Hydrogen is not found in free form H 2 but must be liberated from molecules such as water or methane. It is therefore not an energy source and must be made, using energy. It is already a significant chemical product, about half of annual pure hydrogen production being used in making nitrogen fertilisers via the Haber process and about one-quarter to convert low-grade crude oils especially those from tar sands into liquid transport fuels. There is a lot of experience handling hydrogen on a large scale, though it is not as straightforward as natural gas. Most hydrogen today is made by steam reforming of natural gas or coal gasification, both with carbon dioxide CO 2 emissions.
Experimental studies of a direct methanol fuel cell
Finally, a robust fuel cell that runs on methane at practical temperatures -- ScienceDaily
Direct methanol fuel cell
A new study has made a major addition to the available literature on the economic benefits of ammonia energy. This latest study, published by researchers from CSIRO in Australia, provides the data needed to define the round-trip efficiency of using ammonia as a sustainable fuel and hydrogen carrier. The team at CSIRO, the Commonwealth Scientific and Industrial Research Organization, in Australia, begins its analysis of the round-trip efficiency of using ammonia as a fuel with an examination of the energy efficiency of ammonia synthesis technologies, then considers the energy cost of intermediate processes, like ammonia cracking and hydrogen storage and compression, and concludes with an assessment of fuel efficiency at the point of delivery. Conversion of renewable energy to a fuel would only be considered viable if the energy is to be transported over long distances by ship, the energy needs to be stored for extended months periods of time or there is another engineering constraint that precludes the direct use of the generated electricity. The CSIRO study specifically elucidates three end-use scenarios for ammonia fuel, quantifying the round-trip efficiency of ammonia as: 1 a high-purity hydrogen carrier for fuel cell vehicles PEMFC , 2 a hydrogen carrier for stationary fuel cells SOFC , and 3 a direct fuel for internal combustion engines and gas turbines.
Greenhouse gases mitigation is one of most important challenges facing societies nowadays. Therefore, the way to reduce greenhouse gas emissions should be using carbon free sources that do not generate extra CO2 to the atmosphere. However, there is a great potential in energy carriers and other materials from CO2, with many challenges to overcome. It has been suggested that the reduction of CO2 and conversion to renewable fuels and valuable chemicals may be considered as a promising solution to reduce the greenhouse gas emissions. This chapter discusses the recent developments and remaining challenges of CO2 utilization for the efficient production of methanol.