Influencia de la integración de la generación renovable y la gestión de la demanda en el mercado

Résumé

The main effects of the integration of renewable generation on the electricity wholesale market are widely studied in the literature, however, hardly any research effort has been devoted to the analysis of the effects of demand management or storage. This work tries to mitigate this lack by analyzing the effects in the wholesale market of three types of activities: • Integration of renewable generation, that will be used as a reference for comparison • Demand managment (demand response) - Efficiency and energy saving - Load-shifting • Energy storage - From the generation side (pumping hydropower) - From the demand side (bateries). In this work, the source of information used as reference are the hourly generation and demand curves (offered and cleared) corresponding to the Spanish/Iberian market during the period 2008-2015 (70128 hourly cleared prices), retrieved from the historical archive of the Market Operator OMIE). From these, realistic scenarios of integration of renewables, demand management (demand response) and energy storage have been elaborated, in order to study their effects in the market. With this purpose, first, a simple qualitative model, based on the linearization of the market around the point of operation, has been developed. This qualitative model has lead to the establishment of some hypotheses about the potential impact of any of these actions in the market, especially the variations in energy traded and clearing price. This qualitative model has also been used to describe and establish what could be called the merit-order effect of demand management (energy saving and loadshifting) and storage (generation and demand). Subsequently, what has been called the displacement and continuation of the generation and demand curves, developed for this work, has been introduced. This method allows simplifying the process of optimization of the global welfare (welfare) that leads to the determination of the equilibrium point of the Market (traded energy and cleared price), the most demanding task in terms of computation time for the market operator. A reanalysis of the historical data of the Spanish/Iberian market from 2008 to 2015, incorporating the particular particularities of the considered scenarios, has been carried out with this method. Once the effect on the market has been analyzed, other more general effects on the power system, market agents or the environment, such as variations in the volume of CO2 emissions, technical losses in the transmission system, economic quantification of the merit-order effect and neutral premiums (where applicable), as well as income transfers between the various players involved: conventional and renewable generators, consumers, and possible third parties (storage). The proposed qualitative method, based on the linearization of the market around the real marking point, has allowed establishing a first qualitative evaluation of the expected effect in the market of the adoption of any policy that leads to any kind of variation of the purchase and/or sale bids. In this estimation, the variations in the slopes of the generation and demand curves play a very important role. As a result it can be said that it is an approximate instrument, but very simple and fast to use, which makes it useful as a preliminary analysis tool. This tool has lead to identify merit-order effects, not yet described in the literature, associated with energy saving or efficiency, the load-shifting and energy storage (generation and demand). Particularly noteworthy is the fact that it has been able to predict a net energy saving after a cycle of load-shifting, a result still not described in the literature. It has also made it possible to describe the storage on the demand side (batteries) as form of carry out the load-shifting, without having to alter the scheduling of the production of the industrial plant, but with an investment cost in the battery and a operation cost, derived from the losses in the charge-discharge cycle. It has also allowed describing the storage in the generation side as a variant of load-shifting. The methodology of continuation and displacement of curves, proposed in this work, has made it possible to face the study of multiannual scenarios in affordable computation times, surpassing the almost impracticable computation times resulting from the use of the Euphemia methodology. On the other hand, whenever the energy variations considered in the scenarios are small compared to the traded energy in the base (actual) scenario, we can not expect large errors derived from the proposed method, since the variations will occur only in the last units removed or added from the list of the actually cleared in the base real scenario, which includes hundreds of units of purchase and sale. The method of continuation and displacement of curves has allowed confirming, in general lines, the hypotheses established with the qualitative (linear) method. The method has allowed for a more precise quantification of the merit-order effect corresponding to the energy saving or efficiency, the load-shifting, and the storage, both from generation (pumping) and from load (batteries). It has also allowed confirming the net energy saving that occurs in each cycle of loadshifting.