Ask "what is the success rate of carbon capture?" and you'll often get a deceptively simple answer: "The technology can capture over 90% of CO2." That figure is technically true for many systems under ideal conditions. But in the real world, where billion-dollar projects meet complex geology, fluctuating economics, and engineering realities, success is a spectrum, not a binary pass/fail. If we define success as permanently and cost-effectively removing a projected volume of CO2 from the atmosphere or industrial processes, the story gets complicated. This article moves past the marketing brochures to examine what success really looks like, why projects stumble, and how the industry is learning from both its triumphs and its setbacks.

Defining Success: It's Never Just One Number

The first mistake is using "capture rate" as a synonym for "success rate." It's like judging a restaurant solely on how fast the food arrives, ignoring taste, price, and service. A holistic view of carbon capture and storage (CCS) success involves several interlocking metrics.

Here’s a breakdown of the key performance indicators (KPIs) that collectively define success:

• Technical Capture Efficiency: This is the 90%+ figure. It measures the percentage of CO2 removed from the flue gas or air stream. For post-combustion systems at power plants, 90-95% is common. For some industrial processes like natural gas processing, it can exceed 99%.
• Capacity Factor & Uptime: How often does the plant actually run? A system capturing 95% of CO2 but offline 30% of the year due to technical issues or energy market dynamics captures far less total CO2 than a slightly less efficient but more reliable one.
• Storage Integrity & Verifiability: This is the ultimate test. Success means the CO2 stays put for millennia. It requires proven geological seals, comprehensive monitoring (like seismic surveys and soil gas sampling), and regulatory frameworks to ensure long-term liability. A leak negates all prior capture efforts.
• Economic Viability (Levelized Cost): A project that works technically but bankrupts its operators isn't a replicable success. The levelized cost of CO2 captured and stored must trend downward to be scalable. High costs have been the single biggest killer of proposed projects.
• Energy Penalty Management: Capture processes, especially solvent-based ones, consume significant energy (often 15-25% of a plant's output). A successful project minimizes this parasitic load through heat integration and process optimization.

When the Global CCS Institute assesses projects, they look at this full lifecycle. A project like Norway's Sleipner, which has been injecting about 1 million tonnes of CO2 per year into a saline aquifer since 1996 with no significant issues, scores high on all these KPIs. It's a benchmark for success.

Success Rates by the Numbers: A Reality Check from the Field

Let's look at concrete data. The track record is mixed, revealing a technology still maturing through hard-won experience.

What does this table tell us? The technical success rate for capture itself is generally high—often meeting or approaching design specs once operational. IEA GHG reports consistently show well-engineered capture units perform as expected.

But the overall project success rate—delivering promised volumes on time and budget—is lower. Projects attached to stable revenue streams (like gas processing at Sleipner and Quest) fare better than those tied to volatile power markets (like Boundary Dam).

The Make-or-Break Factors That Determine Real-World Success

Why do some projects become icons while others become warnings? It boils down to a few critical, often underestimated, factors.

1. Geology is the Final Arbiter. You can engineer the perfect capture plant, but if the storage site leaks, you've failed. Successful projects invest heavily in pre-injection characterization—years of seismic imaging, core sampling, and well testing. The failed or troubled projects often cut corners here or faced unexpected subsurface complexity. It's not glamorous, but it's everything.

2. The Economics Have to Add Up (With Help). Without a carbon price, tax credit, or dedicated funding, most CCS projects lose money. The success of the U.S. 45Q tax credit in spurring new project announcements is a clear indicator. Projects that secure long-term offtake agreements for their CO2 (e.g., for use in Enhanced Oil Recovery, where it generates revenue) have a much higher survival rate.

3. Integration vs. Bolt-On. Projects designed with CCS in mind from the start (like Quest or newer hydrogen plants) are inherently more successful than retrofits to old infrastructure. Retrofits face space constraints, inefficient heat integration, and higher costs.

4. Public and Regulatory Acceptance. This is a soft but vital factor. Projects that engage communities early, transparently address concerns about safety and groundwater, and navigate regulatory permitting smoothly avoid fatal delays. The cancellation of the Barendrecht project in the Netherlands due to local opposition is a classic case study.

The Future Trajectory: Is the Success Rate Improving?

Absolutely. The industry is on a steep learning curve. We're moving from one-off megaprojects to more standardized, modular designs. Lessons from past failures are being codified.

The next wave of projects (like the dozens in development in the U.S. Gulf Coast and the North Sea) benefits from:

• Better Storage Site Databases: Shared geological data reduces exploration risk.
• Improved Solvents & Processes: New solvents require less energy and degrade more slowly, improving uptime and cost.
• Infrastructure Clustering: Developing "CO2 hubs" where multiple emitters share a pipeline network and storage site dramatically improves individual project economics and success probability.
• Stronger Policy Support: Instruments like 45Q in the U.S. and the Innovation Fund in the EU provide more predictable revenue, attracting experienced developers.

The success rate for future projects, particularly in industrial applications and carefully selected storage hubs, is poised to be significantly higher than the historical average. However, applying CCS to more challenging sectors like cement or steel production remains a frontier with its own set of technical hurdles to overcome for success.

Your Carbon Capture Success Questions, Answered

Does a 90% capture rate guarantee a carbon capture project is successful?

Not necessarily. While a high capture rate is a crucial technical metric, it's only one piece of the puzzle. A project can achieve 90% capture but still be deemed unsuccessful if the captured CO2 leaks during transport, if the storage site fails to contain it long-term, or if the project's high costs force its premature closure. True success requires reliable integration across the entire chain—capture, transport, and permanent storage—while remaining economically viable.

What is the single biggest risk that can derail a carbon capture project's success?

Geological uncertainty is a paramount, often under-discussed risk. The long-term integrity of a storage site is non-negotiable. Injecting CO2 into the wrong type of rock formation, or one with undetected faults, can lead to leakage, rendering the entire capture effort pointless and potentially creating safety hazards. This is why extensive, upfront site characterization—far beyond initial estimates—is essential. Many early-stage failures can be traced back to overly optimistic geological assessments.

For a policymaker or investor, what is a more meaningful metric than 'capture rate'?

Look at the 'Levelized Cost of Abatement' (LCA) and 'capacity factor.' The LCA tells you the real cost of avoiding one ton of CO2 emissions, factoring in all capital and operational expenses. A project with a 95% capture rate but a sky-high LCA is not a scalable solution. The capacity factor—the percentage of time the plant operates at full design capacity—is equally critical. A plant that's frequently offline for maintenance or due to energy market fluctuations achieves little actual capture, regardless of its peak performance spec.

Are direct air capture (DAC) success rates measured the same way?

The core principles are similar—permanent storage is still the gold standard—but the context flips. For DAC, the "capture rate" from the air is near 100% for the air processed, but the volumes of air needed are colossal. Therefore, the dominant success metrics are energy consumption per tonne and the resulting cost per tonne. A DAC plant running on renewable energy that permanently mineralizes CO2 at a steadily declining cost is a success. One that runs on grid electricity (possibly from fossil fuels) at exorbitant cost is not, regardless of its technical operation.