in July 2021. Recent data published after 2010 were collected and used since area and productivity of plants change with decade. For data with limited availability, such as net primary productivity (NPP) of seagrasses and global area and NPP of wild macroalgae, data collection was extended back to 1980. Total NPP and CO2 sequestration for mangroves, salt marshes, seagrasses and wild macroalgae were obtained by the multiplication of area and NPP/CO2 sequestration density and subjected to error propagation analysis. Data were expressed as means ± standard error.

This article undertakes a ‘backcasting’ analysis exploring strategic approaches for overall systems sustainability in personal transport. Starting from a robust definition of sustainability for the...

Introduction Increases in recent times in electricity costs and in associated emissions of greenhouse gases are having an impact on societies to adopt business and lifestyle strategies based on sustainability practices. The emergence of the smart grid (Xinghuo et al., 2011) facilitates both suppliers and consumers of electricity in reducing carbon footprint and improving the reliability and efficiency of electricity generation, distribution and utilization. The smart grid unifies recent developments in the electrical power area with those in information and communication technologies (ICT) to bring to bear changes to business practices and life styles of consumers. The smart grid recognizes the distributed nature of electricity industry and the unifying power of the ICT. Traditional power grids consist of (i) large-scale electricity generators that are located within easy reach of energy resources, (ii) highvoltage transmission lines to bring bulk electricity to load centres that are close to loads, such as industries, cities, townships etc., and (iii) lower voltage distribution networks which in turn distribute electrical power to smaller consumers of electricity. Unlike such traditional power grids, smart grids have distributed energy generation that encompasses both centrally-located large-scale generators with ratings of 100's of megawatts (MWs) and many geographically distributed smaller generators of widely varying sizes from 10's of MWs that use fossil fuels and renewables to a few kilo watts (kW) that may be solar photo voltaic (PV) panels mounted on the roof of a small house. [FIGURE 1 OMITTED] Several geographically distributed power generators need to be integrated into the smart grid, recognizing the varying capacities, characteristics and technologies associated with generators (Figure 1). Electricity generated using renewable energy sources, such as photovoltaic (PV) solar panels and wind turbines, is variable depending upon the season, weather conditions and the period of any given day. This variability has a strong influence on the delivery of reliable power to consumers. Storage of electrical energy to dampen the effects of variability in the power from renewables is therefore an important aspect of the smart grid. Various types of energy storage: pumped hydro storage, batteries, fuel cells, flywheels etc. need to be integrated into a smart grid. Such distributed energy storages in the grid may serve different networks within the grid so that they continue to operate as self-powered islands during outages resulting from natural causes or system faults (Nourai & Keane, 2010). The electricity generated by solar PV panels and by some wind generators is in the form of direct current (DC). This DC power must be converted (or inverted) to make alternating current (AC) power to enable connection to an AC smart grid. Smart grids need smart inverters with controls to maximise renewable power utilization, and to supply power to either the local load and/or the grid (Xinghuo et al., 2011). The smart grid needs to integrate the action of generators, energy suppliers and customers. The smart grid must provide suitable multi-way communication of relevant information between various business actors associated with the grid. The smart grid includes even a small household as a business actor into its business model because a household contributes towards sustainable business outcomes. There are many research papers on smart grids with a focus on large power systems (Brown, 2008; Ipakchi & Albuyeh, 2009; and Farhangi, 2010) that emphasize the importance of pervasive control and monitoring requirements in a smart grid. They point out the convergence of ICT with power system engineering. There are also many publications (Guinard, 2011; Kamilaris, et al., 2011) that deal with energy management at household levels using the ICT strategy, such as Web of things. …

Abstract The paper presents a life-cycle assessment of costs and greenhouse gas emissions for transit buses deploying a hybrid input–output model to compare ultra-low sulfur diesel to hybrid diesel-electric, compressed natural gas, and hydrogen fuel-cell. We estimate the costs of emissions reductions from alternative fuel vehicles over the life cycle and examine the sensitivity of the results to changes in fuel prices, passenger demand, and to technological characteristics influencing performance and emissions. We find that the alternative fuel buses reduce operating costs and emissions, but increase life-cycle costs. The infrastructure requirement to deploy and operate alternative fuel buses is critical in the comparison of life-cycle emissions. Additionally, efficient bus choice is sensitive to passenger demand, but only moderately sensitive to technological characteristics, and that the relative efficiency of compressed natural gas buses is more sensitive to changes in fuel prices than that of the other bus types.

Abstract In this paper, we have investigated the ignition behaviour of Victorian brown coal under the steam-rich oxy-fuel combustion conditions. Two differently ranked coal, sub-bituminous and bituminous coal, were also tested for comparison. The ignition experiments were conducted in O 2 /N 2 /H 2 O and O 2 /CO 2 /H 2 O atmospheres, in an entrained flow reactor coupled with flat flame burner and in-situ optical diagnosis tools. A transient ignition model and 1-D single film model were also developed and used to predict particle ignition and the extent of char-steam gasification reaction, respectively. As has been confirmed, the injection of external steam to the furnace is beneficial in accelerating the ignition of Victorian brown coal in both air and oxy-firing modes with 21% O 2 . This effect is even more pronounced for the combustion of dense particle stream. In the oxygen-enriched condition, the ignition time was similar regardless of the steam concentration in the bulk gas. The transient modelling prediction confirmed that the homogeneous water–gas shift reaction (CO + H 2 O ↔ CO 2 + H 2 ) was the main cause for the accelerated ignition for brown coal. It produced a highly concentrated flammable gas mixture of CO and H 2 in coal particle cloud, which in turn accelerated the homogenous ignition of volatiles. This promotion effect is the most dominant for brown coal, because its volatile is rich in light hydrocarbons including gaseous CO that can readily react with the external steam via water–gas shift reaction. Moreover, the external steam triggered the heterogeneous char-steam gasification reaction for the brown coal, which further improved the overall char burnout rate. Regarding another two high-rank coals, their changes on both ignition and char burnout rate are however marginal upon the introduction of external steam, due to the shortage of gaseous volatiles (thus no water–gas shift reaction triggered) and the difficulty for their char to undergo steam gasification reaction under the experimental conditions observed here.

This paper presents estimates of short-run sectoral and economy-wide effects of the introduction of a carbon tax in Australia. The results are derived using an enhanced version of the ORANI multi-sectoral model of the Australian economy. We simulate the introduction of a carbon tax at a rate of 1991-92 $25 per tonne, designed to achieve the Toronto target of a 20 per cent reduction in carbon dioxide emissions below the 1988 level by 2005. We find that the macroeconomic impact would depend critically on the extent to which price rises flowed through into wage rates. Assuming fixed money wages, real GDP would be decreased by an estimated 0.9 per cent, and employment by 1.2 per cent. To maintain a given employment level in the face of the carbon tax would require a reduction in the foreign-currency-equivalent wage rate estimated at 2.8 per cent. This would also entail a decrease in the real wage rate (defined with respect to the consumption price deflator) of 2.8 per cent. Government could promote lower wage outcomes by returning the carbon tax revenue to the community through reductions in other taxes. Enhancements to ORANI used in this simulation include disaggregation of the fossil fuel sector and provision for carbon taxation.

This study aims to propose a new process design, simulation, and techno-economic analysis of an integrated process plant that produces glucose and furfural from palm oil empty fruit bunches (EFB). In this work, an Aspen Plus-based simulation has been established to develop a process flow diagram of co-production of glucose and furfural along with the mass and energy balances. The plant's economics are analyzed by calculating the fixed capital income (FCI), operating costs, and working capital. In contrast, profitability is determined using cumulative cash flow (CCF), net present value (NPV), and internal rate of return (IRR). The findings show that the production capacity of 10 kilotons per year (ktpy) of glucose and 4.96 ktpy of furfural with a purity of 98.21 and 99.54%-weight, respectively, was achieved in this study. The FCI is calculated as United States Dollar (USD) 20.80 million, while the working and operating expenses are calculated as USD 3.74 million and USD 16.93 million, respectively. This project achieves USD 7.65 million NPV with a positive IRR of 14.25% and a return on investment (ROI) of 22.06%. The present work successfully develops a profitable integrated process plant that is established with future upscaling parameters and key cost drivers. The findings provided in this work offer a platform and motivation for future research on integrated plants in the food, environment, and energy nexus with the co-location principle.

An extensive number of studies uses trade-to-GDP as a proxy for globalisation in environmental research. Globalisation encompasses much more than just trade in goods. Globalisation is the integration of various countries and includes spillovers of ideas and technology, financial flows, the worldwide movement of labour, and national governments meeting on an international level in a bid to solve social and political problems. This study considers the effect of globalisation on carbon dioxide emissions by using a more flexible and comprehensive measure based on the KOF globalisation index for a panel of 21 OECD nations covering the period 1970–2014. Since the globalisation process is not uniform across countries and time, we use a fully-fledged nonparametric technique to estimate the time-varying coefficient and trend functions. Our results show that the effect of globalization on CO2 emissions is positive up until 2000, then switches to turns negative thereafter.

AbstractFood security remains a critical global issue, made more difficult because of the rising world population, climate challenges affecting food production and a focus on market-based solutions that undermine subsistence production in vulnerable rural areas. Particularly affected are countries across Asia where poverty, hunger and malnourishment affect a significant proportion of the population. Drawing on Sen’s entitlement theory, we argue that a shift in focus from national food production to intra-household food access enables a critical reflection on consumption smoothing strategies adopted at this level. In particular, we draw attention to the tendency for women and girls to eat less as an intra-household adaptation strategy. We present findings from our research in rural areas of Bangladesh and note that adaptation strategies adopted by households in response to food insecurity. We note that strategies designed to address food insecurity must include gender mainstreaming to ensure that women and...