The well-to-wheel analysis of hydrogen enriched compressed natural gas for heavy-duty vehicles using life cycle approach to a fuel cycle

摘要

Increasing urban air pollution, greenhouse gases, and declining fossil energy sources are the three major problems of transportation sector which drive the use of alternative vehicular fuels to prevent energy shortage, reduce oil dependency and decrease tailpipe emissions including air pollutants and greenhouse gas emissions. This research work focused on life cycle analysis of HCNG (R) heavy-duty vehicle in which 20% gaseous hydrogen blended with compressed natural gas has been investigated in terms of net energy ratio, GHG value, and cost-effectiveness over a scale of 'per MJ energy output' in two fuel options, i.e. 0%HCNG and 20%HCNG for an entire well-to-wheel cycle. An engineering economic approach has been used to evaluate cost-effectiveness ratio of CNG and 20%HCNG pathways derived from fuel economy improvement. It has been shown that at pump-to-wheel stage, 7% reduction in fuel consumption can be achieved together with 11% reduction in GHGs, 7% reduction in energy consumption at operation and 7% reduction in total costs (RMB/MJ) for 20%HCNG compared with CNG. Rank (1 means 'best and 10 means 'worst') showed that renewable-based hydrogen pathways such as solar, wind and biomass showed dual benefits of lower energy consumption and lower GHG emissions whereas grid electricity-to-hydrogen displayed the worst case in both scenarios. Usually, biomass-based HCNG pathways may have higher net energy ratio, but the sources are cleaner, and renewable in nature. The energy efficiency of fossil-based pathways such as natural gas, coal, etc., is higher than biomass gasification pathway.