Supplying the global energy demand through renewable sources has never been as accessible as it is now thanks to developments in technology and infrastructure that have enabled low-cost energy production from sources like wind, solar, and hydroelectric power. However, the challenge of integrating variable renewable energy generators into existing grid infrastructure has driven the demand for efficient and inexpensive energy storage technologies to buffer these intermittent energy supplies. Using electrochemical devices like fuel cells and electrolyzers is an attractive approach for both the long- and short-term storage of energy, where excess energy is used to drive the conversion of low energy reactants into high energy, storable fuels which can be consumed when energy supply is low. These devices rely on highly active electrocatalysts in order to drive these reactions efficiently. However, a major challenge for these technologies lies in developing catalysts at commercial scale without compromising their selectivity or lifetime. Several degradation mechanisms like catalyst particle detachment, dissolution, or surface poisoning by undesired species can quickly diminish the activity and selectivity of a given catalyst, and drive up the costs of electrochemical storage systems. Thus, developing catalysts that balance stability, activity, and selectivity is crucial to improve the economic viability of these energy storage devices. One approach towards mitigating the issues of catalyst stability and activity is through adhering a semi-permeable oxide membrane onto the catalyst surface, creating a structure known as an oxide encapsulated electrocatalyst (OEC). These architectures have previously been shown to improve reaction selectivity, poisoning resistance and nanoparticle stability by improving the adhesion of catalyst nanoparticles, preventing poisoning species from reaching the buried catalytic interface, and controlling the local concentrations of reactants as a means of shifting reaction kinetics. Though earlier studies of OECs have demonstrated a wide array of beneficial properties that encapsulated catalyst architectures offer, they have often been based on highly heterogeneous electrodes and been evaluated across a wide range of conditions, which complicates the identification of the mechanisms that underlie these improvements. Currently, little is understood about the governing mechanisms that influence how oxide overlayers interact with – and ultimately affect – the catalyst surface, as well as alter the reactions occurring at the buried interface. Design rules that relate OEC structure to catalytic performance have the potential to greatly accelerate the understanding and development of such architectures, and would allow for more rational, targeted design of OEC structure in a way that would accelerate their application to new electrocatalytic systems.The aim of this dissertation is therefore to systematically investigate the design space of OEC architectures by using well-defined, model planar electrocatalysts in order to draw clear relationships between the structure, composition, and chemical/physical properties of OECs and the resulting effects they have on electrocatalytic performance. Using planar Pt catalysts encapsulated by a thin, highly tunable carbon-modified silicon oxide (SiOₓCy) overlayers, properties like overlayer thickness, carbon concentration, and density can be specifically adjusted during the room temperature photochemical synthesis procedures used for overlayer fabrication. Similarly, changing the composition of the underlying Pt catalyst while keeping overlayer properties constant can provide insights into how catalyst and overlayer materials interact with and influence the structure of one another. Rigorous materials characterization like X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), ellipsometry, and scanning electron microscopy (SEM) coupled with electroanalytical techniques such as cyclic voltammetry and impedance spectroscopy relates observations in the physical and chemical properties of OECs directly to the electrochemical performance of various probe reactions. In Chapter 3, carbon-free, SiO₂-like overlayers of uniform thicknesses were synthesized using a room temperature, Ultraviolet (UV)-ozone photochemical process that allowed for specific control over the resulting overlayer thicknesses, which ranged between 1.8 nm and 18.0 nm. Two different compositions of the planar catalyst substrate were investigated at all thicknesses. The first catalyst investigated was a 50 nm thick, uniform layer of polycrystalline Pt that displayed bulk properties. The second, thinner catalyst substrate was only 3 nm thick, and contained trace quantities of oxophilic Ti species at the buried interface, which migrated to the surface during electrode fabrication. Ultimately it was found that electrodes based on ultrathin, Ti-doped Pt possesses thinner Pt oxide (PtOₓ) interlayers, while exhibiting reduced permeability for Cu²⁺ and H⁺ compared to the bulk Pt species. Thin layer Pt electrodes also demonstrated enhanced retention of the SiOₓ overlayer during stability testing in 0.5 M H₂SO₄, credited in part to the differences in PtOₓ concentration and structure that form at the buried interface as a result of trace Ti concentrations. These observations lead to the study presented in Chapter 4, which sought to assess the impact of chemical and physical overlayer properties on resulting electrochemistry. Compositions of the SiOₓCy overlayer were altered by restricting the exposure of electrodes to the photochemical UV-ozone curing step during synthesis, which was responsible for removing carbonaceous groups in the overlayer’s precursor. Limiting the length of this step between 15 minutes and 120 minutes yielded overlayer with residual carbon concentrations ranging between 30% and 4%, respectively, and demonstrated markedly different physical and chemical properties that impacted species transport through the overlayer. Specifically, the less dense, carbon-rich SiOₓCy layers restricted the flux of H⁺ to the Pt interface during the hydrogen evolution reaction (HER) under transport limited conditions, but displayed high permeability towards dissolved oxygen species for the oxygen reduction reaction (ORR). By contrast, the denser, carbon free SiOx layers blocked oxygen transport almost entirely, but showed limiting current densities for HER that were comparable to an unencapsulated surface. This is believed to occur from the differing transport mechanisms for H⁺ and O₂ through SiOₓ, where the former diffuses through a Grotthuss-type transport mechanism, and the latter through a solution-diffusion mechanism. The high density SiOₓ layers therefore constrain the flux of O₂ due to its lower free volume compared to the carbon rich overlayers, but has a higher concentration of silanol carrier groups that promote H⁺ transport. These results demonstrated the impact that overlayer compositions can have on modulating the local concentrations of reactants, and motivated the further study of OECs on alcohol oxidation reactions (AORs) in Chapter 5. Using the same approach to control overlayer composition detailed above, SiOₓCy overlayers deposited on Pt thin film electrodes were fabricated and their catalytic performance towards the oxidation of carbon monoxide, formic acid, and C₁-C₄ alcohols were assessed. All SiOₓCy - encapsulated electrodes decreased the overpotentials required to oxidize and remove Pt-bound CO species – a poisoning intermediate for a number of AORs, with the largest reductions seen for the carbon poor, SiO₂-like overlayers through a possible Si-OH mediated removal step. Unexpectedly though, electrodes that had the largest reductions in CO oxidation overpotentials showed the least enhancement for AOR activity for all encapsulated samples. These observations suggest that a different rate determining step may be governing the overall reaction rate on encapsulated electrodes over the potential ranges investigated - most likely bond scission of C-H bonds and/or oxidation of formate-based intermediates. Finally, Chapter 6 presents results obtained from state-of-the-art operando ambient pressure X-ray photoelectron spectroscopy (APXPS) studies, which were used to investigate the behavior of SiOₓ overlayers and ions in solution to understand local interactions and electronic effects that arise under wetted, electrochemical operating conditions. It was found that the choice of electrolyte had a clear impact on the overlayer’s response to different applied potentials. Si 1s spectra of the SiOₓ overlayer taken in K₂SO₄ electrolytes showed a slight positive correlation with applied potential that signified a weak electronic interaction between the SiOₓ and the underlying Pt. However, when the anion was switched to Cl⁻, clear, non-linear correlations between the Si 1s binding energy and potential emerged, suggesting a major change in the local chemical and electronic conditions within the overlayer. Analyzing ion concentrations also showed that overlayers demonstrate different distributions and ion rejection properties based on an ion’s valence and size. The mechanism through which these changes manifest is quite complex, as the layers themselves can introduce numerous perturbations in the system by disrupting the electrochemical double layer, introducing steric confinement at the buried interface, or promoting different reaction pathways. Although continued work will be necessary to better de-convolute these effects and develop optimized, concise design rules, the studies presented in this thesis illustrate the unique opportunity that the application of OECs has towards the future customization of electrocatalysts for a wide range of chemistries and applications.

This dissertation investigates the chemical ingenuity into the development of various photoactive supramolecular donor – acceptor systems to produce clean and carbon free energy for the next generation. The process is inspired by the principles learned from nature’s approach where the solar energy is converted into the chemical energy through the natural photosynthesis process. Owing to the importance and complexity of natural photosynthesis process, we have designed ideal donor-acceptor systems to investigate their light energy harvesting properties. This process involves two major steps: the first step is the absorption of light energy by antenna or donor systems to promote them to an excited electronic state. The second step involves, the transfer of excitation energy to the reaction center, which triggers an electron transfer process within the system. Based on this principle, the research is focused into the development of artificial photosynthesis systems to investigate dynamics of photo induced energy and electron transfer events. The derivatives of Porphyrins, Phthalocyanines, BODIPY, and SubPhthalocyanines etc have been widely used as the primary building blocks for designing photoactive and electroactive ensembles in this area because of their excellent and unique photophysical and photochemical properties. Meanwhile, the fullerene, mainly its readily available version C60 is typicaly used as an electron acceptor component because of its unique redox potential, symmetrical shape and low reorganization energy appropriate for improved charge separation behavior. The primary research motivation of the study is to achieve fast charge separation and slow charge recombination of the system by stabilizing the radical ion pairs which are formed from photo excitation, for maximum utility of solar energy. Besides Fullerene C60, this dissertation has also investigated the potential application of carbon nanomaterials (Carbon nanotubes and graphene) as primary building blocks for the study of the artificial photosynthesis process.

In the past decade, research in the field of singlet fission, the process in which one high energy singlet fission exciton forms two lower energy triplet excitons, has seen a resurgence as a process that has the potential to improve solar energy conversion efficiency and contribute to a push for renewable energy. While an impressive motivation, there is still much progress in terms of understanding the physics of the process as well as improving molecular design for actual applications that needs to be made before this motivation can be fully realized. Two significant current hurdles in this field are the extraction of the newly formed triplet excitons from their entangled triplet pair state before recombination, and the lack of stable chromophores with viable energetics for singlet fission and high triplet energies for application purposes. Over the past five years, we have addressed these issues with targeted molecular design. Only a couple of studies have successfully separated the triplet pair state in intramolecular singlet fission systems. We create an intramolecular singlet fission system, a PDI-pentacene-pentacene-PDI tetramer, in which a charge transfer state is utilized to separate an electronically entangled triplet pair. We have also shown that singlet fission can be controlled as well as actually induced in chromophores by employing molecular contortion to tune the energetics. With this work, we have contributed to the motivation of using singlet fission in real-life applications.

Owing to the increased anthropogenic CO₂ emissions over the last several decades, there have been tremendous global efforts in the deployment of renewable energy technologies. However, due to intermittency issues of renewable energy generation and a current lack of reliable long-term energy storage solutions, the development of innovative electrolytes for sustainable energy storage and chemical reactions is an emerging research area. In particular, materials that can host multiple reactions and separations, such as the integrated capture and conversion of CO₂, are highly desired. The direct coupling of renewable energy generation with electrochemical CO₂ conversion to chemicals and fuels is one of the transformative pathways that can aid the global transition to carbon-neutrality, depending on the source of CO₂. However, the current solubility of CO₂ in aqueous electrolytes is quite low (34 mM), thus limiting overall reaction performance. Liquid-like Nanoscale Organic Hybrid Materials (NOHMs) consist of a polymer tethered to a nanoparticle surface and possess a number of favorable properties which are highly desirable in electrochemical applications, including negligible vapor pressure, chemical tunability, oxidative thermal stability and high conductivity. To date, NOHMs have been successfully demonstrated for use as water-lean CO₂ capture solvents, as the polymer canopy can be tuned to capture CO₂ under various sets of operating conditions. Thus, in this dissertation, we have explored the thermal, transport and structural properties of NOHMs in their application as electrolytes enabling the integrated capture and conversion of CO₂. Liquid-like NOHMs functionalized with an ionic bond have been shown to display greatly enhanced oxidative thermal stability compared to the untethered polymer. However, our previous studies were limited in terms of reaction conditions and the detailed mechanisms of the oxidative thermal degradation were not reported. In this study, a kinetic thermal degradation analysis was performed on NOHM-I-HPE and the neat polymer, Jeffamine M2070 (HPE), in both non-oxidative and oxidative conditions. NOHM-I-HPE displayed similar thermal stability to the untethered polymer in a nitrogen environment, but interestingly, the thermal stability of the ionically tethered polymer was significantly enhanced in the presence of air. This observed enhancement of oxidative thermal stability is attributed to the orders of magnitude larger viscosity of the liquid-like NOHMs compared to untethered polymer and the bond stabilization of the ionically tethered polymer in the NOHMs canopy. This study illustrated that NOHMs can serve as functional materials for sustainable energy storage applications because of their excellent oxidative thermal stability, when compared to the untethered polymer. Though NOHMs composed of an ionic bond have demonstrated a high conductivity and an enhanced oxidative thermal stability, their practical application in the neat state is limited by an inherently high viscosity. Thus, when incorporating NOHMs in electrolytes for CO₂ capture and conversion applications, it will be necessary to mix them with a secondary fluid. In this study, a series of binary mixtures of NOHM-I-HPE with five different secondary fluids – water, chloroform, toluene, acetonitrile, and ethyl acetate – were prepared to reduce the fluid viscosity and investigate the effects of secondary fluid properties (i.e., hydrogen bonding ability, polarity, and molar volume) on their transport behaviors including viscosity and diffusivity. Our results revealed that the molecular ratio of secondary fluid to the ether groups of Jeffamine M2070 (λSF) was able to describe the effect that secondary fluid has on transport properties. Our findings also suggest that in solution, the Jeffamine M2070 molecules exist in different nano-scale environments, where some are more strongly associated with the nanoparticle surface than others, and the conformation of the polymer canopy was dependent on the secondary fluid. This understanding of the polymer conformation in NOHMs can allow for the better design of an electrolyte capable of capturing and releasing small gaseous or ionic species. To further investigate the effect of the bond type on the thermal stability as well as the structural and transport properties of the tethered HPE, NOHMs were synthesized by tethering HPE to SiO₂ nanocores via ionic (NOHM-I-HPE) and covalent (NOHM-C-HPE) bonding at two grafting densities. In the neat state, NOHM-C-HPE displayed the highest thermal stability in a nitrogen atmosphere, while NOHM-I-HPE was the most thermally stable under oxidative conditions. Small-angle neutron scattering (SANS) revealed the presence of multiple types of Jeffamine M2070 (HPE) polymers in aqueous solutions of NOHM-I-HPE (i.e., tethered, interacting and free), whereas only tethered HPE chains were observed in NOHM-C-HPE systems. Moreover, the SANS profiles identified clustering of NOHM-C-HPE in dilute aqueous solutions, but not in the corresponding NOHM-I-HPE samples, suggesting that the different types of HPE chains in solutions of NOHM-I-HPE may be crucial to the uniform NOHMs dispersion. Additionally, our investigation of the viscosity and conductivity of different NOHM-based electrolytes revealed that in response to ionic stimulus, the covalently tethered HPE remained fixed at the nanoparticle surface, whereas there was a partial disassociation of HPE chains from the nanoparticle in NOHM-I-HPE. Overall, the results of this study highlight that NOHMs are highly tunable materials whose properties can be strategically altered by changing the bond type linking the polymer to the nanoparticle, as well as grafting density. Finally, two types of aqueous NOHM-based electrolytes were prepared to study the effect of CO₂ Though NOHMs composed of an ionic binding energy (i.e., chemisorption vs. physisorption) on the CO₂ reduction reaction (CO₂RR) over a silver nanoparticle catalyst for the production of syngas, a mixture of H₂ and CO, at various ratios. Poly(ethylenimine) (PEI) and Jeffamine M2070 (HPE) were ionically tethered to SiO₂ nanoparticles to form the amine-containing NOHM-I-PEI and ether containing NOHM-I-HPE, respectively. At less negative applied potentials, PEI and NOHM-I-PEI based electrolytes produced CO at higher rates than 0.1 molal. KHCO₃ due to their enhanced conductivity, while at more negative applied potentials, H₂ production was significantly favored because of the electrochemical inactivity of carbamates and catalyst-electrolyte interactions affecting the selectivity of CO₂RR. Conversely, due to their lower ionic conductivity, HPE and NOHM-I-HPE electrolytes displayed poor CO₂RR performance at less negative applied potentials. At more negative applied potentials, their performance approached that of 0.1 molal. KHCO₃, highlighting how the polymer functional groups of NOHMs are critical to the tunable production of syngas. The results of this study illustrate that more conductive polymer canopies with intermediate binding energies for CO₂ should be explored to improve the performance of NOHM-mediated CO₂ reduction. Altogether, the results of this dissertation demonstrate the ability of NOHM-based electrolytes to be used for systems enabling the integrated capture and electrochemical conversion of CO₂. The polymer grafting density, polymer canopy functionalities, bond type linking the polymer to the nanoparticle, secondary fluid selection and ionic stimulus were all found to play an important role in determining the thermal stability of NOHMs and/or the structural and transport properties of the corresponding NOHM-based fluids/electrolytes, thus highlighting the tunable nature of this class of materials. Additionally, the findings from this dissertation can be applicable to a wide range of energy and environmental applications that require the design and development of novel electrolytes.

Energy Management strategy for sustainable regional development has been selected as the topic of my research due to the fact that energy demand alongside with energy dependency have been continuously growing from a long term perspective. Sustainable development is defined by three imperatives – energy efficiency, ecology and security. Review of the current state and analysis of historical trends in Energetics at global and regional level are covered in this research. Results of the Multi-Criteria Decision Analysis introduce a set of implications and recommendations for Energy Management strategy in the Czech Republic.

Thesis (M.A. (Health Sociology))--University of the Witwatersrand, Faculty of Humanities, 2016. / This study examines use of different energy sources by a poor community of the Ramaphosa Informal Settlement in Gauteng Province, South Africa. The purpose of this study was to investigate the reasons behind continued use of biomass fuel (plant or animal material, wood, charcoal) for cooking and space heating by poor residents. The research questions are: What informs the informal settlement residents’ use of certain energy sources for cooking and heating over other types? Where residents possess knowledge of the harmful effects of continued use of an energy source, yet continue to use it, what are the reasons for this? Whose responsibility does it become to collect a chosen energy source, and how is it collected? The consequences of indoor air pollution vary from short-term – eye and throat irritation – to long-term effects – respiratory disease and cancer. Exposure to high levels of some pollutants, such as carbon monoxide, can even result in immediate death. An exploratory empirical research was performed using mixed qualitative and quantitative methods using data on time-activity patterns collected from eleven households by means of semi-structured interviews, observations, focus group discussions and expert interviews. The results show that the respondents in the researched areas of Reserve and Extension two in Ramaphosa Informal Settlement use a total of thirteen different energy sources to meet their fuel needs. Although possessing the necessary knowledge on negative effects of indoor air pollution, the respondents lack sufficient resources to make decisions that would help improve their conditions regarding effects of air pollution. In thirty of the fifty respondents women and girls collect fuel and only in the remaining twenty wherein electricity, paraffin and liquid petroleum gas (LPG) are used, do men and boys become responsible for fuel collection. In the absence of electricity, respondents reported preferences for LPG, however, the prohibitive costs of the capital outlay of the latter energy source makes it unaffordable to more than half of the respondents. The major finding in this report is that whilst some of the respondents think that electricity remains a key barrier to improving their socio-economic development and well-being, twenty of the fifty respondents who exclusively rely on government grants do not think so. Electricity, although an absolute necessity in the researched areas, is not a sufficient condition for avoidance of effects of indoor air pollution for the poor communities. This was demonstrated by the five respondents who have electricity but alternate its use with coal and firewood. The high cost of electricity means that poorer communities will continue to rely on the less expensive bio-mass fuel – risking their lives in the process – even when electricity is available. Respondents reported difficult conditions under which they live which are shaped by broader sets of unresolved structural aspects in the form of economics, social policies, and politics. / GR 2017

A research report submitted to the Faculty of Humanities, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Arts. March 2016. / Energy poverty is one of the developmental challenges facing the world today. Even though energy poverty affects both men and women, its impacts on the two are different. This is due to diverse gender roles which result in different energy needs. The burden of energy poverty lies mainly on women. Growing evidence indicates synergies between energy use and intra-household relations. An understanding of intra-household relations which culminate in inequalities in energy access is therefore essential in ensuring universal access to energy. This study aimed at exploring the relationship between renewable energy and gender relations at household level. Using the Gender Relations theoretical framework, the study explored the relationship between intra-household gender relations and adoption of RETs. It sought to assess the extent to which RETs affect the division of labour, who makes decisions to adopt RETs and who benefits from them. The study was conducted in Malawi using a qualitative research design. Participant observation and narrative in-depth interviews were used to explore the intra-household decision making processes which influence adoption of RETs. Findings indicated that men and women in Malawi have distinct gender roles which influence their bargaining power. Both social and economic resources were found to have a significant influence on women’s decision making power. The findings further indicated that men dominated decisions on adoption and utilisation of RETs. Women’s lack of economic resources and technical knowledge were found to be barriers in their access of RETs. Findings demonstrated that RETs greatly benefited both men and women, however, men sometimes controlled how the RETs were used which lessened the benefits to women. Though not conclusive, findings indicated that RETs may increase women’s burdens / GR2017

As the cost of variable renewable energy resources like wind and solar decline rapidly the major barrier to decarbonization of the electrical grid becomes that of energy storage. Current storage technologies are much too expensive to justify widespread adoption and it is unclear what type of technology is even capable of fulfilling this role. Flow batteries are an often proposed technological solution to this problem but they are plagued by high cost and reliability issues due to the expensive and complex balance of plant included in the system design. In this work a new design for a gravity driven flow battery is explored which is capable of drastically lowering the cost of flow batteries by removing the pumps and membranes and replacing their function with density stratification and flow driven by the density change of the electrode reactions. A design for a zinc-bromine battery which makes use of this free convection during operation is explored. The system is studied through construction of prototype cells, exploration of key design variables, and a techno-economic analysis of the technology is performed showing cost viability. The free convection phenomenon which underlies the battery operation is expanded upon by connecting non-dimensional correlations in heat transfer with electrochemical transport equations in order to create predictive understanding of flow behavior based on system composition. This correlative understanding is used to construct a model of a zinc-bromine gravity driven flow battery. This model shows results which align with experimental data and gives insight into the complex transport dynamics of the system.

Yes / Daily increasing use of tidal power generation proves its outstanding features as a renewable source. Due to environmental concerns, tidal current energy which has no greenhouse emission attracted researchers’ attention in the last decade. Additionally, the significant potential of tidal technologies to economically benefit the utility in long-term periods is substantial. Tidal energy can be highly forecasted based on short-time given data and hence it will be a reliable renewable resource which can be fitted into power systems. In this paper, investigations of effects of a practical stream tidal turbine in Lake Saroma in the eastern area of Hokkaido, Japan, allocated in a real microgrid (MG), is considered in order to solve an environmental/economic bi-objective optimization problem. For this purpose, an intelligent evolutionary multi-objective modified bird mating optimizer (MMOBMO) algorithm is proposed. Additionally, a detailed economic model of storage devices is considered in the problem. Results show the efficiency of the suggested algorithm in satisfying economic/environmental objectives. The effectiveness of the proposed approach is validated by making comparison with original BMO and PSO on a practical MG. / Iran National Science Foundation; Royal Academy of Engineering Distinguished Visiting Fellowship under Grant DVF1617\6\45

The use of biomass as a renewable fuel source can help the United States reduce its dependence on fossil fuels, especially in providing affordable heat for many middle- and low-income households. However, residential wood combustion (RWC) releases pollutants that can negatively impact the environment and human health, especially for those living in the vicinity of wood-burning locations. Current compliance testing methods are insufficient in capturing the actual in-use emissions of residential wood heaters because they do not represent real-life use, leading to higher emissions during actual use. This thesis investigates emissions during realistic operations of wood-fired heaters to identify and quantify the majority of emissions and ways to minimize such emissions. The study focuses on investigating eight different woody biomass fired heaters, including three pellet stoves, a pellet boiler, two wood chip-fired hydronic heaters, and two outdoor cordwood fired hydronic heaters. This research contributes a new knowledge on the impact of combustion strategies, fuel type, and control strategies to minimize emissions. The obtained data can provide information to manufacturers, policy makers, and consumers, guiding low-emission and more efficient use of wood-fired heating devices. In all chapters, variability was evident due to burn phase, fuel type, and operation. The results from the pellet stoves showed that even while using a homogeneous fuel, different burn phases produce different emissions than the overall period. For the pellet boiler studies, the highest efficiencies were achieved during the high load, steady state tests. The burn phase also affects emissions from woodchip boilers, where low output periods are significantly higher in terms of emissions compared to high output periods. Each individual burn phase of the duty cycle produced different emissions in cordwood testing, with steady-state phases having the lowest emissions and highest efficiency. The variability in emissions from different burn phases is a crucial factor in evaluating the performance of wood-burning appliances. Lower moisture content fuels were found to have better performance in terms of PM emissions and efficiency. Fuel type can impact emissions, but it may be overshadowed by burn phase and technology. Relatively high emissions were often related to low or incorrect air-to-fuel ratios. Gasification techniques used in some woodchip boilers during low output periods significantly increased efficiency and reduced CO emissions. Additionally, gasification techniques used during high burn steady states with wet fuel chips resulted in a 77% reduction in PM emissions. Comparing all the primary heaters studied in this thesis, in terms of PM emission output, showed the units that used gasification, integrated catalysts, or thermal storage had the lowest emissions. The results of the study are compiled into data sets that give a more accurate picture of real-world operation of wood-fired heaters that will benefit air quality modelers and policy makers. Such emission data for various biomass heaters in EPA’s AP-42, under realistic operating conditions, currently either does not exist or is limited. Additionally, this research identifies the most important parameters that need to be included in the development of high-resolution models, optimizing the performance of wood-fired devices and supporting the transition from current compliance testing to more realistic testing. In conclusion, this work provides new insights into the performance and emissions of wood-fired heaters during realistic operation. The results of the study can help manufacturers optimize their products for real-life performance and help policy makers and consumers make informed decisions regarding low-emission and more efficient use of wood-fired heating devices. The study highlights the importance of capturing transient phases and the impact of fuel type and control strategies on minimizing emissions.