Date of Award

8-20-2007

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemical Engineering

First Advisor

Michael D. Mann

Abstract

In this study, I examine various environmental emissions from a hydropower based electric utility from a long-term planning perspective when it starts purchasing electricity from a combined cycle gas turbine (CCGT) under both dispatchable and non-dispatchable modes. The introduction of a CCGT based Independent Power Producer (IPP) in the case of Nepal worsens in terms of CO2, NOx and TSP emissions. However, emissions of SO2 are reduced after the introduction of an IPP. The study also shows that dispatchable IPPs are preferable to non-dispatchable ones in terms of CO2, NOx, and TSP emissions but not SO 2. It is also observed that the adoption of energy efficiency (EE) measures in a utility with IPP participation potentially reduces the economic benefits of EE measures compared to utilities without IPP participation. A case study of India shows that these DG technologies (i.e., biomass gasifiers and small wind turbines) can contribute significantly in utilities' economic and environmental problems when appropriate regulations and policy incentives are present. The study finds out that small wind turbines (backed up by the grid) provide the most cost-effective and an environmentally friendly option for supplying electricity to the rural/isolated area under study when DGs are operated under a net metering scheme. Without net-metering scheme, biomass gasifiers become cost-effective when an appropriate level of CO 2-tax is applied for fossil-fuel generations. For higher CO2-tax schemes, substitution effect is responsible for mitigating more than 90% of CO2 emissions when DGs are operated without net metering. Cost economics, technical efficiency, and environmental benefits are further improved when fossil-fuel based DG technologies are operated in combined heat and power (CHP) applications. When gas turbines (GTs), microturbines (MTs), and internal combustion engines (ICEs) operate in a commercial facility in New York under CHP application, the overall system efficiency reaches to 71.5% compared to 30% when DGs are operated in separate heat and power (SHP) application. CHP results in the reduction of average electricity price by about 25% and environmental pollutants by about 22 to 30%. Efficiency gain as high as 86% can be achieved by increasing the heat to power (HPR) of the supply system.

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