Whats the carbon footprint of a wind turbine?
Dear Sara,  Wind turbines are an absolute joke.  Mike M.  Hi Mike,  Thank you for this apparent attempt at a gotcha question, as it gives me the opportunity to reply with a resounding yes! People have studied, in detail, the amount of carbon pollution emitted during the life of a wind turbine. In fact, this type of analysis constitutes an entire branch of research known as life cycle assessment, with its own handbooks, internationally agreed-upon standards, specialized software, and peer-reviewed journals. To conduct a life cycle assessment of a wind turbine, or any other product, researchers begin by diagramming each stage of its existence, from manufacturing through end-of-life disposal. Next, they inventory the energy and raw materials consumed at each stage, such as the steel, fiberglass, and plastic needed during a wind turbines manufacturing, the diesel burned by ships and trucks in transporting turbine parts from factory to construction site, and the energy used during construction, operation, maintenance, and eventual deconstruction and recycling or disposal. With this information in hand, researchers calculate the carbon pollution produced during a wind turbines life cycle  in other words, its carbon footprint. Search online for the keywords life cycle assessment and wind turbine and youll retrieve dozens of published papers on this topic. Heres a non-comprehensive chart of such papers from the past five years:  The carbon footprint of wind turbines  Study year Location Configuration Rated power (megawatts) grams of CO2-eq per kWh 2019 Texas, USA onshore 2 4.9 2018 United Kingdom onshore 1.5 11.8 2018 China offshore 3.6 25.5 2018 China onshore 1.5, 0.75 8.7 2016 Europe onshore 2.3 6 2016 Europe onshore 3.2 5 2016 Europe offshore 4 10.9 2016 Europe offshore 6 7.8 2013 global onshore 2 8 2012   2000 9.7 2012   1800 8.8  This chart shows how much carbon dioxide, per kilowatt-hour of electricity generated, can be attributed to a wind turbine during its life from cradle to grave. If youre wondering about those awkward-sounding grams of carbon dioxide-equivalent, or CO2-eq, thats simply a unit that includes both carbon dioxide and other heat-trapping greenhouse gases, such as methane. You can see that the results vary by country, size of turbine, and onshore versus offshore configuration, but all fall within a range of about five to 26 grams of CO2-equivalent per kilowatt-hour. To put those numbers in context, consider the two major fossil-fuel sources of electricity in the United States: natural gas and coal. Power plants that burn natural gas are responsible for 437 to 758 grams of CO2-equivalent per kilowatt-hour  far more than even the most carbon-intensive wind turbine listed above. Coal-fired power plants fare even more poorly in comparison to wind, with estimates ranging from 675 to 1,689 grams of CO2 per kilowatt-hour, depending on the exact technology in question. Theres another crucial difference between fossil fuels and wind turbines. A coal or natural gas plant burns fuel  and releases carbon dioxide  every moment that it runs. By contrast, most of the carbon pollution generated during a wind turbines life occurs during manufacturing. Once its up and spinning, the turbine generates close to zero pollution. Whats more, wind turbines often displace older, dirtier sources that supply power to the electricity grid. For example, after a new wind farm connects to the grid, the grid operator may be able to meet electricity demand without firing up a decades-old, highly polluting coal plant. A cleaner, more climate-friendly electricity grid. In fact, its possible to calculate a carbon payback time for a wind turbine: the length of time it takes a turbine to produce enough clean electricity to make up for the carbon pollution generated during manufacture. One study put that payback time at seven months  not bad considering the typical 20- to 25-year lifespan of a wind turbine. Bottom line: Wind turbines are far from a joke. For the climate, theyre a deal too good to pass up. Send it to sara@yaleclimateconnections.org. Questions may be edited for length and clarity. Tom Toro is a cartoonist and writer who has published over 200 cartoons in The New Yorker since 2010.