A field study of the feasibility and the performance of a sustainable drainage technique combined with a renewable energy device to provide heating in a domestic setting was carried out from March 2008 to November 2010 to acquire practical data about the system’s operation. Among all the sustainable drainage techniques, permeable pavement system (PPS) was selected to be applied in this project since this particular technique can be used for driveways and car-parking hard standings, but more specially they can be designed as a tanked system whereby an impermeable membrane is installed at the bottom of the tank in order to hold the rainwater collected as runoff from hard areas and roofs before releasing it in a controlled manner. The renewable energy device applied in this study is a ground source heat pump system (GSHP), which has been found in previous studies to provide a better performance when installed in wet conditions. Based on this, the PPS and the GSHP with horizontal ground heat exchanger (GHE) were integrated in a 350mm deep reservoir under ‘real life’ conditins. The combined system operated in heating mode in a family–sized, three bedrooms detached EcoHouse at the Building Research Establishment Innovation Park, Watford, UK. Monitoring the combined system included taking measurements of the temperature of the conditioned space, the ground around the PPS/GSHP system, and of the ambient air every 10 minutes. Assessing the performance of the PPS/GSHP system involved investigating the effect of extracting heat via the GHE on the ground temperature, the impact of the PPS/GSHP on the thermal profile of the air above the surface of the reservoir, and computing the PPS/GSHP coefficient of performance (CoP). The thesis includes information about the design of the PPS/GSHP system including the structure of the sub-base, types and size of the used aggregate and stone, the depth of the excavated reservoir amongst others, also the technical problems that materialized, largely due to the fact that the PPS/GSHP was installed and operating under real-life circumstances. Results obtained from the study provided evidence for the workability of the combined system in regards of stormwater management and of providing heat to the EcoHouse. However, monitoring the rainwater stored in the reservoir showed that, due to leakage, the top part of the buried coil was not covered with water. The monitoring also revealed that the rainwater surrounding parts of the coil was, in severe weather, frozen. Moreover, highly significant correlations (p<0.01) were calculated for the ambient air and the ground temperature relationships with the CoP. All of these factors resulted in a 1.8 coefficient of performance being obtained. This low figure was related to the shallow depth of the reservoir since it became clear that its ground temperature was greatly influenced by the ambient air temperature. The study also revealed that the evaporation process was prevented from occurring due to the Inbitex™ composite layer, as a result there was no significant effect on cooling the thermal profile of the air near the surface of the pavement. Furthermore, it was concluded that continuous heat extraction from the ground contributed to an underground temperature drop.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The capability of computational fluid dynamics (CFD), in particular the FLUENT ™ commercial software suite, to predict wind loadings on heliostats has been investigated. If CFD proves useful in this area then the overall development costs of heliostats and concentrating solar thermal power plants could be reduced. Due to the largest loading on the heliostat originating from wind loads, by using CFD to determine these loads it could be possible to ensure heliostats are not overdesigned. This thesis contains a first study within the Solar Thermal Energy Research Group (STERG) at Stellenbosch University into the use of CFD for determining heliostat wind loads. The relevant theoretical background concerning the turbulence models used in this study, namely, the RNG k-ε, Realisable k-ε and SST k-ω turbulence models is reiterated. The „standard‟ k-ε model and the large eddy simulation (LES) approach, due to their relevance to bluff body flows, are also revisited. Some analysis is also provided around each model to gain insight as to the role of respective modelling sensitivities and their advantages. Previous work done in the area of heliostat wind studies is reviewed. The geometric considerations when dealing with heliostats leads onto the discussion concerning the requirement of modelling boundary layer profiles. Hence some background is provided on boundary layer modelling techniques. Further insight is drawn from more general previous bluff body CFD reported in the literature, from which observations and recommendations regarding the use of variations of the k-ε turbulence model can be inferred. The simulation procedure from geometry creation to results obtained for the flow over a vertical flat plate is reported. This investigation led to the conclusion that the Realisable k-ε should be used for the heliostat simulations on account of its accurate drag prediction under steady state flow conditions. It was also found that for transient simulations for heliostat like geometries, the SST k-ω model appears most suitable. The Realisable k-ε model is then used to model the flow about a heliostat using the same procedures as for the flat plate; both with flat and boundary layer inlet profiles. The overall conclusions drawn from this work are that the Realisable k-ε would not be suitable for predicting wind loads used in the final design of heliostats although it may be used with flat velocity and turbulence profiles to compare differences between early heliostat designs. The conclusion that the Realisable k-ε model should not be used to predict the flow field in the vicinity of a heliostat is also reached. It is recommended that further work should be carried out by using more advanced modelling techniques, such as the LES, to determine wind loads on heliostats. Furthermore, additional studies focused on accurately reproducing the velocity and turbulence profiles should be done. Lastly a larger set of data containing the orientations mentioned in literature should be generated using the methods contained within this study. / AFRIKAANSE OPSOMMING: Die vermoë van Numeriese Vloei Meganika (NVM), spesifiek die van die FLUENT ™ kommersiële sagtewarepakket, om die windlaste op heliostate te voorspel was ondersoek. As daar gevind word dat NVM wel betekinsvolle resultate kan lewer, kan dit die totale ontwikkelingskoste van heliostate en gekonsentreerdesonkragstasies verlaag. Wind plaas die grootste las op heliostate, dus deur gebruik te maak van NVM om die windlaste op heliostate te voorspel, kan dit gebruik word om te verseker dat heliostate nie oorontwerp word nie. Hierdie tesis bevat „n eerste studie binne die Sontermiese Energie Navorsings Groep aan die Universiteit van Stellenbosch, wat die gebruik van NVM om windlaste op heliostate te voorspel ondersoek. Alle relevante teoretiese agtergrond wat turbulensiemodelle aanbetref, naamlik die RNG k-ε, Realiseerbare k-ε en SST k-ω turbulensiemodelle, word bespreek. Hulle relevansie tot stompligaamvloei toegestaan, word die „standaard‟ k-ε model en die groot werwel simulasie (GWS) benaderings ook bespreek. Elke model word bespreek om die leser insig te gee in dié model se sensitiwiteite en voordele. Vorige studies wat betrekking het tot die studie van heliostate en wind word bespreek. Die geometrie van heliostate lei tot „n bespreking oor die noodsaklikheid vir „n model vir die grenslaagprofiel, dus word grenslaagmodelleringstegnieke bespreek. Verdere insig word verkry van vorige NVM studies uit die literatuur met meer algemene stomp liggame, wat waarnemings en voorstelle vir die gebruik van die k-ε turbulensiemodel en variante verskaf. Die simulasieproses, vanaf geometrieskepping tot die resultate vir die vloei oor 'n vertikale vlak, word bespreek. Hierdie ondersoek het tot die gevolgtrekking gelei dat die realiseerbare k-ε model gebruik moet word vir die heliostaat simulasies, as gevolg van die akkurate sleurvoorspellings onder bestendigetoestande. Daar was ook gevind dat vir heliostaatagtige liggame onder oorgangskondisies, die SST k-ω model mees geskik sal wees. Die Realiseerbare k-ε model word dan gebruik om die vloei om 'n heliostaat te modelleer deur gebruik te maak van dieselfde proses wat gebruik word om vloei oor 'n plat plaat te analiseer: albei met plat en grenslaaginlaatprofiele. Die gevolgtrekkings van hierdie studie is dat die Realiseerbare k-ε model nie gebruik kan word tydens die finale ontwerpfase om die windlaste op 'n heliostaat te voorspel nie. Dit kan wel gebruik word met plat snelheids- en turbulensieprofile om die versikille tussen vroeë heliostaatkonsepte te vergelyk. Daar was ook bepaal dat die Realiseerbare k-ε model nie gebruik moet word om die vloeiveld om 'n heliostaat te voorspel nie. Daar word voorgestel dat verdere studies in hierdie vakgebied met meer gevorderde modelleringstegnieke aangepak word. Dit word aanbeveel dat verdere werk uitgevoer moet word deur die gebruik van meer gevorderde modellering tegnieke, soos GWS, om die wind kragte op heliostats te bepaal. Verder, studies wat akkurate snelheid en turbulensieprofiele produseer sal nog bygelas moet word. Laastens 'n groter stel data met oriëntasies soos wat in die literatuur beskryf word, moet deur middel van die metodes van dié studie gegenereer word.

This thesis has been written for the Bachelor degree in Electrical Engineering held at Blekinge Tekniska Högskola Karlskrona, Sweden. The basis of this thesis is a statistical analysis of the electrical energy situation with emphasis on contribution of wind power and other renewable energy in electricity production in the European area and key countries.   The main parameters, which considered in this thesis are electricity production and consumption, installed capacity trends and also the operation of renewable sources, especially wind power in gross electricity generation. Meanwhile, the whole date and materials are based on real values and investigated from the latest publications of governments and energy agencies of European union and key countries.   The target of European renewable energy is that the member countries must achieve at least 20 percent of final energy consumption from renewable energy by 2020. Germany, United Kingdom, Spain and France and Portugal are members of the highest consumers of electricity in the Europe and still the main source of electrical production in these countries are fossil fuels, the main challenge is that they should start to shutting down the traditional power plant and improve the infrastructure for installing the renewable electrical capacity instead.   According to the statistics, many of the European countries such as United Kingdom, Germany, Spain, Denmark and Sweden have started up to use the renewable energy to produce the electrical energy, but their governments have special keen eye for investment in the wind energy sector. Wind power grew sharply during the past decades in Europe and becoming vital every coming day in comparison to other renewable energy, since the low cost of electricity can be granted through a small investment and relies on the wind blowing compared to the conventional electricity generation sources. The diagrams demonstrate the wind power has a main portion to producing the electrical energy and every year a considerable amount of installed capacity is added to the total electrical grid.   In addition, the expansion of renewable energy  to achieve the high percent of electrical production requires  the improvement of  infrastructure such as ecological research and high coordination between different organizations. Also, the electrical generation cannot be constant, and in winter the overall consumption and demand for electricity increases all over Europe. The exploitation of some renewable sources such as solar and wind power for electrical production can have fluctuation due to the weather condition and wind speed, which can affect the overall generation to the electrical grid.   Therefore, the balancing of several renewable sources in different seasons,  needs the unique power management for reliable electrical production. In this trend, Norway is a successful country in Europe that uses over 90 percent of  renewable sources for total electrical generation. The thesis has covered these challenges and how they are overcoming these issues.

The wind energy industry in the U.S. has seen robust growth within the last two decades. The amount of renewable resources available throughout the U.S. is substantial, and as renewable energy penetration approaches a significant proportion of total electricity generation, grid operators and utilities will be presented with a myriad of challenges. Such is the case in wind’ rich Texas, where the rate of wind installations surpasses every other state and rivals that of China. By the end of 2009, the ERCOT region of Texas had approximately 9000 MW installed, serving 6.5% of the annual electricity load . The intermittent nature of wind energy can place a burden on existing generators as they are increasingly relied on to provide regulation of power, frequency control and back-up energy services when wind production is low. Exacerbating the difficulty of integrating wind energy is the mismatch of wind generation and electricity demand. Although Texas is blessed with plentiful wind resources, the majority of energy produced typically occurs at night when electricity demands are low. The result is transmission congestion that prevents cost effective generators from serving load. Despite these integration difficulties, ERCOT is paving the way forward with transformative infrastructure plans and proactive rulemaking. This report provides a background on the state of the wind energy industry in the U.S., with a review of power system operation strategies and wind integration best practices. With that context, this study concludes that ERCOT’s electricity market operations, transmission plans, and Texas’ renewable energy policies will act to reasonably and reliably accommodate wind generation capacity that serves over 15% of annual load by 2030. / text

There has been an increased interest in renewable energy systems in recent years as a result of concerns on depleting fossil fuel reserves and climate change. Wind and solar energy are amongst the most popular renewable energy technologies. In order to use the full or maximum possible extent of a renewable energy resource in a region, hybrid systems extracting wind and solar energy simultaneously are a popular and obvious choice. It is desired to design hybrid systems that enhance the renewable energy output without increasing the foot print area compared to the base case of only wind or only solar energy. One potential way forward is to consider a vertical axis wind turbine with an enhanced surface area which can be used for mounting solar cells. This way the foot print area remains the same while both wind and solar power are obtained simultaneously. Renewable Energy Solutions LLC has manufactured a novel 2 m high and 2 m in diameter vertical axis wind turbine called Marilyn which has an enhanced surface area, which can be used for the aforementioned purpose. This thesis focuses on the development of a hybrid solar-wind turbine design based on the Marilyn system. Firstly, the wind and solar resource was assessed at Austin, TX using weather monitoring instruments. Typical Meteorological Year 3 (TMY3) data was also used in conjunction with the measured data to estimate the wind and solar resource at Austin, TX. Secondly, the wind turbine performance was assessed based on whether is it able to achieve grid tie in for wind power production starting at wind speeds of 3-4 m/s. It was found that replacing the current generator with different model featuring higher voltage output at lower rotational speeds could help achieve this. Based on this suggested replacement and using the wind resource data, the yearly wind energy production was estimated to be 240 kWh. Finally, a theoretical analysis was performed for estimating the yearly solar energy production. A base case analysis was first made on power production on a particular day of the year if only the top portion of every alternate face of the turbine is covered with flexible 3.4 % efficient solar cells. This analysis is subsequently extended to the case when flexible 20 % efficient solar cells cover the entire top surface of the turbine and the corresponding conservative yearly solar energy output was estimated to be 310 kWh. Thus the total yearly energy output from the Marilyn hybrid system is 550 kWh, which is around 5 % of the annual electricity usage of a typical American home / text

A comprehensive framework is presented for the integration of electrified transportation and renewable energy through repurposing batteries of plug-in electric vehicles towards a sustainable energy future. The framework considers future market penetration scenarios of plug-in electric vehicles, availability of batteries at their vehicular end of life, and the storage capacity required to generate base-load wind power in the region of study. The objective is to develop a model that can be used as a policy tool to investigate how different scenarios and pertinent parameters can effectively meet the challenges of sustainability in the energy and transportation sectors when the ultimate goal is to simultaneously displace fossil fuels with new generation of low-cost intermittent renewable energy. A sample case study is performed for Canada to investigate and verify the performance of the model. The analysis shows that the proposed approach can further improve the energy sustainability performance of Canada in 2050 by 1.65–4.11%, depending on the confidence level and in addition to electrification of transportation. In the framework, a statistical algorithm is developed to calculate the capacity of an energy storage system required for delivering base-load electricity for a wind farm in the future electric grids. The algorithm contributes towards the goal of utilizing low- cost intermittent wind energy to base-load power generation in the future electric grids. The introduced algorithm presents three methods to perform the sizing calculations each representing a scenario associated with the stages of the wind energy industry. The results of the studied case are applied to estimate the cost of wind energy to produce rated power at different confidence levels, which show cost-effectiveness and less intermittency on the power systems allowing for larger penetrations of renewables. Advanced statistical methods are used to more accurately characterize the operational wind power output versus manufacturer’s power curve. This is essential for effective integration of wind power into the power systems. Four parametric and nonparametric models are applied to estimate the power curve of wind turbines based on the available operational wind power data. The results of this study suggest that the penalized spline regression method presents a better performance over the other analyzed methods. Finally, an experimental testing is performed in laboratory to show the proof of concept of the capacity degradation of used batteries of plug-in electric vehicles in stationary applications using a 25 kWh repurposed energy storage system obtained from a taxi fleet in their “as-is” condition. The proposed comprehensive framework herein presents an approach leading to a sustainable transportation system by providing low-cost renewable energy, and can be used as a gold standard to compare other policies like hydrogen energy technologies. / October 2015

This Masters research proposes a new system which deals with the management of renewable energy sources in a domestic/commercial small scale environment. The aim of the project is to develop an intelligent system which will monitor current in individual circuit loads in a domestic/commercial environment and establish whether the load can be powered from mains supply or be switched to an alternative energy supply in a dynamic way. The alternative energy can be solar energy from photovoltaic panels, wind generators or hydro generation. The switching between supplies is decided by monitoring load currents using a microcontroller and the switching action is taken only at specic allowed instants. The CAN (Controller Area Network)communication system is a two-wire differential serial bus system, developed by Bosch for automotive applications in the early 1980s. Its reliability and robustness in communication between nodes within the control system are the reasons for its popularity. The CAN system is implemented in the Eco Energy Controller. The prototype of the Eco Energy Controller is operational and has been tested with 6 resistive load, 24mH inductive load, and three 25W incandescent light bulbs. Experimental measurements and waveforms indicate that the prototype is successful in switching between two supplies to each of the loads without causing high current peaks during turn on.

Despite the UK’s abundance of renewable energy sources and the imperative for renewable energy to make a significant contribution to addressing the problems of climate change and fossil-fuel dependency, renewable energy capacity in the UK has developed slowly compared with some other EU states. The UK has introduced a succession of policies to promote renewable energy, but so far these have failed to meet national and EU targets. This signals the need for detailed examination of the reasons for these ‘failures’ and, in particular, the extent, nature and constraints on ‘policy learning’ within UK renewable energy policy. Policy learning has emerged in recent years as an innovative way of exploring the roles of knowledge acquisition and use in policy change. This study examines the contribution of policy learning to the development of UK renewable energy policy. It is argued that interpreting UK renewable energy policy development through the lens of policy learning yields fresh perspectives on why policies develop in certain directions and not others. In so doing, it critically examines problems caused by failings in policy learning and identifies options for the further promotion of renewable energies in the UK. The study distinguishes four different forms of policy learning: technical, conceptual, social and political. Little research has been conducted on the characteristics of these different learning types, the conditions under which they occur, the psychological, institutional and cultural factors that stimulate or constrain learning, and how they interact to shape policy change. The study utilises a qualitative methodology to analyse and explain changes in UK renewable energy policy over the past 20 years. The main methods employed are content analysis of policy documents (including legislative acts and instruments, consultations and select committee reports); and semi-structured interviews with key stakeholders from government, industry, NGOs, academia and the media. It is argued in the thesis that UK energy policy has tended to become ‘locked’ into low-level forms of technical learning because current government learning mechanisms do not challenge the parameters of existing policy and, thus, fail to stimulate broader processes of conceptual and social learning that might encourage more radical policy change. These forms of policy learning are particularly constrained by hierarchical institutional structures that hinder communication and learning between policy areas. Furthermore, the current style of policy making for renewable energy in the UK privileges the interests of incumbent energy companies, giving them the ability to filter or block new ideas that do not align with their commercial interests. Political learning was shown to operate alongside other types of policy learning and to take multiple forms but focused predominantly on political risk management rather than political innovation: thus, it tended to narrow rather than extend the parameters of debate. These findings were used to develop a model of policy learning in UK renewable energy policy. This was used to conceptualise relationships between different learning types, highlight specific barriers to policy learning, and illustrate dynamics of policy learning and change that might be extended to other policy areas and countries. Finally, it is argued that many of the barriers identified might be overcome by fostering more evidence-based policy making and learning mechanisms that engage with a broader range of stakeholders to stimulate more pluralistic government processes.

This thesis focuses on determining the potential of bio-energy crops to contribute to Europe’s future energy needs and to reduce future greenhouse gas emissions. This requires an end-to-end (seed to exhaust gas) analysis of the crop production and enabling technology in terms of energy use and greenhouse gas emissions. The starting point of this research was to consider which energy crops had the potential to grow in future European climate scenarios and to determine those for which models did not exist to make this prediction. <i>Miscanthus</i> was identified as a relatively new crop with 15 years of European growing experience but with limited previous model development.  MISCANMOD, a simple model of <i>Miscanthus</i> crop growth, was improved and rewritten in FORTRAN so that it could be interfaced to use climate scenario, soil property and land use data bases to predict energy yields for current and future climate scenarios. A greenhouse gas emissions and energy balance model was added to investigate the sustainability of <i>Miscanthus</i> as a bio-energy crop. This model was combined with data from other energy crop predictions to determine the energy yields and GHG mitigation of different crops for the various scenarios of future climate, each considering the soil conditions, land available and climatic conditions. We conclude that <i>Miscanthus</i> is the crop with the highest energy yield and largest carbon mitigation potential of all the available energy crops, and that the maximum amount of primary energy that could be produced by bio-energy crops in Europe would represent only 12% of EU 25’s primary energy needs. The carbon intensity of such energy is estimated to be 24% of that for gas. To achieve this level of energy production we show that it is necessary to develop drought and frost resistant hybrids to increase the range of the <i>Miscanthus</i> crop for current and future climate scenarios. This demonstrates that bio-energy is not a panacea but must be considered as part of the strategy to achieve sustainable energy whilst mitigating greenhouse gas emissions.

Sustainable Built Environments Senior Capstone Project / This paper provides a study on the configuration of Stirling engines and the effect using a solar dish as a heat source on efficiency. The Stirling engine was based on the MIT 2.670 design - a Gamma configuration, low temperature differential Stirling engine. Temperature and speed were measured for the base model Stirling engine to determine the initial efficiency. Modifications were planned to add a parabolic mirror as a solar dish and compare the efficiency to the initial design, however, the completed solar Stirling engine testing and data collection is to be performed in the following summer. The work performed by the engine was to be calculated using the Schmidt formula to then find the power output. Results from the completion of this study would indicate how the solar dish effects the power output of the Stirling engine.