Where solar and wind projects really lose time before COD

Renewable energy project delays now start outside the fence line, in interconnection studies, transformer factories and compliance files. Leading developers are building one live view of every commitment between notice to proceed and commercial operation, so the right person acts while a slip can still be recovered.

Solar and windSegeta Insights
Solar and wind
The number$$169K

a day of slipped COD on a 300 MW solar project

What is at stake

Each month of slippage on a 300 MW solar project can put about $$5 million at risk before delay damages.

Where days are lost
  1. Interconnection and energization
  2. Long-lead equipment and compliance evidence
  3. Mechanical completion to commercial operation

For most of the past decade, the risk in a utility-scale solar or wind project was priced as construction risk: piling refusal, crane availability, a wet season on site. That allocation still shapes EPC contracts, contingency budgets and the way lenders read a schedule. Yet the build itself has become the most predictable part of the project, and the commitments that now decide the commercial operation date (COD) are held by utilities, equipment manufacturers and tax counsel, none of whom work inside the EPC schedule.

The delivery data point in the same direction. In the third quarter of 2025, projects representing about 20 percent of planned US utility-scale solar capacity reported a delay, and most of that capacity sat in late construction or testing, the stage at which outside parties carry the most obligations.1 Schedule control has become a problem of coordination across organizations, and this article sets out where renewable energy project delays originate, what each day costs and what leaders can do about it.

The build-out is accelerating as schedule margin disappears

US developers plan to add 86 gigawatts (GW) of utility-scale capacity in 2026, including 43.4 GW of solar and 11.8 GW of wind, compared with 53 GW of all capacity added in 2025.2 Projects reach construction after a long wait: in the regions with data, the median time from interconnection request to commercial operation exceeded five years, and only 13 percent of the capacity that entered queues between 2000 and 2020 had reached operation by the end of 2025.3 Federal deadlines have hardened as well, because wind and solar projects that began construction by July 4, 2026, generally need to be placed in service by December 31, 2030, to keep their tax credits.4 At the same time, Wood Mackenzie estimates that US demand for generator step-up transformers rose 274 percent between 2019 and 2025, and lead times for large units can reach four years.5

Renewable energy project delays concentrate at three handoffs

Solar and wind are among the most predictable assets an infrastructure company can build. Bent Flyvbjerg's database of about 16,000 projects shows an average cost overrun of 1 percent for solar and 13 percent for wind, against 120 percent for nuclear power plants.6 The days are lost where one organization's commitment depends on another organization's update, and three handoffs account for most of them.

Solar and wind carry smaller average cost overruns than any other type of power plant.

Exhibit 1Solar and wind carry smaller average cost overruns than other power plant typesmean cost overrun, percent
Nuclear120
Hydro75
Fossil16
Wind13
Transmission8
Solar1

Source: Flyvbjerg and Gardner (2023).

01Interconnection and energization

The utility controls network upgrades, backfeed dates, outage windows and witness tests, and it communicates them through study reports, portals and email. The EPC schedule carries a single energization date, so a missed outage window is often discovered late and moved to the utility's next available slot.

02Long-lead equipment and compliance evidence

Transformers, breakers, inverters and modules move through purchase orders in SAP or Oracle, vendor reports, factory tests and customs, and each step sits with a different person. Projects that began construction after December 31, 2025, must also document compliance with foreign entity of concern rules, so a missing certificate can hold up tax equity funding in the same week as the equipment.4

03Mechanical completion to commercial operation

Punch lists, commissioning, SCADA integration, utility testing, the independent engineer's sign-off and lender conversion conditions must close in sequence. EIA data show that most delayed solar capacity is at this stage, with delays that typically run one to two months.1

A connected operating model manages obligations as they move

Leading developers are beginning to manage the months before COD as a network of obligations, each with an owner, a deadline and a cost for every day it stays open. A live layer reads the systems already in use, including Primavera P6, SAP or Oracle, email and site messaging, and runs a four-step loop:

  1. Detect

    risk where it first appears, such as a transformer manufacturer's notice of a failed factory test.

  2. Explain

    which milestones and contract terms it affects, from the outage window to the offtaker's guaranteed COD.

  3. Recommend

    recovery options with owners and expected impact, such as expedited freight or an alternative outage window.

  4. Execute and track

    each agreed action to closure, measuring the exposure retired in days and dollars.

The same record can give lenders, tax equity investors and offtakers current status, and give suppliers one channel for dates, test reports and certificates. Artificial intelligence does the reading, linking and drafting, while people remain accountable for every judgment and commercial decision.

A slipped COD costs a typical solar project about $$170,000 a day

Cost of delay is the daily financial exposure created when a committed milestone slips, including deferred or lost revenue, financing carry, contractual delay damages and, for projects relying on federal credits, eligibility risk.

Each month of slippage on a 300 MW solar project can put about $$5 million at risk before delay damages.

Exhibit 2. Estimated daily cost of delay for a composite 300 MWac solar project

ComponentBasisEstimate per day
Energy revenue deferred or lostAbout 1,800 MWh a day at a 25 percent net capacity factor, priced at the Q2 2026 solar PPA market average of $$61.40 per MWh 78About $$110,500
Construction financing carryCapital cost of about $$510 million at $$1.70 per watt AC; assumes 60 percent drawn at a 7 percent all-in rate 7About $$58,700
Total before delay damages and tax credit riskSum of the two componentsAbout $$169,000

Source: Segeta estimate based on Lawrence Berkeley National Laboratory and LevelTen Energy data; financing assumptions are illustrative.

On these assumptions, a 30-day slip puts about $$5.1 million at risk and a 60-day slip about $$10.2 million, before delay damages owed to the offtaker. EPC liquidated damages may offset part of that exposure, yet they are usually capped and rarely cover delays caused by a utility or supplier.

What developers and EPC leaders can do now

  1. 01Map the obligations that carry a daily cost

    Start with the twenty to thirty commitments that would move the guaranteed COD, and name an owner on each side of every handoff.

  2. 02Price each critical milestone before it slips

    Attach a daily cost of delay to every milestone on the critical path, so a vendor slip is discussed in dollars on the day it is reported.

  3. 03Link utility milestones to the construction schedule

    Outage windows and witness tests belong in the same view as the EPC schedule, updated from utility correspondence as it arrives.

  4. 04Treat compliance evidence as critical path work

    Assemble physical work, continuity and supply chain records as construction proceeds, because late documents delay funding as surely as late equipment.

  5. 05Measure the time from signal to action

    Report monthly how many days pass between the first evidence of a risk and the assignment of a recovery action.

Developers cannot shorten interconnection queues or transformer lead times on their own, yet they can control how quickly a warning becomes a decision. Those that manage every obligation before COD as a live, priced commitment are likely to recover weeks on each project and earn the confidence of lenders and offtakers for the next one.

Questions leaders ask

Why are utility-scale solar projects delayed?

Most delays now arise at handoffs between organizations. Interconnection upgrades and utility outage windows, long-lead equipment such as main power transformers, and the testing and sign-offs needed for commercial operation each depend on parties outside the developer's direct control. EIA data show that most delayed solar capacity is in late construction or testing, where delays typically run one to two months.

How much does a delay in commercial operation cost a solar project?

For a composite 300 MWac solar project, a Segeta estimate puts the cost at about $$169,000 a day, combining about $$110,500 of deferred or lost energy revenue at recent PPA prices and about $$58,700 of construction financing carry. Delay damages owed to the offtaker, fixed site costs and tax credit risk come on top of that figure.

How long does interconnection take for a new solar or wind project in the US?

Lawrence Berkeley National Laboratory reports that the median project took well over three years from interconnection request to a signed interconnection agreement in 2025. In the regions with available data, the median time from request to commercial operation exceeded five years, and most capacity that entered queues between 2000 and 2020 eventually withdrew.

What are the tax credit deadlines for wind and solar projects?

Under the 2025 budget reconciliation law, wind and solar projects had to begin construction by July 4, 2026, or be placed in service by December 31, 2027, to keep the clean electricity credits. Projects that began construction in time generally need to be placed in service by December 31, 2030, to rely on the four-year continuity safe harbor. Developers should confirm treatment with tax counsel.

How long are transformer lead times for renewable projects?

Lead times for high-capacity power transformers can reach up to four years, according to analysts cited by pv magazine USA in May 2026. Wood Mackenzie estimates that US demand for generator step-up transformers rose 274 percent between 2019 and 2025, which keeps pressure on factory slots, testing schedules and delivery dates for solar and wind projects.

How can developers reduce renewable energy project delays?

Developers can map the obligations that carry a daily cost, price each critical milestone in advance, link utility milestones to the construction schedule and treat compliance evidence as critical path work. Bringing suppliers into a single channel of record and measuring the time from first signal to recovery action helps teams act while a slip can still be recovered.

Notes and sources
  1. US Energy Information Administration, "Fewer US solar projects are reporting delays in their expected online date," Today in Energy, November 2025, eia.gov.
  2. US Energy Information Administration, planned 2026 utility-scale capacity additions, Today in Energy, February 20, 2026, eia.gov.
  3. Lawrence Berkeley National Laboratory, "Backlog of power plants seeking transmission grid connection eased somewhat in 2025 amidst high withdrawals," July 2026, emp.lbl.gov.
  4. Norton Rose Fulbright, "The One Big Beautiful Bill's energy tax credit timeline," Project Finance NewsWire, August 2025, projectfinance.law.
  5. Ryan Kennedy, "US transformer market faces severe supply constraints as lead times extend to four years," pv magazine USA, May 11, 2026, pv-magazine-usa.com.
  6. Bent Flyvbjerg and Dan Gardner, How Big Things Get Done, Currency, 2023, as reported in "What Lego (yes, Lego) can teach us about avoiding energy project boondoggles," Inside Climate News, February 2023, insideclimatenews.org.
  7. Lawrence Berkeley National Laboratory, "Utility-Scale Solar, 2025 Edition," October 2025, emp.lbl.gov.
  8. LevelTen Energy, Q2 2026 North America PPA Price Index, as reported by TaiyangNews, July 23, 2026, taiyangnews.info.