PUSHING THE LIMITS OF LARGE-SCALE ENERGY STORAGE: OPTIMIZED COMBINED CYCLE CAES

Project Information

PUSH-CCC

Grant agreement ID: 101115601

DOI

10.3030/101115601

EC signature date 21 June 2023

Start date 1 October 2023

End date 30 September 2027

Funded under

• The European Innovation Council (EIC)

Total cost

€ 3 426 308,75

EU contribution

€ 3 426 308,75

Coordinated by

RIEGO SUR SA
Spain

Periodic Reporting for period 1 - PUSH-CCC (PUSHING THE LIMITS OF LARGE-SCALE ENERGY STORAGE: OPTIMIZED COMBINED CYCLE CAES)

Reporting period: 2023-10-01 to 2024-09-30

Summary of the context and overall objectives of the project

PUSH-CCC proposesto solve the key existing limits of Compressed Air EnergyStorage (CAES)scalability, replicability,
efficiency, and energy density while boosting its cost-effective commercial development in Europe by bringing a
breakthrough CAES concept to TRL4, which is based on a novel optimized integration of advanced technology and
scientific advances beyond the state of the art, pushing the efficiency and profitability of the volatile-fluid-based isobaric
adiabatic Combined Cycle CAES (CCC) patented by RIEGOSUR, a scientifically proven high-potential concept due to
the enhancement of turbomachinery efficiency and cavern volume minimization. The construction of an experimental
cavern lab in the Canary Islands will lead to the first isobaric adiabatic CAES system at TRL4 in Europe, while meeting
the expected outcomes of the Challenge, filling in the existing gaps to accelerate the penetration of renewable energies
in the grid.
PUSH-CCC brings together expert partners to solve the key scaling, efficiency and profitability issues by leveraging
an AI-based optimized heat pump cycle to minimize the energy requirements of the volatile fluid processes in realtime considering climatological conditions (I), a cost-effective large-scale membrane for suitable operation in the hardrock cavern (II), optimized turbomachinery for AA-CAES applications (single-stage compressor) (III), a cost-effective,
efficient heat storage technology based on innovative heat exchangers and heat storage medium (IV), a disruptive AIbased hierarchical control system (V); bringing a high-efficient (>80%), cost-effective technology with high replication
potential (high energy density 11.8 kWh/m3 allows hard rock areas which are a major part of the continental land-use).
Autonomous plants will operate with atmospheric air and closed loop water & CO2, which will be captured (10 kTn of
CO2 per year for a standard 500 MW plant) from the overloaded atmosphere with an innovative system.
As stated in the proposal, the global goal of PUSH-CCC is to research, develop and validate at proof-of-concept level, a large-scale breakthrough advanced Compressed Air Energy Storage (CAES) technology based on the optimal orchestration of equipment and thermodynamic cycles, and scientific advances beyond the state of the art applied to the isobaric adiabatic Combined Cycle CAES (CCC) concept developed by RIEGOSUR (with granted European, USA and other countries patent applications). This global goal remains, of course, fully in force.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Work Package 2: PROCESS AND COMPONENTS MAIN RESEARCH

This Work Package contains the main project research. The project began with an analysis of the proposal and thermodynamic modelling compared to conventional constant-volume CAES in salt domes. The study showed that the CCC process improves air storage but faces drawbacks due to the high density of CO2 at 25 ° C and 65 bar, leading to heat management issues and efficiency drops. While the energy density is higher than conventional CAES, it is lower than that of other systems like hydrogen. The research focused on increasing CO2 temperature and pressure and using auxiliary fluids or water pumping to improve storage. The breakthrough solution uses supercritical CO2 as an auxiliary fluid, allowing significant volume changes without liquefaction/vaporisation. High-pressure storage (>200 bar) is feasible due to the secure natural gas caverns that exist. A new supercritical CO2 plant layout was designed and simulated, incorporating increased flexibility and hybridization with other thermal sources. High-pressure and high-temperature operations require stringent standards for cavern membranes and insulation. Research is ongoing in advanced compression, thermal energy storage, and AI control systems.
MILESTONES
Concerning the milestones, the singular milestone scheduled for this initial evaluation period, MS1, has been accomplished punctually: MS1 'PRELIMINARY LAYOUT DEFINITION'.
Additionally, the research associated with WP2 is advancing in accordance with the projected schedule and conforming to the predefined deadlines for the project's milestones.
Work Package 3: EXPERIMENTAL CAVERN LAB
A comprehensive examination was conducted on a portfolio comprising 44 water galleries on the island of Gran Canaria, recognized as the most well-connected island within the archipelago, in collaboration with a local mining engineer. Furthermore, an analysis was performed on several water galleries and quarries across the islands of Gran Canaria, Tenerife, and La Gomera, in conjunction with the mining authorities of the Canary Islands.
We have already found a very interesting site for our experimental cavern lab

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

'PRELIMINARY LAYOUT DEFINITION'.
the thermodynamic model of the Combined Cycle CAES (CCC)
concept in the PUSH-CCC project, based on an isobaric adiabatic CAES system. The final model
provides a detailed thermodynamic description of the fluid flows used in the PUSH-CCC plant, as well
as the sizing of the various equipment required for the air charging and discharging cycles. The model
has been primarily developed in MATLAB, with support from Refprop software for accurate calculation
of the thermodynamic properties of the fluids under different conditions.

Project Summary