Load-Following Strategies for Evolution of Solid Oxide Fuel Cells Into Model Citizens of the Grid

Abstract

Abstract-Proper converter design can allow solid oxide fuel cells operated as distributed generators to mutually benefit both the load and the electric utility during steady-state conditions, but dynamic load variations still present challenges. Unlike standard synchronous generators, fuel cells lack rotating inertia and their output power ramp rate is limited by design. Two strategies are herein investigated to mitigate the impact of a large load perturbation on the electric utility grid: 1) external use of ultracapacitor electrical storage connected through a dc-dc converter and 2) internal reduction of steady-state fuel utilization in the fuel cell to enable faster response to output power perturbations. Both strategies successfully eliminate the impact of a load perturbation on the utility grid. The external ultracapacitor strategy requires more capital investment while the internal fuel utilization strategy requires higher fuel use. This success implies that there is substantial flexibility for designing load-following fuel cell systems that are model citizens.

Thermal and electrical model of fuel cell in connected to grid/isolated mode

“…In the process of validation, it is observed that, the mass transfer resistances inside the electrode play a key role in determining the transient response of the system. A load following strategy using either ultra capacitor or fuel utilization with an SOFC is able to reduce or eliminate the effect of a dynamic load perturbation on the utility grid is presented in [7]. Along with active power filter proper design of SOFC interconnection can produce model behaviour by improving power quality and eliminating erratic power demands is also coated in [7].…”

“…A load following strategy using either ultra capacitor or fuel utilization with an SOFC is able to reduce or eliminate the effect of a dynamic load perturbation on the utility grid is presented in [7]. Along with active power filter proper design of SOFC interconnection can produce model behaviour by improving power quality and eliminating erratic power demands is also coated in [7]. The dynamic modelling and analysis of SOFC system response to grid connection using PSCAD/EMTDC simulation software is presented in [8].…”