Idemitsu Kosan Co., Ltd. (Head Office: Chiyoda-ku, Tokyo; President and Representative Director: Noriaki Sakai; hereinafter referred to as "the Company") has completed the ZEB (Net Zero Energy Building)※1 conversion of its Production Center, which centrally manages operations at the Hokkaido Refinery (Location: Tomakomai City, Hokkaido; Director: Hideyuki Hara), and has commenced full-scale operations. The Production Center has achieved an energy reduction rate of 109% during the design phase of this renovation project, earning it the 5-star "ZEB" certification under the Building Energy-efficiency Labeling System (BELS)※2. Furthermore, this renovation project, primarily involving the refurbishment of an existing building to obtain ZEB certification, represents an advanced case within Japan. ※1 A building with net zero or negative annual primary energy consumption. ※2 A system where a third-party evaluation body assesses and certifies the energy-saving performance of new and existing buildings. Exterior of the Production Center BELS Certification Plate The Production Center centrally manages the entire process from crude oil reception to product shipment on a 24-hour basis. It operates continuously day and night and is the facility with the largest energy consumption within the refinery. The Company has implemented renovations combining energy saving and energy generation, including the introduction of high-efficiency equipment and the installation of solar power generation facilities at this site. In addition to improving the building's energy efficiency, it also maintains indoor comfort, realizing more sustainable operations. Compared to cases where ZEB certification is assumed from new construction, renovating an existing building involves more constraints, making the realization more challenging. This initiative, primarily focused on renovating an existing building, serves as a pioneering example for obtaining ZEB certification. It is also the largest-scale ZEB c