Hydrogen is an energy carrier not an energy source, which means that its potential role has similarities with that of electricity. Both hydrogen and electricity can be produced by various energy sources and technologies. Both are versatile and can be used in many different applications. However, when the hydrogen is produced using renewables energies, no greenhouse gases, particulates, sulphur oxides or ground level ozone are produced from their use. If the hydrogen is used in a fuel cell, it emits only water.
Hydrogen contains more energy per unit of mass than natural gas or gasoline, making it attractive as a transport fuel. However, hydrogen is the lightest element and so has a low energy density per unit of volume. This means that larger volumes of hydrogen must be moved to meet identical energy demands as compared with other fuels. This can be achieved, for example, through the use of larger or faster-flowing pipelines and larger storage tanks or using high pressure storages. Hydrogen can be compressed, liquefied, or transformed into hydrogen-based fuels that have a higher energy like ammonia, methanol, etc., but the conversion and the subsequent re-conversion uses some energy.
Today, around 70 million tonnes (Mt) of current demand worldwide for “pure” hydrogen, with “pure” meaning that the specific applications require hydrogen with only small levels of additives or contaminants tolerated. The main applications for this hydrogen are oil refining and ammonia production, mainly for fertilisers. A further 45 Mt of demand exists for hydrogen as part of a mixture of gases, such as synthesis gas, for fuel or feedstock. The main applications for hydrogen as part of a mixture of gases are methanol production and steel production. While one-third of hydrogen demand today is for transport sector applications in a broad sense – in refineries and for methanol used in vehicle fuel – less than 0.01 Mt per year of pure hydrogen (less than 0.03 Mtoe) is used in FCEVs, most of which is derived from natural gas.
The potential for hydrogen to power about 10 to 15 million cars and 500,000 trucks by 2030, with many uses in other sectors as well, such as industry processes and feedstocks, building heating and power, power generation and storage. Overall, the study predicts that the annual demand for hydrogen could increase tenfold by 2050 to almost 80 EJ in 2050 meeting 18% of total final energy demand in the 2050 two-degree scenario. At a time when global populations are expected to grow by two billion people by 2050, hydrogen technologies have the potential to create opportunities for sustainable economic growth.