The large scale integration of renewables in the generation portfolio of a country, especially when the wind has an important penetration, raises concerns on the security of supply. 

The transmission system operators of Spain (REE) and Portugal (REN) have jointly hired INESC TEC to develop a model to evaluate the security of supply in Iberia (Spain + Portugal) until 2025 and the operational reserve adequacy, in a set of scenarios including extreme scenarios where relevant wind and hydro resources are absent. The risk of wasting renewable energy was also evaluated.

INESC TEC developed a new approach based on sequential Monte Carlo simulations with hourly resolution and with a detailed representation of wind resources, by dividing the territory into several regions with different wind behaviours, each with its owns set of historical wind series. 

Other renewable resources are considered, namely large and small hydro and solar resources. Pumped storage is also part of the model. The possible dispatch strategies are taken into account, including the presence of nuclear power stations in Spain, and maintenance is also modelled.

This model answers the following question: is the hourly operational reserve enough to compensate for the forecasting errors in load, wind and small hydro power, as well as equipment failures that may occur?

Following the deep study developed by INESC TEC, the software application RESERVAS was delivered to REE and to REN. The methodology followed in the RESERVAS approach has been proposed as the standard methodology to consistently evaluate the security of supply and operational reserve needs in the European Union.