SUMMARY - Carbon Capture, Storage, and the Debate Around Net-Zero

Carbon capture and storage (CCS) has become central to many net-zero scenarios. The technology promises to capture CO2 emissions from power plants and industrial facilities before they reach the atmosphere, or even to remove CO2 already in the air. Proponents see CCS as essential for decarbonizing hard-to-abate sectors and achieving negative emissions. Critics view it as an expensive distraction that prolongs fossil fuel dependence while failing to deliver at scale. The debate around CCS crystallizes fundamental tensions in climate strategy.

How Carbon Capture Works

Carbon capture technologies intercept CO2 at various points. Post-combustion capture removes CO2 from flue gases after fuel is burned—the most common approach for retrofitting existing facilities. Pre-combustion capture converts fuel to hydrogen before burning, separating CO2 in the process. Oxy-fuel combustion burns fuel in pure oxygen, producing concentrated CO2 streams easier to capture.

Once captured, CO2 must be transported (usually by pipeline) and stored permanently. Geological storage injects CO2 into deep underground formations—depleted oil and gas reservoirs, deep saline aquifers, or unmineable coal seams. The CO2 must remain trapped for millennia; leakage would negate climate benefits.

Direct air capture (DAC) represents a different approach: removing CO2 directly from ambient air rather than from concentrated point sources. DAC is currently far more expensive than point-source capture but could theoretically operate anywhere and address emissions from diffuse sources.

Current Status and Scale

Despite decades of development, CCS operates at tiny scale relative to climate needs. Global capture capacity is roughly 40 million tonnes of CO2 annually—about 0.1% of global emissions. Most operating projects use captured CO2 for enhanced oil recovery (EOR), injecting it into oil fields to extract more petroleum—a climate benefit only if the additional oil isn't burned.

Costs remain high. Capture adds significant expense to power generation or industrial production. Transport and storage add more. Total costs of $50-100+ per tonne of CO2 make CCS uneconomic in most contexts without carbon pricing or subsidies. Costs have fallen more slowly than hoped, unlike the dramatic cost declines in solar and wind power.

Many planned projects have been cancelled or delayed. The technology works technically—captured CO2 has been stored successfully—but economics have not cooperated. Projects that depend on enhanced oil recovery face uncertain oil prices. Those requiring carbon prices face uncertain policy environments. Private investment has been hesitant.

The Case for CCS

Some emissions are genuinely hard to eliminate. Cement production releases CO2 from chemical reactions, not just fuel burning. Steel production currently requires carbon. Some industrial processes may need CCS regardless of energy source decarbonization. For these sectors, CCS may be the only viable pathway to deep decarbonization.

Many scenarios limiting warming to 1.5°C or 2°C include substantial CCS. The IPCC median scenario for 1.5°C includes capturing 10 billion tonnes of CO2 annually by 2050. Achieving net-zero may require not just reducing emissions but also removing past emissions from the atmosphere. Bioenergy with carbon capture (BECCS) or direct air capture could provide negative emissions.

CCS could preserve some value in existing infrastructure. Rather than stranding fossil fuel assets entirely, capture technology could allow continued operation with reduced climate impact. For regions dependent on fossil fuel industries, this offers a less disruptive transition pathway. Workers and communities might retain livelihoods while contributing to climate solutions.

The Case Against CCS

Critics argue CCS diverts resources from proven solutions. Every dollar spent on CCS is a dollar not spent on renewables, efficiency, or electrification—approaches with declining costs and growing deployment. CCS risk extends fossil fuel dependence by making continued extraction seem compatible with climate goals.

The technology's track record inspires little confidence. Projects have consistently underperformed, cost more than projected, and faced technical problems. Enhanced oil recovery applications provide dubious climate benefits. Promised cost declines have not materialized. Scaling from today's capacity to scenario requirements would require unprecedented expansion.

Long-term storage presents risks. While geological storage appears secure, guaranteeing permanence over millennia is inherently uncertain. Monitoring requirements extend indefinitely. Liability for any leakage remains unclear. We would be creating obligations for future generations to maintain infrastructure securing our emissions.

Enhanced Oil Recovery Complications

Most operational CCS uses captured CO2 for enhanced oil recovery—injecting it into oil fields to push out additional petroleum. This creates circular logic: capturing carbon to extract more carbon. Net climate benefit depends on whether the additional oil would be extracted anyway and what replaces it.

EOR has driven CCS development because it provides revenue from captured CO2. Without EOR, projects need carbon prices or subsidies to be economic. But EOR ties CCS to fossil fuel extraction, undermining claims of climate benefit. The technology developed for oil industry purposes may not transfer to genuine sequestration.

Net-Zero and Negative Emissions

Scenarios achieving net-zero emissions typically rely on negative emissions—removing CO2 from the atmosphere to compensate for residual emissions from hard-to-abate sources. These scenarios often assume large-scale bioenergy with CCS (growing biomass that absorbs CO2, burning it for energy, and capturing the resulting emissions) or direct air capture.

This reliance on future negative emissions is controversial. It assumes technologies will work at scale that haven't been demonstrated. It potentially justifies continued current emissions based on future cleanup. If negative emissions fail to materialize at projected scale, climate targets become unachievable. Some argue this represents intergenerational burden-shifting of the worst kind.

Proponents counter that some level of negative emissions is likely necessary given already-committed warming and hard-to-eliminate emissions. The question isn't whether to develop these technologies but how much to rely on them versus other approaches. Prudent planning includes developing options even if primary strategies are preferred.

Questions for Consideration

Should public funding support CCS development, or should resources prioritize renewables and efficiency with proven track records?

Can CCS play a legitimate role in climate strategy, or does it primarily serve to extend fossil fuel operations?

How much should climate scenarios rely on negative emissions technologies that don't yet exist at scale?

Who should bear responsibility for monitoring and maintaining CO2 storage sites over centuries or millennia?

Is CCS essential for decarbonizing industrial sectors, or are alternative approaches being overlooked?