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Public-source reference case Version 1

Before relying on a DurationX audit, inspect how DurationX handles public evidence.

Willow Rock is used here only as an inspectable public record. This is not a client report, project review, feasibility conclusion, or endorsement.

How this was compiled ↓Inspect release integrity ↓

Reference snapshot

As of
July 28, 2026
Record scope
2 DOE pages · 0 private files
Readiness score
Not produced
Release integrity
Ed25519 attested

Published by DurationX (legal entity: Dijin Teknoloji Limited Şirketi, Ankara, Türkiye), the vendor-independent, human-reviewed pre-CAPEX assumption-readiness audit for long-duration energy storage. DurationX is run today as a single founder-operated pilot, so this article — like every DurationX report and public page — is attributed to the operating entity rather than to an individual. See Security & Data Handling for the full operator profile, human-review scope, and vendor-independence statement.

What this page proves

1. Atomic sourcing

Every factual entry resolves to a named, dated DOE source.

2. Unknown stays unknown

Absent public evidence produces not evaluable, never an invented answer.

3. Visible transformation

The derived duration exposes its 4,000 MWh ÷ 500 MW inputs.

4. Resolvable exceptions

Every boundary names the evidence that could close or explain it.

5. Signed release

Case v1 binds one canonical hash to an Ed25519 release attestation.

01 · Evidence boundary

What the selected record establishes — and what it does not

The boundary is part of the analysis, not a disclaimer added after it.

Established by the selected record

  • What DOE publicly described in its January 2025 conditional-commitment announcement.
  • That DOE published an Environmental Assessment and Finding of No Significant Impact page in June 2026.
  • How the two records differ in purpose and what each record expressly does not decide.

Not established by the selected record

  • Whether a federal loan guarantee has closed or been issued.
  • The current status or terms of any interconnection agreement.
  • Firm EPC, procurement, or equipment-supply commitments.
  • The project’s current construction schedule or commercial-operation date.
  • Operational performance, availability, efficiency, or achieved cost.

DurationX is not affiliated with, retained by, or endorsed by Willow Rock, GEM A-CAES, Hydrostor, the U.S. Department of Energy, or any project participant.

This public-source reference case is not a feasibility review, investment recommendation, technology ranking, project score, or conclusion about whether the project should proceed.

02 · Atomic fact register

Facts, declarations, and interpretations remain separate

A derived statement is never presented as if the source said it directly.

declared assumption

pft_425dcbb86fec748e97e7c456

DOE described the planned facility as 500 MW with 4,000 MWh of storage capacity in Eastern Kern County, California.

Evidence: U.S. Department of Energy · 2025-01-08

declared assumption

pft_6d58f5cedf661fdaf51b923d

DOE described the planned A-CAES process as capturing, storing, and reusing heat from the compression cycle through a thermal-storage system.

Evidence: U.S. Department of Energy · 2025-01-08

fact

pft_96dd65cfcd7701ff9ee19079

DOE announced a conditional commitment for a loan guarantee of up to $1.76 billion, including up to $279 million in capitalized interest, to GEM A-CAES for the Willow Rock project.

Evidence: U.S. Department of Energy · 2025-01-08

declared assumption

pft_97891e69849a82b5ed1cff83

DOE described an above-ground water reservoir as the means used to maintain constant cavern pressure during generation.

Evidence: U.S. Department of Energy · 2025-01-08

declared assumption

pft_b9a1ddc7cf515c2afcd99d36

DOE separately described the planned facility as able to dispatch stored energy at full power for more than eight hours.

Evidence: U.S. Department of Energy · 2025-01-08

fact

pft_c32180540b67164fb82e3ecd

DOE’s June 2026 page states that it issued an Environmental Assessment and Finding of No Significant Impact concerning potential federal financial assistance for the project.

Evidence: U.S. Department of Energy · 2026-06-30

fact

pft_c37ac581781f017d3f884f8a

DOE identified Willow Rock as a planned advanced compressed-air energy storage system in Eastern Kern County, California.

Evidence: U.S. Department of Energy · 2025-01-08

fact

pft_c694d6a37f894ceebb25c632

DOE identified GEM A-CAES as a subsidiary of Hydrostor USA Holdings, which it identified as a subsidiary of Hydrostor Inc. of Canada.

Evidence: U.S. Department of Energy · 2025-01-08

derived interpretation

pft_d432a20388abd42f289c316b

The stated 4,000 MWh divided by 500 MW implies an eight-hour discharge duration at the declared power level.

Evidence: U.S. Department of Energy · 2025-01-08

fact

pft_d4c2575b3095f70c263caa68

DOE stated that technical, legal, environmental, and financial conditions must be satisfied before definitive financing documents are entered into and the loan is funded.

Evidence: U.S. Department of Energy · 2025-01-08

fact

pft_e2b267f29b029da515d24d09

DOE expressly states that posting the environmental documents, other than a Record of Decision, should not be read as recommending a loan or loan-guarantee decision.

Evidence: U.S. Department of Energy · 2026-06-30

declared assumption

pft_f2adda05e4150f24de70dc13

DOE stated that, if finalized, the planned facility was expected to provide long-duration storage for the southern California grid.

Evidence: U.S. Department of Energy · 2025-01-08

03 · Assumption register

The public record is compiled, not flattened

Declared project values are labeled as declarations. Arithmetic is labeled as derived. Unknown status stays not evaluable.

Implied duration

pas_090c1d0061b2e7f3a124288a

established

8 hours at the declared power level

Arithmetic derived only from the two declared capacity values: 4,000 MWh ÷ 500 MW.

Evidence: U.S. Department of Energy · 2025-01-08

Declared power

pas_1d71b99a6552644e44dca3d8

declared

500 MW

DOE’s 2025 announcement describes the planned project at this power level; it is not an operational measurement.

Evidence: U.S. Department of Energy · 2025-01-08

Intended grid role

pas_4583205c4846ebfa0f7883a1

declared

Long-duration storage for the southern California grid

This is DOE’s stated intended role if financing is finalized, not verified operational performance.

Evidence: U.S. Department of Energy · 2025-01-08

Declared energy capacity

pas_46df49c2dccf1020f0255add

declared

4,000 MWh

DOE’s 2025 announcement describes the planned project at this energy capacity; it is not an achieved-performance result.

Evidence: U.S. Department of Energy · 2025-01-08

Technology description

pas_78e5fd130a8d48a8f32abf6d

declared

Advanced compressed-air energy storage

DOE uses this technology description for the planned project; this reference case does not independently validate technical suitability.

Evidence: U.S. Department of Energy · 2025-01-08

Project location

pas_8b92863c356ebe004ed715af

declared

Eastern Kern County, California

Both selected DOE records locate the proposed facility in Kern County; no exact coordinate is required or reproduced here.

Evidence: U.S. Department of Energy · 2026-06-30 · U.S. Department of Energy · 2025-01-08

Commercial-operation date

pas_c43d447a84d9f441ea5d82b8

not evaluable

Not established by the selected public record

Neither selected DOE page provides a current, integrated commercial-operation milestone.

Evidence: U.S. Department of Energy · 2026-06-30 · U.S. Department of Energy · 2025-01-08

Final financing status

pas_ed0bd506f862b08fa4f91fd8

not evaluable

Not established by the selected public record

The 2025 record is conditional, while the 2026 environmental-review page expressly does not recommend a financing decision.

Evidence: U.S. Department of Energy · 2026-06-30 · U.S. Department of Energy · 2025-01-08

04 · Exception register

Three boundaries that prevent false certainty

These are source-status distinctions, not adverse findings about the project.

conditional status

Conditional commitment is not financial close

The 2025 DOE announcement records an intent to provide a guarantee subject to technical, legal, environmental, and financial conditions. The selected record does not establish that those conditions were satisfied.

This is a status boundary in the source, not a finding that financing failed or will not close.

Evidence: U.S. Department of Energy · 2025-01-08

scope boundary

Declared capacity ratio and duration wording need a shared test basis

The declared 4,000 MWh and 500 MW values imply exactly eight hours at the stated power, while DOE separately describes full-power dispatch for more than eight hours. The selected record does not provide the test conditions needed to reconcile those descriptions.

This is an evidence request, not a finding that either public description is inaccurate.

Evidence: U.S. Department of Energy · 2025-01-08

scope boundary

Environmental review is not a loan decision

The 2026 DOE page records issuance of an EA and FONSI but expressly separates that posting from a recommendation on a loan or loan guarantee.

This does not diminish the environmental milestone or predict a financing outcome.

Evidence: U.S. Department of Energy · 2026-06-30

scope boundary

Planned capacity is not operational evidence

The power and energy values are public project-description values. The selected record contains no achieved performance test.

DurationX does not infer that the declared values are inaccurate.

Evidence: U.S. Department of Energy · 2025-01-08

05 · Dependency map

What follows from what

The arrows expose the reasoning chain; they do not turn a public description into verified project performance.

Satisfaction of financing conditions

would be evidenced by

definitive financing documents and funding status

Evidence: U.S. Department of Energy · 2025-01-08

Full-power duration under defined operating conditions

would be tested through

commissioning acceptance thresholds and procedures

Evidence: U.S. Department of Energy · 2025-01-08

Conditional DOE commitment

depends on satisfaction of

technical, legal, environmental, and financial conditions

Evidence: U.S. Department of Energy · 2025-01-08

EA and FONSI publication

supports an environmental-review milestone but does not establish

a final loan-guarantee decision

Evidence: U.S. Department of Energy · 2026-06-30

Declared 500 MW and 4,000 MWh

arithmetically implies

8-hour duration at the declared power level

Evidence: U.S. Department of Energy · 2025-01-08

8-hour duration at the declared power level

require a shared test basis to establish

full-power duration under defined operating conditions

Evidence: U.S. Department of Energy · 2025-01-08

Commissioning acceptance thresholds and procedures

would determine whether evidence supports

the declared operating-duration basis used in a committee file

Evidence: U.S. Department of Energy · 2025-01-08

06 · Evaluation limits

Not evaluable is a result

DurationX does not convert absent public evidence into a negative project conclusion.

07 · Evidence requests

What would make the next review more decision-useful

Each request includes observable acceptance criteria. It is not a claim that the project lacks the document.

  1. 01

    Final financing-status record

    Closes the distinction between a conditional commitment and executed federal financing.

    Acceptance criteria

    • — Dated record from DOE or the financing parties
    • — Unambiguous status of the loan guarantee
    • — Project identity matches Willow Rock / GEM A-CAES

    Evidence: U.S. Department of Energy · 2026-06-30 · U.S. Department of Energy · 2025-01-08

  2. 02

    Integrated project schedule

    Connects permitting, financing, procurement, construction, commissioning, and commercial operation.

    Acceptance criteria

    • — Single version-controlled schedule
    • — Critical-path dependencies visible
    • — Owner and as-of date identified

    Evidence: U.S. Department of Energy · 2026-06-30 · U.S. Department of Energy · 2025-01-08

  3. 03

    Firm EPC and procurement basis

    Distinguishes planned project values from contracted scope, pricing basis, and delivery dates.

    Acceptance criteria

    • — Executed or binding commercial record
    • — Scope and exclusions visible
    • — Currency year, validity date, and delivery basis visible

    Evidence: U.S. Department of Energy · 2025-01-08

  4. 04

    Executed interconnection evidence

    Establishes the current grid-connection milestone rather than relying on a project description.

    Acceptance criteria

    • — Executed agreement or utility-issued milestone record
    • — Project and point-of-interconnection identifiers visible
    • — Effective date and relevant milestone dates visible

    Evidence: U.S. Department of Energy · 2025-01-08

  5. 05

    Commissioning acceptance plan

    Defines how declared power, energy, duration, and availability would become verified operating evidence.

    Acceptance criteria

    • — Measurable acceptance thresholds
    • — Test duration and operating conditions
    • — Responsible independent or counterparty witness identified

    Evidence: U.S. Department of Energy · 2025-01-08

08 · Version trace

The record changes; the earlier snapshot remains explainable

2026-06-30

DOE published an Environmental Assessment and FONSI page for potential federal financial assistance and expressly separated that publication from a financing recommendation.

Evidence: U.S. Department of Energy · 2026-06-30

2025-01-08

DOE announced a conditional commitment and described the planned facility as 500 MW / 4,000 MWh.

Evidence: U.S. Department of Energy · 2025-01-08

09 · Committee questions

Questions the record makes precise

Question 1

Which evidence joins the public project description to the current interconnection, procurement, commissioning, and commercial-operation schedule?

Evidence: U.S. Department of Energy · 2026-06-30 · U.S. Department of Energy · 2025-01-08

Question 2

Which dated record, if any, establishes final financing status after the conditional commitment?

Evidence: U.S. Department of Energy · 2026-06-30 · U.S. Department of Energy · 2025-01-08

10 · Sources and integrity

Two named sources. No copied assets.

DurationX links to the originals and independently writes every displayed statement.

Source 1 · U.S. Department of Energy

GREEN

EA-2326: Environmental Assessment and FONSI for the Willow Rock Energy Storage Center, Kern County, California

Published 2026-06-30 · Updated 2026-07-01 · DOE web landing page; descriptive paragraph and decision-scope disclaimer

Open the original DOE source

Source 2 · U.S. Department of Energy

GREEN

LPO Announces Conditional Commitment for Long Duration Compressed Air Energy Storage to Enable a Diverse and Reliable Generation Mix

Published 2025-01-08 · Updated 2025-01-16 · DOE web page; announcement body and conditional-commitment explanation

Open the original DOE source

Canonical content fingerprint

97995b6fa0a5c24a393cb86f1964911c8b2a9b90e825f2d38fe2de19659fbe61

Schema v1 · Compiler durationx-public-reference-compiler-v1 · Case version 1

Release attestation · signature verified

This case version was signed after the source-rights, technical, editorial, and publication checklist was completed.

Attestation
pra_10acf143ab8fb0fdfbe99e85
Signing key version
v1
Ed25519 signature
tsR6lV51qTPzjZdEuaB/SK4Cpnej2kALCCjRiHegk63NiX2ow8VAFYg0mprrHQIzmUNXZsIlyPqVKL5OcRJcAQ==
Verify this reference release

Correction path

Found a source change or factual error?

Send the source URL and the affected statement to support@durationx.com. A correction creates a new version; it does not silently rewrite the previous record.

Apply the same discipline to a project file

See the paid decision brief before deciding whether to request an audit.

The worked example shows the reviewed deliverable. The fit check confirms scope before any payment is requested.

See what a reviewed audit includesCheck project fit
Open Reference Room: Willow Rock | DurationX