**9. Conclusions**

This article presented a new bilateral energy contract (STE contract) and new marketplaces designed to allow wind power producers to (eventually) reduce their deviations. The contract and the marketplaces were to some extent tested in a real-world study conducted with the help of the multi-agent system MATREM.

The software agents were 12 producers, representing the supply-side of Portugal, five retailers, representing the demand-side of Portugal and Spain, and one aggregated wind power producer. The data involved hourly prices and quantities of the day-ahead and intra-day Iberian markets, hourly prices and quantities submitted to the Portuguese balancing market, and hourly deviations and prices of the imbalances for producers and retailers. Seven scenarios were considered, involving the participation of wind power producers in the new marketplaces, and also using the new contract.

The simulation results indicated that the new contract and the new marketplaces are beneficial to WPPs at both technical and economical levels, reducing the imbalances and increasing the wind energy value to the market. Also, the STE contract led to a reduction in the imbalances of retailers, resulting in a reduction of their costs with imbalances. Accordingly, market operators and system operators should take into consideration the new products presented here, possibly with particular adaptations and/or extensions, to allow an effective participation of VRE producers in liberalized markets, thus contributing to a new paradigm involving no feed-in tariffs nor other supporting schemes—that is, the paradigm expected in the near future, involving near 100% renewables.

**Author Contributions:** H.A. and A.C. defined the new contract and the new marketplaces, performed the simulation-based study, and wrote a preliminary version of the article. In particular, A.C. developed the forecast models and computed the wind power forecasts. H.A. designed and conducted the simulations with the help of the MATREM system. F.L. performed a deep revision of the initial version of the article, regarding both language and scientific content. F.L. also performed a deep revision of the subsequent versions of the article, taking into account the comments of the reviewers. In addition, F.L. developed the MATREM system (thus enabling to perform the simulation-based study). A.C. and A.E. contributed with expertise in wind power. J.S. and F.L. contributed with expertise in energy markets.

**Funding:** This work was supported by FCT (Fundação para a Ciência e Tecnologia) under grant agreement PD/BD/105863/2014 (H. Algarvio).

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **Abbreviations**


