the objective of this work is threefold. We firstly present an optimization model for a price-taker hydrothermal generation company (Genco) to devise bidding strategies in multi-item dynamic auctions of long-term contracts. The bidding model calculates a willingness-to-supply curve (WSC), which takes into account the key issues on the auctioned contracts, such as its time horizon, the risk factors that affect the future contract outcomes, interdependence between auctioned products, and the agents’ risk profile. Then, the risk profile of the Gencos are represented as piecewise linear utility functions and a practical specification approach is proposed. Finally, we present a simulator of a dynamic multi-item contract auction, where the set of auction rules for multiple products is implemented. The auction convergence price can be estimated from the successive application of the bidding model to each individual player at each round in the auction simulator. A real multi-product descending clock auction is simulated for the Brazilian power system under the proposed bidding scheme.