Photocatalytic methanol and methane production using captured CO2 from coal power plants. Part II - Well-to-Wheel analysis on fuels for passenger transportation services

Photocatalytic methanol and methane production using captured CO2 from coal-fired power plants could be an alternative to reduce climate-related emissions. A detailed Life Cycle Assessment for the photocatalytic production of methanol and methane using captured CO2 is published in Part I (Trudewind and Schreiber, 2014). Beside the use of methanol and methane in the chemical industry the use as fuel for transportation services could be another option. This study determines the environmental impacts of photocatalytically produced methanol or methane as fuel for passenger transportation services. For comparing different passenger transportation services by photocatalytically produced fuels gasoline vehicles and battery electric vehicles powered by electricity from the grid are also considered. Methods and software tools used to calculate the ecological impacts comply with those used in the Life Cycle Assessment for photocatalytic methanol and methane production (Part I). But the functional units of this study are defined as the electricity supply of 1 kWh to the grid as well as the transport service of 7.4 passenger kilometres. Results of the Well-to-Wheel analysis show lower ecological impacts for methane fuelled vehicles than for methanol vehicles, if both fuels were produced photocatalytically. The lowest global warming impact of the considered transport concepts is caused by battery electric vehicles charged with electricity from a power plant with CO2 capture and storage. The reference concept containing a power plant without CO2 capture as well as conventional gasoline vehicles shows the highest ecological impacts. In summary, it can be determined by the Well-to-Wheel analysis that the photocatalytic production of methane and methanol and their use as fuels offer advantages over the conventional concepts. (C) 2014 Elsevier Ltd. All rights reserved.