What to Look for in a Wind Farm Technical Due Diligence Report

You've received a technical due diligence report on a wind project you're evaluating. It's 80 pages. There are tables. There are photos of blade erosion. The executive summary says "generally good condition with some items requiring attention."

That tells you almost nothing.

Here's how to read a wind farm technical DD report — what the good ones cover, what the mediocre ones gloss over, and where the real risk hides.

Start with the asset register

The first thing to check isn't condition data. It's whether the report correctly identifies what you're buying.

A good technical DD report includes a complete asset register: every turbine, its make and model, serial number, commission date, hub height, and rated capacity. Check this against the seller's data room. Discrepancies here — a missing serial number, a commission date that doesn't match — are early indicators that the DD team didn't have full access or didn't verify source data.

If the report lumps turbines into batches ("Turbines 1-15: Vestas V110, 2.0 MW") without individual identification, push back. You need turbine-level data to make turbine-level decisions.

Component-level condition scoring

This is the core of any technical DD report. Look for these qualities:

Consistent scoring methodology

The report should define its scoring system upfront — whether it's a 1-5 numerical scale, a traffic light system, or a risk categorization. Every component should be scored on the same scale. If the gearbox section uses "good/fair/poor" and the blade section uses a 1-10 scale, you're reading a report assembled by different people who didn't coordinate. That's a process problem that produces data problems.

Coverage across all major components

A thorough report assesses at least these component categories for each turbine: gearbox, generator, main bearing, blades, pitch system, yaw system, converter, transformer, and tower/foundation. If any of these are absent, the DD has gaps. Gaps become surprises. Surprises become unbudgeted CapEx.

Evidence behind the scores

A condition score of 3/5 on a gearbox should be backed by oil analysis results, vibration data, and visual inspection notes. If the report gives scores without supporting evidence, you're trusting the evaluator's judgment without the ability to verify it. That's not DD — it's faith.

Compare how Ridgeline structures component-level assessments with traceable evidence at every level.

The maintenance history section

Good reports don't just tell you what condition things are in. They tell you how they got there.

Look for: major component replacement history (especially gearboxes and generators), unscheduled maintenance frequency by turbine, any serial defect campaigns or recalls that affected the fleet, and whether warranty claims were filed and honored.

A turbine with a gearbox replaced two years ago is in a fundamentally different position than one running on its original gearbox from 2012. The current condition score might be identical. The forward-looking risk profile is not.

Performance data and energy yield

The technical report should either include or reference an independent energy yield assessment. What you're looking for:

• ✓ How does actual production compare to the original P50 estimate?
• ✓ Is there a clear trend in annual energy production — stable, declining, or improving?
• ✓ Are individual underperforming turbines identified and explained?
• ✓ Does the report account for curtailment, wake effects, and availability losses?

A report that shows aggregate site production without turbine-level breakdowns is hiding information — intentionally or not. One underperforming turbine can drag fleet averages while the rest of the site looks healthy. Your production projections need to account for this variance at the individual unit level.

Risk register and CapEx forecast

The best DD reports end with a risk register: a structured list of identified risks, their severity, likelihood, and estimated cost to remediate.

This is where the DD data becomes actionable for your deal model. A gearbox scored 2/5 isn't just a condition finding — it's a $180,000 replacement that might happen in the next 18 months. The risk register translates technical findings into financial inputs.

Look for specificity. "Several turbines may require gearbox intervention" is useless. "Turbines 3, 7, and 14 show elevated iron content in oil analysis consistent with advanced gear wear; estimated replacement cost $540,000 within 24 months" is something you can price.

What bad reports have in common

After reviewing hundreds of DD reports, the patterns are clear:

The structural fix

The quality of a DD report depends on the system that produced it. If your DD team is working in spreadsheets and assembling a PDF at the end, the report will reflect those constraints — inconsistent, hard to compare, impossible to carry into operations.

When DD is run in a structured database purpose-built for wind assets, the report is a view of the data, not a separate document. The condition scores, the risk register, and the CapEx projections all come from the same source. And that source becomes your operations database after close.

That's the difference between a report you read once and a system you use every day.