Carbon Capture and Storage (CCS): How Do You Measure Real Climate Impact?
Act2Vision Industrial Carbon Management Series – Blogpost 4 “Measure CCS climate impact”.
Carbon Capture and Storage (CCS) is no longer judged on ambition alone. As projects move from pilots to large-scale deployment, the central question becomes measurable impact: How much CO₂ is actually captured, transported, and permanently stored—and how credible is that claim? For policymakers, investors, NGOs and industrial operators alike, measurement, monitoring and verification (MMV) is what separates credible CCS from greenwashing. Carbon Capture and Storage (CCS) is moving rapidly from policy concept to physical infrastructure. Across Europe, capture units are being installed, CO₂ pipelines and shipping corridors are under development, and offshore storage licences are being granted. And, as this transition accelerates, the central question is no longer whether CCS can be built, but how its real climate impact is measured.
To support net-zero targets, CCS must deliver verifiable emissions reductions. That requires robust measurement across the entire CO₂ value chain—from capture to permanent storage. In this post, we explain how CCS performance is measured across the full value chain, which metrics matter most, and why system-level measurement is becoming critical in Europe.
1. Why Measuring CCS Climate Impact Matters
CCS operates in a highly regulated and politically sensitive environment. Claims about captured CO₂ only translate into climate value if they can be demonstrated, audited and sustained over time. Measurement matters because:
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- Under the EU Emissions Trading System (EU ETS), CO₂ that is captured and permanently stored is counted as not emitted.
- The EU CCS Directive (2009/31/EC) requires proof of long-term storage integrity before responsibility can be transferred to the state.
- Public acceptance of CCS depends on transparent, credible data rather than headline capture rates.
- Investors and public funders increasingly require quantified and verifiable impact.
Without robust measurement, CCS risks losing trust, funding and political support—regardless of technical feasibility.
2. Measuring CCS Across the CO₂ Value Chain
To measure CCS climate impact properly, the entire value chain must be considered. CCS is not a single technology, but a sequence of interdependent steps. In blogpost 5. How is total CO₂ captured (tonnes per year) actually measured?, we provide devices, gauges, equipment for CO₂ captured data collection.
2.1 Measuring CO₂ Capture
At the capture site, measurement focuses on how much CO₂ is removed from flue gas or process streams. Key indicators include:
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- Total CO₂ captured (tonnes per year)
- Capture efficiency (% of incoming CO₂)
- CO₂ purity and impurity levels
- Energy consumption per tonne captured
Measurements are typically based on continuous emissions monitoring systems, mass-balance calculations and periodic verification. However, capture performance alone does not determine climate impact if downstream losses or bottlenecks occur.
2.2 Measuring CO₂ Transport
Once CO₂ is compressed and enters the transport system, measurement shifts to logistics and accounting. Relevant indicators include:
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- Mass balance between injection and receipt points
- Transport losses and venting events
- Inventory changes at terminals and buffer storage
- Allocation of volumes in multi-shipper networks
As Europe moves toward open-access CO₂ networks, accurate transport measurement becomes critical for ETS compliance, contractual settlement and system optimisation.
2.3 Measuring CO₂ Storage and Containment
Permanent storage is the decisive step for CCS climate impact. Under EU regulation, operators must demonstrate that injected CO₂:
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- Remains within the permitted geological formation
- Shows stable long-term behaviour
- Presents no significant leakage risk
Storage measurement relies on a combination of:
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- Injection rate and pressure monitoring
- Subsurface sensors
- Seismic surveys
- Geochemical sampling
- Satellite-based deformation monitoring
Monitoring continues long after injection ends, reflecting the long-term nature of climate responsibility.
3. From “Captured” to “Permanently Stored”: What Really Counts
For climate accounting, the key metric is therefore Verified tonnes of CO₂ permanently stored. This is the unit that matters for net-zero claims, ETS accounting and national climate targets.
3.1 Verified tonnes of CO₂ permanently stored (tCO₂stored)
Not all captured CO₂ delivers the same climate benefit. To measure CCS climate impact correctly, clear distinctions must be made:
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- Captured but later released CO₂ delivers no benefit
- CO₂ used in short-lived products delivers only temporary benefit
- CO₂ permanently stored delivers full climate benefit
- Stored biogenic CO₂ can generate negative emissions
3.2 Practical example: calculating “verified tonnes of CO₂ permanently stored” (one industrial site, one storage operator)
In practice, you calculate this as a mass balance across the chain, and then apply any required deductions for losses, venting, or non-qualifying volumes. Example scenario for a cement plant captures CO₂ and ships it to an offshore storage site.
| Given (annual): | tCO₂ |
| CO₂ captured at plant outlet (metered) | 500,000 |
| CO₂ vented during compression/conditioning (logged event) | 5,000 |
| Transport losses (shipping boil-off/handling, measured by terminal balance) | 2,000 |
| CO₂ received at storage site (metered at injection facility) | 493,000 |
| CO₂ injected into reservoir (metered) | 492,000 |
| CO₂ not injected due to downtime (returned/vented) | 1,000 |
Step 1 — calculate net CO₂ delivered to injection
You can use either the “captured minus losses” approach or the “received/injected” approach. In regulated environments, injection metering is usually the strongest basis. In our Given data example, the most conservative chain-consistent number is: Net injected = 492,000 tCO₂
Step 2 — define “permanently stored” for reporting
In most CCS accounting frameworks, the operational-year claim is:
tCO₂stored (year X) = net injected (year X) − confirmed releases (year X)
Assume monitoring for that year shows:
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- Confirmed surface release: 0 tCO₂
- Containment assessment indicates CO₂ remains within the storage complex (no leakage detected)
Then: Verified CO₂ permanently stored (for year X) = 492,000 tCO₂
Step 3 — optional: calculate “climate benefit” as CO₂ avoided
If your audience also wants a “CO₂ avoided” view, you can show the difference between captured and stored:
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- Captured: 500,000
- Permanently stored: 492,000
- Difference (chain losses / operational events): 8,000 tCO₂
A simple KPI stakeholders understand is Storage efficiency of the chain:
Storage efficiency = stored / captured = 492,000 / 500,000 = 0.984 = 98.4%
This tells you that even with a 90%+ capture rate, the chain still needs strong operational control to ensure CO₂ ends up stored.
3.3 Practical checklist: what evidence supports the “permanently stored” claim?
To make this credible, you typically reference three evidence layers, to show the difference between “CO₂ captured” and CO₂ verifiably stored.
| 1. Metered volumes |
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| 2. Event logs |
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| 3. Storage monitoring |
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A recommended add-on for extra practicality a one-line formula box:
Verified tCO₂ stored = Injection metered tCO₂ − Confirmed releases
And for chain performance:
Storage efficiency (%) = Verified stored / Captured × 100
4. Why Project-Level Metrics Are No Longer Enough
As CCS scales up, measurement challenges increasingly arise at the system level rather than the individual project level, which bring questions like:
- Is transport capacity available when capture comes online?
- Are storage sites ready when CO₂ arrives?
- How do outages, delays or policy changes affect overall impact?
- Are CCS networks resilient under uncertainty?
Answering these questions requires system-wide indicators such as network utilisation, storage availability, and cost per tonne avoided across scenarios.
5. Measuring CCS at System Level: The Role of Digital Twins
System-level measurement connects data from capture plants, transport networks and storage sites. This makes it possible to understand how the whole CCS system performs, not just individual components. Digital system models and digital twins help by:
- Linking capture volumes to transport and storage capacity
- Checking mass balances across the entire CO₂ chain
- Testing scenarios such as ramp-up delays or outages
- Translating technical data into clear decision insights
As CCS scales up, this type of integrated measurement becomes essential for regulators, investors and policymakers.
6. Key Takeaways
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Measuring CCS climate impact requires tracking the entire CO₂ value chain.
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Permanent storage—not capture alone—is what delivers real climate benefit.
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Robust measurement underpins ETS eligibility, funding and public trust.
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As CCS clusters grow, system-level measurement becomes essential.
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Digital twins help connect technical data with strategic decision-making.
Building process clarity today for the value chain of tomorrow.
Maarten van Oost@act2vision.nl | +31 (0) 686 698 026 | Amsterdam, Netherlands, EEA
- Blogpost #1: What is CO₂ and why is it a problem and a value chain?
- Blogpost #2: What Is Carbon Capture and Storage (CCS)? The Complete 2025 Value Chain Explained.
- Blogpost #3: CCUS for Waste-to-Energy: Why Carbon Capture at WtE Plants Matters for Europe’s Net-Zero System
