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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Demand- Side Financing In Education: A Critical Examination of a Girls' Scholarship Program in Malawi- (Case Study)

Sineta, Abraham 01 September 2012 (has links)
Despite the push for universal education, many disadvantaged and poor children in developing countries still do not have access to basic education. This among other reasons is due to poverty where poor families cannot afford the cost of basic education even when it is `free' of tuition (McDonald, 2007). Demand-side financing interventions such as scholarship programs are promising to be viable financing interventions of reaching out to the poor and marginalized children in order for them to access basic education. Although such financing strategies have been praised as having worked in mostly Latin American countries, very little is systematically known about how these interventions would work in poor African countries such as Malawi. This study therefore examines demand-side financing strategy through an evaluation of a scholarship program implemented in Malawi. It uses qualitative mode of inquiry through in-depth interviews of 36 key participants as a primary method of data collection. In addition it reviews program documents and conducts some cohort tracking on beneficiaries in Zomba rural district which is the site of the study. The findings show that community based targeting was used in the program and proved successful in identifying the right beneficiaries in a cost effective manner. It seems to offer a model to be adopted for such interventions in low resource countries. Findings further show that beneficiaries who received scholarships were able to persist however there was a substantial number that dropped out. There were a number of factors that caused this but it seems the internal motivation of beneficiaries to persist was very critical. This puts under the microscope an assumption that once scholarship is received, beneficiaries would persist in school. Last but not least, the findings also show that an assumption that local communities will be able to sustain such programs might be but a mere illusion as communities view themselves too poor to do this. Overall the study praises such programs as effective in targeting the poor and marginalized children however it puts a caution on assumptions about persistence & sustainability. It suggests further scrutiny on these assumptions to improve on the effectiveness of such programs and demand-side financing strategies in general.
142

Energy storage in the future smart grid. An investigation of pricing strategies and dynamic load levelling for efficient integration of domestic energy storage within a virtual power plant and its evaluation using a genetic algorithm optimization platform

Okpako, Oghenovo January 2019 (has links)
One feature that is hoped for in the smart grid is the participation of energy prosumers in a power market through demand response program. In this work, we consider a third-party virtual power plant (VPP) that has “real-time” control over a number of prosumers’ storage units within an envisaged free market. Typically, a VPP with domestic energy storage will involve a bidirectional flow of energy, where energy can either flow from the grid to the prosumers’ battery or from the prosumers’ battery to the grid. Such a system requires prices to be set correctly in order to meet the market objectives of all the VPP stakeholders (VPP Aggregator, prosumers, and grid). Previous work has shown how VPPs could operate, and the benefits of using energy storage, coupled with pricing, in terms of reducing energy cost for stakeholders and providing the grid with its required load shape. The published work either assumes prices or costs or then optimises for least cost within the grid parameters i.e. losses, voltage limits, etc. However, the setting of prices in such a way that energy can be traded among VPP stakeholders that satisfies all stakeholders’ objectives has not been fully explored in the literature, particularly with real-time VPP aggregators. In this thesis, we present novel strategies for evaluating and setting the prices of a community VPP with domestic storage based on the bidirectional flow of energy through the VPP aggregator between the grid and the prosumers that mutually meet all VPP stakeholders’ objectives. This showed that depending on pricing and the VPP objectives, demand-side management could be attractive. However, the effect on the grid in terms of the load was not what was desired. A new performance index called the “Cumulative Performance Index” CPI is proposed to measure the VPP’s performance. Using the CPI, it was possible to compare and contrast between the VPP technical performance and its business case for stakeholders. Optimizing with respect to the grid’s requirement for DSM from the VPP, it was possible to achieve a CPI of 100%. This work was implemented using a novel approach on a genetic algorithm platform. / Niger Delta Development Commission of Nigeria
143

The Potential of Data Centre Participation in Ancillary Service Markets in Sweden

Hansson, Jenny January 2022 (has links)
Today’s society already requires a great connectivity network. This need will only increase in the future, and EDGE data centres are concepts meeting this future need, where the computational power is deployed close to the end user. They are defined, in this thesis, as a concept including different nodes, or data centres, located in proximity connected and participating in the market as one entity. The electricity grid in the Nordics is also a complex system. Many types of interactions with the grid exist and depend on the type of stakeholder. One collection of such interactions is ancillary services, which refer to different types of measures that maintain a reliable grid and electricity system. Electricity consumers within the grid network have the potential to interact and participate in these different functions. In this thesis, the participation of data centres, or EDGE data centres in ancillary services market, is studied. This thesis modelled different scenarios of an EDGE data centre with the grid network. Scenario 1 looked into self-consumption; scenario 2 looked into spot trading; scenario 3 looked into the FCR-N market; scenario 4 looked into the FCR-D markets; and scenario 5 looked into the combination of self-consumption and the FCR-D markets. It is observed from the results that scenario 4 generated the most favourable economic benefits. The results in relation to the price areas (zones in Sweden) were varied for the results. The price area SE4 gave better results for scenarios 1, 2, and 5 as compared to others. The best price area for scenarios 3 and 4 was from the SE1 zone. It is observed from the results that the potential benefit of the different ancillary markets exist and are at times favourable. Hence, there lies a future potential for the participation of EDGE networks in the electricity market thereby generating benefits for the data centres as well as stability for the grid. / Dagens samhälle kräver redan ett bra nätverk för uppkoppling. Detta behov kommer bara att öka i framtiden, och EDGE:s datacenter är koncept som uppfyller detta framtida behov, där datakraften placeras nära slutanvändaren. De definieras i denna avhandling som ett koncept som omfattar olika noder, eller servrar, som är placerade i närheten av varandra och som deltar på marknaden som en enhet. Elnätet i Norden är också ett komplext system. Det finns många olika typer av interaktioner med elnätet som beror på vilken typ av aktör det är fråga om. En samling av sådana interaktioner är stödtjänster, som avser olika typer av åtgärder som upprätthåller ett tillförlitligt nät och elsystem. Elkonsumenter inom elnätet har möjlighet att interagera och delta i dessa olika funktioner. I den här avhandlingen undersöks datacentraler, eller EDGE-datacenter, som deltar. I denna avhandling har olika scenarier för EDGE-datacenter modellerats i förhållande till elnätet. I scenario 1 undersöktes självkonsumtion, i scenario 2 spothandel, i scenario 3 FCR-N-marknaden, i scenario 4 FCR-D-marknader och i scenario 5 en kombination av självkonsumtion och FCR-D-marknader. I korthet gav scenario 4 de mest gynnsamma ekonomiska fördelarna. De potentiella miljöfördelarna diskuteras och kan inte lika lätt kvantifieras. Resultaten i förhållande till prisområdena varierade för resultaten. Prisområde SE4 gav de bästa resultaten för scenario 1 och 2 samt 5. Det bästa prisområdet för scenario 3 och 4 var SE1. Det framgår tydligt av denna avhandling att de potentiella fördelarna med de olika stödmarknaderna finns och att de vid vissa tillfällen är mycket gynnsamma med tanke på de höga lagringskostnaderna. EDGE-nätverkens framtida potentiella deltagande ger positiva resultat i både ekonomiska och miljömässiga termer.
144

Empirical evidence of utility sponsored conservation programs

Shay, Colin Gerald 23 December 2009 (has links)
Utility sponsored conservation programs encourage participants to consume less energy. One of the most popular methods used to achieve this is to offer monetary rebates to purchasers of high-efficiency appliances. The costs of these conservation programs are then passed-on to all customers as increased energy prices. Economic theory predicts that the income and substitution affects should decrease the consumption of non-participants in the programs and may increase the consumption of participants. Recent claims in the literature argue that the standard net benefit tests used to evaluate these programs fail to incorporate the full impact of the income and substitution affects. Relying on these theoretical arguments, new evaluation techniques, referred to as Net Economic Benefits (NEB) tests, are being introduced as solutions to this problem. Using the actual experience of a natural gas utility, this thesis analyzed the need for NEB evaluations. The results show that the price of gas is not a significant factor in determining household gas consumption. Therefore, empirical evidence cannot support the NEB claims. The evidence does show that, on an average annual basis, participants are consuming less than non-participants. / Master of Arts
145

Modelling the expected participation of future smart households in demand side management, within published energy scenarios

Quiggin, Daniel January 2014 (has links)
The 2050 national energy scenarios as planned by the DECC, academia and industry specify a range of different decarbonised supply side technologies combined with the electrification of transportation and heating. Little attention is paid to the household demand side; indeed within many scenarios a high degree of domestic Demand Side Management (DSM) is implicit if the National Grid is to maintain supply-demand balance. A top-down, bottom-up hybrid model named Shed-able Household Energy Demand (SHED) has been developed and the results of which presented within this thesis. SHED models six published national energy scenarios, including three from the Department for Energy and Climate Change, in order to provide a broad coverage of the possible energy scenario landscape. The objective of which is to quantify the required changes in current household energy demand patterns via DSM, as are implicit under these highly electricity dominated scenarios, in order to maintain electrical supply-demand balance at the national level. The frequency and magnitude of these required household DSM responses is quantified. SHED performs this by modelling eleven years of supply-demand dynamics on the hourly time step, based on the assumptions of the published energy scenarios as well as weather data from around 150 weather stations around the UK and National Grid historic electricity demand data. The bottom-up component of SHED is populated by 1,000 households hourly gas and electricity demand data from a recently released dataset from a smart metering trial in Ireland. This aggregate pool of households enables national domestic DSM dynamics to be disaggregated to the aggregate household level. Using household classifications developed by the Office for National Statistics three typical ' households are identified within the aggregate pool and algorithms developed to investigate the possible required responses from these three households. SHED is the first model of its kind to connect national energy scenarios to the implications these scenarios may have on households consumption of energy at a high temporal resolution. The analysis of the top-down scenario modelling shows significant periods where electrical demand exceeds supply within all scenarios, within many scenarios instances exist where the deficit is unserviceable due to lack of sufficient spare capacity either side of the deficit period. Considering the level of participation required within the modelled scenarios in order to balance the electricity system and the current lack in understanding of smart metering and Time-Of-Use (TOU) tariffs within households, it would seem there is a disconnect between the electricity system being planned, the role this system expects of households and the role households are willing to play.
146

The development of an online energy auditing software application with remote SQL-database support

Van der Merwe, Johannes Schalk 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In the last century the earth has experienced an increase in the global mean temperature, with the main contributing factor being the increase in greenhouse gasses. Evidence indicates that the burning of fossil fuels, critical in the supply of energy, contributed towards three quarters of the carbon dioxide (CO2) increase. In 2008 South Africa reached electricity capacity constraints. A subsequent economic downturn experienced in the country, brought about by the worldwide economic recession, has relieved some of the strain on the electricity supply system. However, consumption levels are returning to those experienced during 2008 and no new base load power stations have been added. Short-term capacity constraints can be managed by shifting the peak demand, but the electricity shortage can only be avoided by adding additional capacity or reducing the overall electricity consumption. Supply-side solutions are both overdue and too expensive. The only solutions that can provide lasting results are demand-side solutions. During the past few years the Energy Efficiency and Demand-side Management (EEDSM) programme implemented by South Africa’s electricity supply utility, Eskom, has gained prominence. This programme relies heavily on calculating the savings incurred through any demand-side intervention. Energy audits enable the calculation of various consumption scenarios and can provide valuable insight into load operation and user behaviour. Energy audits involve a two-part procedure consisting of load surveying and an analysis. This thesis describes the development of both these procedures, combined into a single application. The application has been tested and provides an accurate and effective tool for simulating consumption and quantifying savings for various load adjustments. The results gained from the auditing application surpassed the expectations and provides the user with a sufficient base-line consumption estimate. The results do not reflect day-to-day variations, but the simulations are sufficient to quantify savings and determine whether demand-side interventions are financially viable. The application also presents a benchmark for the type of applications required to successfully implement an EEDSM programme. / AFRIKAANSE OPSOMMING: In die afgelope eeu het die aarde se gemiddelde temperatuur toegeneem, met die toename in kweekhuisgasse as die grootste bydraende faktor. Dit wil ook voorkom asof die verbranding van fossielbrandstowwe, wat noodsaaklik is vir die verskaffing van energie, verantwoordelik is vir driekwart van die toename in koolstofdioksied (CO2). Gedurende 2008 het Suid-Afrika elektrisiteitsbeperkings bereik. Die daaropvolgende ekonomiese afswaai wat in die land ervaar is weensdie wêreldwye ekonomiese resessie, het van die druk op die elekriese netwerk verlig. Verbruikersvlakke is egter besig om terug te keer na waar dit in 2008 was, maar geen nuwe basislas-kragstasies is gebou nie. Op die kort termyn kan die kapasiteitsbeperkings bestuur word deur die aanvraag te verskuif, maar die elektrisiteitstekort kan op die lang duur slegs vermy word deur bykomende kapasiteit by te voeg of die totale aanvraag te verminder. Toevoerkant-oplossings is beide agterstallig en te duur. Die enigste oplossings wat blywende resultate kan lewer, is dus aan die verbruikerkant. In die afgelope paar jaar het die effektiewe bestuur van energieverbruik baie aansien geniet. Die nasionale energievoorsiener, Eskom, het ook 'n program geloods om te help met die implimentering van energiebesparingmaatreëls. Die implementering van energie-oudits om met die kwantifisering van besparings te help, is van integrale belang vir die sukses van die program. Energie-oudits stel die eindverbruiker in staat om verskeie verbruiksmoontlikhede te beproef en sodoende waardevolle inligitng te verkry rakende die verbruikspatrone van die fasiliteit. Energie-oudits behels 'n tweeledige proses, bestaande uit 'n lasopname en 'n verbruiksanalise. Hierdie proefskrif beskryf die ontwikkeling van 'n stelsel wat beide die prosesse kombineer in 'n enkele applikasie. Die applikasie is getoets en bied 'n akkurate en doeltreffende instrument om verbruik te simuleer en besparings te kwantifiseer vir verskeie verbruiksmoontlikhede. v Die resultate van die oudit het die aanvanklike verwagtinge oortref en voorsien verbruikers van 'n goeie skatting van die basisverbruik van 'n fasiliteit. Die resultate weerspieël nie dagtot- dag variasies nie, maar die simulasies is voldoende om besparings te kwantifiseer en help om die finansiële lewensvatbaarheid van verbruikerskant-intervensies te bepaal. Die program bied ook 'n verwysingspunt vir applikasies wat besparingstudies wil implementeer.
147

Active human intelligence for smart grid (AHISG) : feedback control of remote power systems.

Fulhu, Miraz Mohamed January 2014 (has links)
Fuel supply issues are a major concern in remote island communities and this is an engineering field that needs to be analyzed in detail for transition to sustainable energy systems. Power generation in remote communities such as the islands of the Maldives relies on power generation systems primarily dependent on diesel generators. As a consequence, power generation is easily disrupted by factors such as the delay in transportation of diesel or rises in fuel price, which limits shipment quantity. People living in remote communities experience power outages often, but find them just as disruptive as people who are connected to national power grids. The use of renewable energy sources could help to improve this situation, however, such systems require huge initial investments. Remote power systems often operate with the help of financial support from profit-making private agencies and government funding. Therefore, investing in such hybrid systems is uncommon. Current electrical power generation systems operating in remote communities adopt an open loop control system, where the power supplier generates power according to customer demand. In the event of generation constraints, the supplier has no choice but to limit the power supplied and this often results in power cuts. Most smart grids that are being established in developed grids adopt a closed loop feedback control system. The smart grids integrated with demand side management tools enable the power supplier to keep customers informed about their daily energy consumption. Electric utility companies use different demand response techniques to achieve peak energy demand reduction by eliciting behavior change. Their feedback information is commonly based on factors such as cost of energy, environmental concerns (carbon dioxide intensity) and the risk of black-outs due to peak loads. However, there is no information available on the significant link between the constraints in resources and the feedback to the customers. In resource-constrained power grids such as those in remote areas, there is a critical relationship between customer demand and the availability of power generation resources. This thesis develops a feedback control strategy that can be adopted by the electrical power suppliers to manage a resource-constrained remote electric power grid such that the most essential load requirements of the customers are always met. The control design introduces a new concept of demand response called participatory demand response (PDR). PDR technique involves cooperative behavior of the entire community to achieve quality of life objectives. It proposes the idea that if customers understand the level of constraint faced by the supplier, they will voluntarily participate in managing their loads, rather than just responding to a rise in the cost of energy. Implementation of the PDR design in a mini-grid consists of four main steps. First, the end-use loads have to be characterized using energy audits, and then they have to be classified further into three different levels of essentiality. Second, the utility records have to be obtained and the hourly variation factors for the appliances have to be calculated. Third, the reference demand curves have to be generated. Finally, the operator control system has to be designed and applied to train the utility operators. A PDR case study was conducted in the Maldives, on the island of Fenfushi. The results show that a significant reduction in energy use was achieved by implementing the PDR design on the island. The overall results from five different constraint scenarios practiced on the island showed that during medium constrained situations, load reductions varied between 4.5kW (5.8%) and 7.7kW (11.3%). A reduction of as much as 10.7kW (15%) was achieved from the community during a severely constrained situation.
148

Cost savings on mine dewatering pumps by reducing preparation- and comeback loads / Charl Cilliers

Cilliers, Charl January 2014 (has links)
Using chilled water within South African gold mines is paramount to the purpose of extracting gold ore efficiently. Using water for cooling, drilling and sweeping and the release of underground fissure water causes the accumulation of vast amounts of water in underground dams. Deep mines use cascading pump systems for dewatering, which is an electrical energy intensive dewatering method. Due to the recent equalisation of demand to generation capacity of electrical energy in South Africa, various methods towards demand side reduction have been implemented. With the introduction of a time-of-use (TOU) tariff structure by Eskom, the implementation of projects that shift load from peak TOU times to times of the day when electrical energy is less expensive has increased. To enable load shifting on mine dewatering pumps, preparation before and recovery after peak TOU is needed for effective results. This induces a preparation- and comeback load in the standard TOU. With an annual increase in TOU tariffs and the rate of increase of standard TOU being greater than that of the peak TOU, a reduction in electrical energy consumption before and after peak TOU is needed. To enable this, a step-by-step control technique was developed to promote the shifting of load from standard- to off-peak TOU, while still realising a full load shift from peak TOU. This technique entails dynamic control ranges of underground dam levels as opposed to the conventional constant control range method. Two case studies were used to test the developed technique. Results indicated significant additional financial savings when compared to conventional control methods. Additional savings of R1,096,056.65 and R579,394.27 per annum were respectively achieved for both case studies. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014
149

Reconfiguring mining compressed air networks for cost savings / Johannes Izak Gabriël Bredenkamp

Bredenkamp, Johannes Izak Gabriël January 2014 (has links)
The world is currently experiencing major issues in the energy sector. The ever-growing human population, limited energy resources and the effect of greenhouse gas emissions have become major global concerns for the energy sector, including the electricity generation sector. This dilemma caused electricity providers to revise their generation methods and created a major need for consumers to utilise electricity more efficiently. Demand side management (DSM) is one initiative developed for consumers to efficiently utilise electricity. Due to their high electricity consumption and technical skills, mines are ideal targets for the implementation of DSM strategies. Therefore, the focus of this study was to investigate South African mines for possible implementation of DSM strategies on their compressed air networks. Compressed air networks at South African mines are relatively old and inadequately maintained. This causes inefficient distribution and use of compressed air. The study will therefore focus on reconfiguring mining compressed air networks for cost savings. Cost savings include financial savings on electricity bills, implementation costs and decreased maintenance. Through several investigations, the possibility of implementing energy savings strategies to reconfigure the compressed air networks of two South African mines was identified. Reconfiguring the networks would respectively entail interconnecting two shafts and relocating a compressor from an abandoned shaft to a fully productive shaft. Theoretical simulations were developed to determine the networks’ responses to the reconfiguration strategies. The simulations assisted in exposing the viability of implementing the reconfiguration strategies on the respective compressed air networks. Positive responses were obtained from the simulations and proposals were made to the respective mines for possible implementation. The proposed initiatives were implemented on the respective mines’ compressed air networks. After implementation of the interconnection strategy, a consecutive three-month performance assessment period commenced to prove the viability of the proposed savings. An average power saving of 1 700 kW was achieved during the performance assessment period. The proposed initiative to relocate the compressor is currently being implemented. A financial saving of approximately R8.9 million per annum was achieved by implementing the interconnection strategy. The large financial saving was due to the utilisation of the mine’s salvaged equipment. Further savings were achieved by the decreased maintenance on the mine’s compressors. Due to the successful implementation of the interconnection strategy, it is safe to state that cost savings can be achieved by reconfiguring mining compressed air networks. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014
150

Integrated high-resolution modelling of domestic electricity demand and low voltage electricity distribution networks

Richardson, Ian January 2011 (has links)
Assessing the impact of domestic low-carbon technologies on the electricity distribution network requires a detailed insight into the operation of networks and the power demands of consumers. When used on a wide-scale, low-carbon technologies, including domestic scale micro-generation, heat pumps, electric vehicles and flexible demand, will change the nature of domestic electricity use. In providing a basis for the quantification of the impact upon distribution networks, this thesis details the construction and use of a high-resolution integrated model that simulates both existing domestic electricity use and low voltage distribution networks. Electricity demand is modelled at the level of individual household appliances and is based upon surveyed occupant time-use data. This approach results in a simulation that exhibits realistic time-variant demand characteristics, in both individual dwellings, as well as, groups of dwellings together. Validation is performed against real domestic electricity use data, measured for this purpose, from dwellings in Loughborough in the East Midlands, UK. The low voltage distribution network is modelled using real network data, and the output of its simulation is validated against measured network voltages and power demands. The integrated model provides a highly detailed insight into the operation of networks at a one-minute resolution. This integrated model is the main output of this research, alongside published articles and a freely downloadable software implementation of the demand model.

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