Its aim is to convert carbon dioxide captured from the power units into synthetic natural gas (SNG). Methane is produced as a result of the reaction of CO2 with hydrogen from water electrolysis. This process may be supplied by the surplus of cheap energy generated, for instance, from renewable sources during “off–peak periods” (when the demand for energy is decreased, for example at night). The technology is, therefore, not only a forward-looking solution for using CO2 but also a method for storing that electrical energy which comes from uncontrollable energy sources, such as wind farms or PV cells. The by-product of the process is oxygen.

Research projects aimed at removing carbon dioxide from flue gases have already been implemented at Tauron Group power stations. “Therefore, central to our concerns are research and development works aimed at developing technologies for the industrial reuse of CO2, especially those which, if the undertaking is commercialised, will allow us to utilise it in large quantities,” underlines Filip Grzegorczyk, President of the Management Board at TAURON Polska Energia.

Excess electrical energy is used during the project to generate hydrogen; subsequently, hydrogen is, together with carbon dioxide captured from boiler flue gases, used in the methanation reactor for the production of synthetic methane. The carbon dioxide required for the process comes from the pilot plant for capturing CO2, which is extracted from flue gases from a working power unit.

“The pilot CO2-SNG plant is aimed at testing, in real conditions, the methanation reactor and the end-to-end installation for generating methane off CO2 and hydrogen. We are testing its conversion capacity, operational flexibility and adjustment to the storage of excess energy in the form of synthetic methane. Therefore, the project combines two trends, which are the reduction of CO2 emissions at the power station and provision of the large-scale accumulation of energy through the production of gas fuels when energy is cheap. The presented plant is an effect of earlier activities and achievements of the TAURON Group in the R&D field of CO2 capture,” explains Jarosław Broda, Vice President of the Management Board at TAURON Polska Energia in charge of asset management and development.

Thanks to this cutting edge technology, the storage capacity will increase for methane; at the same time, CO2 will be reused for industrial purposes. The SNG (synthetic natural gas) produced when there is excess electrical energy may be fed to the existing gas supply network to be used during the peak hours for generating energy, for example in a gas turbine. After compression, it may also be used as CNG (compressed natural gas) for vehicular transport.

It is worth noting that methane burnt by piston combustion engines is characterised by the lowest emission of hazardous substances to the atmosphere from among all the types of fuels used for this purpose. Therefore, public transit bus fleets with classic diesel engines are in many towns and cities replaced for vehicles adjusted to compressed methane. The pilot CO2-SNG plant was designed and built at the Łaziska Power Station within the scope of the project implemented by the international consortium whose leader is TAURON Wytwarzanie. The project is co-financed from the EIT InnoEnergy funds.