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In order to achieve sustainable development, Bangladesh needs to develop its electricity systems to guarantee its citizens access to modern energy services and achieve economic development, while not compromising the global climate. This study aims to examine what mix of technologies leads to the least costs for the electricity system under different scenario assumptions. This is done by creating a model of the electricity system of Bangladesh, using the linear optimisation tool OSeMOSYS. The results show a prominence of ultra-supercritical coal power as the lowest cost option for baseload generation in the business as usual and most other scenarios. Unlike in previous studies, solar power is economically competitive in every single scenario, and only limited by the amount of land available for new capacity additions. However, by following a cost minimisation strategy, without emissions restrictions or high carbon prices, the CO2 emissions of the Bangladeshi electricity sector may increase significantly by the end of the model period in 2045.

Sweden has a large multifamily housing stock that was built between 1960 and 1975. An important current issue is how this stock can be renovated in a sustainable way. The article analyses a strategy used by a suburban municipal housing company that had clear social ambitions and offered the tenants three options of renovation: Mini, Midi and Maxi. Most tenants chose the Mini alternative which meant that they could afford to stay and that there was no increase in costs for the social authorities. An investment analysis showed that the Mini alternative had a positive net present value, but that the Midi and Maxi alternatives were more profitable. Even though there was no clear environmental focus in the renovation, energy use was reduced by 8%. As a conclusion, the study shows that a sustainable renovation is possible but that there are a number of conflicts between the different dimensions of sustainability.

Sustainability is a normative concept, building on ideas such as justice, equity and responsibility, and based on human culture and society. Computers, internet, and the technologies that are central in our network society embed also normative values and are part of a cultural context. But the work looking at computer technologies and sustainability has been mostly oriented towards either calculating the impact of technology or using technology as a tool for solving practical problems. ICT is seen as a neutral system to be used or study, while the more normative aspects are mostly overlooked. This paper explores some of the problems arising from these overlooked normative values, such as focusing only on quantifiable problems while forgetting other aspects that may be as important but not easy to put in numbers, or trusting too much in numbers while hiding assumption and model choices. This paper suggests that more critical reflection on these questions is needed in the research area, as well as developing more connections with existing research on these topics in more traditional disciplines.

Global warming and other environmental concerns drive the search for alternative fuels in international shipping. A life-cycle analysis (LCA) can be utilized to assess the environmental impact of different fuels, thereby enabling the identification of the most sustainable alternative among the candidate fuels. However, most LCA studies do not consider marginal emissions, which are important when predicting the effects of large-scale fuel transitions. The research purpose of this study was to assess the marginal emissions of several currently available marine fuels to facilitate the identification of the most promising marine fuel. Thus, marginal and average emissions for eight marine fuels (high-sulfur fuel oil, very-low-sulfur fuel oil, marine gas oil, liquified natural gas, biomethane, biomethanol, fossil methanol, and hydro-treated vegetable oil) were compared in terms of their environmental impact. Non-intuitively, the results indicate that biofuels exhibit equally or higher marginal greenhouse gas emissions than conventionally used fuel oils (162–270 versus 148–174 kg CO2/MJ propulsion), despite their significantly lower average emissions (19–73 vs. 169–175 kg CO2/MJ). This discrepancy is attributed to the current limited availability of climate-efficient biofuels. Consequently, a large-scale shift to biofuels cannot presently yield substantial reductions in the shipping industry’s climate impact. Additional measures, such as optimized trading routes, more energy-efficient ships, and research on more climate-friendly biofuels and electro-fuels, are thus required to significantly reduce the climate footprint of shipping.

Abstract Biogas upgrading to synthetic natural gas (SNG) is a viable and appealing route for power-to-gas because it combines waste management with the use of the surplus electricity that might arise in energy systems having a considerable share of renewable energy sources in their production mix. In this work, the exergo-economic performance of a biogas upgrading process through integrated electrolysis and methanation is assessed in connection with the current market status to test which conditions could make the proposed option economically viable. Two different configurations, which differ mainly for the operating pressure of the electrolyser, are compared. The exergy efficiencies are high (>80%) and exergo-economic costs of the produced bio-SNG in the two analyzed configurations are 5.62 and 4.87 c€/kWhexergy, for low- and high-pressure respectively. Lower values would be required for the bio-SNG to compete with fossil natural gas. We show how both the input electricity price and the capacity factor have a substantial impact on the economic sustainability of the process. Eventually, the monetary exploitation of the oxygen produced by electrolysis and the participation to the emission trading scheme could contribute further to improve the economic attractiveness of the process.

Here we discuss how personal carbon allowances (PCAs) could play a role in achieving ambitious climate mitigation targets. We argue that recent advances in AI for sustainable development, together with the need for a low-carbon recovery from the COVID-19 crisis, open a new window of opportunity for PCAs. Furthermore, we present design principles based on the Sustainable Development Goals for the future adoption of PCAs. We conclude that PCAs could be trialled in selected climate-conscious technologically advanced countries, mindful of potential issues around integration into the current policy mix, privacy concerns and distributional impacts. Personal carbon allowances (PCAs) could support climate mitigation efforts but would need to be carefully designed to avoid impacts on Sustainable Development Goals (SDGs). This Perspective discusses why the time is ripe for reconsidering PCAs and provides a set of SDG-based design principles for the future adoption of PCAs.

More than 61% of the total population of Nepal has no access to electricity. The majority is poor and live in rural areas. In recent years, rural electrification has had high priority in government policies, and micro hydro and solar PV have been the most commonly adopted off-grid technologies. The financial mix in the off-grid rural electrification is generally characterized by subsidy, equity and credit. In this paper, we analyze how rural electrification has been funded and the impact of subsidy policies on the renewable energy market, focusing on the projects implemented under the ‘subsidy policy 2000’. Our study is based on official data obtained from authorities in Nepal and a survey carried out among private supply and installation companies, NGOs and financial institutions. The study shows that awareness levels in adopting RE-technologies and willingness of people to access and pay for electricity have increased significantly. However, there is a huge financial gap between the cost of electrification and the affordability. Bridging this gap is a crucial issue that needs to be addressed for the smooth expansion of rural electrification in the country.

Abstract The prior goal for a pulp and paper mill is to achieve a chemical recovery system with high availability and good reliability. It is also important that the heat recovery system produces sufficient process heat for the heat-demanding processes in the mill. Black liquor gasification promises to be a future alternative or a complement to the conventional Tomlinson recovery boilers in the pulp industry. Black liquor gasification should offer several advantages from both a chemical recovery and an energy point of view. The gasification process produces a combustible gas which can be used for steam and power generation in many ways. Several studies have shown that the power output from a heat and power cycle integrated with black liquor gasification has potential to get a higher energy efficiency than today's heat recovery technology. Especially with pressurized gasification and a gas-turbine-based cogeneration system, the power output will be significantly improved. However, the gas turbine is very sensitive to corrosive elements. The gas cleaning equipment in the gasification system must therefore have a high removal efficiency and a high reliability. The ambition is to keep the gasification capacity constant during the year, but the fuel consumption for the gas turbine increases at low ambient temperatures. The seasonal variation will cause the gas turbine to operate at partial load and, consequently, there will be a decrease in the gas turbine efficiency. An alternative combined cycle with high power efficiency is given by a hybrid plant in which the gas turbine is fired with natural gas while the fuel gas from the pressurized gasifier is used as a supplementary fuel for the Rankine cycle. A major advantage of the hybrid system is the use of a high purity fuel gas in the gas turbine. The system also allows for variations in pulp capacity which is difficult in an integrated gasification combined cycle (IGCC). This study compares the effect of using an IGCC system and a hybrid combined plant instead of a conventional recovery system. The results indicate a potential to double the power output if the conventional system is replaced by an IGCC system. A hybrid combined cycle system has also a higher net power efficiency than the conventional recovery system. Furthermore, the hybrid system can make the mill self-supporting on power and allows an increase in the heat consumption.