Sensitivity of optimal tradeoffs between cost and greenhouse gas emissions for water distribution systems to electricity tariff and generation

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. © 2012 American Society of Civil Engineers.Wenyan Wu, Angus R. Simpson, and Holger R. Maie

Optimising power transmission options for marine energy converter farms

AbstractThis paper introduces a techno-economic analysis framework to assess different transmission options for marine energy converter (MEC) farms. On the technical front, the feasibility of the transmission options considering supply quality constraints and the optimal sizing of reactive power compensation to allow maximum real power transfer capability in the subsea transmission cable have been considered. The economic viability of different transmission options are measured based on component costs and the costs associated with the transmission losses. A case study has been presented in the paper, which demonstrates the application of this techno-economic analysis framework on a range of MEC farm sizes and distances from the shore. The results characterise the performance of different transmission system options with respect to three key design parameters – distance to shore, array power and transmission voltage – and provide guidance for system design

Gathering around stories: Interdisciplinary experiments in support of energy system transitions

This paper explores the creative uses of stories and storytelling to engage groups and individuals with consideration of changes in energy systems across time and place. It summarises three story-based experiments that responded to the theme of ‘energy utopias’. These are drawn from the three core strands of a much wider body of work undertaken within the Stories of Change project. This took stories as a central motif and organising device to refresh public and political conversations about energy and decarbonisation. Our hypothesis was that stories could offer a popular and engaging route into thinking about the past and present of humanity’s lives with energy and a lively way of imagining possible futures. We also wanted to test the degree to which stories could offer a shared intellectual space that might support both interdisciplinary and co-productive working for a core team that includes social science, humanities, media, computing and design researchers as well as creative and community partners. The paper considers some of the practical, methodological and theoretical considerations and reflects on the strengths and limitations of stories as both motif and technique in supporting action on climate change

Spatio-temporal correlations of available wind power and impact on transmission power flows

This paper presents a description of a number of points of debate concerning the possible impact of future wind power development on power system planning and operation. It is noted that firm conclusions cannot be reached without adequate modelling of available power. Whilst this would normally require many years of experience of wind farm operation across a wide geographical area, in Britain such data are currently unavailable. However, more extensive coverage via national meteorological centre data may be available to facilitate a synthesis of future patterns of available wind power. These can be used by a transmission planner to assess the distribution of possible flows across main transmission boundaries. To be useful, the approach must respect the correlations of available wind power at different locations on the system. Furthermore, trends in wind speed through a day and through a year must be reliably reproduced captured so that the relationship to annual and diurnal load variations can subsequently be studied. A wind synthesis methodology is described. By being based on many years of wind speed data it permits the estimation of long-term risks associated with more extreme wind conditions. After dealing with gaps in the original wind speed dataset, a vector autoregression (VAR) approach is used to model wind speeds. Wind speeds generated by the model are converted to those that may be observed at 'typical' wind farm locations at 10m above ground level for different terrain types in different zones and then converted to hub height. The 'per unit' available wind power is then calculated by use of a wind speed to power curve. After having specified the total wind generation capacity in each terrain in each zone for the scenario they wish to study, the user of the tool is then able to calculate the total available power. When combined with scenarios describing oad demand and the availability and dispatch of conventional generation, future capacity margins and power flows can be studied, e.g. for identification of future system reinforcement requirements. An extension of the approach is presented that permits study of available power and power flows through a year of operation. This also uses vector autoregression (VAR) to model wind speeds but is applied after a careful detrending process to allow diurnal and seasonal effects to be correctly treated. Finally, future developments of the approach are outlined and it is suggested that the same approach may be useful not only in power system planning but also in support of power system operation