Economic Weekly and Seasonal Thermochemical and Chemical Energy Storage for Advanced Power Cycles

Economic Weekly and Seasonal Thermochemical and Chemical Energy Storage for Advanced Power Cycles Economic Weekly and Seasonal Thermochemical and Chemical Energy Storage for Advanced Power Cycles Economic Weekly and Seasonal Thermochemical and Chemical Energy Storage for Advanced Power Cycles Arizona State University Funding Opportunity Announcement Number: DE-FOA-0002064 Topic 2.1: Firm Thermal Energy Storage Summary The inevitable temporal mismatch between energy demand and intermittent renewable energy supply underpins a need for energy storage. It also presents a market opportunity for storage technologiesespecially those that can meet the need for reliable year-round energy dispatch over periods of days and for seasonal shiftsi.e. well beyond the current state of the art. By definition, such extended-term energy storage charge/discharge cycles are infrequent. Low utilization is a major challenge, and implies that economical extended-term storage must: (1) be inexpensive (levelized cost per stored energy, including self-discharge losses), (2) charge opportunistically, i.e. use the low-priced energy (thermal or electrical), such as mid-day solar peaks, and nightly demand minima, and (3) generate broader market revenue, i.e. not be unutilized between otherwise rare power generation discharges. These principles imply that extended-term storage for concentrating solar power (CSP)despite its importancemust be an add-on technology, broadly deployable and compatible with advanced CSP plants, not a specialty item. Our ASU LightWorks-led team will advance key technologies for multi-level energy storage for supercritical CO2 (sCO2) cycles. Our approach integrates two storage components into a conventional CSP plant with daily thermal storage(1) thermochemical energy storage (TCES) and (2) hydrogenand is agnostic with respect to either the solar receiver or the daily storage technologies. For medium term dispatch, TCES stores chemical and sensible energy in thermally reduced metal oxides. For seasonal storage, a two-step electrically heated thermochemical reactoreTCH2 produces affordable hydrogen. These two technologies integrate flexibly with each other and with a CSP plant via two novel subsystems: A compact oxidation heat exchanger (cOx-HEx), which dispatches sensible and chemical energy to a sCO2 loop/power cycle, and a thermally-driven, sorption, oxygen pump (TDSOrP), which provides the low pO2 vital to both TCES and eTCH2. Together, TCES and eTCH2 with associated containment are an economical add-on storage system allowing unprecedented year-round guaranteed dispatchability, significantly extending the value of sCO2 CSP. Additional value stems from H2 and O2 sales into a broader market, and provision of ancillary grid services, e.g., demand response and inverse demand response. Full dispatchability also alleviates over generation concerns (belly of the duck), late afternoon fast ramp up (neck of the duck), and lack of grid inertia, enabling higher transient renewables penetration.