Prospective Life Cycle Assessment Of High Temperature Superconductors For Future Grid Applications

High-temperature superconductors have distinct advantages compared to conventional conductors. Below their critical temperature, superconductors have immeasurably low ohmic losses. To maintain the superconducting state, superconductors require constant cooling. This study aims at identifying the environmental impacts of the application of superconductors in future grid technologies such as superconducting power cables.

This work presents three advances to scale SNSPDs from few-pixel devices to large detector arrays: atomic layer deposition for the fabrication of uniform superconducting niobium nitride films of few-nanometer thickness, a frequency-multiplexing scheme to operate multiple detectors with a reduced number of lines, and the integration of SNSPDs with free-form polymer structures to achieve efficient optical coupling onto the active area of the detectors.

A design process for HTS DC cables was developed for high current applications. Based on the design process, a 35 kA HTS DC cable demonstrator was developed. The superconducting elements of the demonstrator were manufactured and tested individually at 77 K. Afterwards, the demonstrator cable was assembled and tested at 77 K. The assembled demonstrator successfully reached 35 kA at 77 K and self field conditions.

The slow growth of power transmission systems relative to the large growth in demand for power has played a major role in higher electricity prices and reduced reliability in a number of areas across the United States in recent years. This book evaluates the potential of high-temperature superconducting (HTS) power technologies to address existing problems with the U.S. electric power transmission grid, especially problems with transmission constraints. Among other findings, the authors conclude that HTS underground cables provide an attractive retrofit option for urban areas that have existing underground transmission circuits while avoiding the expense of new excavation to increase capacity. When operated at high utilization, HTS cables provide energy savings benefits as compared with conventional cables or conventional overhead lines per unit of power delivered. Whether these energy savings benefits lead to life-cycle cost savings depends on the cost of electricity and, in the case of conventional overhead lines, on siting constraints because overhead lines are typically much cheaper to install than underground cables. In addition, HTS cables can provide a parallel transmission path at a lower voltage to relieve high-voltage transmission constraints.