The challenges of commercial-scale CCS
How to accelerate commercial-scale development and manage risk
The many stakeholders who need to work together to implement commercial-scale CCS face considerable challenges, in particularly in ensuring that individial components along the chain interact safely and effectively under diverse operating scenarios.
Design and operation of safe, commercially-viable CCS chains involves many trade-offs between diverse stakeholders. For example, optimising the economic operation of injection compressors will have an impact on how power and CO2 capture plants are operated, and vice versa.
In order to proceed to commercial-scale operation with confidence, many questions need to be answered, with decisions based on accurate quantification.
Many stakeholders, many interests
The diagram provides some idea of the many stakeholders in a typical CCS chain.
While CCS seems like 'new technology', there is little that is new in terms of individual CCS chain components. Indeed, most have been part of the power and process industry world for decades and are well understood.
However, many challenges arise from the fact that the whole chain – and, eventually, whole CO2 transportation network – needs to be considered as a single system in order to make design and operation decisions that address the commercial imperatives and risk requirements of the various stakeholders.
Decisions: techno-economic, trade-offs, screening & ranking
Many decisions arise at all levels:
- In each area, there are many technical 'local' decisions to be made. However, such decisions can have a significant impact on stakeholders in other parts of the chain.
- Technical and economic decisions are closely related. Technical decisions for process design and operation need to be governed by economic realities, and vice versa.
- Many decisions come down to trade-offs between between economics and operability, or between the interests of different stakeholders. Accurate information is required to quantify the chain-wide impact of decisions and aid negotiation.
- Alternatives need to be quickly screened and ranked according to economic (cost) or operational criteria.
- The techno-economic trade-offs that inevitably arise involve both design and operating decisions, and may require both steady-state and dynamic (transient) analysis.
For example, a decision to implement buffer amine storage in a post-combustion capture plant can result in very different operational requirements – and economics of operation – for the power plant, compression and transmission facilities, and injection & storage. All of the stakeholders involved, need accurate information to quantify the effect of such design decisions on their capital costs and operations.
Ultimately it is necessary for commercial acceptance and public opinion to prove that the whole system will work satisfactorily under a range of current and future scenarios.
Working together to manage risk and interaction
It seems obvious that stakeholders up and down the CCS chain should work closely together. However there are few common tools or approaches.
The many simulation tools currently used in power station design, amine plant design, compressor design, and analysis of transmission and injection operations, while very effective for current use within specific areas, do not allow easy analysis of whole chain steady-state and dynamic operation.
Underpinning all of this is the challenge of getting stakeholders with very different natures and commercial interests, working practices, technologies and tools – for example, power generation and oil companies – to work together.
The key enabling technology for such co-operation is system-wide modelling. This is the challenge that the ETI CCS System Modelling Tool-kit Project set out to address.