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The design and assessment of net-zero buildings commonly focus exclusively on the operational phase, ignoring the embodied environmental impacts over the building life cycle. An analysis is presented on the consequences of integrating embodied impacts into the assessment of the environmental advantageousness of net-zero concepts. Fundamental issues needing consideration in the design process - based on the evaluation of primary energy use and related greenhouse gas emissions - are examined by comparing three net-zero building design and assessment cases: (1) no embodied impacts included, net balance limited to the operation stage only; (2) embodied impacts included but evaluated separately from the operation stage; and (3) embodied impacts included with the operation stage in a life cycle approach. A review of recent developments in research, standardization activities and design practice and the presentation of a case study of a residential building in Norway highlight the critical importance of performance indicator definitions and system boundaries. A practical checklist is presented to guide the process of incorporating embodied impacts across the building life cycle phases in net-zero design. Its implications are considered on overall environmental impact assessment of buildings. Research and development challenges, as well as recommendations for designers and other stakeholders, are identified.

This paper deals with the medium between two reconfigurable sensor nodes characterized by radio interfaces that support multiple channels for exchanging real-time messages under energy constraints. These constraints are violated if the consumed energy in transmission is higher than the remaining quantity of energy. A reconfiguration, i.e., any addition or removal of tasks in devices and consequently of messages on the medium, can cause the violation of real-time or energy constraints at run time. To achieve a feasible scheduling in time (i.e., message deadlines will be respected) and energy (i.e., there is available energy) on the medium, we propose new dynamic solutions: Balance, Dilute, and a Combination of them to manage any addition or removal of messages. The proposed approach utilizes the energy harvesting techniques and the PowerControl algorithm to reduce the nonharvested consumed energy. The proposed strategies achieve significant improvement over existing methods and provide the highest percentage of adding messages, with a lower average in response time and energy consumption. They reach a percentage of success in adding the highest priority messages while meeting deadlines up to 85%.

The potential of renewable energy should be fully exploited in the transportation sector to achieve a cleaner production. Therefore, this paper proposes an on-grid hybrid hydrogen refueling and battery swapping station powered by wind energy. This novel concept can promote the development of low-carbon emission vehicles including hydrogen-based vehicle and battery electric vehicle. During the daily operation of the station, the multiple uncertainties may lead to a higher operational cost. To address this problem, a hybrid stochastic/distributionally robust optimization method is proposed to handle different uncertainties for the energy management problem. The first type of uncertainties can be depicted by a certain distribution, i.e. electricity price and wind power, which is processed by a stochastic optimization method. The second type of uncertainties is associated with human behaviors and is difficult to find its probability distribution, i.e. the hydrogen demand of hydrogen-based vehicles, so the second type is processed by a distributionally robust optimization method. The overall objective is to minimize the total operational cost of the station, which also considers the battery swapping station overstock punishment. Because a reasonable battery swapping scheduling can reduce the waiting time of users and operational cost of the station. The results indicate that the proposed method can effectively address the conservatism of solutions as its total operational cost is 4.4% lower than that of the hybrid stochastic/robust optimization method under a high confidence level.

Urban environments provide opportunities for greater resource efficiency and the fostering of urban ecosystems. Brownfield areas are a typical example of underused land resources. Brownfield redevelopment projects that include green infrastructure allow for further ecosystems to be accommodated in urban environments. Green infrastructure also deliver important urban ecosystem services (UES) to local residents, which can greatly contribute to improving quality of life in cities. In this case study, we quantify and assess the economic value of five UES for a brownfield redevelopment project in Antwerp, Belgium. The assessment is carried out using the “Nature Value Explorer” modelling tool. The case includes three types of green infrastructure (green corridor,infiltration gullies and green roofs) primarily intended to connect nature reserves on the urban periphery and to avoid surface runoff. The green infrastructure also provides air filtration, climate regulation, carbon sequestration and recreation ecosystem services. The value of recreation far exceeds other values, including the value of avoided runoff. The case study raises crucial questions as to whether existing UES valuation approaches adequately account for the range of UES provided and whether such approaches can be improved to achieve more accurate and reliable value estimates in future analyses.

Nanosecond-level transient electromagnetic disturbance (TED), including very fast transient overvoltage caused by operation of disconnectors, high-altitude electromagnetic pulse, and many other fast transients may interfere or even damage the electrical equipment. As one of the main overvoltage protective equipment, the protective performance of metal-oxide surge arresters (MOAs) under nanosecond-level TED should be investigated and then compared with that under microsecond-level TED, especially the lightning impulse. Based on a testing platform containing a 400-kV pulse generator with adjustable rise time from 5 to 100 ns, the behaviors of nonlinearity, fast impulse response, and converting impedances of three types of 10-kV MOAs under TED with different rise time were explored experimentally in this article. The peak residual voltages of 10-kV MOAs under TED with the rise time of 5 ns at 5 kA are 50.2–60.7% higher than those under the lightning impulse. The rise time of TED has significant influence on the peak voltage and impedance converting behaviors of MOAs. A circuit model of 10-kV MOAs under nanosecond-level TED is built and validated by experimental results, which can be applied in insulation coordination and design of protective devices against TED.

The reclosing time of a transmission line has a distinct influence on system stability. A new method of calculating the optimal reclosing time based on the transient energy function (TEF) is presented in this paper. It has been shown that an optimal reclosing time can be used to set the autoreclosing device so that the system stability or power-transfer capability can be significantly improved. Though power-system TEF is based on classical models, the results from simulation studies of a real system (46 generators and 230 buses) with complex models show that the optimal reclosing time calculated using TEF can be used effectively.

AbstractClimate change alters surface water availability (WA; precipitation minus evapotranspiration, P − ET) and consequently impacts agricultural production and societal water needs, leading to increasing concerns on the sustainability of water use. Although the direct effects of climate change on WA have long been recognized and assessed, indirect climate effects occurring through adjustments in terrestrial vegetation are more subtle and not yet fully quantified. To address this knowledge gap, here we investigate the interplay between climate‐induced changes in leaf area index (LAI) and ET and quantify its ultimate effect on WA during the period 1982–2016 at the global scale, using an ensemble of data‐driven products and land surface models. We show that ~44% of the global vegetated land has experienced a significant increase in growing season‐averaged LAI and climate change explains 33.5% of this greening signal. Such climate‐induced greening has enhanced ET of 0.051 ± 0.067 mm year−2 (mean ± SD), further amplifying the ongoing increase in ET directly driven by variations in climatic factors over 36.8% of the globe, and thus exacerbating the decline in WA prominently in drylands. These findings highlight the indirect impact of positive feedbacks in the land–climate system on the decline of WA, and call for an in‐depth evaluation of these phenomena in the design of local mitigation and adaptation plans.