This bill creates a new 30 percent federal tax credit for companies that build or upgrade high-capacity electric power transmission lines. The credit applies to transmission lines with at least 500 megawatts of capacity that cross state or regional boundaries, as well as transmission lines connecting power generation facilities or energy storage systems to the grid. Companies can claim the credit for equipment and infrastructure placed in service after December 31, 2026, through December 31, 2036. The law also allows certain entities—including nonprofits, government agencies, and federal power marketing agencies—to receive direct payments instead of tax credits if they cannot use them. The bill's goal is to help fund grid modernization and expansion by reducing the financial burden on transmission developers, which Congress argues will lower electricity rates for consumers and improve grid resilience against storms and wildfires.