In New Zealand, renewable energy sources have historically dominated electricity generation, yet fossil fuels predominantly supply the transport and industrial heat sectors. Although renewable energy sources produce near-zero emissions during operation, environmental impacts across the technology life cycle stages remain. As the energy system transitions toward more renewable energy use, a holistic perspective is increasingly essential for understanding the environmental impacts and trade-offs involved in energy sector planning. This study applied a Life Cycle Assessment (LCA) framework to quantify the environmental impacts of New Zealand's current energy system, using a cradle-to-grave approach for energy and material flows. Impacts across the electricity, transport, heat, and cogeneration sectors were estimated for New Zealand's specific context. The analysis included electricity generation from wind, solar, hydropower, geothermal, natural gas, and coal; heating and cogeneration from fossil fuels and biomass; and both internal combustion engine and electric vehicles. Furthermore, the LCA framework was applied to a future scenario to understand the trade-offs for transition pathways. The outcomes expose, unsurprisingly, that fossil fuel-based technologies (in particular, petrol, diesel, and coal) disproportionately contribute to environmental impacts across all evaluated categories. In contrast, renewable sources achieve low carbon footprints and superior performance across nearly all impact categories compared to fossil fuels. The defossilisation of the transport sector remains the most pressing challenge for reducing the burdens associated with the energy system. Additionally, energy-efficiency improvements and the penetration of renewable sources in the material supply chain are critical to mitigating environmental impacts related to infrastructure requirements for renewable alternatives. Extrapolating the results to a proposed 2050 pathway scenario suggests that a system relying on solar photovoltaics and battery storage could reduce life-cycle greenhouse gas emissions by 59% while serving a demand that is 1.8-times higher than today and while maintaining a similar cost level. Pressures on mineral availability are expected to be reduced with future technological advancements. Although prospective life cycle assessment is not included in this work, there is a clear shift from environmental burdens stemming from burning fossil fuels today towards manufacturing solar photovoltaics and storage technologies in the future. This work provides the first national-scale, cross-sector LCA of New Zealand's energy system, harmonising electricity, heat, transport and cogeneration and linking current burdens to a 2050 net-zero pathway.
Astorga-Mendoza et al. (Wed,) studied this question.