In the quest for a stable, renewable-powered grid, researchers have long sought effective ways to smooth out the inherent fluctuations of wind and solar power. Now, a groundbreaking study led by Shaobo Wen from the School of Traffic Engineering at Nanjing Institute of Technology offers a promising solution: a hybrid energy storage system (HESS) that combines flywheels and batteries. This innovative approach, detailed in a recent paper published in Energies, could significantly enhance the reliability and economic viability of wind-solar power generation.
Wen and his team have developed a sophisticated method to optimize the configuration of flywheel-battery HESS, aiming to minimize the full lifecycle cost while maximizing the smoothing effect on wind-solar power fluctuations. The key lies in the intelligent allocation of power between the flywheel and battery components, based on their unique strengths.
“By leveraging the high power density and fast response of flywheels, along with the cost-effectiveness and longer response time of batteries, we can create a synergistic system that addresses the challenges posed by intermittent renewable energy sources,” Wen explained.
The researchers employed an improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) to decompose the original wind-solar power signal into a grid-connected signal and a leveling command signal. A low-pass filter then separates the leveling command signal by frequency, assigning appropriate components to the flywheel and battery. This dual-stage power allocation ensures that each component operates within its optimal range, enhancing overall system efficiency.
To determine the optimal capacity configuration, the team established a capacity optimization model based on the particle swarm optimization (PSO) algorithm. This model considers the impact of different cutoff frequencies on power allocation, as well as the effects of the depth of discharge and cycle count on battery lifespan over its entire lifecycle.
The effectiveness of the proposed HESS was validated through simulations on a microgrid consisting of 10 MW wind power generation, 10 MW solar power generation, and the flywheel-battery HESS. The results were impressive: the hybrid energy storage system achieved a significant power smoothing effect, with a maximum power fluctuation rate of just 3.2% in 1-minute intervals and a maximum power fluctuation of less than 8% in 10-minute intervals in most cases. Moreover, under the same stabilizing effect, the HESS reduced costs by 45.1% compared to single-battery energy storage.
The implications of this research for the energy sector are substantial. As the world transitions towards renewable energy sources, the need for effective energy storage solutions becomes ever more pressing. The flywheel-battery HESS offers a compelling alternative to traditional battery-only systems, providing enhanced stability and economic benefits.
“This study demonstrates the potential of hybrid energy storage systems to revolutionize the way we integrate renewable energy into the grid,” Wen said. “By optimizing the configuration of flywheels and batteries, we can create a more stable, reliable, and cost-effective energy storage solution.”
Looking ahead, the research team plans to explore the application of flywheel-battery hybrid energy storage in community energy storage scenarios, considering the impact of “dual-carbon” policies, local electricity market transactions, and frequency regulation. The goal is to maximize economic returns and further optimize hybrid energy storage capacity allocation.
As the energy sector continues to evolve, the insights gained from this study could pave the way for more innovative and sustainable energy storage solutions. By harnessing the strengths of both flywheels and batteries, the flywheel-battery HESS represents a significant step forward in the quest for a stable, renewable-powered future. The research was published in Energies, a peer-reviewed journal that focuses on energy research and technology.