Authors: Robert Höglund & Alexander Rink

Five years ago, the carbon removal field was just getting started and running mostly on projections of potential, with many methods still in the lab, few buyers and almost no methodologies. Now, we have real operational data, successful deployments, published methodologies, and repeat buyers. Lots of progress and success, and also some instructional failures. That makes this a good moment to ask a simple question: how have different CDR methods actually performed relative to expectations?

In this post, we compare our interpretation of what the expectations for different CDR methods were five years ago on permanence, potential for scale, measurability and verifiability, and cost with assessments as of the end of 2025. We also provide our projection of future potential based on the same criteria.

To be clear, this is a subjective exercise. We interpret the expectations from early 2021 through the end of 2025, and provide our expectations for the next five years, 2026-2030. It is not the final truth. It is not an endorsement for any one method or category of methods, nor an indictment of others. Furthermore, exceptional companies can exist within mediocre methods, and underperforming companies within exceptional methods. If there is one thing we all know, it is that all projections are wrong, and the market will ultimately decide.

Key Patterns

BiCRS Delivers

Several Biomass Carbon Removal and Storage (BiCRS)-based methods have met or exceeded expectations: Biochar Carbon Removal (Biochar) has progressed quickly in issuances and deliveries, and several studies (study, study) indicate it is more permanent than previously thought. Biomass Geological Sequestration and Biomass Direct Storage have begun issuing carbon removal credits and delivering to purchasers, and there has been significant progress in their monitoring, reporting, and verification (MRV).

Direct Air Carbon Capture and Sequestration (DACCS) and Direct Ocean Removal, while practically limitless in potential, have progressed more slowly in issuance and delivery. Methods closer to existing operational know-how and lower in capital intensity per tonne have scaled faster. That seems obvious in retrospect. It wasn’t obvious in 2021 which methods would advance most quickly in those respects, when DACCS attracted the most attention and the most optimistic projections, and consequently the lion’s share of venture capital and US Department of Energy funding.

MRV is a Binding Constraint

Five years ago, the conversation was dominated by cost curves and permanence debates. Today, for Enhanced Weathering, Alkalinity Enhancement, Marine Biomass Carbon Capture and Sequestration (MBCCS), and to some extent Mineralization, the bottleneck is measurability. Buyers want proof of what they are getting. The methods with the cleanest measurement stories, such as Biochar, Bioenergy with Carbon Capture and Storage (BECCS), and DACCS, have had an easier time building buyer confidence, even when their costs are higher. Unlike its BiCRS siblings, BECCS hasn’t delivered meaningfully yet but leads the contracted volume race by a large margin, likely because it is the only method equipped to sign multi-million-tonne contracts at an acceptable price point for buyers.

Costs Expectations Almost Universally Higher

The field’s 2021 cost optimism has given way to more sober estimates. Operational realities, financing, permitting, logistics, MRV overhead, and energy costs have all proven harder to optimize than desktop models suggested. DACCS, BECCS, Enhanced Weathering, and mCDR methods have all seen upward cost revisions. Biochar is roughly on track, while Biomass Direct Storage may be lower-cost than expected, given its minimal transformation requirements.

Permanence Confidence Neutral to Positive

This is good news. The permanence of geological storage (DACCS, BECCS, Biomass Geological Sequestration) was already well-understood and remains so. The perspective on Biochar’s permanence, as mentioned above, has strengthened.

Method Reviews

BiCRS

Biochar Carbon Removal (BCR)

↗️ Slightly above expectations.

Biochar has moved from “promising” to one of the few CDR pathways delivering removed tonnes at a meaningful scale today. Permanence confidence has increased relative to expectations five years ago, particularly for high-temperature, high-quality biochar. It is by far the most commonly purchased durable CDR method by number of orders, with expanding corporate offtakes and a growing supplier base. Some difficulties remain, such as expanding the use of biochar, reliably tracking that the char ends up in soils, keeping machine uptime high, and ensuring reliable pipelines for sustainable feedstock. But the market traction and operational learning curve are real and compounding. Compared with early 2021 expectations, both deployment and permanence confidence have improved.

Over the next five years, biochar is well-positioned to continue scaling as the most accessible durable CDR method, with strong fundamentals across permanence, measurability, cost, and scale. The key questions are whether feedstock supply, end-use markets for physical char, and quality assurance can keep pace with growing demand.

BECCS

Slightly below expectations.

Five years ago, BECCS looked like a method that could scale cheaply and quickly. Since then, it has faced higher-than-expected costs, slow project development, significant capex needs, and permitting and transport/storage bottlenecks. There are several serious projects being built (e.g. Stockholm Exergi), and it is by far the method with the highest contracted volumes and Microsoft’s preferred method, but the expectations gap between modelled expectations for cost and scale and on-the-ground delivery remains large.

In the next few years, the serious BECCS projects now under construction should begin delivering, providing real-world data on costs and capture rates at scale. Permanence and measurability are strong, but cost and transport/storage infrastructure remain the bottlenecks.

Biomass Direct Storage (BDS)

↗️Slightly above expectations

This category, which encompasses dry biomass storage engineered to prevent degradation, has gone from a niche concept to a practice. A number of startups have started delivering tonnes with the approach, and several registries have methodologies. It still has MRV and durability questions (water, oxygen, methane emissions, monitoring), but it has arguably progressed faster than expected. Since the biomass requires minimal transformation, the method has among the lowest-cost trajectories. For the future, BDS has strong potential in scale and cost, given its minimal transformation requirements. The open question is permanence and monitoring: resolving durability concerns will determine whether this pathway moves from promising to mainstream.

Biomass Geological Sequestration

Meeting expectations

This is the “put biogenic carbon underground” family, including injected biomass slurries, bio-oil sequestration via deep well disposal, and related approaches. It has gained credibility through concrete commercial moves and very large forward commitments, largely because it builds on mature oil and gas subsurface capabilities and offers a clear durability narrative if executed properly. Development has accelerated, but the underlying assessment of potential is broadly similar to five years ago. A key question going forward is which durable biomass CDR pathway will be cheapest, and this pathway does not have the same side income from product or electricity sales as biochar and BECCS.

Over the next five years, this pathway has strong permanence and measurability credentials, but will need to prove it can compete on cost with biochar and BECCS without the benefit of co-product revenue. Scale is medium, dependent on subsurface storage access and permitting.

Direct Air Carbon Capture and Sequestration (DACCS)

Slightly below expectations.

Much progress has been made on DACCS: 140 companies have been established, many of which have now built operations, and the world’s largest DAC plant, 1PointFive’s Stratos, is almost complete. But at the same time, the development has been slower than many expected, operational complexity has been higher, and cost estimates have shifted upwards.

Over the next five years, DACCS should deliver its first large-scale operational data and begin moving down the cost curve, though costs will likely remain high for most configurations. Permanence, scale potential, and measurability are all strong; cost is the variable that will determine pace.

Enhanced Weathering (EW)

Slightly below expectations.

EW has moved from theoretically promising to multiple startups making commercial deployments, several methodologies published, and repeat buyer interest. It is getting clearer about MRV pathways. But it’s still early; measurement uncertainty, especially, has kept it from breaking out into large-scale deployments. Costs remain relatively high compared to potential, mainly due to high MRV costs. There is also a significant uncertainty about which feedstocks are most viable to measure and, therefore, most cost-effective.

In the coming years, EW’s trajectory depends almost entirely on whether MRV matures enough to give buyers confidence in what they are paying for. Scale and cost potential are both strong, but measurement science needs to converge on credible, cost-effective protocols for the method to break out.

mCDR

Alkalinity Enhancement

Meeting expectations

While this method is progressing healthily, it has suffered from very high expectations. Five years ago, there was hope that the method could cost in the low tens of dollars and be deployed on a multigigatonne scale. Since then, there have been deployments and large-scale sales by companies like Planetary and a methodology published by Isometric. However, MRV uncertainties linger, and total annual deployment costs have shifted slightly upwards, with Frontier estimating $50-160/tonne.

Over the next five years, alkalinity enhancement has strong fundamentals on permanence, scale, and cost potential. The binding constraint is MRV; if measurement science matures enough to give buyers confidence, this could become one of the highest-volume CDR pathways.

Marine Biomass Carbon Capture and Sequestration (MBCCS)

Below expectations

This category encompasses several methods, so the results are mixed. Macroalgae, which represents the majority of the volume, had not delivered to initial expectations. It turned out to be less feasible than expected, and fewer teams are working on it today. Running Tide, which pivoted from macroalgae to terrestrial biomass and then folded, is the prime example here. Several other teams have explored sinking terrestrial biomass, but few sales have been recorded. Some teams are working on alternative approaches, such as microalgae sinking, which shows promise but remains unproven at scale.The future is uncertain. If the method is proven to work, it could become a low-cost, high-scale option and be rapidly scaled up. But much more evidence needs to be published before that can happen. Legal uncertainty and acceptance from buyers and other stakeholders are also needed. A lot of potential, but obstacles to be overcome.

Direct Ocean Removal (DOR)

Slightly below expectations.

Direct Ocean Removal has progressed to credible pilots and a clearer technical narrative (removing dissolved CO₂, allowing the ocean to re-equilibrate). That said, it has the same issues as DACCS with costs and complexity. It also remains politically and scientifically sensitive: monitoring, ecosystem impacts, and governance are still immature. This is not a surprise, though, and expectations were arguably a bit lower than for DACCS five years ago.

Next, DOR will need to demonstrate repeatable, verifiable removal at pilot scale and make progress on governance frameworks. Cost and MRV are the main constraints; without cost decreases and credible measurement, buyer uptake will stay limited.

Mineralization

Slightly below expectations

We have seen progress on mineralization with several startups and methodologies, but it is still not being undertaken on a large scale. The method's main advantage is that durability is inherent - converting CO₂ into rock or binding it into stable materials - and it plugs into big incumbent industries, such as steel slag and mining aggregates. The bottleneck is obtaining evidence of its cost-effectiveness and streamlining MRV, including the counterfactual CO₂ uptake.

Going forward, mineralization’s prospects hinge on demonstrating cost-effectiveness at scale and on building out deployment in heavy-industry contexts. Permanence and measurability are inherent strengths, and if cost trajectories hold, this method has strong long-term fundamentals.

Detailed Assessment

In the table below, we outline our assessment of each method against the factors of permanence, scale, MRV, and cost.

Across nearly all methods, the next five years will be defined by the transition from proof-of-concept to proof-of-scalability. The methods that combine operational maturity, clean MRV, and manageable costs - Biochar, BECCS and other BiCRS pathways - are best positioned to attract the repeat buyer commitments needed to build real supply chains. DACCS and Direct Ocean Removal need significantly lower pricing to attract large-scale offtakes, meaning cost reductions need to occur in the lab or through smaller deployments.

For methods where MRV remains unresolved, particularly Enhanced Weathering, Alkalinity Enhancement, and ocean-based approaches, the next five years are make-or-break: either measurement science catches up, or buyer interest will consolidate around the methods that can prove what they deliver. The field’s centre of gravity has shifted from theoretical potential to operational credibility, and that shift will only accelerate.

We neither endorse nor indict any method or company. We encourage early-stage purchasers to continue balancing business case with seeding the future, and we encourage suppliers to exceed the expectations we have outlined, irrespective of their method.