Flexible operation strategy for formic acid synthesis providing frequency containment reserve in smart grids

Abstract

The demand-side contribution to grid frequency regulation is becoming increasingly important due to the growing penetration of renewable energy in the power system. Among energy-intensive industrial loads, chemical plants have a high potential to offer grid balancing services due to their existing control infrastructure and storage capabilities. However, applying fast ramp rates and providing time-critical grid services is not straightforward due to strict constraints and the nonlinear dynamics of chemical systems. Therefore, adaptive operating approaches are required to increase the process’s flexibility and facilitate the fast demand response operation. This work proposes a flexible operating strategy for the cooperative operation of a Polymer Electrolyte Membrane (PEM) electrolyser and multi-stage compression systems in a chemical process to provide Frequency Containment Reserve (FCR). This strategy aims to realise the desired power regulation dynamics on the grid side while maintaining the reactor’s optimal operating conditions, i.e., temperature, pressure and flow rate ratio. A techno-economic analysis is performed to obtain optimal operating points. The techno-economic analysis shows that operating the process at a baseload of 73% while offering the remaining capacity as a power reserve can create additional revenue and improve the economic profit by around 10%. The proposed approach is validated by dynamic simulations of a Carbon Capture and Utilisation (CCU) process for formic acid production. The results show that the proposed strategy can enhance the process’s operational flexibility and enable FCR provision with a limited impact on reactor efficiency (<1%).