An approach to optimize the cycling operation of conventional combined heat and power plants

Abstract

The implementation of the market mechanism, which includes electricity price fluctuation, and a wide integration of intermittent generation, namely solar PV and wind energy, in energy production have changed the role and operation manner of conventional generation. It is partly or not at all adapted to new running conditions. Therefore, the efficiency and flexibility of conventional generation has to be improved. The numerical approach is developed in the context of combined cycle gas turbine (CCGT) technology to adapt its running conditions to the electricity market mechanism. The developed approach was verified on a case study of the Baltic States (Latvia) examples in a multi-paradigm numerical computing environment MATLab. The obtained results show that the added profit is gained through production of supplementary electricity, and the impact of cycling operation is reduced through the decrease of cycling operation ranges numbers and the substitution of start-up with a less adverse one from a technical and economical point of view. The developed approach can be adapted to various technologies and situations by adding appropriate characteristics and constraints of technology.

Optimisation of Combined Cycle Gas Turbine Power Plant in Intraday Market: Riga CHP-2 Example

“…Combined cycle gas turbine (CCGT) technology is partly adapted to new running conditions [6], [7]. There are a lot of measures [8] to increase the flexibility of power plants from expensive [9], [10] to cost-neutral, for example, by applying the EM & OM (evaluation model & optimisation model) approach developed and presented by the authors in [11] to optimise the cycling operation of CCGT power plants.…”

“…The second ensures the extension of cycling operation range by shifting shutdown "forward" and start-up "backward" and, hence, the added electricity is produced, the numbers of cycling periods are reduced and start-ups are replaced with less adverse ones. In [11], the authors proposed that the EM & OM approach could be used in different Nord Pool physical markets: day-ahead, intraday or real time/balance market, but its performance changes depending on the type of physical market (Table 1). In [11], the developed EM & OM approach was verified on the example of CCGT-2/1 of Riga CHP-2 (the detailed information about this power plant is available in [11], [12]) on the principles of Nord Pool intraday physical market.…”

“…In [11], the authors proposed that the EM & OM approach could be used in different Nord Pool physical markets: day-ahead, intraday or real time/balance market, but its performance changes depending on the type of physical market (Table 1). In [11], the developed EM & OM approach was verified on the example of CCGT-2/1 of Riga CHP-2 (the detailed information about this power plant is available in [11], [12]) on the principles of Nord Pool intraday physical market. It is when the results of unit commitment (UC) and electricity price are known, i.e., the dashed box in Fig.…”

“…Y '1 denotes the first cogeneration unit and Y '2 -the second cogeneration unit of generation portfolio Y', which is Riga CHP-2. [11]. (Y n , Y n+1 , Y m denote the generation portfolio before bid submission to the Nord Pool market; x n , x n+1 , x m -the submitted bids to the market; x' n , x' n+1 , x' m -the approved bids on the Nord Pool market; Y' n , Y' n+1 , Y' m -the generation portfolio after bid approval on the Nord Pool market and optimisation provision in line with the approved bids)…”

“…In [11], the impact of optimised CCGT-2/1 cogeneration unit on the generation portfolio, i.e., Riga CHP-2, was omitted. That is why in this article the authors assess this impact by introducing the evaluation algorithm, which consists of the CCGT-2/2 optimisation according to the EM & OM approach and changes of cogeneration units' (CCGT-2/1 and CCGT-2/2) generation portfolio in multi-paradigm numerical computing environment MATLab.…”