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Abstract In this paper, the possibility of applying a Power System Stabilizer (PSS) via the governor-turbine system of a generating unit is studied for both single-machine and multimachine power systems. The results of analysis and simulation show that the conventional exciter-based PSS can be used in conjunction with the modern high-speed governor to suppress low-frequency oscillations in power systems. This arrangement of stabilizer possesses better robustness to the changes of power system operating conditions. Furthermore, in the environment of a multimachine power system, the control of PSS on the governor of every generator can be locally synthesized to stabilize the whole system, PSS design becomes much easier and simpler.

This study highlights how Chinese economic development detrimentally impacted water quality in recent decades and how this has been improved by enormous investment in environmental remediation funded by the Chinese government. To our knowledge, this study is the first to describe the variability of surface water quality in inland waters in China, the affecting drivers behind the changes, and how the government-financed conservation actions have impacted water quality. Water quality was found to be poorest in the North and the Northeast China Plain where there is greater coverage of developed land (cities + cropland), a higher gross domestic product (GDP), and higher population density. There are significant positive relationships between the concentration of the annual mean chemical oxygen demand (COD) and the percentage of developed land use (cities + cropland), GDP, and population density in the individual watersheds (p < 0.001). During the past decade, following Chinese government-financed investments in environmental restoration and reforestation, the water quality of Chinese inland waters has improved markedly, which is particularly evident from the significant and exponentially decreasing GDP-normalized COD and ammonium (NH4+-N) concentrations. It is evident that the increasing GDP in China over the past decade did not occur at the continued expense of its inland water ecosystems. This offers hope for the future, also for other industrializing countries, that with appropriate environmental investments a high GDP can be reached and maintained, while simultaneously preserving inland aquatic ecosystems, particularly through management of sewage discharge.

Abstract In the last decade, there has been a growing trend towards flexible body wave energy converters (WECs) enabled by rubber-like elastomeric composite membrane structures that can simplify all aspects of WEC design. Currently, there are few literature studies detailing the implementations of membranes into WEC design. This paper aims to overcome this by reviewing the developments, material selection and modelling procedures for novel membrane based wave energy converters (mWECs), providing the reader with a comprehensive overview of the current state of the technology. In the first half of this paper, all of the possible WEC implementation areas are reviewed which include the primary mover, power take-off (PTO) and other sub-assembly systems. For the primary mover, the review has identified three main working surface approaches using membranes, these are: air-filled cells, water filled tubes and tethered carpets; which aim to reduce peak loads for enhanced reliability and survivability. In other areas, the PTO of WECs can benefit from using soft dielectric elastomer generators (DEGs) which offer a simpler designs compared with conventional mechanical turbomachinery. These have been implemented into the membrane working surface as well as replacing the PTO in existing WEC architectures. In the second half of the paper, a discussion is made on the material selection requirements with a few possible compositions presented. Following this, the potential modelling procedures for these devices is detailed. The device numerical models have altered existing procedures to take into account the non-linearities caused by the membrane interface and membrane PTO damping.

Abstract The housing growth programme could offer an opportunity for accelerating the deployment of decentralised renewable energy systems (DRES) in the UK. The Government hopes to leverage private sector investment into DRES as part of new housing projects. The aim of this paper is to assess whether current regulatory and funding frameworks are sufficient to achieve this. The question is explored by drawing on the experience of developers, local authorities, energy utilities and service companies operating in the largest housing growth region in the UK–Thames Gateway. Their experience suggests that the current low intervention approach will be insufficient to generate the shift required in both industries. In order to be more successful economic and regulatory instruments should focus on producers (house-builders and energy providers) rather than consumers (households). Tighter regulation is needed to ensure that producers have a responsibility to install DRES as part of new developments, to enable connection to the grid, to ensure a sustained financial return from investment and revenue is spent on the expansion of new renewable energy infrastructure. This regulatory framework must be under-pinned by substantial funds focused on producers. Greater intervention is needed if DRES is to be included in new housing development.

SummaryMicrobially generated or supported nanocatalysts have potential applications in green chemistry and environmental application. However, precious (and base) metals biorefined from wastes may be useful for making cheap, low‐grade catalysts for clean energy production. The concept of bionanomaterials for energy applications is reviewed with respect to potential fuel cell applications, bio‐catalytic upgrading of oils and manufacturing ‘drop‐in fuel’ precursors. Cheap, effective biomaterials would facilitate progress towards dual development goals of sustainable consumption and production patterns and help to ensure access to affordable, reliable, sustainable and modern energy.

Biomethane production from processed industrial food waste (IFW) in admixture with sewage sludge (primary and waste activated sludge: PS and WAS) was evaluated at a range of C:N ratios using a standard biochemical methane potential (BMP) test. IFW alone had a C:N of 30 whereas for WAS it was 5.4 and thus the C:N ratio of the blends fell in that range. Increasing the IFW content in mix improves the methane potential by increasing both the cumulative biogas production and the rate of methane production. Optimum methane yield 239 mL/g VSremoved occurred at a C:N ratio of 15 which was achieved with a blend containing 11 percent (w/w) IFW. As the fraction of IFW in the blend increased, volatile solids (VS) destruction was increased and this led to a reduction in methane yield and amount of production. The highest destruction of volatile solids of 93 percent was achieved at C:N of 20 followed by C:N 30 and 15. A shortened BMP test is adequate for evaluating optimum admixtures.

Attempts to model any present or future power grid face a huge challenge because a power grid is a complex system, with feedback and multi-agent behaviors, integrated by generation, distribution, storage and consumption systems, using various control and automation computing systems to manage electricity flows. Our approach to modeling is to build upon an established model of the low voltage electricity network which is tested and proven, by extending it to a generalized energy model. But, in order to address the crucial issues of energy efficiency, additional processes like energy conversion and storage, and further energy carriers, such as gas, heat, etc., besides the traditional electrical one, must be considered. Therefore a more powerful model, provided with enhanced nodes or conversion points, able to deal with multidimensional flows, is being required. This article addresses the issue of modeling a local multi-carrier energy network. This problem can be considered as an extension of modeling a low voltage distribution network located at some urban or rural geographic area. But instead of using an external power flow analysis package to do the power flow calculations, as used in electric networks, in this work we integrate a multiagent algorithm to perform the task, in a concurrent way to the other simulation tasks, and not only for the electric fluid but also for a number of additional energy carriers. As the model is mainly focused in system operation, generation and load models are not developed. The financial support from EPSRC for Liz Varga on project entitled "Transforming Utilities’ Conversion Points" (no. EP/J005649/1) is gratefully acknowledged.

Microbe-assisted phytoremediation is emerging as one of the most effective means by which plants and their associated rhizosphere microbes degrade organic contaminants in soils. A pot study was conducted to examine the effects of inoculation with Rhizobium meliloti on phytoremediation by alfalfa grown for 90 days in an agricultural soil contaminated with weathered polycyclic aromatic hydrocarbons (PAHs). Planting with uninoculated alfalfa (P) and alfalfa inoculated with R. meliloti (PR) significantly lowered the initial soil PAH concentrations by 37.2 and 51.4% respectively compared with unplanted control soil. Inoculation with R. meliloti significantly increased the counts of culturable PAH-degrading bacteria, soil microbial activity and the carbon utilization ability of the soil microbial community. The results suggest that the symbiotic association between alfalfa and Rhizobium can stimulate the rhizosphere microflora to degrade PAHs and its application may be a promising bioremediation strategy for aged PAH-contaminated soils.