Does offshore wind actually help with addressing climate change/reduce emissions?

At a Glance:

Turbines do have impacts, but the lifetime carbon footprint of wind farms is tiny compared to electricity generation from burning natural gas and coal--on the order of 42 and 89 times less. Their main impacts come only during the mining, processing, and manufacturing of their parts, and their construction and decommissioning, but they don’t need mined and pumped fuels to run each day for years, as gas and coal do.

 This figure is from https://www.nrel.gov/analysis/life-cycle-assessment.html 

A Deeper Dive:

The U.S. Department of Energy estimates that over its lifetime, "wind energy produces around 11 grams of CO2 (equivalent) per kilowatt-hour (g CO2/kWh) of electricity generated, compared with about 980g CO2/kWh for coal and roughly 465g CO2/kWh for natural gas". Those ratios make the overall lifetime emissions of greenhouse gasses 89 times worse for coal than wind, and 42 times more emissions for natural gas than wind. This does not even count the leaking of methane from gas drilling and transport, which is another contributor to climate change, or the fact that once wind turbines are themselves produced with clean energy, the emissions associated with production will fall even further. In fact, study after study of the lifecycle of wind turbines finds that they produce more energy than it took to produce them in around a year. For example, this study found the payback times for CO2 and energy consumption range from 6 to 17 months for offshore wind. After that time, the turbines are producing nearly zero emissions (except for maintenance and disposal).

Currently, the New England Grid (which is run off a mix of gas, nuclear, hydroelectric and other renewables) emits ~240 grams CO2e/kWh. So offshore wind produces power with 95 percent lower emissions than the current New England Grid.  Compared with “natural” (fracked) gas, wind reduces emissions by 98 percent.

In summary, while offshore wind farms do have a carbon footprint associated with their construction, operation and decommissioning (at least until they are made with electricity generated from solar or other windmills) - that footprint is small relative to the emissions from our current, fossil fuel dependent grid.  To argue otherwise is to ignore the basic fact that windmills aren’t burning anything, they are turning the energy of motion (driven by the sun and the Earth’s rotation) into electricity. Gas fired power plants are burning hydrocarbons and every molecule burned releases CO2 to the air and warms our planet. 

Understanding Complexities:

The massive summary report on climate research, the IPCC Sixth Assessment Report in 2023 listed wind as the #2 best way to produce energy while reducing the emissions of gasses causing climate change (behind solar panels), and it is the #1 resource that New England has to do so (see also this report).  If we want other states and countries to do their part, we need to do ours.