General Electric

ABSTRACT:
The Interim results of a program to develop sodium-sulfur batteries for utility load-leveling applications are presented in this report. The reporting period is October 1977 through May 1979. The accomplishments of the Laboratoires de Marcoussis of the Compagnie Generale d'Electricite, France, while under subcontract to General Electric, are included.

During this report period a major scale-up to the first full-size (615 mm x 49.3 mm OD, 168 Ah) cells was accomplished. Safety tests demonstrated the need for a safety insert for the sodium to limit the rate sodium and sulfur could react in the event of a beta tube failure. Performance testing demonstrated a cell capacity greater than the 168 Ah design value, but the electrical resistance was approximately 30% greater than the design value.

Two concepts for a 100 kWh battery module were investigated. The first uses forced-convection nitrogen cooling. The second uses liquid organic coolant and is more compact, less costly and provides better temperature control. However, the organic coolant design introduces potential fire hazards and corrosion concerns. These studies are continuing.… (mere)

ABSTRACT:
Prior studies have shown that one of the methods that may have near-term potential for generating peaking power by electric utilities is to store thermal energy during low demand periods to produce electricity during high demand periods. The objective of this study is to identify potential concepts, select the most promising ones for conceptual design and make detailed evaluations of their economic feasibility and cost-benefits. Over forty concepts were examined for storage media, forms of containment, and cycle configurations for con- version to electricity.

An extensive analysis and screening process resulted in selecting two coal-fired and two nuclear plants for detailed conceptual design. The coal plants utilized peaking turbines and the nuclear plants varied the feedwater extraction to change power output.

It was shown that the performance and costs of even the best of these systems could not compete in near-term utility applications with cycling coal plants and typical gas turbines available for peaking power. Lower electricity costs, greater flexibility of operation, and other benefits can be provided by cycling coal plants for greater than 1500 hours of peaking or by gas turbines for less than 1500 hours if oil is available and its cost does not increase significantly.… (mere)