Integration of IPP power plant into power system operations planning

Abstract

Each power system is special for itself and it is rare to find two identical ones in the world. The differences are in the very structure of production, and thus in the use of primary energy sources, as well as in ownership, organization, and information technology. The objective function during planning and management is mostly the same everywhere: the optimum (calculation of function extrema) is sought, which defines the minimum costs. The chosen methodology and organization of exploitation determines the efficiency of management in each power system. The implementation of NPE (“independent energy producer”) power plants, due to their contractual obligations, can have a negative effect on the optimization of the power system. The basic problem is the obligation “take or pay” which defines the mandatory dispatching of the power plant regardless of being uneconomical. This is precisely the most difficult and challenging part of the negotiations between the customer and the NPE (“energy purchase agreement - UOKE”). It must be emphasized that this obligation is much stricter and more difficult for gas-fired power plants than for coal-fired power plants. This is because coal can be stored and thereby avoid mandatory dispatching at an unfavorable moment, while the situation with gas is fundamentally different. The gas must be used or if it is not used, it must be paid for. Storage is generally not commercially advantageous. An additional problem is the mandatory monthly dynamics of gas consumption, because gas does not have the same price in winter and summer, so the contract obligates the customer to quarterly gas consumption, i.e. power plant production, which then protects the seller from having to purchase (consume) gas at more expensive tariffs for the time of the winter season.

Ranko Goić

Full Professor | Department of Power Grids and Substations

Full professor at the Faculty of Electrical Engineering, Mechanical Engineering, and Naval Architecture in Split exeperienced in transmission and distribution networks, renewable energy sources (RES), power system planing and economics