HD16 - A Preliminary Feasibility Study of a New Electricity Transmission Line From the Virginia Coalfield to the Virginia Power System

  • Published: 1992
  • Author: Virginia Center for Coal and Energy Research
  • Enabling Authority: House Joint Resolution 441 (Regular Session, 1991)

Executive Summary:
Virginia House Joint Resolution No. 441 (February, 1991) directed the Virginia State Corporation Commission and the Virginia Center for Coal and Energy Research (VCCER) to "study means available, prior to 1998, to 'wheel' power produced by electric power plants in southwestern Virginia" to the Virginia Power transmission network, for purchase by Virginia Power. The Resolution directed that the VCCER study address new transmission line construction options that might be pursued "in addition to" the Wyoming - Cloverdale and Joshua Falls - Ladysmith transmission construction programs currently proposed by Appalachian Power Company (Apco) and Virginia Power. This report summarizes the results of the VCCER study.

The study was conducted by reviewing available information regarding the technical and economic feasibility of power line construction to various points of terminus. Where available information was not sufficient, additional information was requested from the state's two major utilities (Apco and Virginia Power) and from other sources. Load flow modeling studies were conducted by the two utilities for the purpose of evaluating the technical feasibility of specific construction alternatives.

The technical feasibility of new construction options was judged by determining the likely effects of integrating each alternative into the existing transmission system. In order to be considered technically feasible, a construction option must be able to be integrated into the existing transmission network without having a significant negative impact on that network's reliability or performance in meeting current and anticipated uses. The economic feasibility of new construction options was judged by comparing transmission line costs, on a per-kWhr-delivered basis, to the cost of moving equivalent amounts of energy by rail to eastern Virginia.

If Virginia Power is to purchase power from non-utility generators, the power must be transmitted to Virginia Power's load centers, in eastern Virginia, during peak demand periods. One way to accomplish this would be through construction of a new transmission line to provide a direct connection from southwestern Virginia to eastern Virginia. This option does not appear to be economically feasible under the assumptions used to guide this analysis. Factors limiting the economic feasibility of a direct connection are the long distances involved and the resultant high construction costs, the limited amounts of power generation reasonable to consider for development in southwestern Virginia prior to 1998, and Virginia Power's transmission reliability requirements.

Information provided by Apco and Virginia Power was used as the basis for determining the technical feasibility of non-direct new construction options, i.e., those combining new line construction and transmission through the existing system. These options were evaluated as less-costly alternatives to a direct southwestern Virginia - eastern Virginia connection. Present, heavy loadings on the existing transmission system appear to have negative effects on the technical feasibility of all of these non-direct options. Virginia Power maintains that these current transmission loadings limit its system's ability to move additional power inputs that might be provided at Bath County or Lexington to eastern Virginia under peak load conditions. These limitations caused a number of new construction options, including direct connections from southwestern Virginia to Virginia Power in the Lexington - Bath County area and construction options which require wheeling through the Apco system, to be considered technically infeasible without further upgrades of the existing network. All construction alternatives investigated with the intention of providing increased transfer capabilities from Lexington or the Apco system to eastern Virginia were found likely to have the unintended consequence of drawing increased loadings through critical Apco system components west of Cloverdale, and therefore are considered technically infeasible at the present time.

A number of issues were identified which have the potential to influence the feasibility of power line construction, by non-utility interests, for the purpose of selling power that might be generated in southwestern Virginia to the Virginia Power system. These issues concern economic, legal, and institutional factors. Since the primary factors causing available construction options to be considered infeasible were technical, the majority of these issues did not have a major impact on these proceedings. The exception is Virginia Power's requirement that power generation contracts provide double-structure, double-circuit transmission reliability. This requirement adds substantial costs to many of the new transmission options investigated, including a direct connection from southwestern to eastern Virginia, but is justified from Virginia Power's standpoint by the need to maintain high standards of system reliability.

For these reasons, the study concludes that construction of a new power line from southwestern Virginia, prior to 1998, to enable power to be transmitted to the Virginia Power system for purchase by that utility, does not appear to be feasible under present circumstances.

The finding that new power line construction prior to 1998 is not feasible is dependent upon the assumptions of the analysis. If current heavy loadings on the regional transmission network were to be relieved, prior to 1998, by system upgrades or load reductions, a major technical limitation to a number of new construction options would be removed. If the amount of power generation capacity developed in southwest Virginia, prior to 1998, were substantially in excess of 500 MW, the economic feasibility of a direct connection to eastern Virginia would be enhanced through reduction of per-kWhr transmission costs. Negotiation of a lower-cost alternative to Virginia Power's double circuit - double structure transmission reliability requirement, and a southwestern Virginia power generation capacity in excess of 500 MW, would be required in order to establish an economically feasible direct-access 500-kV connection to eastern Virginia.