RECIPROCATING GAS ENGINES IN THE DISTRIBUTED ENERGY SECTOR OF UKRAINE

Abstract

The war in Ukraine has posed new challenges for the country's energy sector. The Ukraine's integrated energy sector was built as a centralised system with large hub power plants and a high-voltage power transmission system. This configuration is vulnerable to enemy attacks. It is actually impossible to protect large power plants (especially thermal power plants and combined heat and power plants), and the destruction of these facilities leads to power outages for a large number of consumers. The purpose of this article is to consider the technical and economic aspects of the constructing distributed generation based on gas reciprocating engines to ensure a stable energy supply in Ukraine.

Gas engine-based cogeneration systems are truly impressive in terms of their energy-saving capabilities and reduction of noise and vibration levels. Their main advantage is high energy conversion efficiency: compared to separate electricity and heat generation systems, cogeneration systems can save up to 40% of primary energy.

Installing such systems in close proximity to consumers significantly reduces energy losses during transmission and distribution. In addition, thanks to low noise and vibration levels, such stations can be located close to end users, making them a convenient solution for urban and industrial areas.

Engine exhaust gases have the highest potential. The typical exhaust gas temperature is around 460°C. Exhaust heat can generate medium-pressure steam for purposes such as heating boiler feed water, and low-pressure steam for processes such as sterilisation, pasteurisation, space heating, tank heating, humidification and others. In addition, supplementary combustion with natural gas can increase exhaust gas temperatures and heat transfer, allowing more steam to be produced at higher volumes and pressures, opening up even more possibilities.

The modular design means relatively low capital investment in the 1 to 60 MW power range. The frequency and complexity of repairs depend on the type of engine (high- or medium-speed engine, number of cylinders, etc.) and the type of fuel used. In general, the engines are designed for continuous operation for 25–30 years at a rate of 8,000 hours per year, provided that scheduled maintenance and proper technical servicing are carried out.

The main types and thermodynamic cycles of engines are analysed, and a comparison with gas turbine installations was made. It was found that a gas turbine is a more efficient solution for a ratio of electrical power to thermal power of less than 0.8. When the ratio of electrical power to thermal power is > ~ 0.8, gas engine systems generally achieve higher overall efficiency and significantly greater primary energy savings.

Conclusions. The construction of distributed generation based on gas reciprocating engines allows solving the problem of stability of the Ukrainian energy system in a short time. Modern gas reciprocating engines are capable of operating efficiently on low- and medium-calorific gases, which can be obtained by thermal conversion of local fuels.

In general, the development of decentralised energy is one of the main directions in the development of Ukraine's energy sector in the near future. This will increase the stability and reliability of the energy system and improve its ability to function uninterruptedly in wartime and post-war conditions.