add Biochar as carbon removal technology by BertoGBG · Pull Request #2231 · PyPSA/pypsa-eur

BertoGBG · 2026-07-13T11:23:07Z

Closes # (if applicable).

Changes proposed in this Pull Request

This PR introduces Biochar as a Carbon Dioxide Removal (CDR) technology, based on #2141.
Biochar is a land-based CDR technology and its technical potential is related to land availability. As with enhanced rock weathering, the land available is calculated from the CORINE Land Cover dataset using the shared build_available_land.py script, which aggregates a per-bus land-eligibility availability matrix into eligible land area pernetwork node (in km²). That availability matrix is itself produced by a new determine_carbon_dioxide_removal_availability_matrix rule, which reuses the existing scripts/determine_availability_matrix.py unchanged (the same script already used for onwind/offwind/solar). Eligibility is governed by CORINE codes for non-irrigated arable land (potential biochar feedstock land).

#NOTE: biochar's land-eligibility settings (corine, natura, cutout, excluder_resolution) live under renewable: rather than a CDR-specific namespace, for the same reason discussed in the enhanced rock weathering CDR PR: build_available_land.py/determine_availability_matrix.py reuse the same atlite ExclusionContainer machinery and config shape already used for onwind/offwind/solar, read generically via config_provider("renewable", w.technology,
...). It's a pragmatic reuse of existing land-eligibility infrastructure, not a claim that biochar is a power-generation technology. Open to moving it to a separate namespace if preferred — worth deciding consistently across all land-based CDR technologies (rock weathering, biochar, and afforestation to follow) rather than per-PR.

The actual implementation of the CDR technology is part of scripts/prepare_sector_network.py (add_biochar()), which adds biochar as Bus/Store/Link components sharing a single co2 biochar carrier, the Link converts solid biomass
and electricity into squestered biochar-carbon (drawn from the atmosphere), and optionally exports pyrolysis waste heat to the urban central heating system (config by sector.biochar.heat_output).
The config.default.yaml contains the main parameters for calculating the CDR potential (application_per_sqkm, max_land_usage, number_years, under a top-level biochar: block), and sets sector.biochar.enable (and sector.biochar.heat_output) to false by default.

NOTE on Technology-data version

Data dependency note (technology-data)

add_biochar() requires a "biochar pyrolysis" cost entry with biomass-input, electricity-input, heat-output, capital_cost, and VOM parameters. Unlike enhanced rock weathering's data (already released in technology-data v0.15.0), biochar's cost data is not yet part of any released technology-data version, not v0.14.0 (currently pinned as "latest supported" in data/versions.csv), nor v0.15.0. It is currently only available in the PR PyPSA/technology-data#258.

Hence, running with sector.biochar.enable: true today will raise a KeyError.

Checklist

Required:

[ OK] Changes are tested locally and behave as expected.
[ OK] Code and workflow changes are documented.
[ OK] A release note entry is added to doc/release_notes.md.
[OK ] The description is human-written and any AI-generated content is marked.

If applicable:

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

Ported from the a_CDRs development branch. Adds biochar production (biomass pyrolysis with stable-carbon soil storage) as an optional CDR technology: a single pyrolysis Link per node converting biomass and electricity into stored biochar-carbon, with optional district-heat export. Land potential comes from the shared CORINE-based availability- matrix machinery (determine_carbon_dioxide_removal_availability_matrix + build_available_land), reused here for biochar only. Off by default (sector.biochar.enable: false). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

BertoGBG · 2026-07-13T11:23:20Z

@martavp @fneum

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martavp

Thanks @BertoGBG , I reviewed and left a few suggestions that you can include

I also tested the code locally and it worked.

Some elements that are missing:

[ ] Comments in config file should be moved to config/schema.default.json

[ ] Move all parameters on biochar under the same section in the config file

[ ] Add release notes

I added @fneum as a suggested reviewer.

martavp · 2026-08-12T11:45:16Z

+        carrier="co2 biochar",
+        e_nom_extendable=True,
+        e_nom_max=(
+            biochar_potentials["potential [sqkm]"].values


similarly to rock weathering, this can be named biochar_land so that we reserve the name "potentials " to the mutiplication

https://github.com/PyPSA/pypsa-eur/pull/2229/changes#r3764341512

solved in commit 9442c2b

martavp · 2026-08-12T12:06:37Z

+            w, config_provider("renewable", w.technology, "cutout")(w)
+        ),
+    output:
+        resources(


Suggested change

resources(

nc=resources(

solved in commit 9442c2b

martavp · 2026-08-12T12:09:37Z

+                    carrier="biochar heat",
+                )
+                biochar_heat_bus_waste = node + " biochar heat waste"
+                n.add("Bus", biochar_heat_bus_waste, carrier="biochar heat")


Suggested change

n.add("Bus", biochar_heat_bus_waste, carrier="biochar heat")

n.add("Bus", biochar_heat_waste, carrier="biochar heat")

solved in commit 9442c2b

Co-authored-by: martavp <30744159+martavp@users.noreply.github.com>

BertoGBG · 2026-08-18T12:52:12Z

@martavp @fneum the comment have been adressed, ready for a new review

Follows the rename in technology-data PR PyPSA#258. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

BertoGBG · 2026-10-16T12:36:54Z

The comment have been adressed and the code runs based on PR #258 from technology-data

BertoGBG and others added 4 commits June 23, 2026 09:15

Remove check_biochar_pipeline.py diagnostic script from PR

91f6bc5

Remove check_biochar_pipeline.py diagnostic script from PR

1bde538

Merge branch 'master' into biochar_PR

d7bb894

[pre-commit.ci] auto fixes from pre-commit.com hooks

d091e7c

for more information, see https://pre-commit.ci

martavp requested review from fneum and martavp August 12, 2026 11:21

Merge branch 'master' into biochar_PR

98bbbba

martavp requested changes Aug 17, 2026

View reviewed changes

BertoGBG and others added 5 commits August 17, 2026 22:57

Update config/config.default.yaml

284424c

Co-authored-by: martavp <30744159+martavp@users.noreply.github.com>

Update config/config.default.yaml

14fb9ed

Co-authored-by: martavp <30744159+martavp@users.noreply.github.com>

Update config/config.default.yaml

2ca326f

Co-authored-by: martavp <30744159+martavp@users.noreply.github.com>

biochar PR small fix variables names

9442c2b

all biochar params under sectors in config.default

cc3414e

BertoGBG requested a review from martavp August 18, 2026 12:51

BertoGBG and others added 4 commits August 20, 2026 14:34

Merge remote-tracking branch 'upstream/master' into biochar_PR

f4527ee

added release notes and schema

6618fa6

Rename biochar pyrolysis cost parameter yield-biochar to biochar-output

a34c553

Follows the rename in technology-data PR PyPSA#258. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

yield-biochar → biochar-output

e61c19a

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add Biochar as carbon removal technology - #2231

add Biochar as carbon removal technology#2231
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	n.add("Bus", biochar_heat_bus_waste, carrier="biochar heat")
	n.add("Bus", biochar_heat_waste, carrier="biochar heat")

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BertoGBG commented Jul 13, 2026

Changes proposed in this Pull Request

NOTE on Technology-data version

Checklist

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