Indiana University-Purdue University Indianapolis (IUPUI) / Combining rooftop solar with energy storage for off-grid residential operation is restrictively expensive. Historically, operating off-grid requires an 'isolated self-consumption' operating strategy where any excess generation is wasted and to ensure reliability you must install costly, polluting generators or a large amount of energy storage. With the advent of Blockchain technology residents can come together and establish transactive microgrids which have two possible operating strategies: Centralized Energy Sharing (CES) and Interconnected Energy Sharing (IES). The CES strategy proposes that all systems combine their photovoltaic (PV) generation and energy storage systems (ESS) to meet their loads. IES strategy establishes an energy trading system between stand-alone systems which allows buying energy when battery capacity is empty and selling energy when battery capacity is full. Transactive microgrids have been investigated analytically by several sources, none of which consider year-round off-grid operation. A simulation tool was developed through MATLAB for comparing the three operating strategies: isolated self-consumption, CES, and IES. This simulation tool could easily be incorporated into existing software such as HOMER. The effect of several variables on total cost was tested including interconnection type, initial charge, load variability, starting month, number of stand-alone systems, geographic location, and required reliability. It was found that the CES strategy improves initial cost by 7\% to 10\% compared to the baseline (isolated self-consumption) and IES cases in every simulation. The IES case consistently saved money compared to the baseline, just by a very small amount (less than 1\%). Initial charge was investigated for March, July, and November and was only found to have an effect in November. More research should be done to show the effect of initial charge for every month of the year. Load variability had inconsistent results between the two geographic locations studied, Indianapolis and San Antonio. This result would be improved with an improved load simulation which includes peak shifting. The number of systems did not have a demonstrable effect, giving the same cost whether there were 2 systems or 50 involved in the trading strategies. It may be that only one other system is necessary to receive the benefits from a transactive microgrid. Geographic locations studied (Indianapolis, Indiana; Phoenix, Arizona; Little Rock, Arkansas; and Erie, Pennsylvania) showed a large effect on the total cost with Phoenix being considerably cheaper than any other location and Erie having the highest cost. This result was expected due to each geographic location's load and solar radiation profiles. Required reliability showed a consistent and predictable effect with cost going down as the requirement relaxed and more hours of outage were allowed. In order to accomplish off-grid operation with favorable economics it is likely that a system will need to reduce its reliability requirement, adopt energy saving consumption habits, choose a favorable geographic location, and either establish a transactive microgrid or include secondary energy generation and/or storage.

This bachelor thesis investigates the implementation of a solar panel and battery storage system in a Swedish church that is intermittently heated focusing on its economic effect and its environmental impact in terms of CO2 emissions. The models are developed to evaluate the costs and CO2 emissions associated with power production, storage, usage and installation of the implemented system. The thesis examines two cases: Case 1, where all the energy is bought from the grid, representing the current energy usage in many churches, and Case 2 which assumes the integration of a solar panel and battery storage system. In terms of economic effects, the thesis reveals that the solar panel and battery storage system results in a negative impact on the church’s costs regarding energy usage. Over a period of 25 years, the church is projected to incur a loss of 956 400 SEK. However, it is worth noting that the direct energy costs when having an implemented solar panel and battery storage system are reduced by 33%, and the sale of surplus solar power generates an income of 1 816 100 SEK. Regarding the environmental impact, the implementation of the solar panel and battery storage system results in increased emissions compared to when only consuming the Swedish electricity mix. This is mainly due to the emissions regarding manufacturing of the solar panel and battery storage system. However, it is visible that the implementation of solely solar panels would lower the system’s total CO2 emissions. The sensitivity analysis demonstrates that replacing the Swedish electricity mix with the EU electricity mix for sold solar energy results in a positive environmental impact. This since the power generated from the solar panels replaces the European electricity mix which has a higher CO2- emission equivalent. This is important to consider since it is impossible to determine which electricity mix the sold PV energy will replace. In conclusion, while the implementation of a solar panel and battery storage system negatively affects the church’s energy costs and leads to increased CO2 emissions in the examined case, there are certain benefits to consider. The reduced energy bought from the grid and lowered direct energy costs, as well as the revenue from selling surplus solar power establishes the potential for the system to provide a positive impact. However, there is a need for advancements in battery technology for this to be a possibility.

As more countries progress towards renewable energy, intermittency in the power system is causing an unreliable power supply. Flexibility solutions from prosumers, which both consume and produce electricity, is one solution to provide stability to the power system. Households with both PV and energy storage are studied for this purpose in this thesis where the following flexibility services for both a household and the electricity grid of Sweden are studied: Increasing PV self-consumption, peak shaving, energy arbitrage at the day-ahead electricity market and providing the frequency regulation reserves FCR-N, FCR-D, aFRR and mFRR. Each house is assumed to have a 10 kW PV capacity and a battery capacity of 7.68 kWh. The services are studied in the software HOMER Grid and are modelled in different scales to see how the load in different aggregated levels affect the services. The case studies are a single family house, an overloaded transformer, an energy community and on a national scale. For the aggregated case studies, the potential capacity for PV will be based on the existing Swedish policies and the number of energy storages will be inspired by one the leading countries in Europe in energy storage installations, Germany. The results showed that for a single household the self-consumption and self-sufficiency increased the most with an addition of a battery. The battery was most efficient in peak shaving and reducing the overall electricity cost when the electricity fee targeted both the electricity consumption during peak hours and the monthly peaks. With this price scheme, the payback time of the battery and PV system is around 14 years. However, when the electricity fee is only targeting the electricity consumption during peak hours, the results showed that the monthly electricity demand peaks actually increase with an addition of a battery. For the aggregated case studies, it showed that decentralized batteries are not as effective in decreasing the electricity demand peaks if the peak lasts more than a few hours. On a national scale the results show that 20% of the aggregated batteries capacity is sufficient to provide around 70-100% of each of the frequency reserves individually. The highest savings are gained for the households when both the primary frequency reserves, FCR-N and FCR-D, are provided by the aggregated batteries together with increasing the PV self-consumption, peak shaving and energy arbitrage. The battery payback time is then reduced to 11 years. Based on a sensitivity analysis, the costs that affects the battery payback the most are the investment cost and the power fee. / I takt med att fler länder använder sig mer av förnybar energi, ökar opålitligheten i kraftsystemet på grund av förnybar energis intermittenta natur. Flexibilitetslösningar från konsumenter som kan både producera och konsumera el är en lösning för att förse stabilitet till kraftsystemet. Hushåll med både PV och batteri studeras för detta ändamål i detta examensarbetet där följande flexibilitetstjänster för både hushållet och elnätet studeras: Öka egenkonsumtionen av solel, kapning av effekttoppar, energiarbitrage samt tillhandahålla frekvensregleringens reserver FCR-N, FCR-D, aFRR och mFRR. Varje hus antas ha en 10 kW installerad kapacitet för PV och 7.68 kWh för batteriet. Tjänsterna studeras i programmet HOMER Grid och modelleras i olika skalor för att undersöka hur elkonsumtionen i aggregerade nivåer påverkar dessa tjänster. Fallstudierna är ett enskilt hus, en överbelastad transformator, en samling av hus samt i nationell skala. För de aggregerade fallstudierna kommer den potentiella kapaciteten för PV baseras på Energimyndighetens målbild för produktion av solel och antalet batterier är inspirerade av ett av de ledande länderna i Europa inom energiinstallationer, Tyskland. Resultaten visar att för ett enskilt hushåll ökar egenförbrukningen och självförsörjningen som mest med både batteri och PV. Batteriet var mest effektiv med att minska effekttopparna och den totala elkostnaden när eltariffen innehöll både effekttariffen och tidstariffen. PV systemet med batteriet hade då en återbetalningstid på 14 år. Med endast tidstariffer visar resultatet att de månatliga effekttopparna ökar med tilläggen av batteriet. För de aggregerade fallstudierna visar resultatet att decentraliserade batterier inte är lika effektiva att minska effekttopparna om de varar mer än några timmar. På nationell skala visar resultaten att 20% av den sammanlagda batterikapaciteten är tillräcklig för att förse cirka 70–100% av varje frekvensreserv. Den högsta besparingen för hushållen för den nationella fallstudien fås när både av de primära frekvensreserverna, FCR-N och FCR-D tillhandahålls av de aggregerade batterierna, tillsammans med tjänsterna för att öka PV-konsumtionen, kapning av effekttopparna och energiarbitrage. Batteriets återbetalningstid reduceras då till 11 år. Känslighetsanalysen visar att de kostnader som påverkar batteriets återbetalning mest är investeringskostnaden och effekttariffen.

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Supercapacitor electrodes were fabricated at a high active mass loading and exhibited enhanced electrochemical capacitance. A conceptually new salting-out extraction processing technique for the synthesis of dispersed Mn3O4-carbon nanotube (CNT) nanocomposites was developed, alleviating the need for hydrophobic solvents. The choice of isopropyl alcohol and NaCl for the extraction process offer advantages of an easy upscaling of this process. The salting out technique was shown to work with Octanohydroxyamic acid (OHA) and Lauryl Gallate (LG) as extractors and dispersants, critical to the success of the extraction. Mechanisms for surface adsorption on Mn3O4 and CNT for both OHA and LG are discussed. A secondary project was also undertaken, to investigate the use of chlorogenic acid and 3,4,5 – trihydroxybenzamide, as co-dispersing agents for MnO2 and CNTs. These molecules are used due to their unique structural properties, which are discussed. The electrodes fabricated using these co-dispersants showed significant increases in their specific capacitances and SEM imaging indicated improved mixing, compared to samples prepared without dispersants. A specific capacitance of 6.5 F g-1 was achieve at low electrical resistance, attributed to the microstructure of electrodes prepared with the co-dispersant molecules. / Thesis / Master of Applied Science (MASc) / The ever-growing realization that our energy consumption as a civilization is not sustainable, has fueled people around the globe to imagine and design new methods of energy storage, in attempts to mitigate this issue. From the foundational works of scientists, it has become clear to see that there is not “one right answer”. Instead, the unique benefits and drawbacks of energy storage technologies should be balanced and applied in situations where their properties permit a high efficacy. The intention of this work is to assist in the development of new materials to be used for energy storage devices called electrochemical supercapacitors. Novel colloidal processing techniques were developed, leading to the fabrication of high-performance electrodes, and providing further insight to the structure-properties relationship of organic extractors and co-dispersing agents for the design of nanocomposites.

Waste heat can be recovered and used in different processes to increase energy efficiency and reduce CO2 emissions. It has become an attractive area of research for scientists and several techniques are being investigated and practiced to recover, store and use waste heat. Thermal Energy Storage is one of the modern techniques that is used to store and use waste heat. Energy can be stored in both sensible and latent forms of heat. Latent heat storage is the most efficient way of storing thermal energy as it provides higher storage density and lower temperature differential between storing and releasing heat. The materials that are used for latent energy storage are termed as Phase Change Materials (PCMs). This thesis work investigates the feasibility of a latent heat storage and heat exchanger performance based on phase change material to recover heat at elevated temperatures. The heat transfer study is done by using state of the art commercial CFD tool. Different model geometries of the Thermal Storage equipped with Shell and tube heat exchanger were built with different pipe configurations. The 1st type of model is a set of three 2D models built in COMSOL Multiphysics. These models constitute a cross section of a small portion of heat exchanger having four 10 mm outer diameter pipes immersed in PCM. Fins were mounted on the pipes to enhance the area for heat transfer and hence the heat transfer rate in modified models. Simulations were carried out for melting and solidification of PCM with these 2D models. After analyzing the results, a 3D model of the small block was created to get more realistic results and analyze the effect of pipe diameter on melting and solidification of PCM. The results of 2D models show the effect of fins on heat transfer rates. The model with eight fins on each pipe shows the best results as compared to other two models. The melting and solidification rates are nearly half for eight fin model as compared to the model without fins. The four fin model shows moderate results but better than the model without fins. The comparison of the results for different diameter pipes in 3D model shows that heat transfer rate increases for increasing diameters of the pipe with same flow rate in the case of melting.

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The adverse effects of climate change, the steady depletion of fossil fuels, and the industrialization of developing countries have resulted in an increased supply and demand of renewable thermal energy. Renewable thermal energy sources like solar thermal energy produce fewer local emissions but have a temporally inconsistent power output. The consumer space heating and domestic hot water demands also vary as a function of time. This creates a mismatch between thermal energy supply and demand. Energy storage is one method of solving this problem. However, conventional methods, like hot water storage, are voluminous and can only store heat for short periods of time. Therefore, compact long-term energy storage technologies, like sorption-based energy storage systems, require research and development. The current work aims to identify and develop suitable materials for sorption-based energy storage systems and to determine the effects of operating conditions on the performance of thermal energy storage systems. A material screening study was performed, which identified MCM-41, SAPO-34, and silica gel, which are all silica-based materials, as suitable materials for sorption-based energy storage. The effects of key operating variables for a silica gel/water-vapour adsorption-based energy storage system were quantified and optimized. The optimized system energy storage density value was nearly double that of unoptimized systems. The effects of salt impregnation were investigated by impregnating different hosts with MgSO4 salt and varying the concentration of the salt in the host material. All composites were stable after three hydration/dehydration cycle. A silica gel/MgSO4 hybrid containing 33 wt% MgSO4 was found to have the highest energy storage density of all of the MgSO4-based composites. Finally, CaCl2, a promising hygroscopic for thermal energy storage was stabilized via impregnation into silica gel and encapsulation in methylcellulose. A novel synthesis technique involving the simultaneous impregnation of silica gel with CaCl2 and encapsulation in methylcellulose produced a stable encapsulated salt-in matrix composite with a high energy storage performance.

The integration of on-site renewable systems with energy storage devices is an important topic in improving energy management for commercial buildings and industrial facilities. Energy storage technologies have the ability to impact the end user’s power reliability while creating measurable energy and cost savings. However, the potential yet remains to increase the application of these systems. To determine the feasibility of renewables and energy storage in commercial and industrial applications, a pre-screening software tool is developed using data-driven algorithms to complete an energy, cost, and carbon savings analysis of storage implementation. A case study of a standalone retail building is also modeled using a comprehensive building energy modeling software program, EnergyPlus, to simulate the energy and cost savings of a solar PV with battery energy storage systems. The work in this project collectively analyzes the future impacts of renewables integrated with energy storage for small-and-medium industrial facilities and commercial buildings.

With a clear correlation between climate change and rising CO2 emissions, decarbonization has garnered serious interest in many sectors to limit the adverse effects of global warming. Heating and cooling systems have been a focus of decarbonization efforts, with heat pumps becoming more popular in the United States and abroad. In fact, heating, ventilation, and air conditioning accounts for nearly 27% of total energy use in the United States [1]. Ground source heat pumps (GSHP) utilizing borehole heat exchangers (BHE) have been shown to be an effective method of electrifying heating and cooling systems, maintaining some of the best performance for any electrified heating and cooling system currently available. Electrification, however, does come with some significant challenges. One of particular importance is the significant increase in peak demand during the heating season, which can result in a serious cost increase for the operator of the electric heating system, as well as adding operational complexities to grid operations by shifting from a summer peak to a winter peak as more heating loads are electrified. Thermal energy storage (TES) has been shown to be effective in mitigating the increase in peak demand that is seen with electrified heating and cooling systems. By storing thermal energy during off-peak hours, demand can be effectively shifted away from the peak hours. In this study, we investigate the potential of a ground source heat pump coupled with a TES system, in the form of water storage tanks, for the University of Massachusetts, as a way of decarbonizing the institution’s HVAC system while minimizing operating and installed costs.