MODERN POWER TO GAS CONCEPTS AND THEIR IMPLEMENTATION

Abstract

The concept of PtG, namely the accumulation of energy in gas, has attracted the increasing attention of energy experts in recent years because:

• it allows solving the problem of using unstable solar and wind energy and thereby creating a powerful incentive for the development of these areas of renewable energy;
• it becomes a significant generator of synthetic methane – an alternative to already expensive and in some cases scarce natural gas.

Today, PtG projects are implemented in many countries of the world. The main efforts of researchers are aimed at increasing the efficiency of hydrogen generation and methanation processes, increasing the productivity of electrolyzers and methanators, and reducing their cost in order to achieve commercialization of the implemented technologies.

Among water electrolysis technologies, the direction of application of solid polymer electrolytic membranes (PEM) is promising and attractive; the main advantage of which compared to alkaline electrolysis is a faster cold start, as well as greater flexibility and a better combination with unstable sources of electrical energy. Also promising is solid oxide (known as high-temperature) electrolysis (SOES), which is characterized by low power consumption and is very well compatible in a single technological scheme with highly exothermic methanation reactions, although they are more sensitive to fluctuations in power sources.

For adiabatic catalytic methanation reactors, the main problem is ensuring the optimal reaction temperature due to cooling, in particular due to the difficulties of its control. One of the ways to overcome these difficulties is the use of three-phase reactors.

For biological methanation reactors, the main problem remains the low level of mass transfer of hydrogen, which limits the productivity of the process.