Why Wind Farms Need Secondary Spill Containment

By Dan Carver
Dec 6, 2023
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By the end of 2018, the total installed capacity of wind power in the United States reached more than 96,000 MW. Wind power is now a major segment of the sustainable power sector with the ability to supply the needs of 24 million homes.

Currently, there are more than 56,000 utility scale wind turbines operating in the US. Each wind turbine connects to its own step-up transformer. From there, power transfers to the grid through an additional step-up transformer called a "collector" in a substation. Generally small in MVA rating, wind turbine step-up transformers are in the base of the turbine itself.

Typical power generation capacity for a wind turbine ranges between 660 MW to 3 MW. However, wind turbines never consistently operate at capacity due to the variable nature of wind. Because of this, it is normal for a wind turbine to produce only 30 to 40 percent of the rated power capacity.

Wind farms also use grounding transformers. A string of individual turbines connects to a single grounding transformer. Operators spread them throughout the wind farm footprint. Grounding transformers play a critical role in providing a path to ground for step-up transformers. This is important if the string becomes isolated from the substation due to a fault. Consequences of not having a path to ground are over-voltage, over-current, and transformer overload leading to failures. If a failure occurs, secondary spill containment becomes a priority to protect any nearby employees and the environment.

What Can Go Wrong with a Wind Turbine Transformer?

Wind turbine transformers are subject to more severe stresses than other transformers so secondary spill containment becomes necessary. Wind is erratic by nature. It gusts and changes direction easily. During a normal day, the output energy of a wind turbine varies. This cycling stresses the windings and seals of the step-up transformers. Heating and cooling oil also releases nitrogen gas, which can create hotspots and potential points of failure.

While wind energy is clean and sustainable, wind farms are not immune to transformer failure and the potential of oil spills. Even clean energy sources, like the wind industry, are subject to EPA and SPCC regulations just like other power generators. Part of EPA and SPCC compliance means having approved secondary spill containment options for your operations.

How Does the SPCC Rule Apply to the Wind Industry?

The Spill Prevention Controls and Countermeasures (SPCC) rule is part of the EPA’s Clean Water Act defined in 40 CFR 112.7. Its purpose is to prevent an oil spill from reaching navigable waters of the United States. Electric transformers qualify as "oil-filled equipment" and fall under this rule. Operators must provide secondary spill containment to capture spills and leaks in case of a transformer failure.

Recommended Solutions for Wind Farms

Secondary containment for the wind industry focuses primarily on the collection step-up transformers located in substations. Depending on the size of the wind farm, substations may collect power from different parts of the farm. BCI supplies the following solutions for substation transformers:

BCI PolySeam^® Barrier Boom Oil Filtration Panels Passive Drainage System This innovative solution combines the extreme durability of our patented PolySeam Liner Attachment System with the reliability of the popular Barrier Boom secondary containment solution. The PolySeam application provides a fast and cost-effective method of attaching a containment liner without the need for traditional batten bar. It allows rainfall to passively drain through the Barrier Boom but becomes an impervious barrier when it comes in contact with oil. Thus, it prevents hydrocarbons from migrating outside of the containment area.
BCI VIPOR Systems Some wind turbine transformers are housed in secondary containment vaults or sumps, which may be underground. As normal rain and snow runoff accumulates, it can mix with oil from the equipment. Using the same technology as the Barrier Boom, the versatile BCI VIPOR system provides automatic, compliant dewatering of those containment areas. In the event of an oil release, its main filter core will solidity, preventing any liquid from passing.

More Spill Contaiment Solutions

BCI Provides Secondary Spill Containment Solutions for the Wind Industry

With more than 10,000 secondary containment installations for diverse applications, BCI has the knowledge and experience to help you solve your secondary containment needs. Our solutions meet and exceed the EPA requirements including the SPCC rule. Contact us for more information.