In a recent study published in the Journal of the Royal Society of New Zealand, researchers from Te Herenga Waka Victoria University of Wellington identified that a turbine can produce all the energy needed over its lifetime in just six months. Researchers also suggested a blade recycling procedure to reduce carbon footprints.
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Compared to thermal power facilities, a wind farm can neutralize the carbon emissions produced during its 30-year lifespan after spinning for less than two years.
The study uses data from New Zealand's Harapaki onshore wind farm in Hawke's Bay, but its authors clarify that their conclusions would apply to most, if not all, wind farms worldwide.
The wind turbine technology employed in New Zealand is consistent with that used internationally, although the carbon offset depends on the exact older technology the wind turbines are replacing, we would expect a similar offset internationally. In New Zealand, it is gas turbines, but many countries will be displacing fossil fuel generators.
Isabella Pimentel Pincelli, Study Lead Author, Sustainable Energy Systems, Wellington Faculty of Engineering, Te Herenga Waka Victoria University of Wellington
Pincelli said, “The outcomes of our study underscore the environmental efficiency of onshore wind farms and their important role in the energy transition. Notably, the manufacturing of wind turbines is the primary contributor to the carbon and energy footprints, highlighting a critical area for targeted environmental mitigation strategies.”
The study analyzed recent literature on wind farms and used actual construction data to account for everything from the production of individual turbine parts to their transportation into position to the decommissioning of the complete 41-turbine wind farm at Harapaki.
According to the findings, this specific farm will have a carbon footprint of 10.8 gCO2eq/kWh, translating to a 1.5–1.7-year payback period for greenhouse gases and a 0.4–0.5-year payback period for energy for avoided combined cycle gas turbines.
Even though the results show how onshore wind farms adhere to the principles of sustainable development, Co-Author Professor Alan Brent, Chair in Sustainable Energy Systems at Wellington, notes that more work needs to be done to make the manufacturing process more environmentally friendly.
The environmental impacts of the installation and transportation phases are important. Together they accounted for nearly 10% of the overall emissions, it therefore remains crucial to continue implementing improvements aimed at limiting negative environmental impacts while maximizing positive contributions throughout the supply chain of onshore wind plants.
Alan Brent, Professor and Study Co-Author, Sustainable Energy Systems, Wellington Faculty of Engineering, Te Herenga Waka Victoria University of Wellington
Brent said, “Notably, the manufacturing of wind turbines is the primary contributor to the carbon and energy footprints, highlighting a critical area for targeted environmental mitigation strategies.”
The expert panel suggests creating a blade recycling procedure for end-of-life blades to mitigate the carbon footprint associated with the development of such wind farms.
Due to their commercial viability, blades are currently disposed of in landfills. However, by recycling the blades chemically or mechanically, emissions could be reduced from the projected 10.8 gCO2eq to 9.7.
Furthermore, the team suggests that regular research be conducted in this field because of the “rapid advancements of technologies” and the “necessity to ensure research remains reflective of current practices to accurately inform decision-making processes.”
Certain methodological issues exist with this study. First, despite other environmental effects, including ozone depletion, human toxicity, acidification, eutrophication, and resource depletion, it solely considers the energy intensity and emissions during the wind farm's life cycle. The effects on society, wildlife, and the economy were also disregarded.
Journal Reference:
Pincelli, P. I., et al. (2024) Developing onshore wind farms in Aotearoa New Zealand: Carbon and energy footprints. Journal of the Royal Society of New Zealand. doi.org/10.1080/03036758.2024.2344785.