Renewable Energy Payback: Carbon Debt vs Avoided Emissions

Every solar panel, wind turbine and hydro dam is built with energy that came from somewhere — usually a fossil-heavy grid — before it ever displaces a single gram of grid carbon. This simulator puts one kW of each technology side by side in 3D and runs the clock: a rising bar tracks each plant's net carbon balance, starting in debt from its own manufacturing footprint and climbing toward, then past, zero as avoided grid emissions accumulate. Tune the carbon intensity of the grid being displaced and the resource quality of the site, then watch which technology repays its energy and carbon debt fastest — and by how much it keeps banking after the crossover.