Compressed Gas H2 Storage by jmartin4u · Pull Request #680 · NatLabRockies/H2Integrate

jmartin4u · 2026-04-15T18:47:44Z

Compressed Gas H2 Storage

This adds in the Compressed Gas Terminal storage cost model from HDSAM, to complement the geologic and pipe storage models that were already (partially) based on HDSAM. HDSAM's "Compressed Gas H2 Terminal" tab contains highly detailed calculations for the cost of H2 stored in many compressed gas tanks, at either 350 bar or 700 bar, as well as the mechanisms needed to load H2 onto shipment trucks. This cost model makes a key simplifications to the HDSAM model to reduce computational complexity and make it match the cost of just storage, without the truck loading pieces that are considered in HDSAM. The principal additions are made in h2integrate/storage/hydrogen/hydrogen_storage_cost.py

The piping, plumbing, and land costs, which are minor cost components compared to the storage vessel and compressor costs, have had their computation simplified. Constant ratios of material to H2 charge/discharge capacity have been established for these costs, by varying the capacity as an input to HDSAM and recording the ratio of material needed to achieve this H2 charge/discharge capacity. Although these ratios varied slightly throughout the range of possible capacities, they have been simplified to a constant for the purposes of this model. These constants are as follows:

Piping: 300 kg/day per meter of pipe
Plumbing: 1600 kg/day per tank storage bay
Land: 4 kg/day per m^2 of land

The tank cost is only modeled in HDSAM at two specific pressures: 350 bar and 700 bar. To allow any storage pressure to be simulated, I have simply used a linear interpolation of the two discrete $/kg costs for these pressure levels.

The compressor model h2integrate/storage/hydrogen/h2_transport/h2_compression.py, also based on HDSAM, is modified to distinguish between pipeline and storage compressors. This was previous using only the pipeline compressor HDSAM model; a new input has been created to distinguish between pipeline and storage compressors.

Regression tests for this new model were added to match the previous existing tests in h2integrate/storage/hydrogen/test/test_hydrogen_storage.py. For this, a distinction was added between expected_capex (used in test_h2_storage_capex_opex) and a new expected_storage_capex (used in test_h2_storage_capex_per_kg) - this is because, while the Papadias polynomial fits were used to calculate storage costs as a single capex value, the new compressed gas model distinguishes between the tank cost per kg (used to calculate expected_storage_capex) and other, minor capex components. The test_h2_storage_capex_per_kg only calculates this first tank component of the capex, not the whole capex.

Feedback is requested on whether the simplifications to the HDSAM model are acceptable, and if this model will serve larger H2 storage modeling goals.

Section 1: Type of Contribution

Section 2: Draft PR Checklist

Open draft PR
Describe the feature that will be added
Fill out TODO list steps
Describe requested feedback from reviewers on draft PR
Complete Section 7: New Model Checklist (if applicable)

TODO:

Step 1
Step 2

Type of Reviewer Feedback Requested (on Draft PR)

Structural feedback:

Implementation feedback:

Other feedback:

Section 3: General PR Checklist

Section 3: Related Issues

#355 and #508

Section 4: Impacted Areas of the Software

Section 4.1: New Files

None

Section 4.2: Modified Files

h2integrate/storage/hydrogen/h2_storage_cost.py
- CompressedGasStorageCostModel: Models compressed gas h2 storage
- HydrogenStorageBaseCostModelConfig: Added inlet_pressure_bar and storage_pressure_bar as fields to allow compressor in/out pressures to vary.
h2integrate/storage/hydrogen/h2_compression.py
- Compressor: Split into pipeline and storage compressors
.gitignore: Not ignoring images within docs
Moved images for docs\storage\hydrogen_storage.md into the right folder so broken images aren't shown

Section 5: Additional Supporting Information

Section 6: Test Results, if applicable

Section 7 (Optional): New Model Checklist

jmartin4u · 2026-04-15T18:53:06Z

        self,
        p_outlet,
        flow_rate_kg_d,
+        compressor_type="pipeline",


The compressor cost model works different for pipeline compressors and storage compressors - see HDSAM, "Cost Data" tab, "Compressor Costs" section (lines 120-131)

…culated)

elenya-grant

Thanks for this PR Jonathan! This is looking awesome! I wanted to give some high-level feedback sooner rather than later but would like to do a more detailed review of the h2_storage_cost.py file and the h2_compression.py file. The doc pages look awesome - and the added cost model looks good I think it's hard with converting spreadsheet models to decide what should be hard-coded vs what should be user-configurable - so feel free to push back on any comments I have related to that!

Again - its looking great and although I'd like to do a more thorough review of two files that were primarily changed, I don't want to hold-up the PR if I can't get to it soon! Great work!

johnjasa

Nice, thanks for this Jonathan! Really smooth addition and I appreciate your fantastic docs and clarity of where your numbers came from in HDSAM. Just some small notes, nothing major for sure. I do want @elenya-grant to re-review before we bring this in to make sure it's meeting her expectations.

johnjasa · 2026-04-21T17:21:28Z

-## Cost Correlations
+## Cost Correlations - Options 1-3

+For the first three options (underground pipe, lined rock caverns, and salt caverns), cost correlations from [Papadias and Ahluwalia](https://doi.org/10.1016/j.ijhydene.2021.08.028) are used for capital cost calculation.


Thanks for this citation addition!

johnjasa · 2026-04-21T17:23:34Z

+
+The model uses the calculation in the HDSAM "Compressed Gas H2 Terminal" sheet.
+Although HDSAM as a whole calculates the "Terminal capacity (kg/day)", and "Design terminal storage capacity (kg)" values from other sheets, our simplified CGT model instead takes these as inputs.
+- "Terminal capacity (kg/day)" from HDSAM is, in our model, set by the maximum value of the `hydrogen_in` input


Minor but maybe worth clarifying in the docs here; is it the max across a 24-hour timespan? Since the capacity is kg/day. Or is it the kg/hr amount multiplied by 24? I bet I'll find out shortly, but worth saying here imo

It's the max across the whole timeseries - happening in lines 614-617 of h2_storage_cost.py. Updating the docs text

johnjasa · 2026-04-21T17:35:37Z

+    Attributes:
+    - max_capacity (float): Maximum storage capacity (kg)
+    - max_charge_rate (float): Maximum charging rate (kg/h)
+    - sizing_mode (str): Mode for sizing storage (auto or set)
+    - commodity_name (str): Name of the commodity
+    - commodity_rate_units (str): Units of the commodity
+    - cost_year (int): Year for cost calculations
+    - labor_rate (float): Labor rate for cost calculations
+    - insurance (float): Insurance cost as a fraction of total cost
+    - property_taxes (float): Property taxes as a fraction of total cost
+    - licensing_permits (float): Licensing and permits cost as a fraction of total cost
+    - compressor_om (float): Compressor operation and maintenance cost as a fraction of total cost
+    - facility_om (float): Facility operation and maintenance cost as a fraction of total cost
+    - inlet_pressure_bar (float): Inlet pressure for compressed gas storage (bar)
+    - storage_pressure_bar (float): Storage pressure for compressed gas storage (bar) - max 700
+    - cg_capex_per_kg_350_bar (float): Capital cost per kg for compressed gas storage at 350 bar
+        Default is $1200 (2013 dollars) from HDSAM, converted to 2018 dollars using CEPCI.
+    - cg_capex_per_kg_700_bar (float): Capital cost per kg for compressed gas storage at 700 bar
+        Default is $1800 (2013 dollars) from HDSAM, converted to 2018 dollars using CEPCI.


Thanks for cleaning this up!

johnjasa · 2026-04-21T17:36:48Z


    commodity_name: str = field(default="hydrogen")
-    commodity_units: str = field(default="kg/h", validator=contains(["kg/h", "g/h", "t/h"]))
+    commodity_rate_units: str = field(default="kg/h", validator=contains(["kg/h", "g/h", "t/h"]))


Marking this for @elenya-grant to review; does this jive with your desired usage of commodity_rate_units for storage? i.e. those are the kg/h units? Was this h2_storage_cost.py just not up-to-date with other naming conventions in H2I?

yes - this one was not up-to-date and thanks Jonathan for updating it!

johnjasa · 2026-04-21T17:39:01Z

+        installed_capex = depreciable_capex + land_capex + other_capex
+
+        # ============================================================================
+        # Calculate OPEX - NEEDS TO BE UPDATED


Is this "NEEDS TO BE UPDATED" note still relevant? part of this PR or follow-on work?

Nope - I put that there in an intermediate commit where I had just copy-pasted code from the geologic storage. Now it is updated, I'll remove the note

…ting for doc string

elenya-grant

Looks good to me! Thanks for putting this together Jonathan! I pushed up a small change (I removed commodity_name from the config since it wasn't being used)

johnjasa

Perfect, thanks for addressing those comments! 🎉

jmartin4u and others added 10 commits April 2, 2026 17:19

Adding in compressed gas storage capex (not complete)

259b895

Capex finished

302aef0

Opex added, compressor model crashing

70d5496

Temporarily using pysam wind for speed

b159329

Calculating storage cost in example, need to fix tests

ea3ac03

First test passing

6483f76

Changed compressor types, capex_per_kg test failing

e3d5d59

Merge branch 'develop' into comp_h2_storage

b27efa3

Storage capex per keg test fixed

04aa292

Reverting example tech_config

0463477

jmartin4u commented Apr 15, 2026

View reviewed changes

jmartin4u added 5 commits April 16, 2026 11:39

Docs + changing h2 storage constants to uninstalled (installed is cal…

e3bc32a

…culated)

Fixing test values

18bc662

Merge remote-tracking branch 'origin/develop' into comp_h2_storage

595c3a5

Moving images

81db005

Changelog update

ee7701e

jmartin4u marked this pull request as ready for review April 16, 2026 17:56

jmartin4u requested review from elenya-grant and johnjasa April 16, 2026 17:56

elenya-grant reviewed Apr 16, 2026

View reviewed changes

johnjasa and others added 5 commits April 16, 2026 16:17

Merge branch 'develop' into comp_h2_storage

70ba6a1

Updating test_hydrogen_storage

d56c333

Fixing h2_storage_cost

c971250

Fixing double CEPCI inflation in tank cost

93d23d0

Merge remote-tracking branch 'origin/develop' into comp_h2_storage

86d0a4b

johnjasa approved these changes Apr 21, 2026

View reviewed changes

removed commodity_name from h2_storage cost config and updated format…

2e14c63

…ting for doc string

elenya-grant approved these changes Apr 22, 2026

View reviewed changes

johnjasa and others added 2 commits April 23, 2026 10:22

Merge branch 'develop' into comp_h2_storage

4f8be20

Addressing Jasa comments

d66659a

johnjasa approved these changes Apr 23, 2026

View reviewed changes

johnjasa merged commit a23ae26 into NatLabRockies:develop Apr 23, 2026
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Compressed Gas H2 Storage

Section 1: Type of Contribution

Section 2: Draft PR Checklist

TODO:

Type of Reviewer Feedback Requested (on Draft PR)

Section 3: General PR Checklist

Section 3: Related Issues

Section 4: Impacted Areas of the Software

Section 4.1: New Files

Section 4.2: Modified Files

Section 5: Additional Supporting Information

Section 6: Test Results, if applicable

Section 7 (Optional): New Model Checklist

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