Carbon Dioxide Removal (CDR)

Meeting net-zero emissions targets will, above all, require swift and meaningful emissions reductions, which are expected to come from efforts such as fossil fuel replacement and efficiency improvement. However, it is becoming increasingly clear that removing carbon dioxide (CO₂) from the atmosphere will be needed to avoid global warming beyond 1.5-2°C. Estimates vary, but climate scenarios suggest that it will be almost impossible to meet the targets set out by the Paris Agreement without leveraging carbon dioxide removal (CDR) solutions. For this reason, negative emissions technologies (NETs) have been receiving increased attention from researchers, governments, investors, entrepreneurs, and various corporations with ambitious climate goals.

 

1. Direct air carbon capture and storage (DACCS), which leverages chemical processes to capture CO₂ directly from the air and sequester it in geologic formations or durable products.

2. Biomass with carbon removal and storage (BiCRS), which involves strategies that use biomass to remove CO₂ from the atmosphere and store it underground or in long-lived products. It includes approaches such as BECCS (bioenergy with carbon capture and storage), biochar, biomass burial, and bio-oil underground injection.

3. Land-based CDR methods that leverage biological processes to increase carbon stocks in soils, forests, and other terrestrial ecosystems, i.e. afforestation and reforestation and soil carbon sequestration techniques.

4. Mineralization NETs that enhance natural mineral processes that permanently bind CO₂ from the atmosphere with rocks through enhanced rock weathering, carbonation of mineral wastes, and oxide looping.

5. Ocean-based CDR methods that strengthen the ocean carbon pump through ocean alkalinity enhancement, direct ocean capture, artificial upwelling/downwelling, coastal blue carbon, algae cultivation/marine seaweed sinking, and ocean fertilization.

 

 

 

These CDR technologies are at vastly different stages of readiness. Some are nearly ready for large-scale deployment, whilst others require basic scientific research and further field trials.

 

Nature-based solutions, particularly land-based, have dominated the supply of CDR historically due to their low cost and high maturity. However, demand for this type of removal carbon credit has been dropping in voluntary markets over the past few years due to several high-profile scandals, and the low durability and low permanence associated with nature-based CDR. Corporate buyers have instead increasingly turned towards highly durable engineered carbon removal credits generated from approaches such as DACCS and BECCS. These removals offer credible climate action, but have a high price tag and are in short supply. Most durable engineered approaches are yet to be included in compliance markets, and therefore rely on pre-purchases from corporate buyers for early-stage commercial development, with this report examining the status of CDR in both voluntary and compliance carbon markets.

 

The report provides insights into the most promising technologies being developed in CDR, highlighting the pros and cons of each method, examining key drivers and barriers for growth, and comparing the removal potential, capture cost, and durability of all technologies. Despite limited current capacity, there has been much interest in DACCS as a solution to permanently remove CO₂ from the atmosphere and reverse climate change. DACCS is immediate, measurable, allows for permanent storage, can be located practically anywhere, is likely to cause minimal ecosystem impacts, and can achieve large-scale removals.

 

However, the rate at which DACCS can be scaled-up is likely a limiting factor. The challenges of deploying DACCS analysed in this report include the large energy inputs (requiring substantial low-carbon energy resources), the high cost, and the sorbent requirements. The industry is aiming for the ambitious target of gigatonne-scale of DACCS removals by 2050. To make this happen, corporate action, investments, policy shapers, and regulatory guidelines need to come together to bring down the costs.

 

Although BECCS is currently the most mature and widely deployed durable engineered CDR technology, scale-up has historically been slow, and planned capacity is modest. Despite the technologies behind BECCS being relatively mature, there is a risk that using biomass for CO₂ removal and storage may compete with agricultural land and water or negatively impact biodiversity and conservation. IDTechEx analysis has indicated that BECCS has a large potential to contribute to climate change mitigation, though not at the scale assumed in some models due to economic and environmental risk factors.

 

There are growing concerns that valuable resources will be allocated to drawing down CO₂ from the air as opposed to preventing emissions from reaching the atmosphere in the first place. Indeed, although most of the world’s mitigation efforts will need to be done by reducing emissions, there is evidence that deploying certain NETs may be more cost-effective and less disruptive than reducing some hard-to-abate emissions.

 

Incremental reductions in anthropogenic emissions will likely become more expensive once they reach very low levels, whilst the cost of effective NETs will likely reduce with deployment. In such a scenario, methods for reduction and removal of emissions may become competitors for an extended period. Nevertheless, a competitive scenario can be desirable as it can improve the world’s ability to manage unexpected risks inherent to mitigation actions. The vast availability of low-cost mitigation solutions will only become a reality if both CDR and emission abatement solutions are developed in tandem and act as complementary components of a diverse mitigation portfolio.

 

Source: idtechex.com