Conceptual design and performance characteristics of firebrick resistance-heated energy storage for industrial heat supply and variable electricity production

Abstract

Concerns of climate change and sustainable energy policy are driving the deployment of wind and solar energy towards the goal of reducing fossil fuel emissions. In liberalized (deregulated) markets, the large-scale deployment of wind or solar energy results in electricity price collapse at times of high wind or solar output to below the price of fossil fuels. This revenue collapse limits economic large-scale use of wind and solar and reduces the revenue for nuclear plants. The current electrical energy storage options are too expensive to be deployed in sufficient quantity to prevent the price collapse. A less expensive approach to energy storage is required to enable a low carbon-energy grid. This thesis explores the potential of a new energy storage technology to address the challenges of a low-carbon energy grid: FIrebrick Resistance-heated Energy Storage (FIRES). FIRES is a storage technology that takes in surplus electricity, stores the energy as high temperature sensible heat (1200°C-1700°C) in a firebrick storage medium, and outputs the stored heat as hot air when the energy is desired. The stream of hot air can be used to (1) provide heat to high temperature industries in place of natural gas, or (2) be added to a power cycle to produce electricity when it is in demand. FIRES heat storage is nearly two orders of magnitude less expensive than the current energy storage options (on the order of dollars per kilowatt-hour capital cost). Cheap electricity transferred to the heating market by FIRES reduces heating costs and carbon emissions by offering industries cheaper energy than that of the competing fossil fuel, while ensuring revenue to the solar, wind and nuclear power plants. FIRES has "unlimited" storage capacity. If the firebrick is fully charged, FIRES electric resistance heaters will provide hot air to furnaces as long as electric prices are less than fossil-fuel prices. In the long term, FIRES stored heat may be used for peak electricity production in advanced nuclear plants with air-Brayton power cycles, with roundtrip storage efficiencies (electricity-to-heat-to-electricity) near 70%, in class with that of existing electrical energy storage options. Conceptual designs of FIRES heat storage on the megawatt-hour scale were found to be chargeable and dischargeable over periods of several hours or several days as needed. FIRES technology is ready for applications under 1200°C using existing technologies; research is required for higher temperature and high pressure (Brayton power cycle) applications. The applications, conceptual designs, system modeling and preliminary performance and economic evaluations are detailed in the following study.