Connecting multiple vehicular PEM fuel cells to electrical power grid as alternative energy sources: A Case Study

Abstract

Advances in fuel cell (FC) technology make them an alternative energy source in several applications such as static, portable, and transportation. Recently, the energy needs of hydrogen electric vehicles, which have developed as an alternative to battery electric vehicles (BEVs) and have significant potential in the future, are met by vehicular hydrogen FCs. In this regard, fuel cell electric vehicles (FCEVs), which have started to take their place in the transportation sector, can also be used as an additional energy source with their energy unit for electrical power grid-connected systems. In grid-vehicle integration, vehicular FCs can meet a significant part of the electricity consumption when parked and help stabilize the grid. In this study, multiple vehicular PEM fuel cells (PEMFCs), the most widely used in FCEVs, support the residential grid by injecting electrical power into the connecting system. For this, a multi-input dc-dc boost converter interface is designed and utilized to manage electrical energy from vehicular PEMFCs to the electrical power grid instead of a conventional single-input dc-dc boost converter. In the dc-dc converter control, Incremental-Conductance (InC) maximum power point tracking (MPPT) method is utilized to extract maximum power from PEMFCs. Subsequently, the extracted electrical energy is supplied to the grid through a full-bridge inverter controlled by hysteresis pulse width modulation. The designed grid-support system supplied by vehicular PEMFCs in the ratings of 75 kW, 100 kW, and 125 kW are connected to local dynamic loads and analyzed for a 24-h operation. The minimum load consumption value is 84.6 kWh at midnight while load consumes at most 396.2 kWh during the daytime. Various connection situations of vehicular PEMFCs are considered to examine the energy flow analysis between vehicles and the grid/consumer side. A detailed economic analysis has been carried out by using hourly energy values in terms of load profile and generated energy to show the profit amount on the user side. While the cost of the energy consumed by the loads is calculated as €1004.8 without connection to the grid of FCEVs, the amount of profit obtained on the load side is measured as €943.9 with the connection.