M.Ing. / The necessity for deployment of Concentrated Solar Power (CSP) technology in the South African energy sector is examined in this dissertation. A background is given on the different technologies that exist in the solar power sector with specific reference to Concentrated Solar Thermal Power (CSTP). The economic, social and environmental benefits that this technology embodies in the near-, medium-, and long-term is discussed in detail. It highlights the local market potential for the establishment and large-scale roll out of CSP technology in a South African context and the economic value-chain that could subsequently be created...

In order to fulfil the goals set by EU and in the Swedish energy agreement an increased share of renewable electricity production, like wind and solar power, is necessary. Due to current legislations photovoltaic (PV) installations are usually limited to the 255 kWp energy taxation rule, or to fit the consumption profile of the building. There is also an uncertainty regarding subsidies from a long-term perspective. Three main questions are examined in this report: Firstly, whether or not a larger PV installation is more beneficial compared to a smaller one regarding LCOE, payback time and IRR. Secondly, if and how a larger PV installation can be optimized using virtual storage. Thirdly, how the virtual storage solution compares to a conventional storage method with a lithium-ion battery. Throughout the project, larger installations have proven more profitable by taking advantage of cost efficiencies. By increasing the size of the installation from 120 kWp to 314 kWp for the investigated pilot project, the LCOE is reduced from 0,938 to 0,767 SEK/kWh, payback time is reduced from 17 to 12 years, and IRR is increased from 8,1 to 10,8 %. To maintain the advantage of the largest installation in the current market, it is necessary to integrate and optimize the storage so that all produced electricity is self-consumed. Some buildings have the possibility to create a virtual storage through using existing possibilities within the facility. Virtual storage is still an unexplored area but has risen in interest since focus on energy efficiency has increased. The project includes a virtual storage solution where the refrigeration system in a grocery store is paired with a water tank to provide more storage capacity. To optimize the use of the virtual storage, it is necessary to maximize the use of the available capacity. Three main applications have been identified as optimization alternatives for the project and those are: 1) storing excess electrical energy from over-production, 2) load shifting from hours with high electricity prices, 3) providing demand response for the primary regulation market (FCR-N, FCR-D). By utilizing the storage capacity, the PV investment can improve with regards to the studied economic measures. When utilizing the most profitable options, 1) and 3), for a 314 kWp PV installation the payback time is reduced from 12 to 10 years and the IRR is increased from 10,8 % to 11,73 %. Compared with a conventional lithium-ion battery (Tesla Powerwall), the virtual storage solution is competitive with respect to initial cost and environmental impact. However, for electrical aspects the battery significantly outperforms the virtual storage with an efficiency of 90 % of the battery and 54 % of the virtual storage and an energy density of 0,108 kWh/kg for the battery and 0,0035 kWh/kg for the virtual storage.

The aim of this thesis is to apply and evaluate potential forecasting models for solar power production, based on data from a photovoltaic facility in Sala, Sweden. The thesis evaluates single step forecasting models as well as multiple step forecasting models, where the three compared models for single step forecasting are persistence, autoregressive integrated moving average (ARIMA) and ARIMAX. ARIMAX is an ARIMA model that also takes exogenous predictors in consideration. In this thesis the evaluated exogenous predictor is wind speed. The two compared multiple step models are multiple step persistence and the Gaussian process (GP). Root mean squared error (RMSE) is used as the measurement of evaluation and thus determining the accuracy of the models. Results show that the ARIMAX models performed most accurate in every simulation of the single step models implementation, which implies that adding the exogenous predictor wind speed increases the accuracy. However, the accuracy only increased by 0.04% at most, which is determined as a minimal amount. Moreover, the results show that the GP model was 3% more accurate than the multiple step persistence; however, the GP model could be further developed by adding more training data or exogenous variables to the model.

In this study, it was investigated how individual households could manage security of supply during an outage by installing a local energy system that could operate independently from the electricity grid. By installing local renewable off-grid energy systems, households could guarantee an uninterrupted supply of energy even during an outage on the electricity grid, while also increasing their energy autonomy during normal circumstances. The results showed that managing an outage during summer was fairly easy. Due to high electricity production, a small energy storage was enough to manage an outage during summer. However, managing an outage during winter was more critical. During winter, the systems needed to be almost fully reliant on the energy storage. This significantly increased the cost of these systems. Due to the high cost for the energy systems today, it was not considered a feasible solution to improve energy security at a national level. However, at a local level, this was considered to have the potential to improve energy security. First, it could to be of interest for people who already have installed solar panels, who could add a battery and thereby be able to manage an outage during summer. Second, it could be of interest for people who are more exposed to outages or have a low trust in the system to work properly. Lastly, this could be of interest for actors for whom backup energy is important, for instance for the industry.

Action on climate change will require an increase in renewable energy projects to support electrification in the transition away from burning fossil fuels. Indigenous peoples throughout Canada are developing community-owned small-scale (producing less than one megawatt of power) renewable energy projects and are interested in developing more. Despite Indigenous peoples’ involvement and interest, there is a lack of research into the impact of these projects for communities. This thesis explores whether and how small-scale renewable energy projects developed by First Nations communities in British Columbia (BC) might contribute to supporting justice within the energy transition. The research included a province-wide survey (First Nations Clean Energy Survey), and a case study with a remote First Nation with multiple small-scale renewable energy projects in operation—the Village of Skidegate on Haida Gwaii. This research found that small-scale projects are a distinct experience within the renewable energy sector, one that is offering First Nations communities an accessible form of power production that provides myriad benefits. Some benefits were easy to measure, such as cost savings and greenhouse gas reductions, while the majority of benefits were not as easy to quantify, such as increasing connection and engagement with energy, increasing self-sufficiency, providing a vision of a future free of oil and gas reliance, community pride and education. As these benefits indicate, the thesis concludes that small-scale renewable energy developments offer a distinctive and important opportunity that First Nations are using to enforce self-determination and build community resilience. / Graduate

Solar panels are used in many different applications for generating sustainable energy. Many countries use solar power as a power generation method. It is also, an excellent option for getting power to difficult areas. There are three main systems used when generating solar power: grid-tied, battery banked, and direct driven systems. Most systems use a combination of grid-tied and battery banked so any unused power can be fed back into the main grid for compensation. The solar power application suggested in this thesis will provide USB power to a picnic table enabling students to charge cellphones and other small devices while at the table. The solar panel will be mounted on the top of the picnic table or on a canopy as shading for the table. These locations along with the power generation systems were researched and tested to find the best option.

This dissertation presents the rectifying antennas potential for harvesting solar power, along with a novel design for a solar rectenna. The suns general features and the characteristics of solar radiation as an electromagnetic wave are treated in depth in order to determine the deficiencies of traditional rectennas as a solar cell. A closed form equation for a MIM rectifiers efficiency as a function of its input power was developed and verified by a simulated behavioral model and measurements. A unique calculation method was also developed to determine the available solar power at the terminal of a [lambda]/2 dipole antenna as a function of its bandwidth. The available power for each diode at the antennas terminal was found to be insufficient for a MIM diode to operate in its high efficiency region. It was concluded that the MIM diode requires an array of high gain antennas to increase the solar power captured at its input in order to operate in its high efficiency region. A dielectric rod antenna is proposed as the high gain antenna element for the solar antenna. In order to minimize losses due to the skin effect in the feed system of the array, a non-radiative dielectric (NRD) wave guide is proposed as the feed structure for the solar array antenna. To increase the rectification efficiency of the solar rectenna, two improvements were introduced: 1) the solar antenna was modified to function as a dual polarized antenna; and 2) a novel technique was used to achieve full-wave rectification. Test results of prototypes of the proposed solar antennas and arrays, show them to be potentially far superior to traditional [lambda]/2 dipole antennas for collecting solar radiation. The interconnection method for rectennas in an array – as well as their associated dc losses – were also investigated. Based on the theoretical results, a novel interconnection method is proposed here, which has the potential to minimize the dc losses in the grid. A series of experiments were conducted to verify the proposed concepts, which yielded promising results.

Power electronic converters have become popular in the field of power transformation for renewable energy. Power electronics converters achieve high efficiency, and the price of their components is falling, thus making them even more beneficial for renewable energy applications. Those systems coupled to the grid need to withstand certain utility-defined circumstances which may occur during operation. Additionally the new net regulations for large generation plants specify that during specified severe grid disturbances the relatively delicate converters should stay connected supporting the system. For PV inverters the forthcoming standards may optionally add the possibility of reactive power compensation where for wind-power those standards are already in use. This thesis focuses on reliable, sensor-less control of the PWM converters coping with varying grid conditions and existing problems. The thesis presents a variety of digital control solutions for interfacing PWM converter with the grid, synchronization, sensorless operation and grid impedance detection. The introductory chapter gives the fundamental theory about three-phase converters and control.The following chapters deal with unbalanced condition and symmetric component decomposition, which is the tool to cope with unbalanced grid voltages or currents. A sensor-less operation method using dual frame virtual flux model is presented with good results. In addition sensor-less synchronization to the grid is shown. Moreover an algorithm based on virtual flux for grid inductance estimation is also successfully demonstrated. Knowing the grid inductance is important during weak grid operation, since it is needed in order to provide unity power factor to the point of common connection. At the end of the thesis, a control algorithm for voltage harmonic compensation during stand alone operation is presented. The presented algorithm gives the possibility to supply high quality power in isolated islands, where the load is unknown. Furthermore, this algorithm can be successfully used for UPS applications. The last chapter applies the voltage harmonic control to the Z-source converter having the possibility of achieving higher ac voltage than in conventional VSI, results are promising.

The Department of Energy funded a project to determine if the specific heat of thermal energy storage materials could be improved by adding nanoparticles. The standard thermal energy storage materials are molten salts. The chosen molten salt was a sodium nitrate and potassium nitrate eutectic, commercially called Hitec Solar Salt. Two nanoparticle types were chosen, alumina and silica. The nanoparticle composite materials were fabricated by mixing the components in an aqueous solution, mixing that solution for a set amount of time using a sonic mixer, then removing the water from the aqueous solution, leaving the composite molten salt behind as a fine white powder. The thermal properties of the composite and plain material were measured using two techniques: American Society for Testing and Materials (ASTM) 1269E and Modulating Differential Scanning Calorimetry (MDSC). These two techniques measured the specific heat and the heat of fusion of the plain and composite materials. The results of all the ASTM and MDSC measurements suggest that the addition of the nanoparticles using the given manufacturing technique increased the specific heat of the molten salt by approximately 20 percent, with both measurement techniques showing approximately the same level of increase. The silica and the alumina improved the specific heat by nearly the same amount over the base material. The heat of fusion did not seem to be significantly altered compared to the observed heat of fusion value of the unmodified material. It was also observed that the nitrate and silica composite material's specific heat decreased if the material was raised to a temperature above 400C. The specific heat was observed to decrease over time, even when the temperature was well below 400C. It is unknown why this occurred. The nitrate plus alumina composite and the plain nitrate were stable to a temperature of 450C for the test duration.

Parts of the auxiliary power systems at Fortum's hydro power stations are usingdirect current, which is fed from the generators at the plant and converted byrectifiers. As photovoltaic solar cells produce direct current there are severalhypothetical advantages to use solar power for the auxiliary power supply, e.g.enabling more of the power from the generator to be sold to the grid. It eliminatesthe need of an inverter, conversion losses are avoided and less load is put on therectifiers. However the exclusion of an inverter also prevents the solar cells to have adirect connection to the grid, which in turn makes them ineligible for the Swedishgovernmental solar power investment support program. The lesser load on therectifiers will not affect their lifetime according to manufacturers and thus achieves noeconomic gain. Avoiding conversion losses will increase the gain from the producedelectricity by enabling even more power to be sold to the grid. The economic gainfrom avoiding conversion losses is however too small to gain any feasibility in a smallsolar power installation at a hydro power plant, as the small size will make itexpensive in terms of investment per Wp.