A systems approach to urban water services in the context of integrated energy and water planning: A City of Cape Town case study

The City of Cape Town derives the bulk of its present water supply from surface water resources and is the central water service authority for metropolitan consumers. The City is also a provider of bulk water to neighbouring municipalities. An exploration of the energy consumption for water and sanitation services for the City of Cape Town was conducted with an emphasis on water supply augmentation options for the near future (2011-2030). A systems analysis of municipal urban water services was undertaken to examine the energy requirements of supply alternatives and the efficacy of the alternatives in respect of supply availability and reliability. This was achieved using scenario based analysis incorporating a simple additive value function, to obtain a basic performance score, to rank alternatives and facilitate a quantitative comparison. Utilising the Water Evaluation and Planning hydrological modelling tool, a model for urban water services was developed for the City and used to conduct scenario analyses for a representative portfolio of previously identified options. Within the scope of the research objectives, the scenario analyses examines the direct energy consumption for the provision of water services for the City as influenced by external factors such as population growth, surface water runoff variability, available alternatives and the policies that are adopted which ultimately determine the future planning. It is contended that the modelling process presented here integrates energy and water planning for an assessment of water and energy resources required for future growth, and the optimal measures that could be pursued to reconcile the demand for water and the concomitant energy requirements

A systems approach to urban water services in the context of integrated energy and water planning: A City of Cape Town case study

The City of Cape Town derives the bulk of its present water supply from surface water resources and is the central water service authority for metropolitan consumers. The City is also a provider of bulk water to neighbouring municipalities. An exploration of the energy consumption for water and sanitation services for the City of Cape Town was conducted with an emphasis on water supply augmentation options for the near future (2011-2030). A systems analysis of municipal urban water services was undertaken to examine the energy requirements of supply alternatives and the efficacy of the alternatives in respect of supply availability and reliability. This was achieved using scenario based analysis incorporating a simple additive value function, to obtain a basic performance score, to rank alternatives and facilitate a quantitative comparison. Utilising the Water Evaluation and Planning hydrological modelling tool, a model for urban water services was developed for the City and used to conduct scenario analyses for a representative portfolio of previously identified options. Within the scope of the research objectives, the scenario analyses examines the direct energy consumption for the provision of water services for the City as influenced by external factors such as population growth, surface water runoff variability, available alternatives and the policies that are adopted which ultimately determine the future planning. It is contended that the modelling process presented here integrates energy and water planning for an assessment of water and energy resources required for future growth, and the optimal measures that could be pursued to reconcile the demand for water and the concomitant energy requirements

Final Preprint of paper published in Omega

Abstract Scenario planning and multiple criteria decision analysis (MCDA) are two key management science tools used in strategic planning. In this paper, we explore the integration of these two approaches in a coherent manner, recognizing that each adds value to the implementation of the other. Various approaches that have been adopted for such integration are reviewed, with a primary focus on the process of constructing preferences both within and between scenarios. Biases that may be introduced by inappropriate assumptions during such processes are identified, and used to motivate a framework for integrating MCDA and scenario thinking, based on applying MCDA concepts across a range of "metacriteria" (combinations of scearios and primary criteria). Within this framework, preferences according to each primary criterion can be expressed in the context of different scenarios. The paper concludes with a hypothetical but non-trivial example of agricultural policy planning in a developing country. Keywords: multicriteria decision analysis; scenario planning; decision making under uncertainty Background and Context Our initial motivation for this paper was a concern that many quantitative decision analytic models do not adequately deal with the many uncertainties and risks that arise in long term strategic decision making contexts. We are particularly concerned with the use of multi-criteria value models and, to some extent, decision trees and influence diagrams, but the same difficulties occur in using other quantitative models: we would contend all other quantitative models. French [1995] has written on the different forms of uncertainty that may arise in decision modelling and analysis and this paper to som

Integrating multicriteria decision analysis and scenario planning : review and extension

Scenario planning and multiple criteria decision analysis (MCDA) are two key management science tools used in strategic planning. In this paper, we explore the integration of these two approaches in a coherent manner, recognizing that each adds value to the implementation of the other. Various approaches that have been adopted for such integration are reviewed, with a primary focus on the process of constructing preferences both within and between scenarios. Biases that may be introduced by inappropriate assumptions during such processes are identified, and used to motivate a framework for integrating MCDA and scenario thinking, based on applying MCDA concepts across a range of "metacriteria" (combinations of scenarios and primary criteria). Within this framework, preferences according to each primary criterion can be expressed in the context of different scenarios. The paper concludes with a hypothetical but non-trivial example of agricultural policy planning in a developing country

An aspiration-level interactive model for multiple criteria decision making

A simple, eclectic approach for solving discrete alternative multiple criteria decision problems is presented. It is based on the concept of the level of aspiration, and draws on ideas of various researchers. It assumes that the user has a set of alternatives with each alternative having a score on each of a number of objectives or measures of performance. The user determines his levels of aspiration for different objectives. He is then provided with considerable feedback as to the degree of feasibility of each level of aspiration as well as the degree of feasibility with respect to all levels of aspiration as a whole. The closest nondominated solution to the solution specified by the levels of aspiration is provided. The proposed method is easy to use and easy to understand and has been implemented on a personal computer (an IBM PC or compatible with 512K RAM). We describe an experimental application in which 49 students in an MBA program used the method to solve two discrete alternative multiple criteria decision problems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29826/1/0000173.pd

Four-electron deoxygenative reductive coupling of carbon monoxide at a single metal site

Carbon dioxide is the ultimate source of the fossil fuels that are both central to modern life and problematic: their use increases atmospheric levels of greenhouse gases, and their availability is geopolitically constrained. Using carbon dioxide as a feedstock to produce synthetic fuels might, in principle, alleviate these concerns. Although many homogeneous and heterogeneous catalysts convert carbon dioxide to carbon monoxide, further deoxygenative coupling of carbon monoxide to generate useful multicarbon products is challenging. Molybdenum and vanadium nitrogenases are capable of converting carbon monoxide into hydrocarbons under mild conditions, using discrete electron and proton sources. Electrocatalytic reduction of carbon monoxide on copper catalysts also uses a combination of electrons and protons, while the industrial Fischer–Tropsch process uses dihydrogen as a combined source of electrons and electrophiles for carbon monoxide coupling at high temperatures and pressures6. However, these enzymatic and heterogeneous systems are difficult to probe mechanistically. Molecular catalysts have been studied extensively to investigate the elementary steps by which carbon monoxide is deoxygenated and coupled, but a single metal site that can efficiently induce the required scission of carbon–oxygen bonds and generate carbon–carbon bonds has not yet been documented. Here we describe a molybdenum compound, supported by a terphenyl–diphosphine ligand, that activates and cleaves the strong carbon–oxygen bond of carbon monoxide, enacts carbon–carbon coupling, and spontaneously dissociates the resulting fragment. This complex four-electron transformation is enabled by the terphenyl–diphosphine ligand, which acts as an electron reservoir and exhibits the coordinative flexibility needed to stabilize the different intermediates involved in the overall reaction sequence. We anticipate that these design elements might help in the development of efficient catalysts for converting carbon monoxide to chemical fuels, and should prove useful in the broader context of performing complex multi-electron transformations at a single metal site

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements