The article presents the current state of the CNG market used as an alternative fuel for car engines. Attention was paid to European Union directives requirements and the current state of the directives’ fulfillment. The economic aspect of CNG usage was analyzed and the approximate costs of driving 10,000 km on different fuels in the last four years were presented. The PtG process which uses electric energy (hydrogen production) and carbon dioxide captured from the flue gas for the production of synthetic methane were discussed. The scheme of the SNG plant with the indication of its most important components was presented, and attention was paid to the mutual complementation of PtG technologies with carbon dioxide capture technology. The benefits of synthetic methane production are presented and the use of compressed natural gas to power engines in vehicles has been described. First, the focus was on the single-fuel use of CNG in bus and truck engines, paying particular attention to the ecological aspect of the implemented solutions. It has been shown that the use of compressed natural gas will reduce almost 100% of the particulates emission from the combustion process. The advantages and disadvantages of the alternative fuel supply are given. Next, the aspect of dual-fuel use in diesel engines was analyzed on the example of a smaller engine. The degree of reduction of harmful compounds emission from the combustion process is shown. Finally, attention was paid to the possible scale effect, referring to the number of motor vehicles in Poland.
In this article, the contribution of renewable energy sources (RES) to the worldwide electricity production was analyzed. The scale of development and the importance of RES in the global economy as well as the issues and challenges related to variability of these sources were studied. In addition, the chemical conversion of excess energy to renewable methanol has been presented. The European Union regulations and targets for the years 2020 and 2030 concerning greenhouse gases reduction were taken into consideration. These EU restrictions exact the further development of renewable energy sources, in particular, the improvement of their efficiency which is closely related to economics. Moreover, as a part of this work, energy storage were described as one of the ways to increase the competitiveness of renewable energy sources with respect to conventional energy. A method for the conversion of carbon dioxide separated from high-carbon industries with hydrogen obtained by the over-production of green energy were described. The use of methanol in the chemical industry and global market have been reviewed and thus an increasing demand was observed. Additionally, the application of renewable methanol as fuels, in pure form and after a conversion of methanol to dimethyl ether and fatty acid methyl esters has been discussed. Hence, the necessity of modifying car engines in order to use pure methanol and its combination with petrol also was analyzed.