Gevo, a renewable biofuels and chemicals company, has developed a novel single-step catalytic process for on-purpose propylene, on-purpose butylene production, or mixtures of C3-C5 olefins via feeding hydrous ethanol, ethylene, or mixtures of each. Carbon accountability and yields for the processes are excellent with only trace amounts of carbon loss to CO, CO2 or methane. An overview of the ‘on-purpose’ processes, technical readiness, and material balances will be discussed.