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How much carbon is used to create an offshore wind turbine? Is it worth it?

Lifecycle emissions analysis (1) of wind turbines typically measures the climate impacts in terms of grams of carbon emitted per kilowatt hour of electricity generated. This allows comparison between the carbon emitted to manufacture a wind turbine with that emitted during fossil fuel-powered electricity generation. Of course, lifecycle emissions analysis produces an estimate, and so different studies have concluded different total amounts of carbon released by offshore wind. Importantly, however, all research agrees that offshore wind power produces considerably less carbon dioxide than almost all other forms of electricity generation.

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The Intergovernmental Panel on Climate Change (IPCC) estimates (2) that offshore wind energy produces 8–35 grams of carbon dioxide (CO2) or its equivalent (CO2eq) per kilowatt hour (kWh) of electricity generated (gCO2eq/kWh). To put that in perspective, their estimates for other sources of energy are:

Graph of life cycle CO2 emissions (in gCO2/kWh) by technology type. Coal = ~1000, Gas = ~450, Hydro = ~100, Solar PV = ~50, Wind = ~11, Nuclear = ~9. "Carbon emissions from renewables is result of from indirect emissions during life cycle and raw materials used in manufacturing.": Hydro = 89%, Solar PV = 75%.

Life cycle CO2 emissions by technology type.

Source: NREL (8)

  • Coal = 740–910 gCO2eq/kWh

  • Natural gas = 410–650 gCO2eq/kWh

  • Rooftop solar = 24–60 gCO2eq/kWh

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In 2019 researchers at the University of Santa Barbara studied the lifecycle carbon emissions of floating California offshore wind (3), and predicted carbon emissions of about 15.35 gCO2/kWh with an uncertainty range of 8.58–30.17 gCO2eq/kWh. A 2023 Chinese study (4) modeled the carbon impacts of a floating wind farm, and found its emissions to be 25.76 gCO2eq/kWh. Even the highest estimates for the carbon emissions of offshore wind are similar to the lowest estimates for rooftop solar energy.


This corresponds with what we know about onshore wind turbines, which consistently perform at lower carbon intensities (5) than almost all other forms of energy production. In fact, a 2012 study (6) of onshore wind turbines found that they “paid back” the energy used to manufacture them in just 7 months. A similar 2018 study (7) of offshore wind turbines estimated that the energy was paid back in 6 to 17 months. Given the fact that these wind turbines can operate for 20 to 25 years, they are absolutely “worth it” from a carbon perspective.

References

  1. U.S. Environmental Protection Agency. (2023, November 27). Lifecycle Analysis of Greenhouse Gas Emissions under the Renewable Fuel Standard. www.epa.gov/renewable-fuel-standard-program/lifecycle-analysis-greenhouse-gas-emissions-under-renewable-fuel

  2. Schlömer S., T. Bruckner, L. Fulton, E. Hertwich, A. McKinnon, D. Perczyk, J. Roy, R. Schaeffer, R. Sims, P. Smith, and R. Wiser, 2014: Annex III: Technology-specific cost and performance parameters. In: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Edenhofer, O., R. Pichs-Madruga, Y. Sokona, E. Farahani, S. Kadner, K. Seyboth, A. Adler, I. Baum, S. Brunner, P. Eickemeier, B. Kriemann, J. Savolainen, S. Schlömer, C. von Stechow, T. Zwickel and J.C. Minx (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-iii.pdf

  3. Bang, J., Ma, C., Tarantino, E., et al. (2019). Life Cycle Assessment of Greenhouse Gas Emissions for Floating Offshore Wind Energy in California. University of California, Santa Barbara. https://tethys.pnnl.gov/sites/default/files/publications/Bang-2019-Floating-Wind-LCA.pdf

  4. Yuan, W., Feng, J., Zhang, S., et al. (2023, February). Floating wind power in deep-sea area: Life cycle assessment of environmental impacts. Advances in Applied Energy, 9. https://doi.org/10.1016/j.adapen.2023.100122 

  5. Evans, S. (2017, August 12). Solar, wind and nuclear have ‘amazingly low’ carbon footprints, study finds. Carbon Brief. www.carbonbrief.org/solar-wind-nuclear-amazingly-low-carbon-footprints/ 

  6. Guezuraga, B., Zauner, R., Pölz, W. (2012, January). Life cycle assessment of two different 2 MW class wind turbines. Renewable Energy, 37(1): 37-44. https://doi.org/10.1016/j.renene.2011.05.008

  7. Chipindula, J., Botlaguduru, V.S.V., Du, H., et al. (2018). Life Cycle Environmental Impact of Onshore and Offshore Wind Farms in Texas. Sustainability, 10(6). https://doi.org/10.3390/su10062022

  8. Musial, W. (2023, May 10). Floating Offshore Wind Technology. National Renewable Energy Laboratory. www.boem.gov/sites/default/files/documents/renewable-energy/state-activities/Musial-Floating-Wind-Technology.pdf

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