Negative Emissions Technologies: Europe’s hope to reach Net Zero?

Negative emissions technologies (NETs) could be a key player in the EU reaching climate neutrality by 2050. The negative emissions approach is when NETs absorb and store carbon and atmospheric greenhouse gas. They are expected to have a significant impact on decarbonising energy-intensive sectors.

December 2015 marked the signing of the Paris agreement. The signing obligated its signatories to work towards limiting global temperature rise in this century to “well under” 2°C above pre-industrial levels and striving to further restrict the increase to 1.5°C. However, the Intergovernmental Panel on Climate Change (IPCC) 2018 report showed that all modelling scenarios to limit global warming to 1.5°C rely upon removing atmospheric carbon dioxide (CO2). It is estimated that around six gigatons of CO2 per annum (GtCO2/an) need to be removed from the atmosphere by 2050 to meet the Paris Agreement (Sustainability Speaks, 2022).

The 2021 European Climate Law outlines that the EU must achieve climate neutrality by the year 2050 and it requires a minimum reduction of 55% in EU net emissions by 2030, a significant increase from the previous target of 40% .

Thus, reducing atmospheric greenhouse gas concentrations to ensure global warming is “well under” 2°C and to reach climate neutrality by 2050 may depend on using the negative emissions approach.

There are numerous different types of NETs that Europe can deploy to help them reach net zero.  The three Key NETs are as follows.

1. Direct Air Capture with Carbon Storage (DACCS)

DACCS technologies extract carbon dioxide directly from the atmosphere. There are two ways this is carried out.

The first technique is liquid-based and involves passing air through a chemical solution that absorbs the carbon dioxide (CO2). The resultant air is then returned to the environment after being stripped of CO2. The liquid form of the obtained CO2 can be stored in secure permanent locations such deep geological formations.

The second technique is solid direct air capture. This involves passing air through a filter that binds with CO2 that is already present in the atmosphere. Next, heat applied to this filter causes it to release the CO2 it has trapped, making it easy to catch more of it and store it in the future.

Although DACCS have low environmental impacts in terms of space and water consumption, they are energy intensive and rely on renewable energy sources. These energy-intensive processes come with substantial expenses, with estimations reaching as high as £750 per tonne of CO2, surpassing both the present carbon pricing in the UK and anticipated rates for 2050. DACCS technology must achieve greater cost-effectiveness and energy efficiency per tonne of extracted CO2 before it becomes a viable commercial option.

One strategy to reduce costs is selling the captured CO2 for use as a fuel or in industrial processes. Nevertheless, this doesn’t consistently guarantee a net reduction in emissions, as subsequent steps might lead to emissions being generated. To establish a consistent and eco-friendly income source, it is probable that the expenses associated with DACCS technology will have to correspond with a carbon price that is deemed acceptable, rendering it an appealing choice for sectors aiming to balance their emissions through investments in carbon capture technology.

2. Bioenergy with Carbon Capture and Storage (BECCS) 

BECCS removes atmospheric CO2. BECCS reduces GHG emissions as the carbon released when the biomass is burned is offset by the carbon that captures and stores it. An IPCC report suggested it could remove between 0.4 to 11.3 billion tonnes of CO2 annually by 2100.

BECCS, crucial for achieving the goal of limiting global warming to below 2°C as outlined in the 2015 Paris Agreement, encounters two significant challenges as it expands.

The first challenge revolves around cost. In the UK for example, Carbon Capture Storage (CCS) infrastructure is currently not widespread. The technology exists but needs to be scaled larger to capture the emissions. BECCS combines biomass for energy production with CCS; therefore, there is a derived demand for CCS for the deployment of BECCS. However, in a pilot BECCS study in the UK, BECCS captured one tonne of co2 per day. To scale this a clear revenue source should be identified. This may be through initial subsides and later via market income.

The second challenge lies in sustainability. Previous experiences of CSS suggest that economic, financial and policy uncertainties could delay the deployment of these technologies. As Carton (2020) argues, the costs should be analysed through a social science lens, and funding should be directed towards their social and environmental implications. Once the trade-offs are identified, they can be mitigated efficiently. Furthermore, emphasis must be placed on regulating and ensuring biomass is sourced responsibly without depleting vital resources, especially forests. The primary emphasis should continue to be on ensuring a consistent and valuable supply of sustainable timber within the commercial forestry sector, rather than placing the main emphasis on bioenergy supply. As BECCS gains traction in global energy markets, maintaining this balance poses a noteworthy regulatory hurdle. However, the implementation of cross-border supply chain regulations, akin to those utilised by the UK and EU for overseeing other sustainable commodity supply chains, could serve as a crucial step in addressing this regulatory challenge.

3. Enhanced Weathering

Enhanced rock weathering is among the NETs under consideration by the European Commission. Enhanced weathering works by absorbing GHG emissions. It accelerates the natural rock process of weathering to capture and store CO2 (Cho, 2018). Enhanced weathering can likely be crucial in ensuring temperatures are “well under” 2°C.

Recent studies found that enhanced weathering could result in 3.7bn tonnes of CO2 per year being sequestered globally. Another study conducted in the UK found that it can capture a total of 430bn tonnes of CO2 at the cost of £15 – £361 per tonne.

However, enhanced weathering is a relatively new technology; more data is needed on the long-term effects. Given its promise the EU can implement regional enhanced weathering strategies whilst giving those involved options to opt in to provide data for continued studies on the long-term effects. Nevertheless, enhanced weathering has a large potential to help the EU reach net zero and should be implemented into the national climate change strategy. At present, there exists no EU legislation that directly pertains to the subject of enhanced weathering.

Conclusion

In conclusion, NETs hold significant promise in aiding the EU in achieving climate neutrality by 2050 and addressing the global imperative of limiting temperature rise to well below 2°C, as outlined in the Paris Agreement of 2015. These technologies play a pivotal role in absorbing and storing carbon and greenhouse gases from the atmosphere. However, they also face substantial challenges, such as cost-effectiveness, sustainability, and regulatory frameworks. Overcoming these obstacles will be essential for realising the full potential of NETs in the transition towards a sustainable and carbon-neutral future. Further research, innovation, and international collaboration are crucial in refining and scaling these technologies to meet the pressing climate goals.