ATHOS Concept Select Study

Objective

The Amsterdam-IJmuiden CO₂ Transport Hub & Offshore Storage (ATHOS) consortium—comprising Energie Beheer Nederland (EBN), N.V. Nederlandse Gasunie, Port of Amsterdam and Tata Steel IJmuiden—engaged io consulting to conduct a concept select study for a Carbon Dioxide Transport & Storage solution as part of a wider Carbin Capture and Storage (CCS) project in The Netherlands.

The goal was to identify the most viable infrastructure solution for capturing, transporting, and storing up to 8 million tonnes per annum (MTPA) of CO₂ from industrial emitters. The study aimed to balance cost, energy efficiency, environmental impact and technical feasibility to guide the project towards investment decision-making.

Project Scope

The study focused on the onshore CO₂ gathering, transport, pressure boosting and offshore export to depleted hydrocarbon reservoirs in the Dutch North Sea. Four primary development concepts were considered:

1. Maximum Greenfield (Concept 1) – New onshore and offshore pipeline infrastructure with liquefaction and pumping at the central facility.
2. Maximum Brownfield (Concept 2) – Re-use of existing pipelines where feasible, with pressure boosting via compression.
3. Marine Transport (Concept 3) – Liquefaction and CO₂ transport via new tanker vessels with onboard compression.
4. Marine Transport with Offshore Boosting (Concept 4) – Similar to Concept 3 but using a converted tanker and an offshore compression platform for injection.

A hybrid concept was also assessed, combining brownfield pipeline re-use with greenfield expansion where necessary.

Findings & Recommendations

Findings

1. Concept Feasibility & Screening:
   • Concepts 1 and 2 were found to be technically viable for further study.
   • Concepts 3 and 4 were ruled out due to the high CO₂ purity requirements of the ATHOS project, which would necessitate impractical high-pressure storage and transport solutions beyond current market capabilities. Even assuming a hypothetical higher-purity CO₂ (99.5%), marine transport was still found to be nearly twice as expensive as pipeline export.
2. Pipeline Transport & Infrastructure Selection: Pipeline transport was more cost-effective and energy-efficient than marine transport.
3. Brownfield Pipeline Re-use Feasibility: The re-use of the Petrogas 20″ pipeline for CO₂ transport was inconclusive at the screening stage due to lack of integrity data.
4. Central Facility Optimisation: The liquefaction and pumping configuration (Concept 1) was found to be more energy-efficient and operationally reliable than compression-based boosting (Concept 2).
5. Technical & Economic Optimisation: A 4 x 33.3% processing train configuration with 3 x 50% export pumps provided the best balance of turndown flexibility, efficiency and cost.
6. CO₂ Storage & Offshore Injection: Offshore storage was confirmed as feasible, but further studies were needed to match injectivity rates with emission capture timelines.

Recommendations

1. Concept Feasibility & Screening: Further study of Concepts 1 and 2.
2. Pipeline Transport & Infrastructure Selection: New offshore pipelines should be prioritised, with further evaluation of brownfield pipeline options where feasible.
3. Brownfield Pipeline Re-use Feasibility: Further assessment was conducted in the definition phase, with findings suggesting that the onshore section could be re-used with modifications, but the offshore section was unsuitable due to material limitations in handling high-pressure CO₂ injection.
4. Central Facility Optimisation: Proceed with Concept 1 (liquefaction and pumping) while keeping a hybrid option open if brownfield pipeline data supports re-use.
5. Technical & Economic Optimisation: Standardise on this configuration to minimise power consumption and maximise operational reliability.
6. CO₂ Storage & Offshore Injection: Align reservoir selection with project phasing to ensure a stable injection strategy.