Oļegs Linkevičs

Formulation of the objective function for economic dispatch optimisation of steam cycle CHP plants

The paper starts the series of publications concerned on production simulation and expansion planning of various cogeneration applications, especially based on distributed generation technologies. This particular paper presents the formulation of optimisation problem for economic dispatch of steam cycle CHP plants widely used in the former Soviet Union. Polynomial quadratic equations were applied to describe interrelations between input steam and output power and heat for cogeneration steam turbines. Mathematical model of turbines was verified by numerical example, taking the input data from normative characteristic graphs.

Combined heat and power plants towards efficient and flexible operation

The integration of large-scale renewable energy sources into the power system and the implementation of market mechanisms have changed the operation of combined heat and power (CHP) plants. Technical and organizational measures should be taken to operate power plants efficiently and flexibly in line with new running conditions. There are different kinds of possibilities to ensure flexible operation of CHP plants. In line with the review and analysis of the provided literature all measures were generalized and divided in five groups. At the end, an example of the research topic is presented in the context of Riga CHP-2 plant.

Electricity Market Liberalisation and Flexibility of Conventional Generation to Balance Intermittent Renewable Energy – Is It Possible to Stay Competitive?

Abstract Intermittent generation (solar PV and wind energy) integration in power production portfolio as well as electricity price fluctuations have changed the running manner of conventional combined heat and power (CHP) plants: the shift from base load operation to running in cyclic modes. These cogeneration power plants are not adapted to new running conditions. The level of CHP plant flexibility should be improved to operate profitably and efficiently from both technical and fuel usage point of view. There are different ways to increase the flexibility of power plants. Before any improvements, the situation at power plants should be evaluated and the weakest points defined. In this publication, such measures are presented on Riga CHP-2 plant example: installation of heat storage tank; extension of operation rang; acceleration of start-ups.

The Latvian experience and problems of the grid integration of renewable energy sources in the power system

This paper considers development trends and perspectives for widespread implementation of distributed generation, based on renewable energy sources (RES) in the Baltic States. The main issue of the research is integration of RES into the power grid and electricity markets. Paper provides an overview of legislative statements and main rules, which regulates formal relationships between power producers using RES and network operators. Major problems and barriers that limit intensive development of RES are identified and possible solutions to overcome them are proposed.

Cost — benefit analysis of CHP plants taking into account air cooling technologies

The ambient temperature has a negative effect on gas turbine (GT) performance, i.e., the power output of GT decreases with the increment of ambient air temperature. This negative effect is solved by means of air cooling at the input of compressor of GT unit. Mainly the air cooling technologies are widely used in the regions with hot climate to produce surplus of electricity and cover the peak demand of it. In this publication the methodology is developed for the evaluation of the economic benefit from air cooling technologies by selling surplus of electricity at electricity power exchange, i.e., the adjustment of combined and heat power (CHP) plants operation to the electricity price fluctuations through the use of air cooling technologies.

Efficient Use of Cogeneration and Fuel Diversification

Abstract Energy policy of the European Community is implemented by setting various goals in directives and developing support mechanisms to achieve them. However, very often these policies and legislation come into contradiction with each other, for example Directive 2009/28/EC on the promotion of the use of energy from renewable sources and Directive 2012/27/EU on energy efficiency, repealing Directive 2004/8/EC on the promotion of cogeneration based on a useful heat demand. In this paper, the authors attempt to assess the potential conflicts between policy political objectives to increase the share of high-efficiency co-generation and renewable energy sources (RES), based on the example of Riga district heating system (DHS). If a new heat source using biomass is built on the right bank of Riga DHS to increase the share of RES, the society could overpay for additional heat production capacities, such as a decrease in the loading of existing generating units, thereby contributing to an inefficient use of existing capacity. As a result, the following negative consequences may arise: 1) a decrease in primary energy savings (PES) from high-efficiency cogeneration in Riga DHS, 2) an increase in greenhouse gas (GHG) emissions in the Baltic region, 3) the worsening security situation of electricity supply in the Latvian power system, 4) an increase in the electricity market price in the Lithuanian and Latvian price areas of Nord Pool power exchange. Within the framework of the research, calculations of PES and GHG emission volumes have been performed for the existing situation and for the situation with heat source, using biomass. The effect of construction of biomass heat source on power capacity balances and Nord Pool electricity prices has been evaluated.