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Abstract: After the implementation of a biofuel target in 2017, China, the second largest consumer of oil in the world, accelerated the development of lignocellulosic biomass technology to produce ethanol and minimized food security risks commonly associated with first generation biofuel production. In this study, Life Cycle Assessment (LCA) is used to investigate three new lignocellulosic biomass refinery systems based on corncob which co-produce ethanol with chemicals and energy. The bioethanol is used in E10 and E85 biofuel mixes and these are compared with a fossil gasoline reference system. Using 1 km distance driven by a compact size flexible fuel passenger vehicle as the functional unit and a exergy allocation approach to the raw material inputs and to the co-products in the simulated multifunctional biorefinery processes, the results indicate that regardless of the configuration of the ethanol-biorefinery, ethanol-blended fuels performed better than gasoline in terms of fossil fuels depletion (E10 6% lower; E85 64–70% lower), global warming potential (E10 1–10% lower; E85 5–113% lower) and human toxicity potential (E10 6–7% lower; E85 72–75% lower), but worst in terms of ozone layer depletion (E10 4.5–6.8 times higher; E85 51.9–78.2 times higher), acidification (E10 30–50% higher; E85 3.3–5.5 times higher) and eutrophication potential (E10 5.2–7.0 times higher; E85 42.4–64.0 times higher) than gasoline.

Abstract Herein, we report the dual functionality of a single n-type gallium nitride (n-GaN) layer as an electron transporter and transparent conductor, which has applications in reusable organic solar cells. After silicon doping with an optimized electron concentration, thin-film layer of GaN showed exceptional electrical properties including charge carrier mobility of 161 cm2 V−1s−1, electrical conductivity of 1.4ⅹ106 S cm−1, and sheet resistance of 11.1 Ω cm−2. Organic solar cells based on n-GaN exhibited power conversion efficiency comparable to those based on a conventional ITO/ZnO bilayered cathode. Furthermore, the n-GaN substrates exhibited reusability; due to excellent chemical stability of n-GaN, the reconstructed organic solar cells maintained their initial performance after the substrates were recycled. We suggest a new type of reusable n-GaN cathode layer featuring an integrated electron transporting layer and transparent electrode.

Abstract The study quantifies the benefits of expanding electric cooking in the residential sector in terms of kerosene and fuel wood saved from the perspective of long term optimal energy system development of Bhutan. It also investigates the reductions in the emissions of CO2 and the indoor pollutants, SO2 and NOx due to fuel switching in the cooking enduse. This study method is based on the first ever integrated long-term energy system modeling in Bhutan, which was undertaken previously by the lead author as a master thesis work but not published. The energy system model for Bhutan was developed under the MARKAL model framework. In Bhutan electricity generation is pre-dominantly hydropower based on run-of-the-river schemes. The model results indicate that a sectoral level policy to promote electric cooking reduces the use of kerosene by 1832 kiloliters and fuelwood by 55 kilotonnes per annum which consequently leads to reductions in the emissions of CO2, SO2 and NOx by 17%, 12% and 8% respectively. The electric cooking scenario also complements the vision of Bhutan to reduce deforestation and to remain carbon neutral for all times to come.

This paper is intended to fill a gap in the current literature comparing and contrasting the experience of a number of European countries, U.S. states, and Australia with regard to wind energy support policy and electricity market design. As wind penetrations increase, the nature of these arrangements becomes an increasingly important determinant of how effectively and efficiently this generation is integrated into the electricity industry. The jurisdictions considered in this paper exhibit a range of wind support policy measures from feed-in tariffs to green certificates, and electricity industry arrangements including vertically integrated utilities, bilateral trading with net pools, as well as gross wholesale pool markets. We consider the challenges that various countries and states have faced as wind generation expanded and how they have responded. Findings include the limitations of traditional feed-in tariffs at higher wind penetrations because they shield wind project developers and operators from the implications of their generation on wider electricity market operation. With regard to market design, wind forecasting and predispatch requirements are particularly important for forward markets, whereas the formal involvement of wind in scheduling and ancillary services (balancing and contingencies) is key for real-time markets.

Abstract This study aims to identify research priorities to enable low cost, high renewable power systems. An evolutionary program optimises the mix of technologies in 100% renewable energy portfolios (RE) in the Australian National Electricity Market. Various technologies are reduced in availability to determine their relative importance for achieving low costs. The single most important factor is found to be the integration of large quantities of wind; therefore wind integration is identified as a research priority. In contrast, photovoltaics are found to “saturate” the system at less than 10% of total energy (in the absence of storage or demand management, installation of further photovoltaics does not contribute significant further value). This indicates that policies to promote utility-scale photovoltaics should be considered in partnership with complementary measures (such as demand side participation and storage). Biofuelled gas turbines are found to be important; a complete absence of bioenergy increases costs by AU$20–30/MWh, and even having only 0.1 TWh per year of bioenergy available reduces average costs by AU$3–4/MWh. Limits on the non-synchronous penetration (NSP) are found to be relatively expensive, suggesting a significant research priority around finding alternative approaches to providing synchronous services, such as inertia. Geothermal and concentrating solar thermal technologies do not appear essential as long as sufficient wind and peaking bioenergy is available.

Abstract In January 1981, the United States Council on Environmental Quality [U.S.C.E.Q.] released a report on “Global Energy Futures and the Carbon Dioxide Problem”. Perhaps more than any other document this report has impressed upon the scientific community the necessity to initiate a detailed and systematic study of a whole range of environmental problems created by the increasing combustion of fossil fuels. It has also helped to bring into perspective the relative risks associated with the utilisation of a number of base load fuel cycles, including, in particular, the nuclear fuel cycle.

Abstract The paper puts forward a proposal that, within Clean Development Mechanism (CDM) projects, investors be allowed to benefit from options; this will require a CDM rule change. Through the presence of options, the downside risk resulting from low carbon prices and/or low achieved emission reductions on projects can be limited, while any upside resulting from high carbon prices and/or high achieved emission reductions can be taken advantage of. It is demonstrated that the presence of options improves the financial attractiveness of CDM projects, and this is at no detriment to any stakeholder. The flow-on from the proposal is that more CDM projects should be realisable if options are available, and this in turn will lead to reduced global emissions and improved sustainability. The proposal is supported by the necessary theory and is demonstrated on two registered CDM projects, one on hydropower and one on wind power.

Abstract Indoor thermal comfort and air quality in school classrooms are of interest worldwide, primarily because of their potential impacts on students’ health, learning performance and productivity. Further, increasing concerns with changing climate and building energy efficiency highlight the importance of ventilation and comfort in educational settings. The existing literature on indoor air quality (IAQ), ventilation, and thermal comfort in classrooms in subtropical regions of Australia is sparse. Here, we present the results of a field study conducted in secondary school classrooms in Sydney during the school year in 2018 and 2019. We collected data with subjective surveys through questionnaires and with field measurements related to IAQ the thermal comfort in two adjacent similar classrooms. The infiltration and ventilation rates were measured during the non-occupied period using the concentration decay method. We analysed the performance of a cloud-connected demand-controlled mechanical extract ventilation system (DCV), which was installed in one of the two surveyed classrooms during mid-season. Before application of the DCV, CO2 levels were similar in both classrooms with a maximum concentration of approximately 2418 ppm during cold season. The DCV reduced the peak CO2 concentration to 1335 ppm, while CO2 raised to 2981 ppm in the classrooms without DCV during mid-season. Further, Volatile Organic Compounds (VOCs) analysed from air samples show improved air quality in the classroom with DCV. Our results highlight the impact of both indoor temperature and CO2 concentration on students’ feeling of fatigue. Students showed adaptability to indoor temperature change. A period of one week is needed for students’ adaptation to a step change in the mean outdoor temperature. Understanding classroom indoor air quality and thermal environment, as well as students’ perceived comfort, is vital to develop child-based design guidelines for schools.