The lightest and simplest chemical element in the universe, hydrogen will be an important energy carrier for the energy transition. It is not free of controversy, though. Hyped by some as the “Swiss army knife” of the energy transition, a one-size-fits all solution to all imaginable energy system challenges, hydrogen is regarded by others as too expensive, inefficient, and dangerous to play a significant role. The reality lies between these two extremes.
Hydrogen has numerous advantages. Its use releases no greenhouse gas emissions, it can be stored, and it can fulfil a variety of functions across the economy, from motive power to high temperature heat. A further advantage of hydrogen is the derived energy carriers that can be produced with it, including so-called synthetic fuels, such as methanol and ammonia.
Hydrogen also has downsides. It is expensive to produce sustainably. The tiny molecule can easily leak out of infrastructure designed for storing and transporting fuel such as natural gas. Any leakage would indirectly increase the atmospheric concentration of known greenhouse gases like methane and ozone. Furthermore, whilst the energy density is quite high per unit of mass, it is relatively low per unit of volume – meaning it takes up a lot of space, not ideal for applications like aviation. Hydrogen also tends to cause embrittlement of steels used for pipelines, which reduces their lifetimes compared to their use for other gases. It is more explosive than other gases, which can present a safety hazard, and in turn may result in lower acceptance from society. Finally, the manufacture of hydrogen via sustainable pathways is more energy and resource intensive than alternatives such as electrification.
Despite these disadvantages, there is an emerging scientific consensus that hydrogen and hydrogen-based fuels make sense in several specific sectors. But even these limited applications will require a massive scale-up of hydrogen production and imply numerous trade-offs, as we explore in the coming pages. Meanwhile, advancing policy to support production and adoption of hydrogen and hydrogen-based fuels is hindered by the complexity of the options, the sheer number of actors involved, and the long-term implications of technological choices that will define the energy system for decades to come.
Keep reading in the latest issue of the PSI Energy Compass. Subscribe for free in German, French, or English.
