The Ultimate Guide to §45Z Clean Fuels Tax Credits

The market for §45Z clean fuels tax credit emerged in 2025. The new technology type is quickly gaining popularity, spurred by new legislation, proposed regulations, and final guidance expected before year-end. This guide gives clean fuels producers and tax credit buyers a clear, practical foundation for navigating the §45Z market.

What's inside:

• Credit basics — which fuels qualify, how carbon intensity determines credit value, and how the June 2026 GREET model update affects different fuel pathways.
• Legislative changes — what the One Big Beautiful Bill changed for ethanol, RNG, SAF, and foreign entity restrictions.
• Claiming and transacting — IRS registration, anti-stacking rules, and how credits move from production to the transfer market.
• Transaction risk — the diligence memos, indemnification structures, and insurance standards that have become market practice.
• Market data — Crux's proprietary view on §45Z tax credit pricing, volumes, and what comes next.