search

IEC-61400-15 / eya_def

This repository provides a digital format for exchange of information on wind plant energy yield assessment reporting as defined by IEC 61400-15-2.
BSD 3-Clause "New" or "Revised" License
10 stars 0 forks source link

To want extent and how do we want to capture interannual variability in plant performance losses? #36

Closed jonssonchristian closed 4 months ago

jonssonchristian commented 10 months ago

We have on different occasions discussed the possibility of assigning an inter-annual variability to each plant performance category and sub-category. Some have suggested this is not commonly done in industry and may be superfluous. I agree it is not common, but some consultancies do consider inter-annual variability in several loss factors, and I have gotten feedback that it would be useful. If we keep things simple, I imagine this could not be complicated to include in the uncertainty framework, but please let me know if you disagree.

There will be interdependencies between inter-annual variabilities. For example, it could be in a high wind speed year, wake losses decrease, availability losses increase, some performance losses decrease, hysteresis losses increase, noise curtailment losses increase and bat curtailment losses decrease. One could argue that interdependencies would likely be higher-order effects and it should be a reasonable baseline to assume they are all independent, when the interdependencies are not sufficiently understood to be modelled. However, I have the feeling those interdependencies may be too large to ignore. If we allow for interannual variabilities in the data model, we need to figure out how to best handle that. The data model could perhaps be agnostic to interdependencies.

If we have space in the model for a single combined dimensionless energy-based inter-annual variability of plant performance losses, that could be the only required field. Then it could be optional to provide the breakdown by the individual losses. And we would not necessarily need to prescribe a method for the combination. We provide the framework for reporting and the user can select the combination method there (in case we do not want to prescribe a method).

jonssonchristian commented 8 months ago

As per the update on #35, I agreed with Mark and Steve on this proposal, and we want to take it to plenum for consensus.

The intention is to move the overall inter-annual variability of plant performance losses to the plant performance uncertainty assessment, and then optionally allow for inter-annual variability in individual plant performance loss components (and subcomponents).

jonssonchristian commented 4 months ago

Closed with #59