Oil, gas, coal all feel like old energy. Wind power feels new even though it isn’t. Certainly, wind has taken off in the past few years.
So why are some wind power systems being “repowered”? Answer: More power.
Full repowering refers to the complete dismantling and replacement of turbine equipment at an existing wind power project site.
Partial repowering is installing a new drivetrain and rotor on an existing tower and foundation. It’s updating with equipment that increases wind power energy production, reduces machine loads, increases grid service capabilities, and improves project reliability at lower cost and with reduced permitting barriers relative to full repowering and greenfield projects. (Source)
Wind power facilities age, and can require new equipment to keep them going.
New technology can increase the power output. Perhaps the owner can now pair-up wind and batteries to add flexibility to electricity dispatch.
Timing of the power purchase agreement, or PPA, can make a difference. “Wind projects are typically developed with 15 to 20-year PPA terms. Repower projects are often facing the end of their initial PPAs — the document that states the underlying revenue stream and financial security for the project. Additionally, redevelopment of the wind farm, which may require a new design of the project and decommissioning of the existing wind turbines, means new negotiations or agreements. (Source)
Here’s an example from CleanTechnica website: “Clearway Energy Group has just finished re-powering the Langford (Texas) wind farm, which was built in 2009. Now that its turbines have been replaced with state of the art equipment from GE Renewable Energy, its generating capacity has increased by more than 25% and its useful life has been extended by at least 10 years.”
How has wind power technology changed? Here’s an extreme example, and one that I think would be a “greenfield” versus repowering candidate. GE’s Haliade wind turbine has these features in its installation in the UK:
- 13 MW capacity
- 220-meter rotor (721 feet)
- 248 meters high (813 feet)
- 107-meter long blades (351 feet)
- One spin can generate enough electricity to power one house for more than two days
If any repowering of a renewable energy project is not going to happen, then the project is shut down. Here’s a good explanation from the Great Plains Institute’s article, Repowering and Decommissioning: What Happens in Communities When Solar and Wind Projects End? “Decommissioning means that the system is deconstructed, removed, and the land is made ready for redevelopment or return to original use … In most places, the estimated costs and a plan for decommissioning are included as part of the initial project application.”
For more about wind power in the Carolinas, see: Wind Power is Coming of Age in the Carolinas.