Integrating variable renewable energy and diverse flexibilities: Supplying carbon-free energy from a wind turbine to a data center
Reo Kontani, Kenji Tanaka
Abstract
Variable renewable energy sources (VREs) have experienced steady global growth. The discontinuation of feed-in tariffs (FIT) for new projects in Japan has necessitated the exploration of alternative revenue certainty mechanisms for VREs. Power purchase agreements (PPAs) for supplying carbon-free energy (CFE) have emerged as a promising business model. This study provides a practical framework for integrating diverse flexibilities, encompassing renewable energy curtailment, battery energy storage systems (BESS), and time-shifting demand response (TSDR) for PPAs. To accommodate the unique characteristics of each type of flexibility, the suggested framework consists of sequential optimization problems that incrementally incorporate flexibility to achieve feasible solutions with minimal flexibility. A simulation-based assessment was conducted using a case study involving the provision of the CFE from an onshore wind turbine to a nearby data center. The synergistic relationships between these flexibilities were examined through simulations. The findings highlight that setting a target for BESS's charge state and leveraging the TSDR are key factors in reducing the required capacity of the BESS. For wind developers, this reduction corresponds to a 7.3% decrease in the initial cost. This study offers strategic insights aimed at strengthening the cost advantages of PPAs and enhancing the viability of renewable energy developers and environmentally conscious energy consumers. • Emergence of Carbon-Free Energy Power Purchase Agreements • Framework for Seamless Integration of Diverse Flexibilities • Simulation-Based Study: Carbon-Free Energy from Wind Turbine to Data Center • Quantitative Analysis Unveils Interactions Among Flexibilities • Leveraging Time-Shifting Demand Response to Trim Battery Capacity