• Energy Research

Abstract Many cities are facing environmental challenges with rapid urbanisation and industrialisation. It is critical to evaluate this new urban reality and its sustainability potential to generate appropriate solutions for a sustainable future. The urban metabolism framework is commonly applied to understand appropriate strategies to achieve sustainability for urban systems. In this study, material flow analysis was applied in conjunction with specific socio-economic indicators to model urban metabolism and evaluate appropriate urban metabolism changes for Jinchang City, China between 1995 and 2014. Structural decomposition analysis and decoupling analysis were used to explain and evaluate the sustainability potential of Jinchang City. Changes in material consumption and the waste generation of Jinchang City indicated a long-term unsustainable trajectory, evidenced by continuously increasing material inputs and outputs. We also found a significant reduction in air pollution, with declining sulphur dioxide emissions and dust; all are indicators of improvement in air quality. What is of special note is that industrial production was concurrently greatly increasing. These indicators suggest a positive improvement in sustainability beyond simple incrementalism. The study showed that MFA techniques can be used as valuable tools for understanding urban metabolism, evaluating urban sustainability, and suggesting strategies for the timely addressing of urban sustainability issues. This strategy is important in the face of China’s increasing industrial capacity.

Photovoltaic (PV) technologies in the energy industry are crucial for transitioning to a decarbonized era that relies on renewable energy sources. This systematic review aimed to identify the potential environmental impacts associated with the entire life cycle of PV technologies. To accomplish this, the review analysed literature from the last five years focused on life cycle assessment and evaluating PV technologies' environmental impacts/toxicity. In total, 72 final articles were collected and analysed, considering the year of publication, research methodology, and geographical context. Although there is substantial knowledge regarding potential impacts associated with end-of-life (EoL) PV technologies, only a limited number of regions have specific regulations regarding PV waste. With the incorporation of circular economy principles, targeted strategies for EoL treatments can be developed and implemented, leading to a substantial reduction in the environmental impacts caused by EoL PV modules, where this aspect represents a critical concern within the context of PV technologies. Therefore, this study emphasises the need to integrate life cycle assessment, circular economy, and systems thinking to achieve more sustainable development when utilizing PV technologies so that the diffusion of PV technologies helps decarbonization transitions without creating major unintended environmental problems in waste systems.

This study aims to investigate the social implications of palm oil biodiesel via a case study using a life cycle assessment framework. The case study was conducted in Jambi Province of Indonesia and involved several stakeholders, such as value chain actors, employees, local community members, government, and nongovernmental organization representatives related in palm oil industry. The assessment was carried out using social criteria developed by adopting the Society of Environmental Toxicology and Chemistry/United Nations Environment Programme Code of Practice, supplemented by an expert survey, and supported by literature review. Stakeholders’ perspectives were evaluated by determining the gaps between expected and perceived quality of each social criterion, which are gauged using seven-point Likert scale. Twenty-four social criteria were developed and aggregated into five social impact categories: human rights, working condition, cultural heritage, social–economic repercussion, and governance. These criteria have been weighted, useful for further application in multicriteria decision analysis. The results of the stakeholders’ survey reveal the critical social hotspots, which are the issues within the impact categories of working conditions and cultural heritage. In order to achieve the social equitability of palm oil biodiesel, which is an important pillar to sustainability, efforts must be put to address these social hotspots through actions in various policy level.

In the last decade, Malaysia has experienced exceptional growth, progressing from primarily agriculture-based to a more developed manufacturing-based industrial economy. The natural rubber industry has been an important sector for Malaysia's economic development, contributing RM33.7 billion (USD101.1billion) or 4.69% of the country's Gross Domestic Profit (GDP) in 2013. This paper aims to apply the industrial symbiosis (IS) concept to the proposed Rubber City bilateral industrial development in Kedah, Malaysia. The concept of IS can be considered a strategic tool to enhance environmental and socio-economic sustainability of rubber industry. This paper involves stakeholder analysis of IS to identify strategic priorities and opportunities for the Rubber City initiative. The IS framework focuses on three main natural rubber downstream products: natural rubber blocks, tyres, and gloves; and identifies synergies in resource cycles and waste management using Materials Flow Analysis (MFA) and the Input-Output (IO) data based on previous Life Cycle Analysis (LCA) data for each of the three natural rubber products. Based on this case study, we identified ten principal synergies which include five potential IS industries integrated within the RC conceptual framework. Stakeholder surveys of natural rubber processors and other actors (such as government agencies) were conducted in Malaysia to identify barriers and enabling factors for IS implementation in the Rubber City. The outcomes of this study will be used as basis for integrated strategic development plan and implementation approach towards a sustainable Rubber City development in Malaysia.

Abstract Besides the apparent need to reduce greenhouse gas emissions, other important factors contributing to the renewed interest in biofuels are energy security concerns and the need of sustainable transportation fuel. Nearly 30% of the annual CO2 emissions in the U.S. come from the transportation sector and more than half of the fuel is imported. Biofuels appear to be a promising option to reduce carbon dioxide emissions, and the reliance on imported oil concomitantly. The interest on (ligno) cellulosic ethanol is gaining momentum as corn-based ethanol is criticized for using agricultural outputs for fuel production. Among many lignocellulosic feedstocks, woodchips is viewed as one of the most promising feedstocks for producing liquid transportation fuels. The renewable and carbon neutral nature of the feedstocks, similar chemical and physical properties to gasoline, and the low infrastructure cost due to the availability of fuel flex vehicles and transportation networks make (ligno) cellulosic bioethanol an attractive option. An in-depth LCA of woodchips shows that harvesting and woodchips processing stage and transportation to the facility stage emit large amount of environmental pollutants compared to other life cycle stages of ethanol production. Our analysis also found that fossil fuel consumption and respiratory inorganic effects are the two most critical environmental impact categories in woodchips production. We have used Eco-indicator 99 based cradle-to-gate LCA method with a functional unit of 4 m3 of dry hardwood chips production.

Failures of countries in setting and achieving renewable energy targets are prevalent, raising uncertainty about the overall contribution of renewable energy to global emission reductions. Lack of policy and incorrect modelling analysis are among the sources of the failures. Thus understanding these two sources is crucial to improve confidence about renewables. We assess errors in the projections of renewable energy capacity and production in the United States and European Union countries, which have high commitments to green energy supply. Our results show that solar energy has the lowest uncertainty due to having the most achievable projections of capacity and production. On the other hand, other renewables may entail attractive policies, and further research is needed related to advancing reliable technology and accurate weather predictions. Our findings also provide ranges of projection uncertainty of six renewable energy technologies and, at the same time, draw attention to ways to rectify the dominant errors in the renewable energy projections.

ABSTRACTIn 2012, a total of 13.1 million tonnes of carbon dioxide were emitted by 14 airlines while transporting 72 per cent of international passengers into and out of Australia in 2012. With passenger and cargo traffic growing at between five to six per cent annually from 2013 to 2033, acquiring more fuel efficient aircraft to both renew the existing fleet and to service growth has the greatest potential in reducing emissions over the next 20 years. Our analysis shows that implementing carbon dioxide emissions abatement options such as installing light weight seats, iPad electronic flight bags, winglets, washing aircraft engines and reducing the number of engines used during taxiing, all offer net financial savings when considered over 20 years. Acquiring new fuel efficient aircraft has the biggest impact on emissions reduction. Low interest loans and longer loan repayment periods may incentivise airlines to acquire more fuel efficient aircraft to service traffic growth but other complimentary incentive...

Renewable energy has been prioritised in decarbonising Indonesia's electricity system. Indonesia aims to attain an efficient energy system by applying renewable energy tariffs that are lower than the cost of fossil fuel-generated electricity. However, the effectiveness of this policy is questionable, as renewable energy investments under previous premium feed-in tariffs did not meet expectations. This study aims to estimate generation costs from renewable energy expansions under three scenarios, namely existing power plant planning, and 11% and 14% emission reductions in Indonesia's electricity sector. We develop an agent-based model (ABM) tool called PowerGen-ABM that employs multi-approaches: linear programming and input-output analysis. The optimisation result shows that the emission reduction targets would increase the average electricity generation costs in 2028 from 65.3 USD/ MWh in the existing plan of power plant expansions to 68.3 USD/ MWh. The increased costs are caused by insufficient dispatchable renewables in several regions such as North Maluku. Renewable energy production share in total electricity production and emission reduction achievement of the existing plan in 2025 will be 22.8% and 6.5% below the targets of 23% and 11%, respectively. In contrast, the emission reduction scenarios could achieve those targets due to higher renewables productions, especially with wind energy from 5,268 GWh in the existing plan into anywhere between 64,472 to 75,085 GWh. Several policy implications are discussed based on these findings.

AbstractBio-based electricity is known for its advantage on reducing negative environmental impact compared to conventional counterparts. However, the question is whether bio-based electricity is socially and economically sustainable. The paper assessed the sustainability of the rice husk based bioelectricity in Vietnam over its life cycle and compared it with that of coal-fired electricity. It is identified that rice husk based bioelectricity is better in some aspects, but worse in other aspect compared to coal-fired electricity. However, if the negative aspect is compensated by the positive ones, the rice husk based bioelectricity in this case study is more sustainable than coal-fired counterpart.