The project, which is being implemented at Novosibirsk State Technical University (NETI), aims to increase the availability and continuity of energy supply in small and medium-sized cities (MSC) by creating a flexible energy infrastructure. The proposed solutions will create conditions for the socio-economic development of MSC, which to a certain extent will increase their investment attractiveness, reduce social tension and increase business activity.
The relevance of the project is due to the fact that in Russia about 30% of the population lives in small and medium-sized cities. In the largest and largest cities, large thermal power plants serve as the basis of heat supply systems, the share of combined energy production is 50-70%, which leads to a high level of energy efficiency in energy production. Separate energy production dominates in MSC: electricity is supplied from large district substations, and the main sources of thermal energy are worn-out boiler houses with high specific fuel consumption.
"In small and medium-sized cities, the problems of providing public services are largely due to the low reliability of heat supply systems and the high cost of thermal energy. Therefore, at the first stage of the study, much attention is paid to the issues of heat supply. Management of the development of heat supply systems is often carried out on the principle of "maintaining operability", but the rate of wear and tear of heating networks significantly exceeds the rate of equipment replacement. The increase in the number of accidents combined with the lack of economic accessibility leads to social tension. Municipal authorities find themselves in a difficult situation, as they do not have the ability to create conditions for improving the efficiency of energy supply. It is not enough to reconstruct heating networks and modernize boiler houses. An integrated approach is needed to improve the energy infrastructure, including heat and electricity supply systems," said Elizaveta Ivanova, an assistant at the Department of Automated Electric Power Systems at NSTU-NETI.
As part of the project, an analysis of the state of the energy infrastructure of the Linevo work settlement was carried out. The source of thermal energy in the village is a boiler house, originally designed to provide steam to an industrial enterprise. Based on open data, NSTU-NETI scientists estimated the number of interruptions of heat supply in Linevo per year. It amounted to more than 45 outages with an average duration of 35 hours. The decrease in the efficiency and reliability of heat production and transfer indicates the lack of necessary flexibility of the heat supply system in the village of Linevo. t is necessary to consider various innovative technical solutions that would improve the reliability and efficiency of energy supply in small and medium-sized cities.
As noted by Elizaveta Ivanova, in relation to energy, flexibility is the ability to cost—effectively cope with the variability and unpredictability of generation and demand for electric and thermal energy, while increasing the reliability of energy supply. In small and medium-sized cities, the creation of mini-CHPs with gas-piston installations should be considered as a first step towards flexible energy infrastructure, since the joint production of thermal and electric energy makes it possible to usefully use up to 87% of the fuel burned. For end users, the reliability of power supply will increase due to the two-way independent power supply of electric receivers. The technical and economic accessibility of electricity for the subjects of the real sector of the economy will increase, which will increase business activity in MSC.
The efficiency of using fuel in cogeneration is maximized under the condition of 100% utilization of associated heat in the heat supply system, however, during the inter-heating period, the demand for heat decreases by 3-4 times. The lack of heat load leads to an "increase in the cost" of electricity, therefore, it is proposed to store excess heat in seasonal thermal accumulators and use it to cover peak loads in winter. Excess heat can also be converted into cold using refrigerating machines.
The availability of "inexpensive" electricity will ensure the development of MSC, in addition, there are prerequisites for the use of electricity for the production of thermal energy. The advent of electric boilers will reduce heat generation in hydrocarbon boilers, which will improve the environmental situation in the region.
Scientists at NSTU-NETI proposed to transform individual heating points into active intelligent heating points by installing an electric boiler, which will save heating in case of accidents in the external system and "warm up" the coolant close to the consumer, i.e. ensure the quality of heating. The proposed technical solution will increase the reliability of the house heating system and will make it possible to "facilitate" the operation of heating networks. Another promising option is a thermal energy storage device that performs the function of a heat load regulator. Its inclusion in the heat supply system will reduce the influence of ambient temperature on the operating mode of the heat source.
The proposed solutions can become a methodological basis for the development and updating of MSC heat supply schemes. The proposed solutions can become a methodological basis for the development and updating of MSC heat supply schemes.
As an approbation of the approach proposed in the study to the formation of a flexible heat supply system, the section "Heat supply schemes for the Linevo work settlement" was performed, where an energy-efficient option for the development of a heat supply system with a mini-CHP consisting of gas piston and boiler installations was proposed.
The project "Transformation of communal energy Supply systems in small and medium-sized cities" is being implemented with the support of the Russian Science Foundation.