Techno-Economic Assessment of Industrial Vanadium Flow Batteries Based on Experimental Data

This work presents a techno-economic model based on experimental and market data to provide forecasts of the profitability of vanadium flow batteries (VFB s), which are emerging as a promising technology for specific stationary energy services 1‒2. Each component affecting the capital and operative costs was analyzed and the impact of side phenomena on capacity losses was considered. Relevant economic parameters were taken from real market data: discount rate was calculated based on the Capital Asset Pricing Model (CAPM) to account for real market conditions; the electricity price follows an arbitrage strategy to profit of the daily price fluctuations taken from the historical data of the Italian energy market 3‒4. Technical parameters are taken from large-area multi-cell stack, rather than from small single cell experiments, thus allow to characterize the behavior of real industrial reactors 5‒6. The economic performance indicators obtained are the capital cost, the operative cost, the Levelized Cost of Storage (LCOS) and the Net Present Value (NPV). The resulting values are: a discount rate of 9. 12% and electricity prices of 200 € MWh –1 in selling and of 100 € MWh –1 in buying. Capital costs and LCOS were calculated for different system power and energy (E/P) ratings. At E/P = 2 h, the values of capital costs and LCOS were in the range of 800 – 900 € kWh –1 and 0. 50 – 0. 55 € kWh –1, respectively, whereas at E/P = 10 h they reduced to 350 – 380 € kWh –1 and 0. 29 – 0. 32 € kWh –1, respectively. In addition, a NPV analysis was carried out in order to evaluate whether these capital costs could provide a profit. The analysis suggests that only at capital cost < 105 € kWh –1 the break-even point (NPV = 0) was reached. The result is that the assumed techno-economic scenario VFBs were not profitable for every considered E/P. A perspective analysis was developed to reveal when VFBs can become profitable. Different screenings were made on both technical and economic parameters. At a technical level, a power density of 0. 25 W cm –2, a RTE = 85%, a SOC = 90%, and a reduced number of regenerating processes in the lifespan (N reg = 4) were considered. Regarding the economic parameters, a discount rate of 7 % was assumed, an electricity selling price of 250 € MWh –1 and a purchasing price of 75 € MWh –1 were used, compatible with a more pronounced Duck Curve of the daily electricity price, induced by the expansion of renewable energy sources expected in the near future. Under this scenario, the system costs decreased considerably: at E/P = 2 h, the Capital Costs and LCOS ranged as 530 – 570 € kWh –1 and 0. 25 – 0. 27 € kWh –1, respectively, whereas at E/P = 10 h, the Capital Costs and LCOS ranges as 260 – 270 € kWh –1 and around 0. 17 € kWh –1, respectively. The latter figures made VFBs profitable for E/P in the range of 4 – 10 hours, as shown in the figure below. References 1 Noack, L. Wietschel, N. Roznyatovskaya, K. Pinkwart, and J. Tübke, “Techno-Economic Modeling and Analysis of Redox Flow Battery Systems, ” Energies 2016, Vol. 9, Page 627, vol. 9, no. 8, p. 627, Aug. 2016, doi: 10. 3390/EN9080627. 2 Minke and T. Turek, “Materials, system designs and modelling approaches in techno-economic assessment of all-vanadium redox flow batteries – A review, ” J. Power Sources, vol. 376, pp. 66–81, Feb. 2018, doi: 10. 1016/J. JPOWSOUR. 2017. 11. 058. 3 Viswanathan et al. , “Cost and performance model for redox flow batteries, ” J. Power Sources, vol. 247, pp. 1040–1051, Feb. 2014, doi: 10. 1016/J. JPOWSOUR. 2012. 12. 023. 4 Ha and K. G. Gallagher, “Estimating the system price of redox flow batteries for grid storage, ” J. Power Sources, vol. 296, pp. 122–132, Nov. 2015, doi: 10. 1016/J. JPOWSOUR. 2015. 07. 004. 5 Bonaldo and N. Poli, “Vanadium Redox Flow Batteries: Characteristics and Economic Value, ” Lect. Notes Networks Syst. , vol. 482 LNNS, pp. 1721–1731, 2022, doi: 10. 1007/978-3-031-06825-6₁66/COVER. 6 Schmidt, S. Melchior, A. Hawkes, and I. Staffell, “Projecting the Future Levelized Cost of Electricity Storage Technologies, ” Joule, vol. 3, no. 1, pp. 81–100, Jan. 2019, doi: 10. 1016/J. JOULE. 2018. 12. 008. Figure 1