Hydrogen as a Clean Energy Carrier

Abstract

In this chapter, the role of hydrogen as a clean energy carrier is discussed. In the first part of the chapter, a historical perspective on hydrogen exploration, production, and use is presented. It appears that the modern world evolved from a mechanization period (when heat engines were developed to generate motive force from fossil fuels) to an electrification era (when the motive power developed by power plants is converted to electricity to supply large national or regional grids) and to a hydrogenation era (when the energy from primary sources is converted by clean processes to hydrogen as an energy carrier). It is argued that the hydrogenation era just started and will be implemented during the first century of the current millennium. Furthermore, this section reviews the main national/regional research programs deployed in the last 20 years on hydrogen research. Various uses of hydrogen including as energy carrier in transportation sector, energy storage medium, and greenhouse gas reduction agent are discussed in detail. It is shown for a case study of comprehensive life cycle analysis that among six vehicle types hydrogen and fuel cell vehicles show the greatest potential. Also, the use of ammonia as synthetic fuel produced from clean hydrogen and nitrogen represents an attractive alternative to conventional fuels for vehicles.

Nomenclature

AP:

Air pollution indicator, g/100 km

GW:

Global warming indicator, kg CO₂/100 km

GWP:

Global warming potential, kg CO₂/100 km

LHV:

Lower heating value (MJ/kg)

$\dot{m}$ :

Mass flow rate (kg/s)

$\dot{Q}$ :

Heat flux (kW)

1.1.1 Greek Letters

$\eta$ :

Efficiency

1.1.2 Subscripts

Fuel:

Natural gas or hydrogen