length Negligible carbon costs of UHVDC infrastructure delivering renewable electricity

Ultra-high voltage direct current (UHVDC) transmission make it possible for efficient large-scale long-distance renewable energy deliver, while the infrastructure construction consumes significant amounts of material and energy. The carbon tradeoffs are often overlooked, however, hindering a holistic evaluation of its climate ben-efits. Here, by collecting field construction data from fifteen 500 kV transmission projects and applying the field data in a Life Cycle Assessment framework, we estimate the infrastructure-induced emissions of nine recently -constructed UHVDC projects in China to be 16.7 Mt CO2, which is negligible compare to an annual reduction of 305.2 Mt CO2 these projects contribute by delivering renewable electricity at full load, multiplied by a 40-yr service lifetime. The tradeoff results may evolve with advancing energy storage technology at exporting region or CCUS application at importing region. Low-carbon strategies for UHVDC construction are therefore favored, especially under China's commitment to expanding UHVDC construction along the Belt and Road Initiative.

Automated summary

Ultra-high voltage direct current (UHVDC) transmission enables efficient large-scale long-distance delivery of renewable energy, but the construction of its infrastructure consumes significant amounts of material and energy. The carbon tradeoffs are often ignored, hindering a comprehensive evaluation of the climate benefits. By collecting field construction data from fifteen 500 kV transmission projects and applying a Life Cycle Assessment framework, this study estimates the infrastructure-induced emissions of nine recently constructed UHVDC projects in China to be 16.7 Mt CO2, which is negligible compared to the annual reduction of 305.2 Mt CO2 contributed by these projects delivering renewable electricity at full load over a 40-year service lifetime. The tradeoff results may change with advancements in energy storage technology or CCUS application.