Benedict Rowton, strategy lead for energy systems at the National Physical Laboratory (NPL), argues that measurement science, or metrology, is needed to accelerate solutions in the carbon capture and storage (CCS) space.
- There are a variety of CCS solutions being considered to reduce emissions, such as post-combustion capture processes (PCC).
- PCC, however, poses challenges regarding technology, storage and transportation infrastructure, and issues around developing suitable business models and commercial arrangements.
- Scientists and manufacturers are working together to address these challenges and work towards commercialisation.
There are challenges with implementing CCS schemes across the UK, with several technologies available, each one with its own variations. These include technologies such as PCC processes, direct air capture (DAC) and mineralisation of sediments.
PCCs pose challenges regarding technology, storage and transportation infrastructure, and issues around developing suitable business models and commercial arrangements. They capture industrial process and flue gases, which are then pre-treated before being fed into an absorber tower, where carbon dioxide reacts with a solvent (the secret sauce). The carbon dioxide is then stripped from the solvent, and the solvent can be re-used.
There are a number of challenges that must be addressed associated with PCCs and measurement science, or metrology, is needed to accelerate solutions.
Technological challenges
PCC technology and its deployment are novel, so there is a limited amount of experience to call upon. We need to know what happens to the solvent as it degrades over time and with repeated use or cycling, and how the operational process and solvents used impact impurity levels within the carbon dioxide stream. Furthermore, we must identify the emissions and associated pollutants from capture technology, and how they can and should be measured, monitored, and reported.
Carbon capture materials
Not only are there a variety of capture processes being developed and investigated there are also a variety of different materials that can be used to capture CO2. However, our understanding as to how effective these materials are under the different operational environments they are expected to face is limited. An increased understanding is needed to provide confidence to developers and adopters.
Infrastructural challenges
The manufacturing sector in the UK consists of numerous regionally clustered organisations. To deploy CCUS cost-effectively, infrastructure such as pipelines, compressors, and ancillary equipment needs to be developed to transport carbon from multiple sources within the same region.
Challenges occur as CO2 can be transported in different phases (solid, liquid, gas or supercritical), dependent upon various factors. The interaction of CO2 with materials changes considerably depending on the phase, composition, and any impurities present in the CO2. We need to understand this further to support material selection for large infrastructure projects which can be very challenging, especially when you have to be overly conservative due to lack of reliable data – adding considerable cost.
Storage challenges
The two main clusters progressing in the UK – HyNet and the East Coast Cluster – will transport CO2 captured from various industries via pipelines to undersea offshore storage locations and depleted gas fields. Injected and stored CO2, however, mustn’t leak from these subsea locations and methods must be developed and validated that can be used for leak detection.
Metering challenges
Government schemes will likely be used as mechanisms to incentivise investment into CCUS due to high upfront costs (amongst other complexities around pricing mechanisms). Therefore, metering will be important for fiscal purposes. Validated methods are needed to accurately measure and quantify composition, impurities, and volumes of CO2 transmitted and exchanged between stakeholders involved in the end-to-end process.
To address all of these challenges, research must continue in these crucial areas, and key industry stakeholders should look to prioritise the measurement challenges. Organisations across the UK and internationally, including NPL, are conducting this research to enable the safe, sustainable and economical rollout of CCS schemes.
What are the solutions ?
To this day, scientists have been working to provide solutions to those challenges or minimise the issues.
Scientists and manufacturers are working together to develop analytical methodologies to identify impurities in CO2. Together they have already developed a range of services to analyse compounds to extremely low limits and are continuing to make developments. The methods can be used for various purposes; to help understand and optimise the capture process, to determine the impact of impurities on infrastructure, or to validate in-line analyser capability, to give a few examples.
Controlled test rigs have been developed that can be used to test the effectiveness of different carbon capture materials under various operational conditions, to provide data on performance characteristics, and to provide confidence to developers and adopters alike.
Furthermore, scientists are investigating CO2 emissions from CCS infrastructure and associated pollutants from the capture process, for instance, amine-breakdown products including nitrosamines. They are also developing measurement methods and services for end-users, for environmental compliance testing.
Regarding cost-effective ways to transport the carbon from organisations cross-regionally, scientists located in Teddington, have been working to provide assurance that materials can be safely used within CCUS environments to a range of companies. More recently, they reviewed available corrosion rate data for different materials, and concluded that there is a clear need for standardisation of test methodologies to increase confidence in the reliability and inter-comparability of test data.
The opinions of guest authors are their own and do not necessarily represent those of SG Voice.
