Learnings

Outcomes

The overall result of the LCA is that the carbon emissions associated with the 40-year lifecycle of the 2000 MW HVDC converter stations and connecting cables are 749,662,358 kgCO2e for the Holistic Transition scenario (1,383,598,052 kgCO2e for the Counterfactual scenario), before any benefit from the use of recovered materials is taken into account. The recycling of materials and equipment means that new products can be produced in the future that do not require so many raw materials to be extracted and processed as the recycled materials within the equipment onsite can be reused. In total, material recovery could prevent up to 10,141,404 kgCO2e of emissions.

For the Holistic Transition scenario, the carbon emissions from the supply of raw materials (43.96%) and the use phase (44.51%) are the main sources of emissions. They are also the largest for the Counterfactual scenario, but in this instance the use phase is significantly greater (67.38% to 23.82% for the raw materials). The operational use phase, where the emissions associated with the power losses from the converter stations and cables are accounted for, are naturally related to the carbon intensity of electricity generation.

Lessons Learnt

It is recommended that NGET:

• Review any site-specific data they obtain regarding HVDC systems for comparison with the data used in this report to identify any areas where the LCA could be refined in future.
• Review where carbon savings could be made throughout the lifecycle of HVDC systems.
• Continue to monitor technological developments regarding HVDC assets and potential carbon reductions such as energy efficiency improvements.
• Discuss carbon emissions and sustainability with supply chains and request/require low-carbon options where feasible.