• Energy Research

Increased awareness of climate change has shifted the focus of water distribution system (WDS) optimization research from cost minimization only to the incorporation of energy or associated greenhouse gas (GHG) minimization. In this study, a sensitivity analysis is conducted to investigate the effect of electricity tariff and generation (emission factors) on the results of multiobjective WDS optimization accounting for both total economic cost (both capital and operating costs) and GHGs. A multiobjective genetic algorithm-based optimization approach is used to conduct the analysis. The results show that electricity tariff has a significant effect on the total economic cost of WDSs and the selection of optimal solutions. In contrast, the changes of emission factors in the future have a significant effect on the total GHGs from WDSs. However, it does not alter the final solutions on the Pareto-optimal front. DOI: 10.1061/(ASCE)WR.1943-5452.0000169. © 2012 American Society of Civil Engineers. CE Database subject headings: Water distribution systems; Optimization; Emissions; Climate change; Sensitivity analysis; Algorithms. Author keywords: Water distribution systems; Multiobjective optimization; Greenhouse gas emissions; Climate change; Sensitivity analysis; Genetic algorithms.

Previous research has demonstrated that there are significant trade-offs between the competing objectives of minimizing costs and greenhouse gas (GHG) emissions for water distribution system (WDS) optimization. However, upon introduction of an emission trading scheme, GHG emissions are likely to be priced at a particular level. Thus, a monetary value can be assigned to GHG emissions, enabling a single-objective optimization approach to be used. This raises the question of whether the introduction of carbon pricing under an emission trading scheme will make the use of a multiobjective optimization approach obsolete or whether such an approach can provide additional insights that are useful in a decision-making context. In this paper, the above questions are explored via two case studies. The optimization results obtained for the two case studies using both single-objective and multiobjective approaches are analyzed. The analyses show that the single-objective approach results in a loss of trade-off informa...

The modern layout and configuration of cities create power generation and storage possibilities through the urban water system. Surplus energy in water and wastewater networks has come to the researchers’ attention for exploitation as micro hydropower (MHP). Also, the gravitational potential energy of stored water on highrises makes them a sustainable option for distributed energy storage as micro pumped-storage (MPS). Many studies have investigated technical aspects and estimated capacity of urban micro hydro systems (UMHS) in urban infrastructures. However, there is no systematic review of relevant literature to signify challenges and opportunities of different urban infrastructures as UMHS, from economic, technical, and environmental viewpoints. Therefore, this article applied a reference-by-reference method to provide a systematic assessment and concept review of UMHS, including the characteristics, challenges, and drivers of potential sites for MHP and MPS development. Examining the challenges of real case studies worldwide identifies economic feasibility and energy generation reliability as obstacles in developing MPS and MHP, respectively. Nevertheless, overlooked opportunities are recognised that may accelerate UMHS proliferation. UMHS synergies, such as water saving and peakload shaving, are introduced as influential factors in the economic feasibility of the UMHS that can be achieved through deploying sustainable stormwater management strategies and considering real-time analysis in the volatile energy market. Furthermore, simulation-optimisation tools are concisely presented for both the design and operation stages. Finally, some future research directions are offered to clarify the role of urban UMHS in addressing water and energy issues as individual systems or integrated into other decentralised energy sources. ; Arezoo Boroomandnia, Behzad Rismanchi, Wenyan Wu

Water distribution networks (WDNs) are significant users of energy and contributors to greenhouse gas emissions. Energy recovery strategies (ERSs) have potential for switching WDNs to a renewable energy source, thereby assisting with the transition to net-zero emissions and reducing the dependency of water utilities on power-grids. To address the current lack of understanding of the potential for ERSs to achieve these goals, this work presents a holistic review, which considers all available devices, i.e. turbines, pumps as turbines, and other alternative strategies, such as the GreenValves, as well as all the kinds of application in the literature. Besides describing the latest most significant achievements in the context of ERSs, the review also identifies the most common issues and proposes several future research directions, including the need for a better test and comparison of the various available solutions in field applications, and more thorough analyses of the socio/political problems hampering their diffusion.

AbstractThe high‐mountain system, a storehouse of major waterways that support important ecosystem services to about 1.5 billion people in the Himalaya, is facing unprecedented challenges due to climate change during the 21st century. Intensified floods, accelerating glacial retreat, rapid permafrost degradation, and prolonged droughts are altering the natural hydrological balances and generating unpredictable spatial and temporal distributions of water availability. Anthropogenic activities are adding further pressure onto Himalayan waterways. The fundamental question of waterway management in this region is therefore how this hydro‐meteorological transformation, caused by climate change and anthropogenic perturbations, can be tackled to find avenues for sustainability. This requires a framework that can diagnose threats at a range of spatial and temporal scales and provide recommendations for strong adaptive measures for sustainable future waterways. This focus paper assesses the current literature base to bring together our understanding of how recent climatic changes have threatened waterways in the Asian Himalayas, how society has been responding to rapidly changing waterway conditions, and what adaptive options are available for the region. The study finds that Himalayan waterways are crucial in protecting nature and society. The implementation of integrated waterways management measures, the rapid advancement of waterway infrastructure technologies, and the improved governance of waterways are more critical than ever.This article is categorized under: Engineering Water > Sustainable Engineering of Water

Considerable research has been carried out on the optimization of water distribution systems WDSs over the last three decades. In previous research, attention has mainly focused on the minimization of cost, due to the high expenditure associated with the construction and maintenance of such systems. However, the impacts of WDSs on the environment usually have not been considered adequately. The recent increasing awareness of sustainability and climate change, especially global warming, has led to research where greenhouse gas GHG emissions are considered. In the study described in this paper a multiobjective genetic algorithm for WDS optimization has been used as an explorative tool to investigate the trade-offs between the traditional economic objective of minimizing costs and an additional environmental objective of minimizing GHG emissions. The impacts of minimizing GHG emissions on the results of WDS optimization have been explored for a case study in this paper. The results indicate that the inclusion of GHG emission minimization as one of the objectives results in significant trade-offs between the economic and environmental objectives. Furthermore, a sensitivity analysis has been conducted by using different discount rates in a present value analysis for computing both ongoing costs and GHG emissions. The results obtained show that the Pareto-optimal front is very sensitive to the discount rates used. As a result, the selection of discount rates has a significant impact on final decision making.

<p>Compound weather and climate events are combinations of climate drivers and/or hazards that contribute to societal or environmental risk. Studying compound events often requires a multidisciplinary approach combining domain knowledge of the underlying processes with, for example, statistical methods and climate model outputs. Recently, to aid the development of research on compound events, four compound event types were introduced, namely (a) <em>preconditioned</em>, (b) <em>multivariate</em>, (c) t<em>emporally compounding</em>, and (d) <em>spatially compounding</em> events. However, guidelines on how to study these types of events are still lacking. Here, we consider four case studies, each associated with a specific event type and a research question, to illustrate how the key elements of compound events (e.g., analytical tools and relevant physical effects) can be identified. These case studies show that (a) impacts on crops from hot and dry summers can be exacerbated by preconditioning effects of dry and bright springs. (b) Assessing compound coastal flooding in Perth (Australia) requires considering the dynamics of a non-stationary multivariate process. For instance, future mean sea-level rise will lead to the emergence of concurrent coastal and fluvial extremes, enhancing compound flooding risk. (c) In Portugal, deep-landslides are often caused by temporal clusters of moderate precipitation events. Finally, (d) crop yield failures in France and Germany are strongly correlated, threatening European food security through spatially compounding effects. These analyses allow for identifying general recommendations for studying compound events. Overall, our insights can serve as a blueprint for compound event analysis across disciplines and sectors.</p>