The energy transition is progressing slowly in the ten member states of the Association of Southeast Asian Nations (ASEAN). To achieve ASEAN’s target of 23% renewables in the primary energy supply by 2025, the region would need to invest USD 27 billion in renewable energy every year. However, the ASEAN countries attracted no more than USD 8 billion annually from 2016 to 2021. Through a comparative review of three key factors for attracting investment—renewable energy legislation, energy governance reform, and general conditions for investors—this study examines why the region’s renewable energy sector has not attracted more capital. The contribution of the article is threefold. First, it develops a new review model for assessing the business climate for renewable energy in any country. Second, it offers an update on the state of renewable energy deployment in the ASEAN countries. Third, taking into account international best practices, it identifies the obstacles and solutions to attracting investment in renewable energy in Southeast Asia. The article finds that carbon lock-in is pervasive, regulatory practices have been copy-pasted from the fossil-fuel sector to the renewables sector, and, except for Malaysia and Vietnam, no ASEAN country has implemented a major pro-renewable energy governance reform. Certain advanced renewable energy measures, such as auctions and feed-in tariffs, have been adopted in some member states, but the institutional capacity to implement them is limited. The share of renewables in the energy governance system needs to be increased.
Government policies are key to combating climate change and biodiversity loss. Here, we examine whether environmental messages on Twitter by UK politicians can be used to predict the probability of politicians voting-in pro-environmental policy. Using historical Twitter data and voting records, we determine that the number of tweets by UK politicians regarding environmental subjects has increased over the last decade, although this is not consistent across all parties. The probability of voting environmentally has not increased, instead, voting trends are highly heterogeneous over time, varying by political party. This suggests that there is little association between politicians that promote environmental messages on social media and the odds of them voting-in environmental policy. However, in some cases, politicians do deviate from political party lines, and so we assessed whether politicians that posted more environmental messages were more likely to break party lines and vote-in environmental measures. We found evidence that, after accounting for party, politicians who tweet more frequently about environmental subjects are more likely to vote against party lines in favour of environmental measures. This work suggests that politicians’ that post more environmental messages are more likely to support pro-environmental policy, but this signal is low relative to the predominant driver—political party association.
| • | Environmental tweeting by UK MPs has increased over the past decade but environmental voting has not. |
| • | Party lines account for much of the variation in environmental vote patterns. |
| • | Political association is a stronger predictor of vote intentions than whether an MP tweets about environmental issues. |
By linking agricultural and livestock products, integrated crop-livestock systems produce economic and environmental benefits. Using emergy analysis, the current study evaluates the effect of an integrated system for producing agricultural crops and livestock on efficiency and ecological sustainability, and compares it to separate crop and livestock production systems. This study was conducted in 2019, with data collected from the smallholding farmland and livestock systems of Boland Village in Sistan, Iran. Purchased inputs accounted for 51.08, 99.96, and 30.94% of the total inputs of cropping, livestock, and integrated production systems, respectively. The values of Emergy Yield Ratio, Emergy Sustainability Indices, and Gross Benefit and Net Benefit showed that, due to the positive interactions between the crop and livestock components along with high environmental sustainability, the integrated system results in a higher net profit in comparison to the individual cropping and livestock systems. Due to the suitable weather and richness of natural resources in the Sistan region, various crops are produced all year round, and many opportunities exist for integrating agricultural and livestock products in this region. The results also indicated that while the integration of crops and livestock has the potential to reduce economic risks and to increase profitability, it can also provide great benefits regarding the preservation of soil and water resources and the productivity of nutrient cycling. An integrated crop-livestock system is suggested as a suitable option for diversifying agricultural practices, which could prevent risks, improve crop ecological production, and prevent soil erosion and nutrient loss.
Longitudinal dispersion of multiple Microcystis patches is significant for understanding the mechanisms of Microcystis blooms in ambient waters. Presented in this paper is an analysis of multiple Microcystis patches in a turbulent open channel flow, based on the concentration transport equation. Results show that the total amount of Microcystis on a streamline, centre-of-mass motion, as well as longitudinal dispersion finally stabilise for multiple Microcystis patches as they do for a single Microcystis patch. The centre-of-mass velocity exhibits a weak oscillation with a small amplitude in the vertical direction for multiple Microcystis patches, but it can reach the same migration velocity for long time evolution. The large results in an asymptotic increase of centre-of-mass velocity towards a positive value except for very early time for the Microcystis patches in close proximity to the free surface, and an initial reduction to zero, subsequent increase to a maximum, and final decrease to a constant for the bed bottom, where represents the relative strength of vertical swimming and the total effective diffusion in the vertical direction. For the case of large , the longitudinal dispersion coefficient first increases to a maximum, then decrease to a minimum, and finally increases to a constant for the Microcystis patches near the free surface. The effects of initial distribution on the evolution of the concentration of Microcystis patch mainly appear during the initial stage and can be negligible for the long time evolution. The Microcystis patches tend to accumulate near the free surface due to the vertical migration velocity caused by density differences between the Microcystis and the ambient water.
Biofilms are the predominant habitats of microbes and have been suggested as potential biosorbents for water pollutants. The electric charges of extracellular polymeric substances (biofilm polymers) are essential characteristics of biofilms as promising biosorbents. In order to clarify the electric charge properties along with biofilm formation, the electrophoretic mobilities of biofilms formed on stones after 15, 30, and 60 formation days collected from Lahor Reservoir, Indonesia, were analyzed, as were the Fourier-transform infrared spectra. In addition, the adsorptions of Cu(II) by mature biofilms at different pH (pH 9, 7, 5) were also investigated. The results indicated the amount of Cu(II) adsorbed to the biofilms differed at various pH values (i.e., 92, 73, and 21 μmol/g at pH 9, 7, and 5, respectively). The greatest amount of Cu(II) at pH 9 may have been due to the abundance of the negatively charged sites in the biofilm polymers, in natural aquatic ecosystems. Such electric charges should be considered to utilize biofilms as biosorbents for water pollutants, such as heavy metals.
This work aimed to investigate the combustion characteristics of rubberwood sawdust pellet (RSP), teak sawdust pellet (TSP), eucalyptus bark pellet (EBP), cassava rhizomes pellet (CRP), and their corresponding raw biomass. The experiments were performed in a thermogravimetric (TG) analyzer and a fluidized-bed combustor (FBC). Thermogravimetric analysis (TGA) was conducted in the temperature range of 30–1000 °C at a heating rate of 10 °C/min in a dry air atmosphere. The combustion experiments were conducted in a twin-cyclone FBC at 120 kilowatts (kWth) heat input with three values of excess air (EA): 40, 50, and 60%. The combustion reactivity of the pellets was lower than raw biomasses, as indicated by higher values of peak, ignition, and burnout temperatures, as well as a lower comprehensive performance index value. The activation energies of the biomass pellets were greater than the as-received biomasses, indicating that the biomass pellets required higher energy and temperature and a longer time for complete combustion. The pellet fuels had a higher residence time and better mixing of the fuel and bed particles, leading to higher combustion intensity in a fluidized bed. Carbon monoxide (CO), hydrocarbon (CxHy), and nitric oxide (NO) emissions of the combustor when firing the pellets were lower compared to the burning of as-received biomasses. When firing the pellets at optimal EA (about 40%), the combustor operated at high combustion efficiency of 99.0–99.8%. This study indicated that the biomass pellets have desirable combustion characteristics that could be used as alternative fuels for sustainable energy production.
A one-dimensional numerical model characterizing the coupled heat transfer between a three-layer PCM wall and a closed cavity is elaborated. This model is applied to study the passive control and stability of the indoor air temperature of a closed cavity which can designate a living space. The wall exposed to external disturbances consists of a phase change material, encapsulated in a rectangular container, and framed by an insulating and a building material. Phase change heat transfer is modeled by the use of the apparent heat capacity method where the heat capacity is numerically evaluated by the Hsiao approach. This approach is adequate and well adapted to numerical solution without the need to specify the solidification–melting temperature range for phase change materials. The numerical analysis is performed using an implicit finite difference scheme. The model is validated by comparison with previous work. The numerical simulations are performed with three types of PCM, namely calcium chloride hexahydrate CaCl (6H O), polyethylene glycol 900, and RT25-30. The results showed that for stability and control of indoor air temperature, the choice of PCM is based on its melting temperature which is preferably chosen close to the temperature of thermal comfort and with a significant latent heat. This model can be extended to the multilayer wall, PCM–porous medium wall, and used to determine the optimal position and thickness of the PCM layer.