Resource Planning for Gas Utilities: Using a Model to Analyze Pivotal Issues
With the advent of wellhead price decontrols that began in the late 1970s and the development of open access pipelines in the 1980s and 90s, gas local distribution companies (LDCs) now have increased responsibility for their gas supplies and face an increasingly complex array of supply and capacity choices. Heretofore this responsibility had been share with the interstate pipelines that provide bundled firm gas supplies. Moreover, gas supply an deliverability (capacity) options have multiplied as the pipeline network becomes increasing interconnected and as new storage projects are developed. There is now a fully-functioning financial market for commodity price hedging instruments and, on interstate Pipelines, secondary market (called capacity release) now exists. As a result of these changes in the natural gas industry, interest in resource planning and computer modeling tools for LDCs is increasing. Although in some ways the planning time horizon has become shorter for the gas LDC, the responsibility conferred to the LDC and complexity of the planning problem has increased. We examine current gas resource planning issues in the wake of the Federal Energy Regulatory Commission`s (FERC) Order 636. Our goal is twofold: (1) to illustrate the types of resource planning methods and models used in the industry and (2) to illustrate some of the key tradeoffs among types of resources, reliability, and system costs. To assist us, we utilize a commercially-available dispatch and resource planning model and examine four types of resource planning problems: the evaluation of new storage resources, the evaluation of buyback contracts, the computation of avoided costs, and the optimal tradeoff between reliability and system costs. To make the illustration of methods meaningful yet tractable, we developed a prototype LDC and used it for the majority of our analysis.