From Policy to Code: RFS/45Z Reset Drives Domestic‑First Diesel Economics

Opening Insight RFS reallocation, revised HEFA/FAME equivalence values, and a proposed half‑RIN for imports are resetting diesel economics and operating risk.

Coupled with the expiration of the blender’s credit and the onset of Section 45Z rewarding verified, lower‑CI production, the incentive stack now favors domestic, auditable pathways. Consumption has softened and imports fell to the lowest since 2012— below 10 thousand b/d in November 2025 —while ILUC remains in lifecycle accounting, tightening feedstock choices and documentation stakes. The legacy compliance and sourcing playbook is breaking; policy timing has become a hard operating dependency. This post quantifies the costs of ignoring regulatory certainty (mispriced imports, idle time, noisier P&L, elevated VaR and audit exposure) and the gains from codifying it (faster decisions, domestic‑first routing, higher utilization, cleaner books). We translate that into a regulatory‑ready operating model—rules‑as‑software governed by a cross‑functional Control Tower, event‑driven ETRM and finance integration, CI chain‑of‑custody for 45Z, and governed agents—backed by architecture, roadmap, human changes, and KPIs, with Arcelian’s diagnostic to accelerate execution. For the specifics behind these shifts and how to act on them, proceed to Context and Analysis.

Costs of Ignoring Certainty

Treating RFS and Section 45Z timing as background noise multiplies risk. As volumes, equivalence values, and credit mechanics shift, inaction propagates errors across barrels, books, and audits.

• As import optionality shrinks—imports fell below 10 thousand b/d in November 2025—mis‑timed swaps and rack nominations incur demurrage, dwell time, and line‑space charges.
• Idle time compounds with OMB/45Z‑GREET slippage: a Gulf Coast unit sat nine days—two Fridays lost—and several hundred million gallons per year paused pending final RFS and 45Z.
• Ignoring half‑RIN math misprices imports; at $1.20/RIN, a 50% haircut surrenders roughly $0.60 before logistics, bleeding margin.
• Under‑hedged RINs, feedstock, and crush basis lift VaR into mandate and reallocation resets; RVO/equivalence‑value errors distort P&L.
• Wrong SRE and reallocation assumptions plus CI chain‑of‑custody gaps break reconciliation when half‑RIN applies—triggering audit findings.
• Domestic‑first exposure concentrates in smaller counterparties; slow collateral updates amplify wrong‑way risk and liquidity strain.
• Miss diesel‑linked constraints in LNG, LPG, and bunker portfolios, adding avoidable idle time as schedules desynchronize.

Result: margin leakage, noisier P&L, bottlenecks, elevated counterparty and regulatory exposure—cumulatively a sustained competitive drag.

Operational Gains from Certainty

When regulatory certainty becomes operating code—embedding mandates, reallocation, equivalence values, half‑RIN logic, and 45Z‑GREET CI —trading and supply run faster and with less risk. Domestic, verifiable pathways take the

Lead, shrinking import exposure, stabilizing compliance, and lifting utilization at lower delivered cost.

• Faster decisions and less latency: auto‑pushed reallocation updates hit ETRM by 7:00 a.m. next day, halving cycle time.
• Stronger margins with domestic‑first routing: at $1.20/RIN, the proposed half‑RIN imposes roughly a $0.60/gal haircut on imports, narrowing offshore arbitrage and favoring U.S. barrels.
• Higher utilization and throughput: several hundred million gallons per year of idle capacity can restart as CI‑verified pathways firm up; one 150 MGY site moved after CI improved from 54 to 41, adding roughly $0.20–$0.30/gal ($8–$13/bbl) of value.
• More stable run‑plans: clarified reallocation for 2026–2027 and tighter SRE treatment compress D4 basis swings and keep mandates whole, reducing scramble risk.
• Reduced import exposure: imports already slipped below 10 thousand b/d in November 2025, and embedding half‑RIN and CI rules makes the domestic stack the default backstop.
• Cleaner P&L and credit: standardized RIN, feedstock, and CI attribution improves collateral confidence, lowers settlements variance, and cuts disputes and audit findings.

Regulatory‑Ready Operating Model

A regulatory‑ready operating model—anchored by a rules‑as‑software engine paired with a cross‑functional RFS/45Z Control Tower—turns regulatory certainty into operating certainty. It synchronizes trading, risk, scheduling, and finance to prioritize domestic‑first routing, shrink import reliance, and stabilize compliance costs as rules lock. With imports slipping below 10 thousand b/d, the lowest since 2012, and roughly $0.60 lost on imported gallons at $1.20/RIN with a 50% half‑RIN haircut, the economics now reward verifiable, low‑CI domestic pathways.

• Encode rules: percentage standards, SRE outcomes, reallocation, equivalence values, and half‑RIN eligibility.
• Integrate via events and APIs into ETRM, scheduling, inventory, credit, and the general ledger.
• Automate with agents to monitor dockets, ingest final rules, and trigger RVO recalculations and attestations.
• Prove traceability with CI chain‑of‑custody, supplier attestations, and auditable lineage to secure 45Z recognition.
• Optimize pathways using CI‑driven 45Z value, crush economics, logistics, and hydrogen/catalyst constraints across biodiesel, renewable diesel, and SAF.
• Forecast prices and spreads with ML; detect mandate and import inflections; scale scenarios in the cloud.

Outcome: lower delivered compliance cost, steadier diesel supply, reduced import exposure, and de‑risked compliance.

How Arcelian Operationalizes Certainty

Regulatory certainty becomes operating certainty when rules flow straight into decisions, schedules, and books. Arcelian codifies RFS and Section 45Z so trading, risk, accounting, and operations act on a single, verifiable rulebook—lifting throughput, tightening controls, and steering toward domestic‑first,

Verified-CI Barrels: Architecture, Execution Path, and Operating-Model Changes

Verified-CI barrels become durable when architecture, execution, and operating cadence work in lockstep across RFS and Section 45Z. The blueprint below details the rules-as-software core, ETRM and finance integration, event-driven automation, a traceability fabric for auditability, and a pragmatic roadmap that compresses cycle time while unlocking GREET-aligned credit recognition.

Architecture: Rules-as-Software Engine and RFS/45Z Control Tower

• Rules-as-software engine and Control Tower: A configurable engine, governed by an RFS/45Z Control Tower, encodes percentage standards, SRE outcomes, 2026–2027 reallocation logic, HEFA/FAME equivalence values, and half-RIN eligibility. It recalculates RVOs and propagates changes across trading, scheduling, risk, credit, and accounting.
• ETRM and finance integration: Event updates flow into ETRM, scheduling, inventory, credit, and the general ledger with single-source reference data and lineage. Section 45Z recognition aligns front-to-back, reducing settlements variance and P&L noise.
• Event-driven APIs and agents: EPA/EIA events stream via APIs; agents monitor dockets, ingest finals, trigger RVO recalcs, and draft attestations. Reallocation updates auto-push by 7:00 a.m. the next day, a pattern that has cut cycle time by half.
• Data and traceability fabric: CI chain-of-custody, supplier attestations, reconciliations, and audit trails secure 45Z benefits and avoid clawbacks while enabling domestic-first routing.
• Forecasting and scale: ML forecasting informs D4 prices, feedstock spreads, and obligated-fuel volumes; cloud scale bursts scenario runs when rules land.

Execution Roadmap for RFS/45Z and CI Operations

• 1) Encode and backtest: Stand up single-source reference data and lineage; encode percentage standards, reallocation scenarios, equivalence values, half-RIN, and SRE outcomes; backtest vs. EPA/EIA history.
• 2) Final RFS rule → act: When 2026–2027 volumes and percentage standards publish, auto-recalculate RVOs, apply reallocation and equivalence values, and propagate to ETRM, hedging, scheduling, credit, and accounting.
• 3) Reallocation cadence: Wire event-driven integration to push next-day 7:00 a.m. reallocation updates into positions and books—tightening reconciliations and sustaining the cycle-time cut.
• 4) 45Z-GREET unlock: On OMB review completion and 45Z-GREET publication, activate CI verification and credit recognition workflows to enable financing and restarts; domestic-first routing strengthens as imported gallons face half-RIN haircuts (e.g., $1.20/RIN with a 50% haircut ≈ ~$0.60).
• 5) Restart and ramp: Execute restart cadence—notices within weeks of finalization; utilization ramps within a quarter—illustrated by a 150 MGY restart where CI moved 54 → 41 and created roughly $0.20–$0.30/gal ($8–$13/bbl) in value.

Human and Organizational Changes for Durable Compliance

• Cross-functional RFS/45Z Control Tower: Traders, schedulers, risk, credit, compliance, and IT co-own cadence, rule changes, and exceptions.
• Rules-as-software engine ownership (CIO/IT): Govern rule sets, event/API fabric, single-source reference data, lineage, and audit trails.
• COO/Operations (scheduling, blending, routing): Execute domestic-first routing, ingest 7:00 a.m. updates, and maintain CI documentation flows.
• CFO/Finance and Accounting: Align 45Z recognition and settlements with ETRM flows; reduce settlements variance and P&L noise.

Trade‑offs and KPIs for RFS/45Z Compliance and Supply Optimization

Reduce settlements variance and ensure general‑ledger integrity.

• Risk, Credit, and Compliance: recalibrate scenarios and concentration as counterparties skew domestic; reflect reallocation and half‑RIN mechanics; enforce CI chain‑of‑custody and attestations.
• Domestic‑first vs. import backstop: imports slipped below 10 thousand b/d in November 2025; half‑RIN haircuts narrow offshore arbitrage without bans.
• Collateral and concentration: tighter domestic supplier concentration shifts credit limits and haircuts; SRE and reallocation assumptions must align across books.
• Operate to targets: throughput; delivered compliance cost per gallon; cycle time (target the proven halving); settlements variance; verified CI; audit readiness.

Operationalize Regulatory Certainty

Regulatory clarity under the RFS and Section 45Z is not a backdrop; it sets your routing, run‑rates, and credit exposure. With reallocation keeping mandates whole, half‑RIN pre‑pricing offshore barrels, and 45Z‑GREET CI unlocking domestic pathways, import exposure is shrinking— imports fell to the lowest since 2012 and below 10 thousand b/d in November 2025 —and idle U.S. capacity is poised to restart.

The leadership ask is operational: make policy timing an input to scheduling, RVOs, hedging, credit, and accounting so uncertainty premiums compress instead of compounding into dwell, P&L noise, and audit findings. The firms that wire shared truth across trading, risk, and finance will lift utilization and lower delivered compliance cost as rules finalize. Treat rules as software to synchronize commercial, risk, and compliance.

Schedule the RFS/45Z Diagnostic

Arcelian turns regulatory clarity into operating certainty so you can stabilize diesel supply, cut import exposure, and lower delivered compliance cost. We bridge commercial strategy, controls, and modern architecture to align trading, risk, accounting, and IT on the same rulebook.

• Deploy rules‑as‑software for RFS/45Z—reallocation, equivalence values, half‑RIN—propagated across ETRM, scheduling, and finance.
• Optimize feedstocks and pathways for domestic‑first routing and CI to restart idle capacity and displace imports.
• Establish CI chain‑of‑custody, supplier attestations, and lineage to secure 45Z recognition and reduce audit risk.
• Stream EPA/EIA updates to auto‑refresh RVOs, hedges, and accounting; retire brittle data and workflows.

Schedule the RFS/45Z Diagnostic now to convert policy timing into operating certainty.

Risk, Credit & Compliance Modernization: RegTech adoption choices that operationalize RFS and 45Z

RegTech adoption for RFS and 45Z should be anchored by a rules‑as‑software engine and a Control Tower pattern that encode percentage standards, reallocation logic, SRE treatment, HEFA vs. FAME equivalence values, proposed half‑RIN eligibility, and 45Z‑GREET CI verification with chain‑of‑custody.

The core decision is build vs.

Buy vs. Hybrid: Prioritize Explainability, Event-Driven APIs, and Deterministic Lineage

Prioritize explainability with auditable rules and effective-dated versions, event-driven APIs for auto-RVO recalculation, and deterministic lineage into ETRM, scheduling, credit, accounting, and the general ledger.

API-First, Event-Streamed ETRM with a Canonical CI/RIN Schema

Favor an API-first, event-streamed ETRM architecture with a canonical CI/RIN schema, so compliance adjustments propagate as immutable events rather than manual corrections. This reinforces the thesis that RegTech-driven automation stabilizes mandates, reduces settlements variance and audit findings, and shifts routing toward verifiable, low-CI domestic barrels.

Integration Strategy and Control Boundaries

Define clear control boundaries: the Control Tower orchestrates attestations, CI verifications, and reallocation decisions; the ETRM persists exposures and executes postings; credit recalibrates headroom as RVOs and equivalence values change intra-month.

Governed Agentic AI for Docket Monitoring and Rule Management

Use agentic AI where it is observable and governed: docket-monitoring agents propose rule diffs, simulate impacts, and open pull requests to the rules repository, but promotions to production require dual control, segregation of duties, and model governance sign-off.

Deployment Strategy: Effective-Dating, Blue/Green Rules, and Replayable Event Logs

Plan for retroactive effective-dating, blue/green deployments of rules, and replayable event logs to avoid ledger reversals under late regulatory updates.

Practical Sequencing and Measurable Outcomes

• Phase 1 (90–120 days): Stand up canonical data model, rules service, attestations, and ETRM hooks; cut manual RVO adjustments by 60–80% and reduce settlements variance by 20–30%.
• Phase 2 (next 90 days): Deploy the RFS/45Z Control Tower with event-driven recalculation and credit integration; target a 50% drop in audit findings and 1–2 days improvement in DSO through faster, cleaner postings.
• Phase 3 (ongoing): Enable agentic docket monitoring, scenario sandboxes, and routing optimization to low-CI barrels; improve CI verification pass rate to >98% and quantify margin lift per CI-point improvement.

Frequently Asked Questions

How does the proposed half-RIN change import economics, and what should we adjust in pricing and compliance?

It cuts RIN value by 50% for imports or for domestic gallons made with foreign feedstocks. At $1.20 per RIN, that’s roughly a $0.60/gal haircut before logistics, which narrows offshore arbitrage and favors U.S. barrels. Reflect this by encoding half-RIN eligibility and HEFA/FAME equivalence values in a rules engine, auto-recalculating RVOs and unit yields in your ETRM, and pushing updates to scheduling and accounting so rack nominations, transfer pricing, and audits stay aligned.

What are the key steps to secure Section 45Z credits with CI verification and chain-of-custody?

Stand up a traceability fabric: supplier attestations, CI chain-of-custody, reconciliations, and auditable lineage. On OMB completion and 45Z-GREET publication, activate CI verification and credit

recognition workflows integrated with ETRM and the general ledger. This reduces settlements variance and audit risk and can unlock restarts—one site moved after CI improved from 54 to 41, adding about $0.20–$0.30/gal of value and enabling a 150 MGY ramp.

What integration pattern keeps RVOs, hedges, and books in sync as rules finalize?

Use a rules‑as‑software engine governed by an RFS/45Z Control Tower, with event‑driven APIs that stream EPA/EIA updates. Auto‑recalculate RVOs, apply reallocation and equivalence values, and push updates by 7:00 a.m. next day into ETRM, scheduling, credit, and accounting using single‑source reference data and deterministic lineage. Plan for effective‑dated rules and replayable event logs. Proven outcomes include halving cycle time, 20–30% lower settlements variance, and up to a 50% drop in audit findings as controls tighten.

Trend Watch

RegTech is now the operating spine for diesel compliance and margin capture. With renewable diesel and biodiesel imports retreating and import optionality squeezed, the proposed half-RIN for imported biofuels makes domestic-first routing the economic default. The pivot from the blender’s credit to the Section 45Z clean fuel production credit elevates data, lineage, and CI proof from back-office hygiene to front-line P&L.

What to operationalize next:

• Rules-as-software: Encode RFS 2026–2027 volumes, HEFA vs FAME equivalence values, RIN reallocation and SRE treatment, and half-RIN eligibility. Drive automated RVO recalculation and reallocation updates into ETRM integration so positions, prices, and postings reflect the rulebook before the desk opens.
• CI as collateral: Stand up 45Z-GREET carbon intensity verification with CI chain-of-custody to secure 45Z. Lenders now underwrite to verifiable CI; gaps risk 45Z clawbacks and stranded restart capital.
• Trading and risk analytics: Align domestic-first routing with D4 RIN price signals and crush/feedstock basis. Model import haircuts explicitly; when half-RIN and HEFA/FAME shifts bite, offshore arbitrage narrows fast.
• Control Tower governance: Orchestrate attestations and approvals, keep SRE treatment aligned across books, and enforce effective-dated versions. Pair docket-monitoring agents with dual control to avoid model-governance surprises.

Outcome for energy trading modernization: cleaner books, faster cycle time, and lower delivered compliance cost as rules finalize. Firms that wire deterministic lineage around 45Z-GREET and automate RVO math will out-execute competitors still hand-editing spreadsheets each time renewable diesel and biodiesel imports or equivalence values lurch.

Closing Insight

RFS and 45Z have become operating code; advantage shifts to firms that industrialize certainty—encoding rules, proving CI, and routing domestic-first before the desk opens.

Make policy timing a hard dependency and deploy a Control Tower with rules-as-software , event-driven ETRM hooks , and governed AI agents to auto-recalculate RVOs and push updates by 7:00 a.m.

The payoff is structural:

• Lower delivered compliance cost
• Cleaner books
• Tighter VaR
• Faster restarts

Half-RIN economics pre-price imports while 45Z-GREET de-risks financing.

Standardizing deterministic lineage and CI chain-of-custody turns volatility into managed throughput and compresses uncertainty premiums across diesel, feedstocks, and linked LNG/LPG/bunker schedules—modernization that compounds into resilience and margin.

Partner with Arcelian

As RFS volumes, reallocation, half‑RIN eligibility, and 45Z‑GREET CI move from policy to operating code, Arcelian helps leadership turn uncertainty into throughput—wiring a rules‑as‑software engine and Control Tower into your ETRM, credit, and ledger so RVOs, equivalence values, and CI recognition flow before the desk opens.

Our clients are targeting:

• Halved cycle time
• 20–30% lower settlements variance
• Cleaner RIN/CI attribution
• Domestic‑first routing that restarts idle capacity and compresses import exposure now priced with ~$0.60/gal haircuts

Connect with our team to explore an RFS/45Z diagnostic and a sequenced modernization plan that aligns trading, risk, finance, and operations around a single, auditable rulebook.