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A priority of the industrial applications of microalgae is the reduction of production costs while maximizing algae biomass productivity. The purpose of this study was to carry out a comprehensive evaluation of the effects of pH control on the production of Nannochloropsis gaditana in tubular photobioreactors under external conditions while considering the environmental, biological, and operational parameters of the process. Experiments were carried out in 3.0 m3 tubular photobioreactors under outdoor conditions. The pH values evaluated were 6.0, 7.0, 8.0, 9.0, and 10.0, which were controlled by injecting pure CO2 on-demand. The results have shown that the ideal pH for microalgal growth was 8.0, with higher values of biomass productivity (Pb) (0.16 g L-1 d-1), and CO2 use efficiency ([Formula: see text]) (74.6% w w-1); [Formula: see text]/biomass value obtained at this pH (2.42 [Formula: see text] gbiomass-1) was close to the theoretical value, indicating an adequate CO2 supply. At this pH, the system was more stable and required a lower number of CO2 injections than the other treatments. At pH 6.0, there was a decrease in the Pb and [Formula: see text]; cultures at pH 10.0 exhibited a lower Pb and photosynthetic efficiency as well. These results imply that controlling the pH at an optimum value allows higher CO2 conversions in biomass to be achieved and contributes to the reduction in costs of the microalgae production process.

This study assesses the socio-economic impacts in terms of value added, imports and employment of sugarcane-derived bioethanol production in Northeast (NE) Brazil. An extended inter-regional Input–Output (IO) model has been developed and is used to analyse three scenarios, all projected for 2020: a business-as-usual scenario (BaU) which projects current practices, and two scenarios that consider more efficient agricultural practices and processing efficiency (scenario A) and in addition an expansion of the sector into new areas (scenario B). By 2020 in all scenarios, value added and imports increase compared to the current situation. The value added by the sugarcane–ethanol sector in the NE region is 2.8 billion US$ in the BaU scenario, almost 4 billion US$ in scenario A, and 9.4 billion US$ in scenario B. The imports in the region will grow with 4% (BaU scenario), 38% (scenario A) and 262% (scenario B). This study shows that the large reduction of employment (114,000 jobs) due to the replacement of manual harvesting by mechanical harvesting can be offset by additional production and indirect effects. The total employment in the region by 2020 grows with 10% in scenario A (around 12,500 jobs) and 126% in scenario B (around 160,000 jobs). The indirect effects of sugarcane production in the NE are large in the rest of Brazil due to the import of inputs from these regions. The use of an extended inter-regional IO model can quantify direct and indirect socio-economic effects at regional level and can provide insight in the linkages between regions. The application of the model to NE Brazil has demonstrated significant positive socio-economic impacts that can be achieved when developing and expanding the sugarcane–ethanol sector in the region under the conditions studied here, not only for the NE region itself but also for the economy of the rest of Brazil.

Water supply systems (WSS) frequently present high-energy consumption values, which correspond to the major expenses of these systems. Energy costs are a function of its real consumption and of the variability of the daily energy tariff. This paper presents a model of optimization for the energy efficiency in a water supply system. The system is equipped with a pump station and presents excess of available energy in the gravity branch. First, a water turbine is introduced in the system in order to use this excess of hydraulic available energy. Then, an optimization method to define the pump operation planning along the 24 h of simulation, as well as the analysis of the economic benefits resulting from the profit of wind energy to supply the water pumping, while satisfying the system constraints and population demands, is implemented, in order to minimize the global operational costs. The model, developed in MATLAB, uses linear programming and provides the planning strategy to take in each time step, which will influence the following hours. The simulation period considered is one day, sub-divided in hourly time steps. The rules obtained as output of the optimization procedures are subsequently introduced in a hydraulic simulator (e.g. EPANET), in order to verify the system behaviour along the simulation period. The results are compared with the normal operating mode (i.e. without optimization algorithm) and show that energy cost's savings are achieved dependently of the initial reservoir levels or volume. The insertion of the water turbine also generates significant economical benefits for the water supply system.

Abstract This work presents a performance analysis of a waste-heat-to-power Reverse Electrodialysis Heat Engine (RED-HE) with a Multi-Effect Distillation (MED) unit as the regeneration stage. The performance of the system is comparatively evaluated using two different salts, sodium chloride and potassium acetate, and investigating the impact of different working solutions concentration and temperature in the RED unit. For both salt solutions, the impact of membrane properties on the system efficiency is analysed by considering reference ionic exchange membranes and high-performing membranes. Detailed mathematical models for the RED and MED units have been used to predict the thermal efficiency of the closed-loop heat engine. Results show that, under the conditions analysed, potassium acetate provides higher efficiency than sodium chloride, requiring a smaller MED unit (lower number of effects). The maximum thermal efficiency obtained is 9.4% (43% exergy efficiency) with a RED operating temperature of 80 °C, KAc salt solution, adopting high-performing ion exchange membranes, and with 12 MED effects. This salt has been identified as more advantageous than sodium chloride from a thermodynamic point of view for the RED-HE technology and is also recommended for a cost-effective technology implementation.

Abstract The literature and policy base for fuel poverty in the UK and Ireland is well established, and there is a growing body of single country studies beyond these two EU member states (for example Brunner et al., 2012 , Dubois, 2012 , Robine et al., 2008 ), however, on a European level, the last analysis of fuel poverty was conducted in 2004, prior to the enlargement of the EU. Using survey data this paper presents an updated overview of the prevalence of European fuel poverty in the context of the accession of numerous former social states, and rising fuel prices. Analysis reveals the phenomenon of fuel poverty is occurring across the EU, with particularly high levels of fuel poverty found in Eastern and Southern European states. It is argued that there are both EU and national policy frameworks in place that address climate change and these could be used as a starting point for countries to address fuel poverty through improved domestic energy efficiency measures. This paper reflects research undertaken in 2011, supported by eaga Charitable Trust, within the umbrella of work examining issues of poverty and social exclusion across the EU, which has enabled access to the EU-SILC dataset.

Abstract Dirty cooking fuels are a significant source of indoor air pollution in developing countries, resulting in millions of premature deaths. This paper investigates the health impacts of household access to cleaner fuel using a nationwide fuel-switching program, the largest household energy transition project ever attempted in the developing world, affecting more than 50 million homes in Indonesia. This program focused on replacing a dirty cooking fuel (kerosene) with a cleaner one (liquid petroleum gas). The difference-in-differences estimates and within-mother estimates suggest that the program led to a significant decline in infant mortality with the effects concentrated on the perinatal period. The program also reduced the prevalence of low birth weight, suggesting that fetal exposure to indoor air pollutants is an important channel. These findings elucidate how a policy that combines a subsidy on the use of cleaner-burning fuel with a restriction on the dirty fuel can pay public health dividends.

Abstract With climate change mainly originating from the extensive use of fossil fuels and having impacts on many aspects of life, changing the way energy is utilised constitutes a challenge that the world collectively must tackle. In this respect, all countries should implement a variety of measures focusing on energy efficiency and use of sustainable energy sources towards decarbonising their economies and achieving effective greenhouse gas emission reductions and sustainable development. Technological innovations, economic growth, societal compliance, and the regulatory and institutional frameworks constitute prominent factors that could promote, hinder or shape energy transitions as well as indicate the capacity of energy systems to be transformed. Therefore, investigating energy transitions and the extent to which countries are prepared to carry out such transitions requires the consideration of insights into multiple dimensions. This study outlines a multicriteria analysis framework to assess a country's sustainable energy transition readiness level, drawing from four pillars—social, political/regulatory, economic and technological—comprising a consistent set of eight evaluation criteria. The proposed decision analysis framework builds on the PROMETHEE II and AHP methods. Fourteen countries of different profile and level of progress towards sustainable development are evaluated and ranked, in an effort to highlight areas for improvement, and to support policymakers in designing appropriate pathways towards a greener economy.

Sustainability is an important concept for the whole world. Generally, in order to measure the sustainability of the environment, carbon dioxide emissions and ecological footprint indicators are used. However, these variables do not reflect the supply side of natural resources. Therefore, load capacity factor is an important environmental indicator for a sustainability. Environmental assessment based on the load capacity factor is more meaningful. Besides, improved access to financial services can contribute to environmental sustainability. The effect of financial inclusion on the load capacity factor in Türkiye has not been examined in the current literature. In this context, this study analyzes the impact of financial inclusion, hydropower energy consumption, and life expectancy at birth on environmental sustainability from a different perspective by focusing on load capacity factor. To this end, this study used the newly developed Augmented ARDL method to determine the cointegration relationship between the series and measure the values of the long-term coefficients. Based on the Augmented ARDL method, there is a cointegration relationship between the series. In the long run, hydropower energy consumption reduces pollution, while financial inclusion decreases load capacity factor. The effect of life expectancy at birth on pollution is not significant. Moreover, the results reveal that the load capacity curve hypothesis is valid in Türkiye. As a result, the Turkish government should promote renewable energy sources, especially hydropower energy consumption, align financial services with pollution reduction measures, and contribute to the creation of an environmentally conscious society.

Electrolytic hydrogen production faces technological challenges to improve its efficiency, economic value and potential for global integration. In conventional water electrolysis, the water oxidation and reduction reactions are coupled in both time and space, as they occur simultaneously at an anode and a cathode in the same cell. This introduces challenges, such as product separation, and sets strict constraints on material selection and process conditions. Here, we decouple these reactions by dividing the process into two steps: an electrochemical step that reduces water at the cathode and oxidizes the anode, followed by a spontaneous chemical step that is driven faster at higher temperature, which reduces the anode back to its initial state by oxidizing water. This enables overall water splitting at average cell voltages of 1.44–1.60 V with nominal current densities of 10–200 mA cm−2 in a membrane-free, two-electrode cell. This allows us to produce hydrogen at low voltages in a simple, cyclic process with high efficiency, robustness, safety and scale-up potential. Conventionally, the two half reactions involved in water electrolysis occur simultaneously, presenting materials and process challenges. Here, the authors decouple these to split water efficiently in two steps: electrochemical hydrogen evolution, followed by spontaneous oxygen evolution at elevated temperature.