What would Sandy do to turbines? 

Now that the destruction from Hurricane Sandy is quite evident, it should force Cape Codders into thinking about the proposed Cape Wind project and visualizing the image of 130 giant (400-foot-tall) wind turbines in Nantucket Sound being subjected to hurricane-force winds, rain and large ocean swells.

In a September 2010 report titled “Large-Scale Offshore Wind Power in the United States,” the National Renewable Energy Laboratory, or NREL, initially downplays the probable strength of New England nor’easter storms and hurricanes. However, it indicates that risks associated with hurricanes have not been fully explored.

The report goes on to state: “In shallow water, hurricane-generated breaking waves may also create an extreme load case that has not yet been properly evaluated, especially in the Atlantic.” Supporters of the Cape Wind project have assured the public that Category 3 hurricane-strength wind (up to 129 mph) and nor’easter storms have been part of the design. But NREL noted, “There is a very substantial risk that Category 3 and higher hurricanes can destroy half or more of the turbines at some locations.”

Looking at history, it would be wise for the public to have a healthy skepticism about Cape Wind’s claims. Supporters of Cape Wind assured us for years that the massive offshore wind project would lower electric rates. But it is now abundantly clear from Cape Wind’s overpriced contracts with NStar and National Grid that the project would, in fact, substantially increase rates for Massachusetts households and businesses.

Cape Wind’s website has no mention of hurricanes in its design or the risks associated with them. But what we have seen is that wind turbines offshore from Denmark had to be replaced in 2004 at a cost of $50 million after they failed due to damage resulting from storm and salt water. The same thing happened off the coast of England in 2005 – and these countries don’t even get hurricanes!

According to Cape Wind, the strength of the proposed turbine blades comes from “a matrix of fiberglass, polyester and epoxy.” These composite materials cannot be recycled once their useful life has expired, so landfilling is the only way to dispose of them. Further, stress damage to wind turbine fiber composites like these has not been completely studied. Is Cape Wind going to inspect for stress fractures each and every blade on 130 turbines after a hurricane or nor’easter rips through Cape Cod?

There are also other safety concerns to consider. What if the brakes, intended to keep the blades from moving during a hurricane, fail?

Electric utilities like NStar generally have power up and running within two weeks from a major storm. It seems highly implausible that hurricane storm damage to these wind turbines could be fixed in that period of time, and thus there would be no electric power generated from them for a long time to send back to the transmission grid.

Further, potentially oil-leaking motors and gearboxes could pollute oceanic waters, shipping channels could be obstructed by floating debris, and seafloor areas could become the final resting places for heavy debris (like turbine blades) that have sunk to the bottom.

Cape Wind is not a done deal and faces stiff opposition all through Massachusetts, numerous lawsuits and financing challenges. Given the nature of the hurricane-force winds that just hit Cape Cod and the likelihood of this occurring again, combined with the very real risk of severe damage to the wind turbines, does it really make sense to construct offshore wind turbines in our environmentally healthy Nantucket Sound in the first place?

Dan A. Miller of Mashpee is a registered professional geologist.