Assessment of highly distributed power systems using an integrated simulation approach

In a highly distributed power system (HDPS), micro renewable and low carbon technologies would make a significant contribution to the electricity supply. Further, controllable devices such as micro combined heat and power (CHP) could be used to assist in maintaining stability in addition to simply providing heat and power to dwellings. To analyse the behaviour of such a system requires the modelling of both the electrical distribution system and the coupled microgeneration devices in a realistic context. In this paper a pragmatic approach to HDPS modelling is presented: microgeneration devices are simulated using a building simulation tool to generate time-varying power output profiles, which are then replicated and processed statistically so that they can be used as boundary conditions for a load flow simulation; this is used to explore security issues such as under and over voltage, branch thermal overloading, and reverse power flow. Simulations of a section of real network are presented, featuring different penetrations of micro-renewables and micro-CHP within the ranges that are believed to be realistically possible by 2050. This analysis indicates that well-designed suburban networks are likely to be able to accommodate such levels of domestic-scale generation without problems emerging such as overloads or degradation to the quality of supply

Developing and testing a generic micro-combined heat and power model for simulations of dwellings and highly distributed power systems

This paper elaborates an approach to the modelling of domestic micro-combined heat and power (μ-CHP) using a building simulation tool that can provide a detailed picture of the environmental performance of both the μ-CHP heating system and the dwelling it serves. The approach can also provide useful data for the modelling of highly distributed power systems (HDPS). At the commencement of the work described in this paper no μ-CHP device model that was compatible with a building simulation tool was available. The development of such a model is described along with its calibration and verification. The simulation tool with the device model was then applied to the analysis of a dwelling with a Stirling engine-based heating system. Different levels of thermal insulation and occupancy types were modelled. The energy and environmental performance of the μ-CHP device was quantified for each case; additionally, the potential for its participation in the control and operation of an HDPS was assessed. Analysis of the simulation results indicated that the parasitic losses associated with the μ-CHP system balance of plant reduced the overall heating system efficiency by up to 40 per cent. Performance deteriorated with increasing levels of insulation in the dwelling, resulting in reduced thermal efficiency and increased cycling, though overall fuel use was reduced. The analysis also indicated that the device was generally available to participate in HDPS control for greater than 90 per cent of the simulation time. The potential length of the participation time ranged from 1 to 800+min and depended upon the state of the μ-CHP system thermal buffer and prevailing heat loads. Probabilities for different participation times and modes were calculated

Hydrogen and fuel cell technologies for heating: A review

The debate on low-carbon heat in Europe has become focused on a narrow range of technological options and has largely neglected hydrogen and fuel cell technologies, despite these receiving strong support towards commercialisation in Asia. This review examines the potential benefits of these technologies across different markets, particularly the current state of development and performance of fuel cell micro-CHP. Fuel cells offer some important benefits over other low-carbon heating technologies, and steady cost reductions through innovation are bringing fuel cells close to commercialisation in several countries. Moreover, fuel cells offer wider energy system benefits for high-latitude countries with peak electricity demands in winter. Hydrogen is a zero-carbon alternative to natural gas, which could be particularly valuable for those countries with extensive natural gas distribution networks, but many national energy system models examine neither hydrogen nor fuel cells for heating. There is a need to include hydrogen and fuel cell heating technologies in future scenario analyses, and for policymakers to take into account the full value of the potential contribution of hydrogen and fuel cells to low-carbon energy systems

The status of river water quality in some rural areas, in state of Johor and its effects to life

Water is a basic requirement of human and other life. Water resources stems from rivers, streams, drains, ponds and so forth. The river is the natural water resources are very important for a human habitat. Malaysian water quality assessment is determined by the water quality Index (IKA) issued by the Department of environment (DOE) based on class I, II, III and IV. Now a water pollution also occurs in rural areas has affected the water quality and marine life. The objective of this writing is to determine river water quality in rural areas based on IKA. Kajian telah dijalankan di beberapa batang sungai di kawasan luar bandar di negeri Johor bermula dari bulan Februari sehingga April 2015. Water quality sampling was done three times in four different study locations. Determination of water quality involves measurement parameters pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammoniacal nitrogen (AN) and suspended solids (SS). The Measurements are made IKA the total calculated and used to classify the river either as untainted, slightly polluted moderately polluted, contaminated and polluted. The study found the status of three rivers polluted level contaminated (class IV) and a river are classified at the level of medium-polluted (class III). Deterioration of the status of IKA for all rivers surveyed not only affects marine life, even limiting water use to humans, for example, to daily activities

The Local Dimension of Energy

In this paper, we postulate that some of the best opportunities for reducing energy demand and carbon emissions are through stronger involvement and leadership from local government. We show that local government can and do have a significant impact on both energy production and energy consumption and are important participants for the implementation of distributed generation (DG). the progress being made by successful local governments can be narrowed to three key factors. First, they have all recognised the co-benefits of a local energy strategy: a reduction in fuel poverty, increased employment, improved quality of life and mitigation of uncertain fuel supplies and prices. Secondly, successful councils have strong political leadership and employee support to implement the structural change to bring about change. Thirdly, leading councils have gained momentum by working in partnership with utilities, private companies, NGO’s, DNO’s and government departments to raise finance and garner support. While climate change remains a global issue, some of the best strategies for mitigation are implemented at the local level

A new method to energy saving in a micro grid

Optimization of energy production systems is a relevant issue that must be considered in order to follow the fossil fuels consumption reduction policies and CO2 emission regulation. Increasing electricity production from renewable resources (e.g., photovoltaic systems and wind farms) is desirable but its unpredictability is a cause of problems for the main grid stability. A system with multiple energy sources represents an efficient solution, by realizing an interface among renewable energy sources, energy storage systems, and conventional power generators. Direct consequences of multi-energy systems are a wider energy flexibility and benefits for the electric grid, the purpose of this paper is to propose the best technology combination for electricity generation from a mix of renewable energy resources to satisfy the electrical needs. The paper identifies the optimal off-grid option and compares this with conventional grid extension, through the use of HOMER software. The solution obtained shows that a hybrid combination of renewable energy generators at an off-grid location can be a cost-effective alternative to grid extension and it is sustainable, techno-economically viable, and environmentally sound. The results show how this innovative energetic approach can provide a cost reduction in power supply and energy fees of 40% and 25%, respectively, and CO2 emission decrease attained around 18%. Furthermore, the multi-energy system taken as the case study has been optimized through the utilization of three different type of energy storage (Pb-Ac batteries, flywheels, and micro—Compressed Air Energy Storage (C.A.E.S.)

Scheduling of Multiple Chillers in Trigeneration Plants

The scheduling of both absorption cycle and vapour compression cycle chillers in trigeneration plants is investigated in this work. Many trigeneration plants use absorption cycle chillers only but there are potential performance advantages to be gained by using a combination of absorption and compression chillers especially in situations where the building electrical demand to be met by the combined heat and power (CHP) plant is variable. Simulation models of both types of chillers are developed together with a simple model of a variable-capacity CHP engine developed by curve-fitting to supplier’s data. The models are linked to form an optimisation problem in which the contribution of both chiller types is determined at a maximum value of operating cost (or carbon emission) saving. Results show that an optimum operating condition arises at moderately high air conditioning demands and moderately low power demand when the air conditioning demand is shared between both chillers, all recovered heat is utilised, and the contribution arising from the compression chiller results in an increase in CHP power generation and, hence, engine efficiency

The development and calibration of a generic dynamic absorption chiller model

Although absorption cooling has been available for many years, the technology has typically been viewed as a poorly performing alternative to vapour compression refrigeration. Rising energy prices and the requirement to improve energy efficiency is however driving renewed interest in the technology, particularly within the context of combined cooling, heat and power systems (CCHP) for buildings. In order to understand the performance of absorption cooling, numerous models are available in the literature. However, the complexities involved in the thermodynamics of absorption chillers have so far restricted researchers to creating steady state or dynamic models reliant on data measurements of the internal chiller state, which require difficult-to-obtain, intrusive measurements. The pragmatic, yet fully-dynamic model described in this paper is designed to be easily calibrated using data obtained from the measurements of inflows and outflows to a chiller, without resorting to intrusive measurements. The model comprises a series of linked control volumes featuring both performance maps and lumped mass volumes, which reflect the underlying physical structure of the device. The model was developed for the ESP-r building simulation tool. This paper describes the modelling approach, theory and limitations, along with its calibration and the application of the model to a specific example

Electricity network scenarios for 2020

This report presents a set of scenarios for the development of the electricity supply industry in Great Britain in the years to 2020. These scenarios illustrate the varied sets of background circumstances which may influence the industry over the coming years – including political and regulatory factors, the strength of the economy and the level to which environmentally-driven restrictions and opportunities influence policy and investment decisions. Previous work by the authors (Elders et al, 2006) has resulted in a set of six scenarios illustrating possible developments in the electricity industry in the period up to 2050. While such scenarios are valuable in gauging the long-term direction of the electricity industry and its economic and environmental consequences, shorter-range scenarios are useful in assessing the steps necessary to achieve these long-range destinations, and to determine their relationship to current trends, policies and targets. In this chapter, a set of medium-range scenarios focused on the year 2020 is developed and described. These scenarios are designed to be consistent both with the current state of the electricity supply industry in Great Britain, and with the achievement of the ultimate electricity generation, supply and utilisation infrastructure and patterns described in each of the 2050 scenarios. The consequences of these scenarios in terms of the emissions of carbon dioxide are evaluated and compared with other predictions. The SuperGen 2020 scenarios described in this report were developed as a collaborative effort between the SuperGen project team and the ITI-Energy Networks Project team both based at the University of Strathclyde

Dynamic simulation model of trans-critical carbon dioxide heat pump application for boosting low temperature distribution networks in dwellings

This research investigates the role of new hybrid energy system applications for developing a new plant refurbishment strategy to deploy small scale smart energy systems. This work deals with a dynamic simulation of trans-critical carbon dioxide heat pump application for boosting low temperature distribution networks to share heat for dwellings. Heat pumps provide high temperature heat to use the traditional emission systems. The new plant layout consists of an air source heat pump, four trans-critical carbon dioxide heat pumps (CO2-HPs), photovoltaic arrays, and a combined heat and power (CHP) for both domestic hot water production and electricity to partially drive the heat pumps. Furthermore, electric storage devices adoption has been evaluated. That layout has been compared to the traditional one based on separated generation systems using several energy performance indicators. Additionally, a sensitivity analysis on the primary energy saving, primary fossil energy consumptions, renewable energy fraction and renewable heat, with changes in building power to heat ratios, has been carried out. Obtained results highlighted that using the hybrid system with storage device it is possible to get a saving of 50% approximately. Consequently, CO2-HPs and hybrid systems adoption could be a viable option to achieve Near Zero Energy Building (NZEB) qualification