MME proposes P90 for solar firm energy and curtailment added to average generation

Until now, the initial firm energy of a solar plant was based on P50. The public consultation opened by MME on 4 November proposes replacing that criterion with P90 and adding to the average generation of wind and solar plants the energy lost to curtailment caused by external constraints.

According to pv magazine Brasil, reviews based on verified generation cut the firm energy of 47% to 54% of the solar plants analysed each year. The draft requires at least 48 months of generation for solar reviews and 60 months for wind reviews, and instructs ONS to estimate each plant's curtailed energy month by month.

New projects are likely to come out with more conservative and stable firm energy, which limits the energy they can commit under contract. Operating plants will have curtailment recognised in the average, provided they have a productivity curve at ONS and submit valid wind or irradiance data.

Contributions are open until 18 December. Owners of curtailed plants or projects under modelling have until then to test the rule against their own data and take the result to the consultation.