DWQ-2024-003412

Fact Sheet and Statement of BasisUnderground Injection and Control (UIC) Class III & V Area PermitModification and RenewalUTU-27AP-718D759and UTU-27-AP-BDCCF0CApril 2024
Location:
Millard County, Utah
Operator:
Advanced Clean Energy Storage I (ACES I), LLC
Facility Contact:
William Myers
ACES I, LLC
3165 E. Millrock Dr. Suite 330
Holladay, Ut 84121
[e-mail]
Tel. [phone]
Regulatory Contact:
Porter Henze
Utah Division of Water Quality
195 North 1950 West
Salt Lake City, UT 84116
[e-mail]
Tel. [phone]
Purpose of the Fact Sheet
Pursuant to section §144.39 of the Underground Injection Control (UIC) regulations in Title 40 of the Code of Federal Regulations (CFR) which is incorporated by reference in the Utah
UIC Administrative Rules (R317-7), the purpose of this fact sheet is to briefly describe the principal facts and considerations that went into preparing a permit renewal for the ACES
Clean Energy Storage Class III & V Permit (Permit) by the Division of Water Quality (DWQ), the UIC permitting authority. To meet these objectives, this fact sheet contains a description
of the permitted facility, a description of the injectate, information on the permitting process, a statement of basis for the major modification. This Permit was drafted under UIC permit
regulations for Class III &V injection wells associated with the production of electric power (R317-7-3.5.M and 40 CFR §146.5(e)(12) by Utah UIC Director authority as incorporated by
R317-7-1.8.
Brief Description of the Facility
ACES I plans to inject, store and withdraw hydrogen from underground storage caverns constructed in a tectonically thickened salt body located approximately 9 miles north of Delta, Utah
in Millard County and at depths greater than 3,000 feet below the surface. The construction of these caverns is permitted by ACES I’s solution mining UIC Class III Permit UTU-27AP-718D759.
The operation of the storage caverns is permited by UIC Class V Permit UTU-27-AP-BDCCF0C.
Description of Injectate
The storage caverns are created by solution mining with fresh waterunder the UIC Class III Permit which limits cavern capacity by imposing strict cavern diameter to pillar width (salt
mass between caverns) ratios and standoff distances to the edge of the salt formation itself. Brine created by the solution mining process is stored in nearby surface solar evaporation
ponds which are regulated by Ground Water Discharge Permit UGW270010. The completedcaverns are then used to store and recover gaseous hydrogen by injection and recovery under pressure
as regulated by this UIC Class V permit. The hydrogen is generated on site by electrolysis of water and is used to generate electricity by combustion. The total storage volume in the
two caverns (H-1 and H-2) that will be constructed for this project is 11 million barrels. The limits of total hydrogen capacity and injection and withdrawal rates by mass and volume
are constrained by the total cavern volume, the maximum allowable hydrogen gas pressure (Specified in the Storage Cavern Field Operating, Monitoring and Reporting Plan (SCFOMRP) which
is Permit Attachment C)
Information on the Permitting Process
The Class III & V Permit Major Renewal and Modification was prepared by the DWQ for public notice and public comment according to 40 CFR§144.39 which is incorporated by reference by
R317-7-1. Public comments will be accepted by the DWQ for 30 days following the first day of public notice in the local newspaper that serves the affected community. A hearing may be
held by the DWQ if public comments are substantial and the Draft Permit requires revision based on these comments. Only conditions subject to the modification are reopened (40 CFR §144.39(c)).
Statement of Basis for Establishing Permit Conditions
The basis for permitting for the UIC Class III & V permitsfor hydrogen storage is to ensure compliance with the Utah UIC administrative rules for Class III &V injection well activities,
R317-7. The operating plans in the approved DWQ Storage Cavern Field Operating Plan (SCFOP) were found to be conflicting with the operating requirements for the permit. The Permit is
being requested to correct conflicting operational requirements, modify existing permit boundaries, and add boundary changes as a minor modification in the class V permit.
Summary of Conditions of the Permit for Hydrogen Storage
Permit Modifications
Class III Cavern Operation Requirements
The Modification alters the permit requirements under the operating requirements found in the second paragraph of Part III.D.10. of the Class V Permit UTU-27-AP-718D759. The Permit requirements
will be changed to match the language and requirements written in the SCFOP.
Prior Language:
“ACES I shall maintain at all times, including but not limited to, cavern siting, development, expansion, and operation, a minimum spacing between all hydrocarbon caverns of a two-to-one
(2:1) pillar-to-diameter ratio (P:D), which is the equivalent of a three-to-one (3:1) center-to-center or S:D ratio, where S is the distance between the centers of two caverns or between
a cavern and the edge of the salt body, D is the average of the maximum diameter of the two caverns, and P is the minimum pillar thickness between adjacent caverns (the “Required Pillar
Width”).
Corrected Language:
“ACES shall maintain at all times, including but not limited to, cavern siting, development, expansion, and operation, a salt back thickness equal to a minimum of 4.0 cavern diameters
above the cavern, a minimum spacing between all hydrocarbon caverns of a two-to-one (2:1) pillar-to-diameter ratio (P:D), which is the equivalent of a three-to-one (3:1) center-to-center
or S:D ratio, where S is the distance between the centers of two caverns or between a cavern and the edge of the salt body, D is the average of the maximum diameter of the two caverns,

and P is the minimum pillar thickness between adjacent caverns (the “Required Pillar Width”).”
Class V Cavern Operation Requirements
The Modification alters the permit requirements under the operating requirements found in the second paragraph of Part III.D.4. of the Class V Permit UTU-27-AP-BDCCF0C. The Permit requirements
will be changed to match the language and requirements written in the SCFOP.
Prior Language:
“ACES I shall maintain at all times, including but not limited to, cavern siting, development, expansion, and operation, a salt roof thickness equal to 75 percent of the maximum cavern
height or depth, minimum spacing between all hydrogen storage caverns of a two-to-one (2:1) pillar-to-diameter ratio (P:D), which is the equivalent of a three-to-one (3:1) center-to-center
or S:D ratio, where S is the distance between the centers of two caverns or between a cavern and the edge of the salt body, D is the average of the maximum diameter of the two caverns,
and P is the minimum pillar thickness between adjacent caverns (the “Required Pillar Width”).
Corrected Language:
“ACES I shall maintain at all times, including but not limited to, cavern siting, development, expansion, and operation, a salt roof thickness at a minimum of 4.0 cavern Diameters above
the cavern of the maximum cavern height or depth, minimum spacing between all hydrogen storage caverns of a two-to-one (2:1) pillar-to-diameter ratio (P:D), which is the equivalent of
a three-to-one (3:1) center-to-center or S:D ratio, where S is the distance between the centers of two caverns or between a cavern and the edge of the salt body, D is the average of
the maximum diameter of the two caverns, and P is the minimum pillar thickness between adjacent caverns (the “Required Pillar Width”).
Modify Existing Boundaries
ACES has requested that the boundary for the UIC area permit for both the Class III and Class V permits be modified. The new permit boundary can be found in Attachment B of the Permit.
The permit area has been altered as requested.
Boundary change as a Minor Modification
Under CFR § 144.41, the director may modify a permit to make the corrections or allowances under a minor modification without the need for a public notice as required in § 144.39. Previously,
UDWQ had modified Class IIIPermit UTU-27-AP-718D759 to classify boundary changes as a minor modification. ACES has requested to add the same provision in the Class V permit under Part
III.J.2.
Language:
“Changes in the permit area boundary may be made through a minor modification of the permit according to Part II (D)(6)(c)(4) of this permit.”