1. Life Cycle Costs Model for Vanadium Redox Flow Batteries
Jens F. Peters1, Jacob Fulton2, Manuel J. Baumann2, Marcel Weil1,2
1 Helmholtz-Institute Ulm for Electrochemical Energy Storage (HIU), Karlsruhe Institute of Technology (KIT)
2 Institute for Technology Assessment and System Analysis (ITAS), Karlsruhe Institute of Technology (KIT)
Contact:
BACKGROUND + -
Increasing importance for energy storage systems due to the transition towards renewable energy sources
Vanadium-Redox-Flow-Batteries (VRFB; Fig. 1) with high potential for balancing intermitted renewables
Determining the total costs of ownership for a VRFB comparable with other battery types is still a challenge
Existing studies provide very different cost estimations and identify different cost drivers
Thus, a life cycle cost (LCC) model has been developed based on a review of literature data and first hand manufacturer information
Fig. 1. Working principle of a VRFB [7]
METHODOLOGY
Review of existing economic studies and technical datasheets of VRFB providers as input for an Excel-based cost calculation model
Operation and maintenance (O&M) costs over lifetime are still widely unknown. System providers where contacted in order to obtain first- hand estimations from experts with field experience, considering the durability and lifetime expectancy of each component
The investment costs (based mainly on literature) and the O&M costs are complementary used for creating the LCC model
Varying system parameters allows for identifying critical components and main cost driver under a lifetime perspective
In the present results, no end-of life benefit is considered, though this is expected to be highly relevant due to the value of Vanadium
RESULTS
Key findings:
High variation in investment costs between existing studies [1- 6], caused by different assump- tions and different dimensioning of the VRFB (Fig.2).
Stack identified as critical component. Thus, a full replace- ment after 10 years is assumed. Gaskets are considered critical over the whole lifetime.
Capital costs per unit of storage capacity decrease significantly with bigger battery size (Fig. 3).
Power related components are the main cost driver; especially for smaller batteries (Fig. 4)
Higher power requirements increase costs of VRFB significantly (Fig.3 & 4)
Stack components (power driven; see Fig. 5) become dominant from an energy-to-power (E/P) ratio of > 2 (Fig.4)
For a low power VRFB (E/P = 8), the electrolyte contributes more than 50% to the total system costs (Fig.5).
Fig. 2. Investment costs per kWh of storage capacity in comparison with other works
Fig. 3. Degression of investment costs with increasing storage capacity
Fig.4. Investment costs broken down to component groups
Fig. 5. System costs of a 1MW/8MWh VRFB broken down to component level
Positive Net present value (NPV) is obtained for arbitrage spread (difference between electricity purchase i.e., charge price and selling i.e, discharge price) between 0.1€ (0% IRR) and 0.18€ (8% IRR) (Fig. 6). This gives an idea of the economic viability of the VRFB and the obtainable added value.
Fig.6. Net present value (NPV) depending on arbitrage spread and IRR
CONCLUSIONS
Keys for reducing the life cycle costs of the VRFB are the battery performance and the lifetime of the individual components
Finding suitable gasket materials for avoiding leakages and oxidation of the electrolyte is one of the biggest challenges in this regard
High potential for reducing investment costs by introducing automated stack production. This requires finding appropriate materials
Electrolyte as main single cost driver. However, recycling / end of life is not considered; while (theoretically unlimited) recyclability
REFERENCES
[1] Minke C. Techno-ökonomische Modellierung und Bewertung von stationären Vanadium-Redox-Flow-Batterien im ind. Maßstab. TU Clausthal, [2] Noack J, Wietschel L, Roznyatovskaya N, Pinkwart K, Tübke J. Techno-Economic Modeling and Analysis of Redox Flow Battery Systems. Energies 2016;9: [3] Zeng YK, Zhao TS, An L, Zhou XL, Wei L. A comparative study of all-vanadium and iron-chromium redox flow batteries for large-scale energy storage. J Power Sources 2015;300:438– [4] Ha S, Gallagher KG. Estimating the system price of redox flow batteries for grid storage. J Power Sources 2015;296:122– [5] Zhang M, Moore M, Watson JS, Zawodzinski TA, Counce RM. Capital Cost Sensitivity Analysis of an All-Vanadium Redox-Flow Battery. J Electrochem Soc 2012;159:A1183– [6] Viswanathan V, Crawford A, Stephenson D, Kim S, Wang W, Li B, et al. Cost and performance model for redox flow batteries. J Power Sources 2014;247:1040– [7] Creative Commons License: Nick B, benboy00 -