Bidding wind energy under uncertainty

The integration of wind energy into electricity markets implies that the wind energy must commit their production for a given time period. This requires the use of short term wind power prediction tools to prepare the bids for the spot market. The output of these tools have a limited accuracy, and, therefore, these predictions are uncertain. Optimal bids must take into account this uncertainty in order to get the maximum revenue from the sell of energy, minimizing losses due to imbalance costs. The consequence is that the optimal bids sent to the market do not coincide with the best predictions. Regulatory authorities must consider if this situation is good for the system operation, and encourage TSOs to have their own prediction tools and have results independent of bidding strategies.International Conference on Clean Electrical Power, ICCEP '07 (Capri, 21-23 May 2007). P. 754-759Publicad

Coalition Formation and Combinatorial Auctions; Applications to Self-organization and Self-management in Utility Computing

In this paper we propose a two-stage protocol for resource management in a hierarchically organized cloud. The first stage exploits spatial locality for the formation of coalitions of supply agents; the second stage, a combinatorial auction, is based on a modified proxy-based clock algorithm and has two phases, a clock phase and a proxy phase. The clock phase supports price discovery; in the second phase a proxy conducts multiple rounds of a combinatorial auction for the package of services requested by each client. The protocol strikes a balance between low-cost services for cloud clients and a decent profit for the service providers. We also report the results of an empirical investigation of the combinatorial auction stage of the protocol.Comment: 14 page

Price Wars and Collusion in the Spanish Electricity Market

We analyze the time-series of prices in the Spanish electricity market by means of a time varying-transition-probability Markov switching model. Accounting for changes in demand and cost conditions (which re°ect changes in input costs, capacity avail- ability and hydro power), we show that the time-series of prices is characterized by two signi¯cantly di®erent price levels. Based on a Green and Porter (1984)'s type of model that introduces several institutional details, we construct trigger variables that a®ect the likelihood of starting a price war. By interpreting the signs of the triggers, we are able to infer some of the properties of the collusive strategy that ¯rms might have followed. We obtain more empirical support to Green and Porter's model than previous studies