ENGIE La Haute Borne, 4 x Senvion MM82 (8.2 MW), 10-minute SCADA, 2014 to 2015

464 MWh of production was lost, and two turbines account for 63 percent of it

Lost energy by driver, against 24,630 MWh produced (1.8 percent of potential).

Downtime 281 MWhUnderperformance 168 MWhSuspected icing 10 MWhCurtailment 4 MWh

What to act on first

Ranked by lost MWh. Reference power curves fitted on 2014 only, so 2015 is an out-of-sample year.

R80790 is the priority asset. Highest downtime loss in the fleet (106 MWh over two years) and its underperformance loss rose from 20 MWh in 2014 to 39 MWh in 2015, out of sample. Its performance index sat 2.1 and 2.9 points below the fleet median in September and December 2015. Next step: review its alarm log and pitch and converter events for 2015 with site operations.
R80711 reads 2 to 3 points above the fleet from April to August 2015. A sustained gain is flagged on purpose, because it is often a sensor change rather than real output. The anemometer check shows no step during the flagged window (its wind speed ratio to the fleet is 1.04 in Q2 and Q3 2015, within its 2014 range of 1.04 to 1.05), so the cause is open; next check is a directional and wake-sector comparison.
No static yaw misalignment above 4 degrees on any turbine in any month, and curtailment and suspected icing are small (4.4 and 10.4 MWh). These are reported as negative results, not omitted.

Performance index gap to fleet median, by month

Points of performance index (actual over expected, excluding downtime and curtailment). Outlined cells meet the persistence rule: more than 2 points from the fleet for 3 or more consecutive months.

Power curve check

2015 records (1 in 40) against the 2014 reference curve, density-normalized wind speed.

Monthly availability

Time-based availability during windy periods, per turbine.

Data quality and traceability

Every excluded record maps to one rule in sql/02_dq_flags.sql. Our downtime estimate (281 MWh) is within 9 percent of the operator's own unavailability counter (308 MWh).

Caveat: the plant meter, availability and curtailment tables are the example plant-level series distributed with NREL OpenOA, and the meter equals 0.98 of SCADA energy almost every month, so they test the reconciliation code rather than provide an independent audit.