Hydrogen Carbon Light is a modular system that uses solar or LED-driven photothermal energy to decompose methane into two high-value products: clean hydrogen and solid carbon nanotubes (CNTs). Operating without external power or fossil-fuel inputs, the system avoids CO₂ emissions entirely by converting methane into stable solid carbon. Its reactor design enables efficient thermal decomposition at controlled temperatures, supporting continuous operation and on-site production of hydrogen fuel and CNTs for applications in energy storage, electronics, and structural materials