The U.S. Treasury Department’s design of the Inflation Reduction Act’s 45V hydrogen production tax credit will determine both the level of greenhouse gas (GHG) emissions caused by electrolytic hydrogen production and the viability of the clean hydrogen industry. Loose guidance could increase hydrogen production emissions by up to five times and set the industry up for failure. However, setting standards that comply with three principles—additionality, deliverability, and time-matching—and that account for grid power emissions can spur robust growth of clean electrolytic hydrogen and support emissions reductions today and long after the policy expires.