Authors: Ameli, H., Pudjianto, D., Strbac, G.

 

Abstract:

Negative emission technologies (NETs) are recognized as essential components for achieving decarbonization in energy systems, given their capability to capture atmospheric CO₂ while supporting the cost-effective transition to low-carbon electricity and gas networks. Their ability to offset residual emissions and to provide firm capacity in systems with high shares of variable renewables has been widely demonstrated. In this chapter, the applicability of NETs, including carbon capture and storage (CCS), bioenergy with CCS (BECCS), and direct air CCS (DACCS), is examined, and their technical roles, system interactions and deployment challenges are assessed. A set of UK-2050 scenarios is optimized using the integrated whole energy system and integrated hydrogen and electricity system modeling frameworks in which net-zero emissions are assumed as constraints in the presence of NETs. The system value of NETs is quantified by comparing least-cost system configurations, and it is demonstrated that when CCS is excluded, system costs increase by approximately £19 billion per year due to the required expansion of renewables, electrolyzers, hydrogen networks, and storage. When CCS, BECCS, and DACCS are included, net-negative emissions can be delivered while allowing the limited use of low-cost high-carbon technologies, such as hybrid heating and unabated gas generation, while keeping the net-zero emission constraints. Key drivers for NET deployment are identified, such as the scale of residual emissions, hydrogen pathway choices, and access to low-cost heat or electricity for capture processes. The importance of coordinated planning and operation of different energy vectors is highlighted, along with the need for stable long-term support strategies to enable large-scale investment in NETs.

 

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