Grid Scale Virtual Energy Storage to Enable Renewable Energy Penetration

The normal operation of a power system is regulated via the functionality of load frequency control which detects and removes any imbalances between generation and load by using synchronous generators and other resources. With the widespread interest in renewable energy as well as active development of renewable energy projects, there is a new challenge for system regulation due to its well-known intermittent nature. The usual approach of expanding generation reserve, transmission lines and transmission limits is costly in installation and implementation. This paper presents a novel approach called "grid scale virtual energy storage" that addresses this challenge with no added cost. Grid scale virtual energy storage does not require installation and implementation expenses because it takes advantage of the existing diversity of area control errors in interconnected systems and employs an appropriate frequency control method. It also helps in reducing the reserve requirement, regulation capacity, transmission limit, and wear and tear on power system by functioning as normal energy storage. These features of grid scale virtual energy storage support greater penetration of renewable energy into the grid. In this paper, the new approach is explained and its operation is analyzed with a mathematical model and simulation in order to establish its effectiveness.

I. Introduction

For decades, researchers have been interested in renewable energy (RE) due to its environmental benefits and abundant supply. With recent technological advances in this area, the levelized cost of renewable energy production is becoming economically competitive with that of conventional technologies. According to a PNNL report [1], RE will contribute a significant portion to the total electricity generated in the coming years. For example, the United States established a target of 27% of the overall electricity production coming from RE by 2030, while the European Union set a goal of 35% penetration by 2030 [2]. However, there are challenges associated with integrating RE into the grid that need to be addressed in order to meet these objectives. The variability of most RE resources creates several operational challenges that are well understood. Other challenges with RE integration include reduced frequency regulation, transmission capacity violation [3]–[9], and voltage instability [10]–[12].