Phoenix DC 50 MW: operating team owns the model.

Engagement state at handoff

§ 01 · STATEMENT OF WORKWhat's in, what's out.

Tier 3 has the largest scope of the three engagements, and an explicit SOW prevents drift mid-engagement. The Phoenix engagement was scoped at 8 weeks fixed-fee, with a written status cadence and event-driven decision calls. The full SOW is in the bundle; the operationally-critical part is what's not in scope.

Out of scope by design: direct utility or counterparty negotiation (Saguaro counsel runs negotiations, we supply the package); EPC bid solicitation, scoring, or contract negotiation (Saguaro procurement runs the bid, we supply the assumption pack); construction-phase support beyond the engagement window; operating-phase model maintenance (the analyst owns it post-handoff); permit applications.

This division matters because it sets up the cadence rules. Sgridworks is the model's author, not the project's owner; the model's outputs feed the owner's decisions, and once handed off, the model leaves Sgridworks's hands.

§ 02 · UTILITY + EPC PACKSTwo artifacts that leave the model.

Two of the engagement deliverables are not internal documents — they go to counterparties. The Utility Negotiation Package is what counsel takes into APS. The EPC Assumption Pack is what procurement puts in front of three named bidders. Both are produced by deterministic generators in the BTM-Optimize repo, so a refresh after a counterparty position changes is a single CLI invocation, not a rewrite.

§ 03 · CADENCE TAXONOMYEvent-driven, not scheduled.

Tier 3's risk-register update cadence is event-driven, not on a calendar. A scheduled-check-in cadence has a sponsor-team-flavored failure mode where snapshots arrive on time and contain nothing of substance — the project hasn't moved, so the snapshot duplicates the previous one. We trigger updates only when something material changes. The taxonomy below is the pre-commitment to what counts.

§ 04 · SNAPSHOTS IN FLIGHTThree triggers, three updates.

During the 8-week Phoenix engagement, three triggers fired. None warranted a Tier 2 reversion. The first two were favorable (project-execution risks resolving on schedule); the third was an adverse market event that compressed the IRR margin from 0.7 pp to 0.5 pp without flipping the recommendation.

§ 05 · HANDOFF BUNDLEWhat ships on day 56.

The bundle is one tarball. It contains every Tier 1 + Tier 2 + Tier 3 artifact, the BTM-Optimize repo at the engagement commit, all three update logs, all four risk-register snapshots, and a SHA-pinned reproducibility manifest. The acceptance test for the engagement: the client analyst regenerates the Tier 2 IC memo PDF byte-identically against the handed-off repo.

saguaro-phoenix-dc-tier3-bundle.zip
├── README.md                                # Bundle table of contents
├── 01-statement-of-work.md
├── 02-model-handoff-spec.md
├── 03-utility-negotiation-package.md
├── 04-epc-assumption-pack.md
├── 05-risk-register-cadence.md
├── 06-update-log-template.md
├── 07-engagement-close.md
├── METHODOLOGY.md
├── REPRODUCE.md
├── repo/                                    # BTM-Optimize at engagement commit
├── outputs/
│   ├── tier1/  (Site Screen artifacts)
│   ├── tier2/  (Power Stack Model artifacts)
│   └── tier3/
│       ├── utility-negotiation-pack.{pdf,xlsx}
│       └── epc-assumption-pack.{pdf,xlsx}
├── engagement/
│   ├── scenarios/
│   ├── runs/
│   ├── risk-register-snapshots/
│   │   ├── manifest.json
│   │   ├── ...kickoff.json
│   │   ├── ...bess-loi.json
│   │   ├── ...permit-clear.json
│   │   └── ...fuel-strip.json
│   └── update-logs/
│       ├── 2026-07-08-bess-loi.md
│       ├── 2026-07-22-permit-clear.md
│       └── 2026-08-04-fuel-strip.md
└── handoff-bundle.tarball.sha256            # Reproducibility manifest

After handoff, the model is the client's. We make no commitment to operate, update, or maintain the bundle post-engagement. The cadence transfers with the bundle; the analyst owns trigger detection from day one. Sgridworks remains available on a follow-on retainer if the client requests it, scoped and priced separately.