Dongmei Chen

Bio: Dongmei Chen is an academic researcher from University of Texas at Austin. The author has contributed to research in topics: Wind power & Turbine. The author has an hindex of 15, co-authored 98 publications receiving 1482 citations. Previous affiliations of Dongmei Chen include University of Michigan & General Motors.

Battery Energy Storage for Enabling Integration of Distributed Solar Power Generation

Abstract: As solar photovoltaic power generation becomes more commonplace, the inherent intermittency of the solar resource poses one of the great challenges to those who would design and implement the next generation smart grid. Specifically, grid-tied solar power generation is a distributed resource whose output can change extremely rapidly, resulting in many issues for the distribution system operator with a large quantity of installed photovoltaic devices. Battery energy storage systems are increasingly being used to help integrate solar power into the grid. These systems are capable of absorbing and delivering both real and reactive power with sub-second response times. With these capabilities, battery energy storage systems can mitigate such issues with solar power generation as ramp rate, frequency, and voltage issues. Beyond these applications focusing on system stability, energy storage control systems can also be integrated with energy markets to make the solar resource more economical. Providing a high-level introduction to this application area, this paper presents an overview of the challenges of integrating solar power to the electricity distribution system, a technical overview of battery energy storage systems, and illustrates a variety of modes of operation for battery energy storage systems in grid-tied solar applications. The real-time control modes discussed include ramp rate control, frequency droop response, power factor correction, solar time-shifting, and output leveling.

A Thermodynamic Model of Membrane Humidifiers for PEM Fuel Cell Humidification Control

Abstract: Maintaining proper membrane humidity is crucial to ensure optimal operation of a polymer electrolyte membrane fuel cell system. A membrane humidifier using the fuel cell exhaust gas to humidify the dry air is studied in this paper. We first develop a thermodynamic model, which captures the crucial dynamic variables of the humidifier, including the pressure, flow rate, temperature, and relative humidity of the air flow. Steady-state simulations are then conducted to optimize the humidifier design. Subsequently, dynamic simulations are performed to predict the behavior of the humidifier during transient operations typical for automotive applications. A simple proportional controller was designed to control the humidifier operation.

Utilization of Optimal Control Law to Size Grid-Level Flywheel Energy Storage

Abstract: This paper presents a method for sizing grid-level flywheel energy storage systems using optimal control. This method allows the loss dynamics of the flywheel system to be incorporated into the sizing procedure, and allows data-driven trade studies to be performed which trade peak grid power requirements and flywheel storage capacity. A demonstration of the sizing methodology will be illustrated through a case study based on home consumption and solar generation data collected from the largest smart grid in Austin, Texas, USA.

Electrical energy storage systems: A comparative life cycle cost analysis

Abstract: Large-scale deployment of intermittent renewable energy (namely wind energy and solar PV) may entail new challenges in power systems and more volatility in power prices in liberalized electricity markets. Energy storage can diminish this imbalance, relieving the grid congestion, and promoting distributed generation. The economic implications of grid-scale electrical energy storage technologies are however obscure for the experts, power grid operators, regulators, and power producers. A meticulous techno-economic or cost-benefit analysis of electricity storage systems requires consistent, updated cost data and a holistic cost analysis framework. To this end, this study critically examines the existing literature in the analysis of life cycle costs of utility-scale electricity storage systems, providing an updated database for the cost elements (capital costs, operational and maintenance costs, and replacement costs). Moreover, life cycle costs and levelized cost of electricity delivered by electrical energy storage is analyzed, employing Monte Carlo method to consider uncertainties. The examined energy storage technologies include pumped hydropower storage, compressed air energy storage (CAES), flywheel, electrochemical batteries (e.g. lead–acid, NaS, Li-ion, and Ni–Cd), flow batteries (e.g. vanadium-redox), superconducting magnetic energy storage, supercapacitors, and hydrogen energy storage (power to gas technologies). The results illustrate the economy of different storage systems for three main applications: bulk energy storage, T&D support services, and frequency regulation.

Battery Energy Storage for Enabling Integration of Distributed Solar Power Generation

Abstract: As solar photovoltaic power generation becomes more commonplace, the inherent intermittency of the solar resource poses one of the great challenges to those who would design and implement the next generation smart grid. Specifically, grid-tied solar power generation is a distributed resource whose output can change extremely rapidly, resulting in many issues for the distribution system operator with a large quantity of installed photovoltaic devices. Battery energy storage systems are increasingly being used to help integrate solar power into the grid. These systems are capable of absorbing and delivering both real and reactive power with sub-second response times. With these capabilities, battery energy storage systems can mitigate such issues with solar power generation as ramp rate, frequency, and voltage issues. Beyond these applications focusing on system stability, energy storage control systems can also be integrated with energy markets to make the solar resource more economical. Providing a high-level introduction to this application area, this paper presents an overview of the challenges of integrating solar power to the electricity distribution system, a technical overview of battery energy storage systems, and illustrates a variety of modes of operation for battery energy storage systems in grid-tied solar applications. The real-time control modes discussed include ramp rate control, frequency droop response, power factor correction, solar time-shifting, and output leveling.