improving Carbon Manangement Modeling

[toniseibold]

Changes

• Added config to include the investment and electricity demand for compressor stations for the transport of CO2 in pipelines in dense phase
• Moved costs for sequestration from the storage sites capital_cost to the sequestration link marginal_cost to avoid problems when optimizing the network again (since investment decisions are then forced into the system)
• Added electricity demand for the post combustion carbon capture in multiple links
• adjusting the capital costs for post combustion capture depending on the flue gas concentration of carbon dioxide

A few comments
Carbon capture from industrial sources come from multiple sources:

• gas for industry: dominated by HVC, cement, aluminium
• process emissions CC: dominated by steel, cement, aluminium
• solid biomass for industry CC: paper, pulp, cement, food, beverages, tobacco, wood, textile
  Flue gas in Europe needs to meet air pollution standards. Additional investment for filters are negligible.

waiting for PyPSA/technology-data#273 to be approved since assumptions for liquefaction were currently based on shipping of CO2.

Flue Gas Properties

From the DEA technology data Table 8 and Figure 12

Flue gas source	CO₂ concentration range (vol-%)	relative CAPEX/t_CO2
Gas turbine	2–4	100 %
Waste-fired power plant	9–14	60 %
Biomass-fired power plant	13–17	55 %
Cement plant	20–30	50 %

0.1 - 0.5 kg/tCO2 caustic soda consumption depending on flue gas quality (SO2, HCl) which is negligible compared to other VOM (400 - 600EUR/t_NaOH)

Checklist

Required:

• Changes are tested locally and behave as expected.
• Code and workflow changes are documented.
• A release note entry is added to doc/release_notes.rst.

If applicable:

• Changes in configuration options are reflected in scripts/lib/validation.
• For new data sources or versions, these instructions have been followed.
• New rules are documented in the appropriate doc/*.rst files. not_applicable

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR extends the sector network CO₂ modeling by optionally adding a dense-phase (liquefaction/compression) step prior to CO₂ transport, moving sequestration costing to marginal costs, and adding electricity demand terms to several carbon capture links.

Changes:

• Add co2_network_liquefaction option to model CO₂ compression/liquefaction buses and links and to route CO₂ pipelines on dense-phase buses.
• Move sequestration cost from store capital_cost to sequestration link marginal_cost.
• Add electricity-demand penalties for (post-combustion) CC in multiple conversion links and add plotting colors for new CO₂ carriers.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
scripts/prepare_sector_network.py	Adds dense-phase CO₂ buses/links, adjusts sequestration costing, updates several CC links to include electricity demand, and threads new option through network construction.
scripts/lib/validation/config/sector.py	Adds validation schema field co2_network_liquefaction.
config/schema.default.json	Exposes co2_network_liquefaction in generated JSON schema.
config/config.default.yaml	Adds default value for co2_network_liquefaction.
config/plotting.default.yaml	Adds plotting colors for new CO₂ carriers.
doc/release_notes.rst	Adds release note entry describing the new option and CC electricity demand update.

Comments suppressed due to low confidence (2)

scripts/prepare_sector_network.py:1

• The link’s efficiency is changed to efficiency_cc, but cost scaling remains tied to costs.at["CCGT", "efficiency"]. Given the established convention elsewhere in this file (scaling per-MWel costs by the link efficiency), this produces inconsistent economics (net efficiency changes but capex/VOM scaling doesn’t). Align the cost scaling with the effective efficiency being modeled, or alternatively keep the original generation efficiency and model CC electricity demand via an additional electricity bus/output (similar to how other multi-bus links account for auxiliary electricity).

# SPDX-FileCopyrightText: Contributors to PyPSA-Eur <https://github.com/pypsa/pypsa-eur>

scripts/prepare_sector_network.py:1

• When options["biomass_spatial"] is false, bus4 is set to "" but efficiency4 is set to 1.0, which then becomes efficiency4=-1.0. If PyPSA interprets bus4="" as “no 4th terminal”, the corresponding efficiency should be 0.0 to avoid an unintended (or invalid) extra balance term. Set efficiency4=0.0 in the non-spatial branch (and apply the same pattern anywhere else a busX is disabled via an empty string).

# SPDX-FileCopyrightText: Contributors to PyPSA-Eur <https://github.com/pypsa/pypsa-eur>

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[bobbyxng]

This introduces degeneracy/potential zero cost loops. Do you have marginal_cost and capital_cost available? Also propose to set p_nom_extendable to True and remove the arbitrary high p_nom --> let the model decide.

[bobbyxng]

Looks good to me (apart from minor remarks, see dedicated comments)
One aspect I do not have an answer to yet is how we treat, e.g. how the new co2 dense carrier is shown in balance maps. co2 compression is basically equivalent with CO2 being transported through pipelines and eventually stored. Right now you would need two bus carriers to plot the whole picture:

and

[toniseibold]

Stream lining efficiency and capital_cost:
Changes for MeOH CCGT CC: efficiency before 60% efficiency after 57.7%
Changes for MeOH reforming CC: electricity demand 0.075 MWh/t_CO2
Changes Coal CC: efficiency before 35.6% efficiency after 32.4%
capital_costs consist of two components (coal power plant + carbon capture unit depending on coal carbon intensity)
biomass for industry CC: electricity demand 0.0341 MWh/t_co2
gas for industry CC: electricity demand 0.018414 MWh/t_co2
process emissions CC: electricity demand 0.093 MWh/t_co2

sanity checks
total system costs: + 2.29 bnEUR/yr
electricity supply: + 68.8 TWh/yr of which 33.1 TWh for co2 compression (269.3853 Mt compressed into dense phase at 0.123 MWh/Mt electricity consumption)

[bobbyxng]

Thanks @toniseibold for the updates
I made a proposal to update the two plot_balance_map* scripts to include the balances from the new co2 dense bus carrier, if it is enabled.