The increase in demand for renewable energy sources has been exponential in recent years and is mainly driven by factors that include the growth of greenhouse emissions and the decline in fossil fuel reservoirs. Photovoltaic (PV) energy, one of the more prominent renewable energy sources, produces electricity directly from sunlight, noiselessly and harmlessly to the environment. Additionally, PV energy systems are easy to install and financially supported by many governments, which has helped disseminate PV technology worldwide. The total generated power from PV installations (and the number of installations) has increased more than two-fold during the past 3 years, so that now more than 177 GW of PV-generated power is delivered per year. Researchers have been led to work on the obstacles facing PV systems from different perspectives, including: installation cost, inconsistency, and conversion and interface efficiency. The aim of this thesis is to design a high-efficiency PV inverter system configuration. The contribution to the knowledge in this thesis can be divided into two parts. The first part contains a critical analysis of different maximum power point tracking (MPPT) techniques. The second part provides a detailed design of the inverter system, which consists of a boost converter and a low-frequency H-bridge. Together, the three parts in this contribution present a complete high efficiency PV inverter system. The proposed system maintains high-efficiency energy delivery by reducing the number of high-frequency switches, which waste a significant amount of energy and reduce system efficiency. In order to show the superiority of the proposed configuration, a power loss analysis comparison with the other existing configurations is presented. In addition, different scenarios have been simulated with Matlab/Simulink. The results of these simulations confirm the distinction of the proposed configuration as well as its low-loss, high-efficiency characteristics which is rated at 98.8%.

This thesis is about the energy audit in Fridhemsskolan which is an educational facility. Fridhemsskolan is a preschool for children in Gävle municipality for children up to the age of six years and comprise of nine buildings in total. The project begins with an energy survey on the school facilities which ranges from checking the ventilation system, lightning system, number of occupants, equipment’s types and so on. The next step was to use a simulation program software called indoor climate and energy (IDA ICE) to create the base model for the building and input the data collected during the energy survey directly into the software and simulate it for a period of one year. After creating the base model, the total electricity use of the building was around 89 MWh/year while the district heating was 157 MWh/year.The energy conservation opportunities in Fridhemsskolan for the building was divide into two categories and these are referred to as non-retrofitting (no or minimal cost) and retrofitting (with cost) recommendations. The non-retrofitting involves reducing the indoor temperature and with this approach; the district heating consumption was reduced to 147.6 MWh/year which amount to 9.34 MWh/year in savings for the district heating while the electricity consumption was reduced to 86.4 MWh/year which amount to 2.6 MWh/year in savings for the electricity.Retrofitting (with cost) recommendations involves looking at the base model and see where some improvements can be carried out. In this research, the roof of the building has more energy losses and retrofitting with cost analysis was performed on that part of the building envelope.After retrofit, the district heating consumption was reduced to 142 MWh/year which is about 15 MWh/year in saving for the district heating while the electricity consumption was reduced to 26 MWh/year which also amount to 63 MWh/year saving in electricity consumption. The reason for this sharp decrease in the electrical consumption was because, the electrical radiators in the base model of the building was replaced with ideal heaters that uses district heating as the energy carrier and 170 mm of mineral wool was also added to the roof.Finally the research further looks at the thermal comfort and the indoor air quality of the occupants in the building by analysing the data on both thermal comfort and the indoor air quality to see if the value obtained are within the acceptable range. In most cases the value is within the acceptable range like in the case of carbon dioxide (CO₂) concentration in theiiioccupied zone, the value obtained after reducing the indoor temperature was less than 1000 parts-per-million (ppm) and that shows that the carbon dioxide (CO₂) concentration is within an acceptable level in the room. The thermal comfort of the occupants in the occupied zone was within the acceptable limit. However, lowering indoor temperature increases the PPD for both buildings. The percentage of the total occupant hours with thermal dissatisfaction increases to 13% from 14 % for Hus 9 and from 13% to 15% for Hus (4-8).

This thesis has investigated how the energy consumption can be reduced in a mobile sensor unit by using a dynamic measurement scheme. This was done by developing a scheme based on inspiration from existing works in related areas and on techniques found in literature. The developed scheme was then implemented on a mobile sensor unit and tests were conducted where the energy consumed by the scheme was measured. This was compared to a static baseline approach in order to evaluate the efficiency of the scheme. The results showed that on the platform used in this thesis the developed scheme can reduce the energy consumption in a typical scenario by 4.7% or 6.7% depending on which sensors are used. A conclusion drawn is that the platform has a major impact on how effective the scheme can be.

Climate change is one of the global challenges of our time. The energy sector is at the focus of the European efforts to combat climate change as it accounts for 80% of the total greenhouse gas emissions in the European Union. Buildings, on the other hand, represent 40% of the energy use and 33% of the total greenhouse gas emissions in the European Union, giving the buildings sector also a key role in the European climate strategy. There are, at the same time, strong interdependencies between the energy and buildings sectors due to the high amount of energy used by buildings and their rising importance as active components in the future energy systems. These interdependencies do not only influence the investment decisions in the energy and buildings sectors, but also the effectiveness of the European climate strategy. Cooperation between the energy and buildings sectors can create beneficial outcomes for the both sectors as well as the environment. It may also encourage innovation, improve the energy performance of buildings, and help achieve a higher penetration of renewable energy into the energy system. This licentiate thesis investigates the relationship between the energy and buildings sector at the inter-company level. Presenting the data collected from interviews and a web survey answered by the energy and buildings sectors in Sweden, this thesis examines the level of cooperation between these two sectors, discusses trust issues between stakeholders, presents the factors that negatively impact cooperation, and provides recommendations for the minimisation of these factors. The findings presented in this thesis indicate an insufficient level of cooperation between the energy and buildings sectors in Sweden, to which the following factors have been identified to contribute in a negative a way: district heating monopolies; energy efficiency in buildings; building regulations; self-generation of electricity; and energy use patterns. The emphasis on self-interest by stakeholders within the both sectors appears to create trust issues between stakeholders. Accordingly, shifting the focus from self-gains to mutual gains is deemed necessary to improve the cooperation between the energy and buildings sectors. This, however requires significant changes in current practices and business models. It has been identified that the development of smart energy systems that allow a closer interaction between the energy and buildings sectors through flexible energy supply and use would minimise many of the factors that negatively impact cooperation. / Klimatförändringen är en av de stora globala utmaningar vi står inför. I Europa läggs idag stort fokus på energisektorn, som står för 80 procent av det totala utsläppen av växthusgaser. Byggnader representerar 40 procent av energianvändningen och 33 procent av växthusutsläppen, vilket också ger byggsektorn en nyckelroll i den europeiska klimatstrategin. Samtidigt finns det starka beroendeförhållanden mellan energi- och byggsektorn på grund av den höga energianvändningen i byggnader och deras ökade betydelse som en aktiv komponent i det framtida energisystemet. Dessa beroendeförhållanden påverkar inte bara investeringsbeslut i de båda sektorerna, utan även effektiviteten i den europeiska klimatstrategin. Samarbete mellan energi- och byggsektorn kan få positiva effekter för både dem själva såväl som för miljön. Samarbete mellan sektorerna kan även uppmuntra innovation, förbättra energieffektiviteten i byggnader och tillåta en högre användning av förnyelsebar energi i energisystemet.  Denna licentiatavhandling utforskar förhållandet mellan energi- och byggsektorn på företagsnivå genom att analysera data som samlats in med hjälp av intervjuer och en webbaserad enkät.  Intervjuer och enkäter har besvarades av både energi- och byggsektorerna i Sverige. Denna avhandling studerar nivån av samarbete mellan de två sektorerna, diskuterar problem gällande förtroende mellan intressenter, presenterar de identifierade faktorer som försvårar samarbete och ger rekommendationer för att minimera dessa. Resultatet visar på en otillräcklig nivå av samarbete mellan energi- och byggsektorerna i Sverige. De faktorer som försvårar samarbetet är följande: fjärrvärmemonopol; energieffektivitet i byggnader; byggregler, egenproduktion av el och användarmönster. Naturligt finns ett egenintresse hos olika intressenter inom de båda sektorerna, och detta tycks ha skapat ett förtroendeproblem mellan de olika sektorerna Att byta fokus från egen vinning till gemensamma mål bedöms vara nödvändigt för att öka samarbetet mellan energi- och byggsektorerna. Detta fodrar dock stora förändringar både i nuvarande verksamhet samt i affärsmodellerna. Det har påvisats att utvecklandet av smarta energisystem som tillåter en större interaktion mellan energi- och byggsektorerna genom flexibel energiförsörjning och användning skulle minimera många av de faktorer som inverkar negativt på samarbetet.

Magister Legum - LLM / The methods of energy use and production in South Africa are currently unsustainable, and have dire environmental and health impacts. This is largely due to fossil fuel based energy generation and use. Currently 89% of energy generated in South Africa is derived from fossil fuels including coal, oil and gas. This figure is likely to increase in the near future with the construction of new coal-fired electricity generation and coal/gas to liquid fuels stations. South Africa has an abundance of both non-renewable and renewable energy resources.Renewable energy technologies will be key in the battle to reduce carbon and greenhouse gas (GHG) emissions, as they do not produce the large amounts of carbon and GHG emissions that conventional fossil-fuel based methods do. Renewable energy, as the name indicates, can be considered an infinite reserve. Most renewable energy is generated from solar power it can be relied upon as long as the sun keeps shining. Energy efficiency as well as improvements in technologies relating to energy generation can play a significant role in reducing carbon and GHG emissions. For example, the 'Basa njengo Magogo' method used to ignite coal in coal-fired power stations makes use of a 'top-down ignition process' which reduces smoke emissions by 80-90 percent, heats up quicker and uses less coal than the conventional method. The barriers to the implementation of sustainable and renewable energy measures are: the relatively cheap cost of coal based energy, due to the abundance of the resource in South Africa, as well as the uncoordinated nature of legislation dealing with energy, and the implementation of sustainable energy practices. However the means and resources do exist for South Africa to reduce its carbon and GHG emissions and reliance on carbon based energy. Therefore this paper will examine the legislative and international obligations government has to sustainable and renewable energy and what policies have been developed to give effect to these obligations. Section 24 of the Constitution explicitly recognises the obligation to promote justifiable 'economic and social development', which is essential to the well-being of human beings. Development both social and economic require energy, however South Africa's energy is derived mainly from fossil fuels, which when used have a significant detrimental effect on the environment.

This thesis is an investigation of why and how homeowners decide to renovate their homes. Energy efficient renovations are of particular interest given their potential contribution to public policy goals including greenhouse gas emission reduction. Policies seeking to improve energy efficiency in existing homes have to influence homeowners’ decisions. This requires a psychologically and behaviourally realistic understanding of the renovation decision process. Different research traditions offer competing models. These are tested through a series of hypotheses on the form and content of the renovation decision. The empirical dataset used combines both stated and revealed preference data. 809 homeowners in British Columbia were surveyed at three different cross-sections of the renovation decision process. The sample included both energy efficient (e.g., windows, insulation) and amenity renovators (e.g., kitchens, bathrooms), and was broadly representative of the population of renovating homeowners in British Columbia. Survey responses were calibrated using actual energy consumption data, and a supplementary survey of realtors. Calibration allowed homeowners’ expectations of the financial costs and benefits of renovating to be evaluated. Firstly, sampled homeowners systematically over-estimated their energy costs. Secondly, these estimates were subject to common information processing and recall biases. Thirdly, even homeowners in the middle of energy efficient renovations had expectations of capital costs, energy cost savings, and property value impacts that were largely unknown or unreliable. More generally, sampled homeowners lacked the basic knowledge necessary to appraise energy efficient renovations as financial investments. Homeowners’ motivations for renovating were more likely to be emotional and aesthetic in the case of amenities, but related to functional outcomes like thermal comfort in the case of energy efficiency. Social norms were influential in both cases but were underreported by homeowners. This was consistent with rationalisation biases which help individuals maintain self-esteem by emphasizing instrumental explanations for their actions. This psychologically realistic characterisation of the renovation decision suggests a range of design criteria for policy, and questions the effectiveness of narrowly-targeted information and incentive policies in their current form. However, policy implications should be generalised with caution given the low energy price and appreciating real estate market characteristics of the study region. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

This thesis discusses the implementation of EU Energy efficiency directive into national legislatures and the fulfilment of its goals. It expands on the past reports, correct for their mistakes and provide a new unique approach to track the current progress. The thesis analyzes all member states national action plans for energy efficiency (NAPEE) and compares them in between each other. The quality of NAPEEs is critically evaluated and described. In first section it explains and narrows the most crucial definitions. In second section it gives the basic summary of the regulation to interested readers. Followed by in depth analysis and evaluation of all EU member states national action plans for energy efficiency. The following chapter then deals with solely with Czech NAPEE. The last section provides the hard data and exclusively developed indices that tracks the progress toward EU 2020 goals.

In this paper, we propose an adaptive and multi-sector-based user clustering algorithm which increases energy efficiency in a cellular network. Adaptive sectoring with dynamically changing sector angles is illustrated with a number of randomly distributed mobile stations. Transmitted power is equally shared by sectors before adaptive user clustering. The sector angles vary from 30 to 360 degrees by merging neighboring sectors and a sector is switched off till the user density exceeds a threshold (Td). The Td value is computed from the total number of users that the cell can accommodate over the area of the cell. The sectors with less than Td density exhibits transmit power which approaches to zero or sleeping state and so that the cumulative power is saved. Simulation results show that an average of 45% to 50% energy can be saved in 10 iterations.

Spectral efficiency (SE), energy efficiency (EE), and transmission reliability are basic parameters to measure the performance of a cellular network. In this paper, spectral efficiency and energy efficiency tradeoff is considered keeping in mind the transmission reliability, where all the three are function of signal to noise ratio (SNR). SNR, in turn is a function of constellation size (or the number of bits per symbol) and data rate. Then, we propose a new power model which is as function of this SNR. Based on the power model, SE-EE trade-off function is evaluated taking transmission reliability in to consideration. Results confirmed that increasing constellation size results an increase in SNR and leads to a significant increase in energy efficiency without changing the transmit power. To demonstrate the validity of our analysis, channel gain and constellation size are varied keeping transmit power constant. The results also indicate that securing transmission reliability, the EE-SE trade-off is optimized by increasing the constellation size.

The point of departure for this thesis is how a traditional service sector shifts towards becoming more energy efficient and the processes that enable environmental action. Traditional services are generally considered to be poorly innovative and inclined towards routine activity; this leaves a gap in understanding how these adapt to the challenge of taking environmental action. The study argues that service firms adapt by deploying capabilities to multitask or to carry out innovative activity alongside routine activities related to service delivery. The research problem is addressed through three objectives: i) explicating how dynamic capabilities enable environmental action in traditional services with a focus on energy efficiency; ii) investigating the interface between the service firm and a type of intermediary, the knowledge intensive business service firm (KIBS), and how this acts as a locus for intermediation activity, or the exchange of knowledge about energy efficient technologies and measures; and iii) exploring how developments in the external context may influence the firm’s capabilities to adapt.The key contributions are two-fold. Firstly, the research links different combinations of capabilities with particular innovative behaviours in service firms; this underscores the presence of a differential multitasking potential across firms in the same sector. Secondly, it demonstrates a link between the service firm’s internal capabilities and the extent to which it mobilizes absorptive capacity to obtain knowledge about energy efficiency measures from its relation with KIBS.A qualitative study is designed with the hotel sector in Malta as the empirical setting. The fieldwork was undertaken through interviews with 26 hotel managers, 14 engineering consulting firms and 16 actors in the broader institutional environment. The data from the hotels were clustered to derive different adaptation modes characterized by particular capabilities and patterns of environmental action. Then, pairs of hotels and engineering consulting firms were identified in order to investigate the relational dynamics that may be influencing intermediation activity. The findings distinguish between hotels with a low multitasking potential that adopt a narrow range of energy efficient measures and those with a higher multitasking potential that modify activities and make deeper structural changes to shift towards improved energy efficiency. Accounting for the range of multitasking potential are different combinations of capabilities to sense signals in the external environment and interpret these in the firm and the capability for problem-solving for energy efficiency. The findings demonstrate a different pattern of KIBS use by hotels that is suggestive of a cluster differentiation. This is linked to different levels of absorptive capacity in hotels that determines whether intermediation activity and therefore the exchange of knowledge and learning about energy efficient measures is constrained or otherwise enhanced at the KIBS-client interface. The conclusion provides policy implications and areas for future research.