Advanced power systems — Temperature optimization of district heating network

Flexibility is crucial to enable the penetration of high shares of renewables in the power system while ensuring the security and affordability of the electricity dispatch. In this regard, heat–electricity sector coupling technologies are considered a promising solution for the integration of flexible devices such as thermal storage units and heat pumps. The deployment of these devices would also enable the decarbonization of the heating sector, responsible for around half of the energy consumption in the EU, of which 75% is currently supplied by fossil fuels. This paper investigates in which measure the diffusion of district heating (DH) coupled with thermal energy storage (TES) units can contribute to the overall system flexibility and to the provision of operating reserves for energy systems with high renewable penetration. The deployment of two different DH supply technologies, namely combined heat and power units (CHP) and large-scale heat pumps (P2HT), is modeled and compared in terms of performance. The case study analyzed is the future Italian energy system, which is simulated through the unit commitment and optimal dispatch model Dispa-SET. Results show that DH coupled with heat pumps and CHP units could enable both costs and emissions related to the heat–electricity sector to be reduced by up to 50%. DH systems also proved to be a promising solution to grant the flexibility and resilience of power systems with high shares of renewables by significantly reducing the curtailment of renewables and cost-optimally providing up to 15% of the total upward reserve requirements.

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Operational Planning and Bidding for District Heating Systems with Uncertain Renewable Energy Production

Energies ◽

10.3390/en11123310 ◽

2018 ◽

Vol 11 (12) ◽

pp. 3310 ◽

Cited By ~ 4

Author(s):

Ignacio Blanco ◽

Daniela Guericke ◽

Anders Andersen ◽

Henrik Madsen

Keyword(s):

Renewable Energy ◽

Power Systems ◽

Power System ◽

Electricity Markets ◽

Electricity Market ◽

Renewable Energy Sources ◽

District Heating ◽

Operational Planning ◽

Solution Approach ◽

The Impact

In countries with an extended use of district heating (DH), the integrated operation of DH and power systems can increase the flexibility of the power system, achieving a higher integration of renewable energy sources (RES). DH operators can not only provide flexibility to the power system by acting on the electricity market, but also profit from the situation to lower the overall system cost. However, the operational planning and bidding includes several uncertain components at the time of planning: electricity prices as well as heat and power production from RES. In this publication, we propose a planning method based on stochastic programming that supports DH operators by scheduling the production and creating bids for the day-ahead and balancing electricity markets. We apply our solution approach to a real case study in Denmark and perform an extensive analysis of the production and trading behavior of the DH system. The analysis provides insights on system costs, how DH system can provide regulating power, and the impact of RES on the planning.

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Optimal scheduling for combined district heating and power systems using subsidy strategies

CSEE Journal of Power and Energy Systems ◽

10.17775/cseejpes.2019.00360 ◽

2019 ◽

Keyword(s):

Power Systems ◽

District Heating ◽

Optimal Scheduling

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The Nuclear Gas Turbine: Towards Realization After Half a Century of Evolution

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/95-gt-262 ◽

1995 ◽

Cited By ~ 4

Author(s):

Colin F. McDonald

Keyword(s):

Power Systems ◽

Gas Turbine ◽

Nuclear Reactor ◽

Electrical Power ◽

District Heating ◽

Small Scale ◽

Closed Cycle ◽

Furnace Gases ◽

The Usa ◽

Space Power Systems

This paper has been written exactly 50 years after the first disclosure of a closed-cycle gas turbine concept with a simplistic uranium heater. Clearly, this plant was ahead of its time in terms of technology readiness, and the closed-cycle gas turbine was initially deployed in a cogeneration mode burning dirty fuels (e.g., coal, furnace gases). In the 1950s through the mid 1980s about 20 of these plants operated providing electrical power and district heating for European cities. The basic concept of a nuclear gas turbine plant was demonstrated in the USA on a small scale in 1961 with a mobile closed-cycle nitrogen gas turbine [330 KW(e)] coupled with a nuclear reactor. In the last three decades, closed-cycle gas turbine research and development, particularly in the U.S. has focused on space power systems, but today the utility size gas turbine-modular helium reactor (GT-MHR) is on the verge of being realized. The theme of this paper traces the half century of closed-cycle gas turbine evolution, and discusses the recent enabling technologies (e.g., magnetic bearings, compact recuperator) that now make the GT-MHR close to realization. The author would like to dedicate this paper to the late Professor Curt Keller who in 1935 filed the first closed-cycle gas turbine patent in Switzerland, and who exactly 50 years ago, first described a power plant involving the coupling of a helium gas turbine with a uranium heater.

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Modelling and Analysis of Plate Heat Exchangers for Flexible District Heating Systems

Energies ◽

10.3390/en12214141 ◽

2019 ◽

Vol 12 (21) ◽

pp. 4141

Author(s):

Serafym Chyhryn

Keyword(s):

Heat Transfer ◽

Power Systems ◽

Heat Exchangers ◽

District Heating ◽

Estimation Procedure ◽

Computational Effort ◽

Seamless Integration ◽

Plate Heat ◽

Temperature Levels ◽

Flexible Operation

Seamless integration of district heating (DH) and power systems implies their flexible operation, which extends their typical operational boundaries and, thus, affects performance of key components, such as plate heat exchangers (PHXs). Despite that the heat transfer in a PHX is regulated by mass flows, flexible operation and demand variations cause shifts in temperature levels, which affects the system operation and must be efficiently accounted for. In this paper, an overall heat transfer coefficient (OHTC) model with direct relation to temperature is proposed. The model is based on a linear approximation of thermophysical components of the forced convection coefficient (FCC). On one hand, it allows to account for temperature variations as compared to mass flow-based models, thus, improving accuracy. On the other hand, it does not involve iterative lookup of thermophysical properties and requires fewer inputs, hence, reducing computational effort. The proposed linear model is experimentally verified on a laboratory PHX against estimated correlations for FCC. A practical estimation procedure is proposed based on component data. Additionally, binding the correlation to one of varying parameters shows reduction in the heat transfer error. Finally, operational optimization test cases for a basic DH system demonstrate better performance of the proposed models as compared to those previously used.

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Development of a Simulation Model of Transient Operation of Micro-Combined Heat and Power Systems in a Microgrid

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4037962 ◽

2017 ◽

Vol 140 (3) ◽

Cited By ~ 4

Author(s):

Francesco Ippolito ◽

Mauro Venturini

Keyword(s):

Energy Storage ◽

Power Systems ◽

Thermal Energy ◽

Energy Demand ◽

Electric Energy ◽

District Heating ◽

Transient Behavior ◽

Daily Basis ◽

Combined Heat And Power ◽

Electric Energy Storage

This paper presents the development of a simulation tool for modeling the transient behavior of micro-CHP (combined heat and power) systems, equipped with both thermal and electric storage units and connected with both electric and district heating grid (DHG). The prime mover (PM) considered in this paper is an internal combustion reciprocating engine (ICE), which is currently the only well-established micro-CHP technology. Different users, characterized by different demands of electric and thermal energy, both in terms of absolute value and electric-to-thermal energy ratio, are analyzed in this paper. Both summer and winter hourly trends of electric and thermal energy demand are simulated by using literature data. The results present a comprehensive energy analysis of all scenarios on a daily basis, in terms of both user demand met and energy share among system components. The transient response of the PM and the thermal energy storage (TES) is also analyzed for the two scenarios with the lowest and highest daily energy demand, together with the trend over time of the state of charge of both thermal and electric energy storage (EES).

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Increasing the share of RES in Polish district heating systems using power-to-heat technology

E3S Web of Conferences ◽

10.1051/e3sconf/201911600042 ◽

2019 ◽

Vol 116 ◽

pp. 00042

Author(s):

Małgorzata Kwestarz ◽

Maciej Chaczykowski

Keyword(s):

Power Systems ◽

Power System ◽

Renewable Energy Sources ◽

District Heating ◽

Policy Framework ◽

Heating Systems ◽

Heat Technology ◽

District Heating Systems ◽

The Stability ◽

Energy And Climate Policy

The power systems in European Union operate under energy policies where the greenhouse gases reduction, the increase of the share of renewable energy sources (RES) and the improvements in energy efficiency are the main objectives. Polish energy sector is currently based on inefficient usage of coal and must be transformed according to the requirements of EU energy and climate policy. A policy framework for climate and energy in the period from 2020 to 2030 established the target of 27% of share of RES in energy consumption. With the continuing increase in the use of RES, it is likely that more and more generation will have to be curtailed to maintain the stability of the power system which was not originally designed to integrate renewable generation. In this context, the conversion of renewable electricity to heat in connection with its storage in district heating systems, known as Power-to-Heat (PtH) can be considered as a viable option in increasing the share of RES and facilitating the stability of the power system. In this paper an attempt is made to estimate the potential of PtH technology for Poland up to 2030, including the high RES share scenario for the energy mix development.

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