A windfarm can offset carbon emissions generated across its 30-year lifespan in under two years, a new study says.
The study published in the Journal of the Royal Society of New Zealand also demonstrates that within six months a turbine can generate all the energy consumed across its life-cycle.
The research draws on data from the Harapaki onshore wind farm in Hawke’s Bay, New Zealand, but the authors say their findings “would be replicated across most, if not all, wind farms internationally”.
The study reviewed current literature on wind farms, as well as using real construction data to take into account everything from the manufacturing of individual turbine parts, to transporting them into place, to decommissioning the entire 41-turbine wind farm at Harapaki.
The results indicate that this particular farm would leave a carbon footprint of 10.8 gCO2eq/kWh, which equates to a greenhouse gas payback time of 1.5–1.7 years for avoided combined cycle gas turbines, and an energy payback time of 0.4–0.5 years.
“The outcomes of our study underscore the environmental efficiency of onshore wind farms and their important role in the energy transition,” lead author Isabella Pimentel Pincelli from the Sustainable Energy Systems research group, Wellington Faculty of Engineering, at Te Herenga Waka Victoria University of Wellington, 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,”she said.
To address the carbon outlay of the process of developing such wind farms, the expert team recommend developing a recycling process for end-of-life blades.
Currently blades are disposed of in landfill due to commercial feasibility, but recycling the blades – either mechanically or chemically – could result in a drop in emissions from the current 10.8 gCO2eq to a potential 9.7.
The authors note the study has some methodological limitations, as it focuses only on the energy intensity and emissions throughout the life cycle of the wind farm, even though there are other environmental impacts. It also focuses on onshore structures.
These impacts would include ozone depletion, human toxicity, acidification, eutrophication, and resource depletion. Social, wildlife, or economic impacts were also not considered.
