Life cycle assessments (LCAs) for wind farms are like those for electric vehicles (EVs): there are many available (not as many as for the EVs, to be sure), so it would take some time to become familiar with the entire, or even most of, the body of work. For this installment I’ve chosen a 2015 study from Denmark, being reasonably recent, in a country which has led the charge toward both on- and offshore wind energy for several years, and is home to the European leader in wind power installations, Örsted.
European market share of various wind farm engineering companies, 2020.
Share of electricity provided by wind power in Denmark, 2009-2020.
This study analyzes the effects on climate change and the physical environment of the construction of two onshore (2.3 MW geared drive and 3.2 MW direct drive) and offshore (4.0 MW geared drive, and 6.0 MW direct drive) turbines. (These are considered somewhat small now, with 8.0 MW turbines on the market and 13.0 MW turbines coming soon.) Denmark is highly dependent on wind power for its electricity: 42% of the country’s electricity came from wind in 2015, and 48% in 2020.
From the 2015 report by Alexandra Bonou et al. System boundaries of the engineering study.
From the 2015 report by Alexandra Bonou et al. Percentage of total materials by weight for each component of the wind turbine assembly, both onshore and offshore.
Review of previous LCAs showed very inconsistent treatment of the end-of-life (EoL) stage. This study’s results in that area are tentative because of varying equipment life spans, and that not all components, such as fiberglass, are commercially recyclable yet. In the main, construction materials were found to dominate the environmental impacts, with concrete for the foundation dominating the onshore installations, and steel for the foundation and tower dominating the offshore.
From the 2015 report by Alexandra Bonou et al. Climate change impact\s and energy payback time for the four turbine types in the study.
From the 2015 report by Alexandra Bonou et al. Climate change impacts, as a percentage of the whole, for each phase of turbine life.
The cost in terms of greenhouse gas (GHG) emissions ranged from 5.0 (onshore) to 10.9 (offshore) g CO2eq/kWh (grams CO2 equivalent per kilowatt-hour). This is roughly one hundred times better than the climate impacts of typical coal or natural gas (990, 530 g CO2eq/kWh respectively) plants. And in all four cases, the energy payback time (EPBT) was under a year, meaning the investments pay themselves off quickly.
From the 2015 report by Alexandra Bonou et al. Modeled impacts of each turbine type on a range of specific aspects of the environment.
The report looks at effects as
specific as particulates, ozone (O3) formation and eutrophication
(organic pollution of water, leading to algal blooms and subsequent hypoxic
effects). This is considered important because, even in the drive to make
energy systems less carbon-intensive, these other environmental effects can be
as or more severe in renewable than conventional energy.
From the 2015 report by Alexandra Bonou et al. Detailed breakdown of component contributions to global warming.
Tomorrow: US Department of Defense reports on climate threats and readiness.
Be brave, be steadfast, and be well.
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