Impacts of plug-in hybrid vehicles and combined heat and power technologies on electric and gas distribution network losses

Distribution network operators (DNOs) require strategies that can offset the tradeoffs new embedded technologies have on their assets. This paper employs modelling to show that through control device manipulation, gas and electric (G&E) network operators can influence savings in energy losses under the presence of plug-in hybrid vehicles (PHEVs) and combined heat and power technologies (CHPs). An integrated gas and electric optimal power flow (OPF) tool is introduced to undertake various case studies. The OPF tool evaluates the technical impacts experienced in the networks when DNOs apply a "plug and forget" operation strategy and then compares the results against a "loss minimisation" strategy. Results show the benefits in applying different strategies are more considerable in electric networks than in gas networks. The study corroborates that an integrated G&E analysis offers a fresh perspective for stakeholders in evaluating energy service networks performance under different operation strategies

Spatio-temporal changes of land use land cover dynamics and its implication on urban flood vulnerability in Makurdi, Nigeria

Makurdi as one of the major city located on the flood plain along river Benue in Nigeria is exposed to the recurring flooding events which results to loss of life and properties. Hence there is need to analysed the spatio-temporal Land use Land cover (LULC) Dynamics and its implication on Urban Flood Vulnerability in Makurdi, Nigeria. LULC change was determined using Remote Sensing techniques and Geographic Information System; the land use was classified into five classes from 1986 - 2016 to monitor the changes that have taken place over time and space. Digital Elevation Model (DEM) of the study area were created and classified into three classes; High, Moderate, and Low risk areas. Soil infiltration analyses were performed in some selected sample points across the study area. The result revealed that Wadata area have a high bulk density and moisture content of 1.46g and 89% respectively indicating low rate of infiltration thereby accelerating runoff and flood event. Similarly, from the interpretation of the different epoch of Landsat images it shows that built-up areas have been on increase from 4.82% in 1986 to 35.36% in 2016 which has resulted to encroachment into the flood plain. The classified DEM -slope shows that about 40016.09 hectares (48.43%) of the land mass is within the flood plain. Consequently, there is need to identify and developed strategies for sustainable urban flood plain development for the attainment of resilience urban flood.Keywords: Spatio-temporal, LULC, Urban Flood, Bulk Density and encroachmen

Diagnostic tools of energy performance for supermarkets using Artificial Neural Network algorithms

Supermarket performance monitoring is of vital importance to ensure systems perform adequately and guarantee operating costs and energy use are kept at a minimum. Furthermore, advanced monitoring techniques can allow early detection of equipment faults that could disrupt store operation. This paper details the development of a tool for performance monitoring and fault detection for supermarkets focusing on evaluating the Store's Total Electricity Consumption as well as individual systems, such as Refrigeration, HVAC, Lighting and Boiler. Artificial Neural Network (ANN) models are developed for each system to provide the energy baseline, which is modelled as a dependency between the energy consumption and suitable explanatory variables. The tool has two diagnostic levels. The first level broadly evaluates the systems performance, in terms of energy consumption, while the second level applies more rigorous criteria for fault detection of supermarket subsystems. A case study, using data from a store in Southeast England, is presented and results show remarkable accuracy for calculating hourly energy use, thus marking the ANN method as a viable tool for diagnosis purposes. Finally, the generic nature of the methodology approach allows the development and application to other stores, effectively offering a valuable analytical tool for better running of supermarkets

Optimal charging strategies of electric vehicles in the UK power market

In order to gain the most from their deployment, it is imperative for stakeholders to exploit the main benefits electric vehicles bring to utilities. Therefore, this paper focuses on the aspects required to model the management of electricity supply for electric vehicles. The framework presented details a time coordinated optimal power flow (TCOPF) tool to illustrate the tradeoffs distribution network operators (DNO) might encounter when implementing various load control approaches of electric vehicles. Within an UK context, a case study is performed where the TCOPF tool functions as the intermediary entity that coordinates cost-effective interactions between power markets, network operators, and the plugged vehicles. Results depict the stochastic but optimal charging patterns stakeholders might visualise from electric vehicles in local networks as they are operated to reduce energy and emission costs. Furthermore, results show current emission costs have a negligible weight in the optimisation process when compared to wholesale electricity costs

Integrated Modelling of Gas and Electricity Distribution Networks with a High Penetration of Embedded Generation

Gas-based combined heat and power (CHP) has matured enough to be regarded as the next evolutionary step in promoting energy efficiency use in the urban environment. Although its potential market is increasing, little research has been conducted into the combined technical effects that a high penetration of these units may have on both natural gas and electric (G&E) distribution networks. This paper presents a power flow tool that performs a simultaneous assessment on some technical impacts that a high penetration of heat-driven cogeneration units may have on G&E networks. A case study is presented and results show that as expected, the gas demand increases as well as the losses associated with its delivery, while the opposite effects occur in the electrical system. However, less evident is the load profile variations distribution networks will experience and that overall energy losses will vary according to the CHP penetration and the type of technology used. The study shows that an integrated G&E analysis offers a fresh perspective in quantifying the effects cogeneration technologies will have on energy distribution networks

Optimal Technology Selection and Operation of Bio-methane CHP Units for Commercial Buildings

This paper explores the optimal implementation of bio-methane fuelled combined heat and power (CHP) systems to satisfy heat and electricity demands of commercial buildings; with the overarching goal of making cost-effective investments and decarbonizing building operations. The research work consisted in the development of a CHP technology selection and operation (TSO) optimization model. Its results can be utilized to develop a strategy for investment in bio-methane CHP projects for a portfolio of buildings. The TSO model enables a new approach for the selection and operation of CHP units that encompasses whole life costing, carbon emissions as well as real-time energy prices and demands, providing a more comprehensive result than current methods. Utilizing historic metered energy demands, projected energy prices and a portfolio of available CHP technologies, the mathematical model simultaneously solves for an optimal CHP unit selection and operational strategy for a determined building based on a preferred objective: minimizing cost, minimizing GHG emissions, or a mix of both. Results of this model prove that attractive cost and emissions savings are possible through the optimal selection and operation of CHP technologies fuelled by bio-methan

Operational and Economic Analysis of GSHP Coupled with Refrigeration Systems in UK Supermarkets

Ground Source Heat Pumps (GSHP) are capable of reducing energy consumption by operating at higher efficiencies than conventional gas systems, especially if coupled with refrigeration units such as in supermarkets. In principle, the heat rejected by refrigerators can be harnessed to raise the efficiency of the heat pumps. This paper presents the results of an operational and economic analysis conducted on this innovative system. Overall, the efficiency of all the GSHP systems under consideration appears to be above the eligibility threshold for the UK Government’s incentive (Renewable Heat incentive, RHI), with the average Seasonal Coefficient of Performance (SCOP) of the stores being 3.0 in 2014. From an economic perspective, such average performance leads to more than £120,000 of operational savings per year compared to gas boiler systems. Calculations show an investment Payback Time (PBT) of less than 8 years. Finally, the paper highlights potential cost reductions achievable through operational and design modifications. Overall results show that GSHP coupled with refrigeration systems present sound fundamentals to be considered as an attractive investment opportunity for food retailers

Evidences of a consolute critical point in the Phase Separation regime of La(5/8-y)Pr(y)Ca(3/8)MnO(3) (y = 0.4) single crystals

We report on DC and pulsed electric field sensitivity of the resistance of mixed valent Mn oxide based La(5/8-y)Pr(y)Ca(3/8)MnO(3) (y = 0.4) single crystals as a function of temperature. The low temperature regime of the resistivity is highly current and voltage dependent. An irreversible transition from high (HR) to a low resistivity (LR) is obtained upon the increase of the electric field up to a temperature dependent critical value (V_c). The current-voltage characteristics in the LR regime as well as the lack of a variation in the magnetization response when V_c is reached indicate the formation of a non-single connected filamentary conducting path. The temperature dependence of V_c indicates the existence of a consolute point where the conducting and insulating phases produce a critical behavior as a consequence of their separation.Comment: 5 pages, 6 figures, corresponding author: C. Acha ([email protected]

Optimal Design and Operation of Distributed Low-Carbon Energy Technologies in Commercial Buildings

Commercial buildings are large energy consumers and opportunities exist to improve the way they produce and consume electricity, heating and cooling. If energy system integration is feasible, this can lead to significant reductions in energy consumption and emissions. In this context, this work expands on an existing integrated Technology Selection and Operation (TSO) optimisation model for distributed energy systems (DES). The model considers combined heat and power (CHP) and organic Rankine cycle (ORC) engines, absorption chillers, photovoltaic panels and batteries with the aim of guiding decision makers in making attractive investments that are technically feasible and environmentally sound. A retrofit case study of a UK food distribution centre is presented to showcase the benefits and trade-offs that integrated energy systems present by contrasting outcomes when different technologies are considered. Results show that the preferred investment options select a CHP coupled either to an ORC unit or to an absorption chiller. These solutions provide appealing internal rates of return of 28–30% with paybacks within 3.5–3.7 years, while also decarbonising the building by 95–96% (if green gas is used to power the site). Overall, the TSO model provides valuable insights allowing stakeholders to make well-informed decisions when evaluating complex integrated energy systems