For an older wind or solar project, the most valuable asset may no longer be the equipment producing electricity. It may be the right to use a well-located site with an established connection to the grid.
That is the investment question in Wood Mackenzie's September 2026 Horizons report. The firm forecasts that more than 2.5 terawatts of wind and solar projects will face decisions about retirement, life extension or repowering in the 2040s. The figure describes projects approaching a decision, not capacity already scheduled for removal. Wood Mackenzie says developers are increasingly looking at operational projects as potential acquisition and redevelopment sites because they combine grid access with a known wind or solar resource, land rights and a history of local approvals.
Wood Mackenzie Tracks Nearly 50 GW of Wind Already Past 20 Years Old
The scale is already visible in the installed base. Wood Mackenzie's report finds that almost 50 GW of wind capacity has been operating for more than 20 years as of 2026, a figure it expects to exceed 230 GW by 2040. More than 30 GW of wind capacity will have been decommissioned worldwide by the end of 2026, two-thirds of it taken offline just since 2022, according to the same analysis. Solar's aging fleet started later but is forecast to overtake wind's before 2040.
Repowered sites are not simply swapped one-for-one. The U.S. Department of Energy's (DOE's) wind end-of-service guide describes a 2020 example in which three fully repowered projects replaced 343 aging turbines totaling 120 MW with 50 new turbines totaling 148 MW, fewer machines producing more capacity from the same footprint. This pattern is central to why Wood Mackenzie expects repowering to drive an increasing share of new installations as the 2040s approach.
A change in valuation follows from that math. Continuing to operate may preserve near-term revenue, while replacing turbines or modules could increase output from the same location. Selling may also make sense if another owner has the capital or technical capacity to rebuild. A valuation based only on the remaining life of the existing equipment could miss the opportunity associated with the site.
A Repower Still Needs Its Own Interconnection and Permit Review
An existing connection is an advantage, not an unrestricted right to rebuild. Its value depends on what the new project proposes to deliver to the grid and what the governing agreement permits. A repower that changes generating capacity, equipment or electrical characteristics needs review against the applicable interconnection terms. Owners also need to establish whether substations, collector lines and other infrastructure can serve the replacement project. Transformer and switchgear shortages have already collided with specific projects that did not reserve equipment early enough.
Permitting creates a separate test. DOE's guide says a full repower is typically a redesign and will likely undergo review under current local zoning or other applicable rules. Taller turbines or a changed layout can affect nearby residents and landowners. Even a partial repower may require permit review. Existing approval, therefore, does not guarantee that a replacement project can be built on the original terms.
This matters to buyers as well as sellers. Before assigning a premium to an older project's grid position, a prospective buyer needs to examine the interconnection agreement, permitted capacity, land leases, remaining contract term, equipment condition and likely replacement design. It should price the time and cost of any required studies and approvals. A seller needs the same analysis to judge whether to operate, repower or sell, particularly where an aging project's power purchase agreement is nearing expiration and post-contract revenue now depends on a very different market than the one the project was built into.
The Portfolio-Level Question Rarely Gets Its Own Line Item
Wood Mackenzie argues that established locations can sometimes bring new equipment online faster than developing an entirely new site. It is a project-specific possibility, not a general exemption from grid studies or permitting. Portfolio owners weighing that possibility across multiple assets face a related gap: few organizations have a clear owner for aggregating what individually reasonable contract and asset decisions add up to across an entire fleet.
For owners reviewing portfolios before year-end, the useful first step is to separate three values. The income the present equipment can still earn, the cost of extending its life and the development potential of its grid connection and site each belong on their own line. The strongest repowering candidate may be an asset whose turbines or modules are aging, but whose location remains difficult to replace.
