Identifying derates on wind turbines can lead to AEP gains.

Asking whether or not a wind farm or individual turbine is curtailed isn’t in a simple yes or no answer. Derates are applied for a variety of reasons, from grid faults or balance of plant to shadow flicker, noise constraints, wildlife management or technical faults. Calculating lost energy due to derating is often difficult, but it is an important metric to measure. The relevant information often isn’t readily available to owners and operators but is hidden in different data streams and formats, such as event logs, park controller data, turbine ten minute SCADA data or set points.

Identifying and extracting the data relating to the derate from all the data received from each turbine is the first step but can take a considerable length of time if done manually. The process is simplified by implementing machine learning and artificial intelligence. Clir Renewables’ software detects and distinguishes between different types of derates for all major turbine manufacturers. With algorithms based on manufacturer specified logic and Clir Renewables’ domain expertise, derates are flagged to the owner. The corresponding losses are also highlighted, enabling owners and operators to calculate the monetary value they are missing.

Using the Clir Explore environment for further investigation can identify patterns across the farm or periods of time for different types of derates. These investigations have identified cases where individual turbines or the whole farm has excessive derates in place. By restructuring the derate plan, AEP gains are achievable. An example is farm-wide grid derating, where OEMs don’t typically use a strategy optimized on production. They often curtail the entire farm as soon as a sample turbine reaches rated output. Using Clir, it’s easy to confirm whether the entire farm is curtailed when curtailing only a few turbines would have been enough. By optimizing the curtailment strategy, the amount of lost energy is reduced, resulting in AEP gains.

Rebecka Klintstrom, Renewables Science Team Leader, said, “Many owners and operators are unaware of the potential gains available if a derate is investigated and its implementation restructured. This is a substantial undertaking if carried out manually; however, using software designed for this purpose makes this task more streamlined.”

One owner with a grid-curtailed farm identified the site was not reaching its expected export level following analysis through the Clir software. Following a discussion with the manufacturer, this curtailment was reduced and the site now reaches its export limit. As a result, the client has realized a 0.2% increase in annual energy production gain at the site.