Dissertations / Theses on the topic 'Dwellings – Energy consumption – Nigeria'

Res-IRF is an energy-economy model of heating consumption in French dwellings developed at CIRED and calibrated against 2012. It is meant to project the evolution of the building stock and the heating demand by 2050 in response to socio-economic parameters, such as energy price and population, and public policies, such as thermal regulations or incentives for renovation. Res-IRF captures the relevant determinants of household decisions related to energy efficiency improvements and energy demand (sufficiency). The aim of the work presented in this report is to calibrate the model against a past year, to run it from this start date to 2012, and to compare the simulation results with observed data on this period. After an overview of the French residential sector in the last 40 years, this report aims at presenting the model and how it was calibrated against year 1984 and adjusted to the past situation of the building stock. Then, the results of a sensitivity analysis on key parameters of the model are compared to reality and it is discussed how the model can be improved to fit the data better. The main results show that the model accurately replicates the evolution of the building stock until 2012. However, the results do not fit well the data of repartition of heating fuels, especially for fuel oil and natural gas. This may be due to the structure of the model which allows fuel switch only for renovating dwellings; then it could miss possible fuel switches from fuel oil to natural gas without renovation due to the expansion of the natural gas network in France between 1980 and 2000. Furthermore, the actual unit consumption, which is a key output of the model, is well replicated by the model, with an error of 5 to 10%.
Res-IRF är en energi-ekonomi modell av värmebehovet i franska byggnader utvecklad av CIRED och kalibrerad mot data för 2012. Det är avsett att förutsäga utvecklingen för byggnadsbeståndet och värmebehovet fram till 2050 med utgångspunkt från socio-ekonomiska parametrar såsom energipriser och befolkningsmängd, politiska beslut som regleringar rörande uppvärmningssektorn och incitament för renoveringar. Res-IRF fångar upp de relevanta faktorer som påverkar hushållens beslut relaterade till förbättringar av energieffektiviteten och energibehoven. Målet med arbetet som presenteras i denna rapport är att kalibrera modellen mot ett redan passerat år, att köra modellen från startåret till 2012, och att jämföra simuleringsresultaten med verkliga observationer för denna period. Efter en översikt över den franska bostadssektorn de senaste 40 åren, följer i rapporten en presentation av modellen och hur den kalibrerades mot året 1984 och sedan anpassats till det dåvarande läget i byggnadsbeståndet. Därefter jämförs resultaten av en känslighetsanalys av nyckelparametrar i modellen med verkligt utfall och en diskussion följer om hur modellen kan förbättras för att bättre passa verkliga data. Huvudresultaten visar att modellen på ett korrekt sätt avbildar utvecklingen av byggnadsbeståndet fram till 2012. Däremot ger resultaten inte god överensstämmelse vad gäller fördelning av bränslen, speciellt inte fördelningen mellan olja och naturgas. Detta kan bero på modellens struktur, som tillåter bränslebyte bara vid renovering; därmed missar den bränslebyten som görs utan samtidig renovering, som tillkommit på grund av utbyggnaden av naturgasnäten i Frankrike mellan 1980 och 2000. Vidare visar modellen god överensstämmelse vad gäller energitillförsel per enhet, vilket är en nyckelparameter bland resultaten från modellen. Denna parameter predikteras med ett fel av 5 till 10%.

Energy including electricity plays a significant role in the economic development of a country as it enhances the productivity of capital and labour. Many of the developing countries are plagued with energy problems: predominantly by their over dependence on low quality, traditional fuel and the over reliance on imported commercial fuel-oil. Some of the problems associated with energy forecasting in developing countries may include lack/insufficient data. This study was conducted in two phases and begun with the reviewing of literature on energy and the different determinants of energy in a developing nation. Access to electricity is particularly crucial to human development as electricity is, in practice, indispensable for certain basic activities, such as lighting, refrigeration and the running of household appliances, and cannot easily be replaced by other forms of energy. Yet, many developing countries are faced with the challenge of providing adequate and modern energy services to its communities, which in turn is expected to improve the standards of living through increased income and employment generation. The second phase of this research was developing and modelling demand for residential electricity using secondary data. This task was challenged by the inadequacies in the quality and availability of data on the one hand and the unrealistic assumptions of many existing models used to predict energy consumption in developing countries on the other. The contribution of this thesis here was also to consider a wider set of factors that are traditionally used in energy modelling. Many previous studies had been focusing on income as a determining factor affecting demand for energy (for example, the energy ladder theory). However, this study found that there are many other factors such as the informal economy (activities within the economy that is not declared or included in the gross domestic product of a nation), urbanisation and transformation from rural to urban areas that may have a significant impact on how energy in the residential sector is demanded. It was therefore important to exceed beyond unquestioned assumptions of the orthodox belief and to focus on the processes of urbanisation and change as realities facing many developing countries. In order to develop a deeper understanding and analysis of the residential energy sector, this research offered a thorough examination of the literature on modelling techniques, their underlying theories and assumptions and the choice of variables and measurements. This led to the selection and identification of the factors influencing energy demand and helped determine the modelling techniques finally used in the thesis. In order to achieve the aims of the study, a mixed method approach was adopted. The use of quantitative (secondary and primary) data as well as qualitative (case studies, face-to-face interviews and semi-structured questionnaires) helped the researcher to test a number of established hypotheses and offer a deeper understanding of the questions in hand. Through using various statistical techniques the study was able to examine the relationship between different selected variables which can help forecast the demand for residential energy. Furthermore, with the use of a structured questionnaire survey of the households, socio-economic data were collected from 501 households in Ibadan metropolis in Nigeria which provided the premise for understanding factors other than income that are responsible for determining the type and level of energy consumed in households. The analysis involved the use of ordinal regression as households neither use the same fuel in the same combination or at the same level. In sum the thesis made the following contributions: i) a better understanding of households energy consumption which have implications for a successful energy analysis for households in Nigeria as well as other developing countries; ii) a tested methodology for analysing the determinants of household energy. The results showed that household income and price of energy do not have a significant effect on the consumption of energy in the household. It was rather factors such as the location of the property, the ownership status of the property and the expenditure spent on energy that seemed to be more relevant in determining the consumption of energy in the households. The evidence from the study suggests that there is divergence in the energy need of households and hence the different determinants for various fuels. The concept of energy ladder as suggested by earlier researchers was not confirmed by the findings. Instead the study supported the work carried out by Heltberg (2003) and confirmed that income alone may not be sufficient to determine the consumption of energy by a household. It was rather factors such as the location of the property, the ownership status of the property and the expenditure spent on energy that seemed to be more relevant in determining the consumption of energy in the households. This research also highlighted the importance of the various socio-cultural factors that affects the consumption of energy within the household, and in the same vein, it showed that economic contribution is not the sole determinant in the choice of fuel energy.

This study examines the change in the space heating energy consumption and its associated cost and carbon emissions following retrofit energy efficiency upgrade. 3 to 4 week fuel consumption and temperature data were collected from some 1500 dwellings over two successive winters in 2001/2002 and 2002/2003. The case study dwellings were occupied by elderly householders or families with young children and were either awaiting or had received a combination of draught proofing, insulation and central heating measures under England’s Warm Front Scheme. The findings show that the Warm Front Scheme resulted in a mean increase of 1.6 °C in indoor temperature and a mean increase of 12 % in fuel consumption. Nevertheless, the switch from electricity to gas for space heating following the introduction of gas boilers resulted in a mean reduction in heating cost by 7 %. The scheme was found to have negligible impact on carbon emissions. Characteristic differences were observed with individual energy efficiency measures. Central heating resulted in the greatest temperature rise by 2.3 °C followed by insulation by 0.7 °C with a negligible impact from draught proofing. Clear evidence was found in householders increasing the demand temperature following the introduction of a central heating system while no evidence of this was found following the introduction of insulation. In terms of energy use, insulation resulted in a mean saving of 9 % but fell short by 74 % to 84 % from the theoretical prediction while central heating resulted in a mean increase of 29 % in the energy consumption. Draught proofing was found to have little impact on the energy use. When examined in terms of energy cost, insulation and central heating all resulted in mean cost savings of 13 % and 9 % respectively but falling short by 55 % to 72 % and 57 % to 82 % compared to their respective theoretically predicted mean cost savings. Insulation also resulted in mean carbon emissions saving of 13 % but fell short by 56 % to 73 % from the theoretical prediction while central heating resulted in insignificant carbon emissions saving. Combining insulation with central heating was found to be beneficial in terms of mitigating the energy consumption rise associated with central heating from 29 % down to 16 % while maximizing the temperature gain by as much as 3.1 °C.

This paper explains typical knee wall construction and insulation in homes in Indiana and demonstrates the energy inefficiencies caused by such methods. Literature research gives examples of possible opportunities for changing the standard methods of knee wall construction and insulation. The methodology of the study is explained, as is energy intensity (EI) — the main evaluation tool used in this paper. EI allows a researcher to compare homes of different sizes in different locations. Overall, the study shows that homes whose knee walls have an air barrier backing use less energy than homes without knee walls. Additionally, as expected, homes with improperly constructed knee walls use the most energy. Finally, the paper contains recommendations about what methods might be used to change the standard practices involved in building and insulating knee walls.
Department of Urban Planning

The perception of thermal comfort is an important factor influencing the acceptability of residential heating strategies. The perceived thermal comfort may affect a person's inclination to try a strategy or to use it on a long-term basis. In the study, perceived thermal comfort was assessed in relation to room temperature, humidity, clothing worn, preferred room temperatures, personal control over the temperatures, and energy consumption. The relationships among these variables were examined for five families participating in a live-in study comparing five residential heating strategies. The strategies tested included closing off bedroom vents/doors, setting the thermostat at 65°F, and the use of a solar greenhouse and a woodstove as supplemental heat sources. The families lived in a retrofitted solar test house for a period of four to six weeks. The house was equipped with a computer which monitored 37 channels of information at ten-second intervals and recorded the data hourly. The data collected included temperatures in every room, inside and outside humidity, wind velocity, and other variables that interplay in comfort levels and energy use. The ten adult respondents completed daily and weekly questionnaires containing Likert-type scales of thermal comfort and checklists of clothing worn. The results suggest the following conclusions: 1) the use of a residential setting to measure thermal comfort under varying environmental conditions can be successfully accomplished, 2) psychological variables such as personal control should be considered and tested by persons involved in standards development for the thermal environment, 3) the ability and experience of the persons to use a strategy can affect the achieved energy saving benefits of the strategy, 4) personal preference in the amount of personal effort a person is willing or able to give will impact on the decision on whether to use certain strategies, 5) heating strategies that can produce a direct source of heat or at least some warmer areas were rated higher by the project participants, and 6) weather can play an important role in the effectiveness of the solar greenhouse as a heating source.
Ph. D.
incomplete_metadata

Installation and utilization of residential distribution transformers has not changed substantially over a long period of time. Utilities typically size their transformers based on a formula that takes into account broadly what types and how many dwellings will be connected. Most new residential dwellings feature 200 Amp service per household with an anticipated energy demand of under 20,000 kWh per year. Average electrical energy consumption varies from state to state but averages to 11,280 kWh per year. Energy demand is expected to fall into a typical residential load curve that shows increased demand early in the morning, then decreasing during the day and another peak early to late evening. Distribution transformers are sized at the limit of the combined evening peak with the assumption that the transformer has enough thermal mass to absorb short overloads that may occur when concurrent loading situations among multiple dwellings arise. The assumption that concurrent loading is of short duration and the transformer can cool off during the night time has been validated over the years and has become standard practice. This has worked well when dwelling loads follow an averaging scheme and low level of coincidence. With the arrival of electric vehicles (EV's) this assumption has to be reevaluated. The acquisition of an electric vehicle in a household can drive up energy demand by over 4000 kWh per year. Potentially problematic is the increased capacity of battery packs and the resulting proliferation of Level 2 chargers. The additional load of a single Level 2 charger concurring with the combined evening peak load will push even conservatively sized distribution transformers over their nameplate rating for a substantial amount of time. Additionally, unlike common household appliances of similar power requirements such as ovens or water heaters, a Level 2 battery charger will run at peak power consumption for several hours, and the current drawn by the EVs has very high levels of harmonic distortion. The excessive loading and harmonic profile can potentially result in damaging heat build-up resulting in asset degradation. In this thesis I present a device and method that monitors pole mounted distribution transformers for overheating, collect and wirelessly upload data and initiate commands to chargers to change output levels from Level 2 to Level 1 or shut down EV charging altogether until the transformer returns into safe operational range.

Energy demand reduction has become a global issue involving all countries, including China. As major energy consumers in today s society, the need for buildings to be built and operated more energy efficiently is well recognized. In 1995, the national standard on building energy efficiency in China (JGJ 26-95) was refined and updated to become the new residential Buildings standard (JGJ 26-2010) published in 2010. In the new version, many changes have been made to support the construction of more energy efficient buildings in China. For example, in the new standard, all buildings are highly recommended to install personal control on the heating system, such as by Thermostatic Radiator Valves (TRVs), together with pay for what you use tariffs. Previous practice comprised uncontrolled heating with payment based on floor area. In order to reduce building energy consumption, Chinese government has revised the Chinese building design standard. In the new guide the use of individual room temperature control is highly recommended for new and refurbishment buildings. However, evidence to quantify the extent to which this improvement impact upon on the building energy consumption is currently lacking. This thesis evaluates the impact of updated building design standards on thermal conditions and energy consumption in Chinese residential buildings. In order to evaluate the impact on the building energy consumption, two types of residential buildings have been chosen, one complying with the old Chinese building design standard, while the other complies with the new standard. The study was carried out in seven apartments in each type of building, a total of fourteen apartments and comprised with a longitudinal monitoring of indoor air temperature, outdoor air temperature, window position and energy consumption of each apartment. The impact of the new design standard has been evaluated in relation to a number of aspects, that include building construction, indoor thermal environment, occupant behaviour, thermal comfort and building energy consumption. It is concluded that updating the building design standard has had a positive influence on the building conditions and energy consumption. Furthermore, a thermal comfort survey was carried out in both new and old apartments according to updated standards. The results show that the Predicted Mean Vote (PMV) model has a efficiently adequate predictor of occupants thermal comfort in both type of apartments. Thereby allowing confirmation that the new control refine did not compromise on thermal comfort. The percentage of acceptable of occupants is higher in new apartments compared with the old apartments.

Philosophiae Doctor - PhD
South Africa was considered to have attained universal access to modern energy, this meant that the number of households that have access to energy had successfully increased from 30% in 1994 to 87% in 2012. However, the situation in Nigeria is such that electricity generating figures are very poor and they cannot meet half of the demand of Nigerian households, and the majority of the states have challenges in accessing sufficient fossil fuels. However, recent trends in domestic energy consumption for both countries are becoming biased in favor of fuel-wood energy especially among low-income households, “descending the energy ladder”.

This study explored energy-related attitudes and energy-saving behaviors that are no- or low-cost and relatively simple to perform. This study relied on two data sources: a longitudinal but cross-sectional survey of 4,102 U.S. residents (five biennial waves of this survey were conducted from 2002 to 2010) and a 2010 cross-sectional survey of 2,000 California residents. These two surveys contained data on two no- and low-cost behaviors: changing thermostat setting to save energy (no-cost behavior) and CFL installation behavior (low-cost behavior). In terms of attitudes, two attitudinal measures emerged from these data following a Cronbach's alpha and Confirmatory Factor Analysis (CFA): the pro-environmental attitude and concern for the energy use in the U.S. society. These two attitudes, along with other socio-demographic and external factors (home ownership, weather, price of energy, etc.), were examined to assess whether attitude-behavior relationships persisted over time, were more prominent across certain groups, or were constrained by income or other socio-demographic factors. Three theoretical viewpoints of how attitudes may relate to behavior guided the analysis on how attitudes and contextual factors may inter-relate either directly or through a moderator variable to affect thermostat-setting and CFL installation behavior.

Results from these analyses revealed four important patterns. First, a relationship between the pro-environmental attitude and the two behaviors (thermostat-setting and CFL installation behavior) was weak but persistent across time. Second, financial factors such as income moderated the pro-environmental attitude and CFL installation relationship, indicating that the pro-environmental attitude could influence the behavior in those situations where financial resources are sufficient to comfortably allow the consumer to participate. Third, this study documented that most people reported changing thermostat settings to save energy or having one or more CFLs in their homes. This finding suggests that organizations, policy makers, or energy efficiency program administrators may want to assess whether they should pursue these two behaviors further, since they appear to be very common in the U.S. population. Last, this study showed that thermostat-setting and CFL installation behavior have multi-factorial influences; many factors in addition to attitudes were significantly associated with these behaviors, and all these factors together explained no more than 16% of behavioral variance. This suggested that if energy-saving behaviors are a function of many different variables, of which none appear to be the "silver bullet" in explaining the behaviors (as noted in this study), then policy analysis should explore a broader number of causal pathways and entertain a wider range of interventions to influence consumers to save energy.

Buildings account for about 40% of global energy consumption and contribute 30% of all CO2 emissions. This research project investigated extant office building development in Abuja, Nigeria with a view to establishing typical energy performances. Energy end uses were critically analysed to identify energy saving potentials. The research evaluated design variables that can be used to facilitate low energy building design and determine enhanced performances in the Nigerian and regional context. The research initially adopted a case study approach that involved fieldwork surveys and walk-through energy audits in which 22 office buildings were investigated belonging to four performance based categories developed for the research. Also, based on a building inventory survey form developed for this research, building information obtained included the buildings physical components, energy use management and energy end uses. This enabled typical energy performances of the office building categories to be deduced using three widely used indicators; the Energy Use Index (EUI), the Energy Cost Index (ECI) and the Carbon Emission Index (CEI). Also, disaggregated energy end use showed an average distribution pattern of air conditioning, lighting, equipment and building services in the ratio 59%, 15%, 43% and 4% respectively. This showed the potentials of energy savings by reducing cooling load. With the aid of computer based simulation (using IES-VE software) the research further evaluated the impacts of nine architectural design variables (identified from design guidance for low energy buildings as well as design recommendations for tropical climates) on building energy consumption using simplified models of the case study office building categories. From all these, an impact hierarchy of the design variables was deduced and the appropriate low energy design strategies were developed. This showed potential energy savings of up to 20% was achievable. Also benchmarks for enhanced building performance targets for all the categories were proposed for the furtherance of a sustainable built environment in a developing world context.

This thesis investigates the impact of physical planning policy on combined transport and dwelling-related energy use by households. Separate analyses and reviews are conducted into dwelling-related and transport-related energy use by households, before a model is developed to investigate the city-wide implications of different land-use scenarios in Sydney, Australia. The analysis of household energy use in Chapter 3 suggests that medium density housing (i.e. lose-rise apartments, townhouses, and terraces) is likely to result in the lowest per-capita energy use, while also allowing for sufficient densities to make frequent public transport service viable. The analysis of transport energy in Chapter 4 confirms that increasing urban density is associated with decreased car ownership and use, independent of other factors. However, land use changes alone are likely to result in modest changes to travel behaviour. The results of the scenario modelling in Chapters 7-9 support the view that changes to land use alone can reduce household energy consumption, but the changes, even over a long time period (25 years) are small (~0-10%) for all but the most extreme land-use policies. Instead, a coordinated (land-use/transport and other policy levers) approach is much more effective. The results confirm that it is transport energy that is most sensitive to planning policy, but that a combined consideration of dwelling-related and transport-related energy use is still useful. The micro-simulation model developed to assess the impact of different land-use planning scenarios allows the establishment of a lower-bound estimate of the effect that housing policy has on household energy use, assuming ‘business as usual’ transport policy, household behaviour, and technology.

The study investigated critical factors that affect office building energy performance in Nigeria compared to the UK; and developed an assessment and benchmarking framework for identifying appropriate operational, technical and behavioural solutions to improve energy performance of existing buildings. The mixed methods, multiple-case study approach was adopted for collecting energy used data from selected ten existing office buildings in both countries. A literature review was used to established worldwide view on factors influencing building energy performance. The selected factors were transformed into theoretical framework variables. These variables were further translated into an operational sustainability as an audit tool for establishing initial cases’ energy performance assessment. Operational energy data from case buildings were collected via: electricity bills, meter readings and fuels’ receipts/ invoices. Also, three online questionnaire surveys: a post occupancy evaluation for the assessment of comfort and energy performance of the ten buildings; a survey of facilities managers’ perception of managerial, operational and technical issues; and a model validation survey for confirmation of established factors from earlier two surveys, was employed. Likewise, a one-on-one semi-structured interview was utilised for owners/ managing directors and facilities managers of case buildings. Whilst, Structural equation modelling, analysis based on the validation survey, was employed to examine the dependencies and interdependencies of the critical factors. The IBM, SPSS 22 and AMOS 23 were used for the exploratory factor analysis and confirmatory factor analysis based on maximum likelihood estimations; which produced validated measurement and structural models. The study identified 52 critical factors that were transformed into 17 most critical factors impacting building energy performance in Nigeria and UK. The model identified new indicators for building energy performance; and established causality between building energy performance, management policy, operations and strategic driver as standard metrics for building energy efficiency assessment and benchmark. Likewise, it established a strong network of strategic drivers underpinned by strategic sustainability policy/ facilities management as mediator. The Nigeria buildings’ performance was found to depend largely on the context in which they operate in apart from the weather. Whereas, validity of climate variability as a critical factor of the UK case buildings’ energy performance was established. Institutionalised regulatory framework is suggested for Nigeria and sub-Saharan Africa countries as a control measure. The building energy performance model and its operational sustainability tool could be used as energy assessment and benchmark. It serves as a dashboard that encapsulates the energy efficiency performance and the absolute impacts of intervening factors. Finally, it presents insight into a critical path for intervention schemes as implemented; and the use of the strategic sustainability policy/ facilities management as mediation for improving building energy performance.

The thesis addresses the contributions of urban geometry under hot-arid summer condition in the Riyadh City, Saudi Arabia, toward both; the development of comfortable microclimate conditions in outdoor spaces at pedestrian level, and energy consumption from urban dwellers. The urban geometry is described in this thesis by three variables, including building height to street width aspect ratios (H/w), sky view factor (SVF) at pedestrian level, and the solar orientations of the canyons. These three variables are used in this study to investigate their influence on the microclimate conditions and the associated outdoor thermal comfort and energy consumption from urban dwellers. The work intends to shed light on the existing geometries of different urban locations in Riyadh City and the associated thermal conditions, as well as the thermal perceptions and preferences of outdoor users. Therefore, integrated empirical studies that are composed of three original surveys are carried out, including a study of land surface temperature of Riyadh City, outdoor thermal comfort survey, and in situ microclimate measurements in different urban locations at neighbourhood scale and within urban canyons. Following that, microclimate and energy modelling are carried out on a number of hypothetical urban geometries that proposed according to the current buildings and planning regulations in the Riyadh City, i.e. building materials, opening ratios on building facades, buildings and streets layouts and minimum width of local streets. Yet, since the study measures the impact of scenarios modifications of urban geometry on the issues under investigation, thus, additional buildings heights and different setback aspect ratios have been added. The proposed hypothetical urban geometries investigated include various street aspect ratio (H/st.) equal to 0.5, 1, 1.5 and 2, and setback aspect ratio (H/sb.) equal to 0, 2, 4 and 8. The proposed urban settings that resulted from the combination of the various streets and setbacks aspect ratios are modelled on four different orientations, including EW, NS, NE-SW and NW-SE, and a total of 64 different urban geometries were evaluated.

The Consumer's Guide is designed to help consumers by providing guidelines for the purchase of specific energy-efficient household appliances- water heaters, air conditioning and heating systems, windows, dishwashers, refrigerators, clothes washers, and dryers. This serves two major purposes: to decrease the environmental impact of those products and to save consumers money over the lifetime of the products. The seven major appliances covered in this work are things that consumers tend to purchase quickly when their older models wear out and with little research into their energy and/or water efficiency. The guide begins with a general introduction and an explanation of the need for energy conservation. Explanations of how they work, purchasing tips, installation tips, maintenance tips, tips for additional energy efficiency, and case studies are given for each appliance. Printable pamphlets are included at the end.

碩士
中國文化大學
國際企業管理學系
103
ABSTRACT The purpose of this study is to explore relationships among energy consumption (EC), real gross domestic product (GDP), Oil Price (WTOILP), export (EXP) and import (IM) for Nigeria and Ethiopia. This study is interesting in the sense that Nigeria and Ethiopia are currently one of the fasted growing economics and largest population in Africa, but still endure energy problems. The data are collected at the yearly interval from the World Bank, IMF, EIA, spanning from 1980 to 2012. Time series techniques especially Granger causality test, Johansen test, Cointegration, and VAR were utilized to test the causal relationships. In Nigeria, there is a bidirectional causality between energy consumption and GDP for both Nigeria. There is a unidirectional causalities running from Oil price to energy consumption, energy consumption to exports, GDP to oil price. In Ethiopia, there is a bidirectional causality between energy consumption and GDP. There is also a unidirectional causal relationship running from import to export, energy to imports. After reviewing the results, the author suggests specific policies. Key words: energy consumption, gross domestic product, oil price, import, export, Granger causality, Johansen, Cointegration, VAR

Air pollution is the world’s greatest environmental health risk factor and reducing exposure remains an ongoing challenge around the world. Among the world’s poor, marginalized, and rural populations, household air pollution from the inefficient burning of biomass fuels like firewood, charcoal, dung, and agricultural residues for daily household energy needs is a leading cause of morbidity and mortality, especially for children under the age of five years. However, household air pollution exposure is a modifiable risk factor and clean-burning cooking fuels like gas and electricity promise substantial health benefits for the 2.8 billion people reliant on biomass fuels. But, clean fuels remain prohibitively expensive or inaccessible for those most reliant on biomass fuels. It is in this context that I examine Ecuador – where substantial cooking gas subsidies have facilitated a nationwide transition to household clean fuel use over four decades – as a long-term case study to understand the potential for widespread clean fuel uptake to reduce air pollution exposure and improve children’s health. Chapter 1 provides background information that contextualizes the work presented in this dissertation. In Chapter 2, I discuss the development of Ecuador’s clean fuel policies. Originally established as a part of broad social support reforms in the 1970s, direct-to-consumer subsidies that lowered the cost of liquefied petroleum gas (LPG) – a popular clean-burning cooking fuel used widely around the world – have driven a transition from 80% of households cooking primarily with firewood in the 1970s to now 90% relying primarily on LPG. However, widespread clean fuel use has come at a cost; each year, the Government of Ecuador spends approximately 1% of the national growth domestic product subsidizing LPG (300-700 million USD). To reduce this financial burden, the government has offered incentives to households to install and use induction electric stoves, which can be powered by the nation’s growing hydroelectric capacity, thereby reducing the cost of LPG subsidies and greenhouse gas emissions. To supplement national data, I administered household energy surveys in a northern province, finding that while all households regularly used LPG, 80% still used firewood for cooking. In these remote regions along the Colombian border, limited access to LPG cylinder refills remains a significant barrier to exclusive LPG use, even after decades of building a robust distribution system. In Chapter 3, I describe results from tailored household surveys – covering energy end uses, costs and access to fuels, and fuel use preferences – administered in 808 households across coastal and Andean Ecuador. Nearly all participants reported using LPG for more than a decade and having frequent, convenient access to cheap LPG cylinder refills. Nonetheless, half of rural households and one-fifth of peri-urban households relied on firewood for cooking and to meet specific household energy needs, like space heating or heating water for bathing. Induction stoves were rare and many induction stove owners reported zero use because the required equipment had never been installed by electricity companies, their stove had broken, or they feared high electricity costs. Here, I show that nationally-representative surveys reporting only “primary cooking fuel” use may underestimate solid fuel use as a secondary option, particularly in rural areas where LPG fuel availability issues play an important role in cooking fuel decision making. These findings additionally indicate that persistent biomass use may curtail the benefits from even the most aggressive clean fuel policies and suggest that additional targeted interventions may be needed to more fully displace biomass. Furthermore, they highlight the need for more nuanced nationally- and subnationally-representative surveys to better understand the extent to which biomass fuels are used secondary to LPG throughout all regions of Ecuador. In Chapter 4, I present results from a sensor monitoring study where we measured personal PM2.5 exposure and stove use for 48-hour monitoring periods among 157 households in peri- urban and rural Ecuador. Firewood-using participants had higher distributions of 48-hour and 10-minute PM2.5 exposure as compared with primary LPG and induction stove users. Accounting for within-subject clustering, contemporaneous firewood stove use was associated with 101 μg/m3 higher 10-min PM2.5 exposure (95% confidence interval: 94–108 μg/m3). Cooking events with clean fuels were not associated with contemporaneous increases in PM2.5 exposure. These findings confirm our expectations that in a region with low ambient air pollution, long-term cooking gas subsidies can lead to relatively low personal air pollution exposures. And yet, persistent secondary firewood use led to higher average and peak exposures, further motivating the displacement of firewood use to reduce health risks from air pollution. I also outline the methodological challenges faced in combining time-resolved sensor data on participant location, stove use monitors, and PM2.5 concentration and offered advice for future studies. In Chapter 5, I assess whether Ecuador’s increased clean cooking fuel use has resulted in improvements in under-5 lower respiratory infection (LRI) mortality. Globally, LRIs are the leading cause of death for children under-5 and household air pollution exposure is a leading risk factor. I employ public use data on cooking fuel use and cause-coded mortalities from 1990 to 2019 to estimate the association between clean cooking fuel use and the rate of under-5 LRI mortalities at the canton (county) level in Ecuador. Using generalized additive mixed models with fixed effects for canton and study period, I observed a significant, non-linear negative association providing evidence that when more than 60% of households in a canton cook primarily with a clean fuel, increased clean fuel use is associated with reductions in under-5 LRI mortality. In total, I estimated that increased clean cooking fuel use is associated with 7,343 under-5 LRI mortalities averted since 1990. In Chapter 6, I conclude by discussing the broader implications of my work. Energy is an important thread connecting climate change, air pollution, and human health, and pathways towards cleaner energy generation will be important drivers of climate change mitigation, reduced environmental exposures, and improved population health. Investments in clean cookstoves have had mixed results over the last 40 years, with many studies revealing only limited uptake of intervention stoves and substantial continued use of polluting traditional fuels, resulting in lower-than-expected exposure reductions and health benefits. Ecuador’s transition has been remarkable in the context of its peer low- and middle-income countries in the rest of Latin America and beyond. The findings presented in this dissertation demonstrate that cooking gas is popular; when it is made cheap and available, gas significantly displaces the use of polluting fuels. Nevertheless, even under ideal cost and access circumstances, my work also reveals that policies and interventions will need to consider specific local needs – like space heating in cold climates – to further encourage a transition toward cleaner indoor air. In the context of efforts to eliminate the use of polluting fuels in the Americas, my work offers hope that ambitious clean cooking fuel policies will improve health.

In the United States, commercial and residential buildings are responsible for 40% of total energy consumption, which provides an important opportunity for energy impact. As we spend the majority of our active moments during the day in transportation, commercial buildings, streets, and infrastructure, some of the greatest opportunities to reduce energy usage occur when we are outside of the home. A large percentage of energy consumption in the built environment directly or indirectly services humans; thus, there is a significant amount of untapped energy savings that can be achieved by involving humans in the optimization process. By including occupants in the building co-optimization process, we can gain a better understanding of individual energy responsibility and significantly improve energy consumption, thermal comfort and air quality over non human-in-the-loop systems and strategies. First, we present ePrints, a scalable energy footprinting system capable of providing personalized energy footprints in real-time. ePrints supports different apportionment policies, with microsecond-level footprint computation time and graceful scaling with the size of the building, frequency of energy updates, and rate of occupant location changes. Finally, we present applications enabled by our system, such as mobile and wearable applications to provide users timely feedback on the energy impacts of their actions, as well as applications to provide energy saving suggestions and inform building-level policies. Next, we extend the idea of energy footprinting to the city-scale with CityEnergy a city-scale energy footprinting system that utilizes the city's digital twin to provide real-time energy footprints with a focus on 100% coverage. CityEnergy takes advantage of existing sensing infrastructure and data sources in urban cities to provide energy and population estimates at the building level, even in built environments that do not have existing or accessible energy or population data. CityEnergy takes advantage of LFTSys, a low frame-rate vehicle tracking and traffic flow system that we implement on New York City's traffic camera network, to aid in building population estimates. Evaluations comparing CityEnergy with building level energy footprints and city-wide data demonstrate the potential for CityEnergy to provide personal energy footprint estimates at the city-scale. We then tackle the challenge of involving humans in the building energy optimization process by developing recEnergy, a recommender system for reducing energy consumption in commercial buildings with human-in-the-loop. recEnergy learns actions with high energy saving potential through deep reinforcement learning, actively distribute recommendations to occupants in a commercial building, and utilize feedback from the occupants to better learn four different types of energy saving recommendations. Over a four week user study, recEnergy improves building energy reduction from a baseline saving (passive-only strategy) of 19% to 26%. Finally, we extend the recommender system to co-optimize over energy consumption, occupant thermal comfort, and air quality. The recommender system utilizes a multi-task deep reinforcement learning architecture, and is trained using a simulation environment. The simulation environment is built using different models trained on data captured from a digital twin of a real deployment. To measure occupant thermal comfort, the digital twin utilizes a real-time comfort estimation system that extracts and integrates facial temperature features with environmental sensing to provide personalized comfort estimates. We studied three different use cases in this deployment by varying the objective weights in the recommender system, and found that the system has the potential to further reduce energy consumption by 8% in energy focused optimization, improve all objectives by 5-10% in joint optimization, and improve thermal comfort by up to 21% in comfort and air quality focused optimization by incorporating move recommendations.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in ful lment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2015
The work presented extends and contributes to research in Non-Intrusive Load Monitoring (NILM), focussing on steady-state and transient power measurement disaggregation techniques for circuits containing household ap- pliances. Although previous work in this area has produced and evaluated a wide range of NILM approaches, much of it has involved the use of datasets captured from real-world household implementations. In such cases, the lack of accurate ground truth data makes it di cult to assess disaggregation tech- niques. In the research presented, three NILM techniques are comparatively evaluated using measurements from typical household appliances assembled within a laboratory environment, where accurate ground truth data could be compiled to complement the measurements. This allows for the accu- racy of the various disaggregation approaches to be precisely evaluated. It is demonstrated that the correlation of transient event edges in aggregated power measurements to individual appliance transient exemplars performs better than the matching of steady-state power levels against individual ap- pliance state combinations. Furthermore, the transient approach is shown to be the most appropriate technique for further development.
MT2017