Maintaining and Enhancing Hydroelectricity and River Restoration Act of 2023

This bill creates a 30% federal tax credit for owners of hydroelectric dams who make specific upgrades to their facilities. It directly affects dam operators who install qualifying improvements like fish passage systems, water quality enhancements, dam safety upgrades, or river restoration projects (such as removing obsolete structures). The credit applies to property placed in service after December 2022, requires prior approval from the Federal Energy Regulatory Commission or state officials, and expires for approvals received after 2031. It also includes special provisions for small, off-grid "approved remote dams" under 20 megawatts.