published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

Many public and private entities have heavily invested in efficiency measures and renewable sources to generate energy savings and reduce fossil fuel consumption. Private utilities have invested over $4 billion in energy efficiency with 56% of these investments directed towards consumer incentives. However, the magnitude of the expected savings and the effectiveness of the technological measures remain uncertain. Multiple studies attribute the reasons driving these uncertainties to behavioral phenomena such as “the rebound effect.” This work provides insights on the uncertainties generating potential differences between expected and observed performances of demand-side measures (DSM) and distributed generation strategies, using mixed methods that employ both empirical analyses and engineering economics. This study also provides guidelines to stakeholders to effectively use the benefits from DSM strategies towards asset preservation for affordable multifamily houses. Section 2 describes how joint efficiency gains compare to similar singular efficiency gains for single-family households and discusses the implications of these differences. This work provides empirical models of marginal technical change for multiple residential electricity end-uses, including space conditioning technologies, appliances, devices, and electric vehicles. Results indicate that the relative household level of technological sophistication significantly influences the performance of demand-side measures, particularly the presence of a programmable thermostat. As to space conditioning, results demonstrate that sufficient consistent technical improvement leads to net energy savings, which could be due to technical factors or to a declining marginal rebound effect. Section 3 empirically evaluates the performance of distributed residential photovoltaic (PV) solar panels and identifies the technological and demographic factors influencing PV performance and adoption choice. Results show that modeling PV adoption choice significantly impacts the household energy demand, suggesting that the differences in the actual evaluated behavioral responses and the self-reported changes in electricity consumption are more complex than assumed by other studies. The analysis indicates that electricity use decreases marginally for PV adopters if sufficient efficiency improvements in space conditioning are made. Results further imply that households that adopt solar panels might “take back” roughly 24% of the annual electricity production for PV technologies. Section 4 describes replicable engineering economic models for estimating conventional rehabilitation, energy, and water retrofit costs for low-income multi-family housing units. The purpose of this study is to prioritize policy interventions aimed at maintaining property location and use, and to identify the capital investment needs that could be partially provided by local and state housing authorities. Section 5 synthesizes the work, describes the future work, provides guidelines for local and state efficiency program administrators, and insights on prioritizing and designing efficiency interventions. / text

An ever increasing body of legislation and regulation is transforming the UK’s energy system and its surrounding national energy framework. Depending on the mechanisms that result from this process, new forms of engagement with energy, particularly electricity, might emerge. The current trajectory of UK energy policy leans towards a centralised scenario with a portfolio of centralised renewable energy technologies (i.e. geographically concentrated such as offshore wind), nuclear power stations and gas fired power stations with the option of Carbon Capture and Storage technologies if it becomes a commercially viable option (CCC, 2011). Forecasts predict that a combination of these technologies could place the UK on the right path to reach its 2050 carbon reduction commitments (UKERC, 2008). However, this approach fails to take broader benefits of decentralisation and localisation into account and many official documents such as the Microgeneration Strategy (DECC, 2011a) and those surrounding Community Energy Online (DECC, 2011b) point to a need for greater public engagement in the generation of energy in order to ‘derive greater benefits locally’ (DECC, 2011a: 45). The question remains in how far these diverging objectives can be achieved within the current regulatory environment as there is a lack of coordinated incentives in place to facilitate the development of new scales and ownership structures capable of promoting new forms of engagement at scales below the point at which economies of scales apply. This thesis seeks to establish what barriers are preventing community energy with the capacity to increase acceptance of renewable energy technologies while also contributing towards climate change action, energy security and the strengthening of local economic cycles from becoming more widely embedded in the UK. The main focus is on how ‘niche creation’ policies such as the feed-in tariff might provide the basis for overcoming these barriers by diffusing new scales and ownership structures of renewable energy technologies. Accompanying social innovations could potentially include more meaningful engagement with energy in general and renewable energy in particular, while also enabling communities willing to invest in renewable energy technologies to build resilient local energy infrastructures with the capacity to reduce the impact of increasing energy insecurity, fossil-fuel depletion and climate change constraints. In order to appreciate the potential of community energy in the UK, parallels are drawn to the governance of national energy frameworks in other European countries, Germany and Denmark in particular, that have provided the basis for successful community energy engagement.

<p>Lignocellulosic biomass is a renewable, sustainable resource that can replace or supplement fossil fuels use for liquid fuels and chemicals. However, its recalcitrant structure including interwoven cellulose, hemicelluloses, and lignin biomacromolecules is challenging to deconstruct. Pretreating biomass so that it can be converted to useful liquids dominates process economics. Many pretreatment methods exist, but most require hazardous chemicals or processing conditions. Many ionic liquids (ILs), salts molten below 100&deg;C, can be used to deconstruct lignocellulosic biomass and are less hazardous than the volatile organic compounds typically used. </p><p> While effective, relatively safe, and recyclable, ILs are expensive. To reduce costs, dilution with other safe compounds is desirable, if there is no impact on deconstruction efficiency. Glycerol, a food additive, is inexpensive and becoming even more so since it is a by-product of the burgeoning biodiesel industry. Use of glycerol as an additive or diluent for ILs is extensively evaluated in this work. </p><p> Rice hulls are an abundant biomass, with over 100 million tons produced per year, but with little practical use. The IL 1-ethyl-3-methylimidazolium formate ([C2mim][O2CH] or EMIM Form) when mixed with an equal amount of glycerol has been shown to be effective in pretreating rice hulls. Ambient pressure, a pretreatment temperature of 110&deg;C, and a reaction time of three hours produced rice hulls that could be enzymatically hydrolyzed to give reasonably good glucose and xylose yields considering the recalcitrance of this silica-armored biomass. </p><p> The IL [C2mim][O2CH] was also effective when mixed with an equal amount of glycerol to pretreat loblolly pine, a fast-growing softwood. Loblolly pine was pretreated at 140&deg;C for three hours to produce a solid rich in cellulose and hemicelluloses, while a lignin-rich product could be precipitated from the IL. Similar products were obtained from pretreatment with a mixture of 75% 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc] or EMIM Ac) and 25% glycerol. Enzymatic hydrolysis of the pretreated solids gave glucose, mannose, and xylose yields up to 18 times that of the raw pine. </p><p> Viscosity measurements of pure glycerol, [C2mim][O2CH], [C2mim][OAc], and IL-glycerol mixtures were very different at ambient temperature, but were similar at typical biomass pretreatment temperatures. Biomass pretreated by mixtures with higher viscosity tended to give better carbohydrate yields after enzymatic hydrolysis. Higher excess molar volumes, <i>V_m^E</i>, tended to align with better carbohydrate yields after enzymatic hydrolysis. This phenomenon may relate to more energy put into shearing flow of the IL-glycerol-biomass system resulting in biomass particle shearing or stretching that allowed better solvent access into the biomass. </p>

Climate change and energy security are issues facing municipalities throughout the world. Efficient, resilient, sustainable, community-based energy systems, such as district energy systems (DES), fuelled mostly by renewables, are an important tool for addressing both climate change and energy security at the municipal level. In spite of their benefits, DES are not widely adopted in Canada (CDEA, 2011). This is due to the complex nature of the barriers which project proponents face. This thesis examines the experience of the City of Prince George in adopting and implementing the Downtown DES. Using a case study methodology, data was collected through a review of relevant municipal documents and a series of semi-structured, open-ended interviews. A thematic analysis revealed unexpected barriers related to lack of adequate public consultation and negative perceptions regarding biomass as a fuel for the DES. These `lessons learned' were then developed into recommendations for other municipalities considering DES.

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This thesis explored the opportunities to reduce energy demand and renewable energy feasibility at an off-grid science “community” called the Experimental Lakes Area (ELA) in Ontario. Being off-grid, ELA is completely dependent on diesel and propane fuel supply for all its electrical and heating needs, which makes ELA vulnerable to fluctuating fuel prices. As a result ELA emits a large amount of greenhouse gases (GHG) for its size. Energy efficiency and renewable energy technologies can reduce energy consumption and consequently energy cost, as well as GHG. Energy efficiency was very important to ELA due to the elevated fuel costs at this remote location. Minor upgrades to lighting, equipment and building envelope were able to reduce energy costs and reduce load. Efficient energy saving measures were recommended that save on operating and maintenance costs, namely, changing to LED lights, replacing old equipment like refrigerators and downsizing of ice makers. This resulted in a 4.8% load reduction and subsequently reduced the initial capital cost for biomass by $27,000, by $49,500 for wind power and by $136,500 for solar power. Many alternative energies show promise as potential energy sources to reduce the diesel and propane consumption at ELA including wind energy, solar heating and bio-mass. A biomass based CHP system using the existing diesel generators as back-up has the shortest pay back period of the technologies modeled. The biomass based CHP system has a pay back period of 4.1 years at $0.80 per liter of diesel, as diesel price approaches $ 2.00 per liter the pay back period reduces to 0.9 years, 50% the generation cost compared to present generation costs. Biomass has been successfully tried and tested in many off-grid communities particularly in a small-scale off-grid setting in North America and internationally. Also, the site specific solar and wind data show that ELA has potential to harvest renewable resources and produce heat and power at competitive rates compared to diesel and propane.

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