Perhaps some of the turbines on a wind farm are starting to have major failures. Maybe some are demonstrating lower availability than normal. Owners and operators of wind farms that have been around for a decade or two might be wondering if some of their assets are reaching the end of their productive lives.
Fortunately, owners and operators have options to repower their established installations — and some of those options are more financially attractive than ever.
Why Choose to Repower?
There are two primary reasons to repower: production concerns and financial considerations.
Many wind farms are advancing in age. U.S. wind capacity more than tripled from 47 gigawatts (GW) in 2010 to 147.5 GW by the end of 2023. Of the 1,000-plus projects that were installed from 2004 to 2016, representing more than 71 GW of installed capacity, an estimated 15% to 20% already have been repowered, suggesting that a large portion of the remaining projects should consider following suit.
Operators of these older assets might be starting to see significant concerns, such as failures in gearboxes or blades. Availability of some machines might be dropping off significantly from past performance. Operations and maintenance (O&M) costs could be spiking.
Some might choose to continue investing in the equipment to continue operating as-is or “run to failure.” While this might be an economical option in the short term, is it the right investment? Wind farms are unlikely to be abandoned, given the value of existing interconnections, so repowering options might make sense for the long term.
One partial repower option is to replace major components — gearboxes, hydraulic pumps and various other mechanical aspects — in order to qualify for the wind Production Tax Credit (PTC). This could extend a turbine’s lifetime from 2-5 years up to 10-20 years. Suddenly, the operator effectively has a new engine in a vintage car.
Another option involves embracing advances in technology since the wind farm was initially installed. Blades have gotten larger and nameplate capacity has grown. Taking an existing foundation and tower and putting in a new nacelle and generator blades could qualify for the PTC and eliminate a lot of mechanical concerns.
Finally, it’s possible that existing towers can’t support the new, larger nacelles or blades, or their foundations might be too small for that option. Those owners might consider taking everything down and building anew on the same footprint.
Factors and Financing
All of these options have pros and cons. With so many wind facilities approaching or past the 10-year mark, these considerations are going to become much more common. Any repowering option could entail issues around permitting, as well as mechanical, structural, electrical and interconnection details. Energy implications should be reviewed: All of the repower options should increase production, but by how much, and do any existing contracts need to be reviewed with that increased generation considered?
Newer machines that extend over 500 feet tall could trigger new Federal Aviation Administration (FAA) screening issues. These approvals are not automatic; the FAA is careful to vet for issues affecting weather and air defense radars.
Putting new, larger blades on towers could trigger setback issues as well, requiring new permits. Sound and shadow flicker also could trigger county-level concerns. These are not necessarily fatal flaws, but they should be evaluated as part of any potential repowering project.
Financial modeling has a large role to play as well.
Historically, the wind industry has been at the mercy of Congress for extensions of the PTC. Going into the pandemic, the PTC was undergoing a phase-out. But under the Inflation Reduction Act (IRA) passed in 2022, the credits were extended well into the future.
For wind farms where the PTC had already expired or for owner/operators who hadn’t taken advantage of them previously, there is a fresh opportunity to utilize the credits. The IRA also allows those tax credits to be transferred or sold. Additionally, domestic content thresholds can add a 10% boost to tax credits, which means local sourcing for a repowering initiative could help satisfy IRS requirements.
Putting the ‘Win’ in Wind
Any repowering initiative should be undertaken holistically to identify concerns as early as possible, allowing project teams to eliminate some scenarios or prioritize others for deeper analysis. The resulting repower should significantly extend the life of aging renewable resources while delivering cost efficiency for owner/operators.
Renewable energy technologies are revolutionizing energy production. The associated assets have limited end-of-life potential, but there are viable recycling options.
