Electricity markets are changing because of (1) the addition of wind and solar generating capacity and (2) the goal of a low-carbon electricity grid. The large-scale addition of wind and solar photovoltaics results in low wholesale electricity prices at times of high wind and solar output and high prices at times of low wind and solar input. Today, gas turbine combined cycle (GTCC) plants burning natural gas or oil provide dispatchable electricity and provide the most economic method to match electricity production with demand. Nuclear Air-Brayton Combined Cycles (NACCs) with heat storage and a thermodynamic topping cycle enable base-load nuclear plants with sodium or salt coolants to provide dispatchable electricity to the grid and heat to industry. This capability maximizes nuclear plant revenue and enables a base-load nuclear reactor with NACCs to be a low-carbon replacement for a GTCC. The NACC power cycle, alternative heat storage technologies, and development status of the different technologies are described. The technology applies to other heat generating technologies including high-temperature concentrated solar power and future fusion systems.