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

Project: Research project

Project Details


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
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
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.
Effective start/end date3/1/202/28/21


  • DOE: Office of Energy Efficiency and Renewable Energy (EERE): $3,306,866.00


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