Green hydrogen has the potential to play a significant role in the transformation to relying entirely on renewable sources. Its advocates see it as an attractive promise to preserve economic progress, wealth, jobs, and health. Hydrogen can be made from different sources, including from natural gas; here, we are discussing the topic of green hydrogen, or hydrogen which is made from renewables, thereby avoiding greenhouse gas emissions.

Hydrogen is primarily an energy carrier, much like electricity. Electricity is a versatile energy carrier that allows us to shift our energy demand to renewable resources while also allowing for high flexibility in use. Green hydrogen may also have features similar to electricity. Therefore, parallel to electricity, green hydrogen may well become a second, complementary energy carrier. In fact, hydrogen is even better suited than electricity for many applications.

Green hydrogen enables us to store power from sources like wind, water, and sun, and can be used regardless of when or where the energy was produced. Therefore, a successful future will most likely include green hydrogen because it enables us to store excess energy from intermittent renewable sources, even across seasons. Its energy storage capabilities are similar to electric batteries or pumped-storage hydroelectricity.

Given the massive energy transformation ahead, the need to provide reliable energy sources for a range of applications makes it clear that both electric batteries and hydrogen will be needed. In some domains, hydrogen is clearly the more effective choice for long-distance applications such as intercontinental flights or shipping. Hydrogen has a significant weight advantage over electric batteries, which is an important consideration in some applications, such as long-distance transport. No wonder Scotland is experimenting with hydrogen ferries.

Whether hydrogen is a more effective energy carrier than electric batteries overall is still to be determined, but it is wise to create competition between technologies, given what is at stake. Most likely, both will be needed because of their complementary characteristics.

As mentioned previously, to decarbonize our economies, hydrogen must be produced with renewable energy. But not all of today’s hydrogen production is green; One barrier to this is the lack of sufficient renewable electricity. But the opportunity is even bigger as green hydrogen has massive potential for load-leveling if produced during times of high electricity availability, while not pulling from, or even recharging, the electric grid when demand exceeds simultaneous renewable production.

The hydrogen economy is already becoming real in many places around the world. For instance, California is investing in hydrogen as part of its clean energy transition. A major focus is building a green hydrogen fueling infrastructure, which is heavily funded by the California Energy Commission (CEC). Germany is also investing in this transition through a public private partnership.

Andrew Forrest, one of Australia’s leading entrepreneur and a recent Ph.D. graduate in Marine Sciences, has transformed Fortescue, his iron ore mining company, to green hydrogen within just a couple of months. He believes that green hydrogen will become highly cost-competitive and that it is one of the best bets in humanity’s efforts to eliminate carbon emissions. He states in his recent Boyer lecture, “the question is not whether green hydrogen will become the next global energy form, but who will be the first to mass-produce it?” He also sees another advantage of a green hydrogen economy: it is not as dependent on large amounts of rare metals as battery systems are. He concludes: “Battery materials are finite …[but] we will never run out of green hydrogen or the stuff we need to make it, and it can handle all parts of our economy, not just cars or transport.”

Hydrogen is not only advantageous because of its lower dependence on special materials. It is also a non-toxic, odorless gas that is not self-igniting and has been used prevalently in the gas industry for over 100 years. Still, like in other applications involving high flows of energy, there are certain risks which need to be managed and mitigated. Additionally, the use of hydrogen at public refueling stations is relatively modern and is not something the general public is accustomed to.

For example, in Germany, a country-wide hydrogen refueling infrastructure is being built as the basis for a mobile future of rapid refueling, long range travel and clean, quiet electric mobility. While so far, the focus has been on serving passenger vehicles and buses, the momentum may shift to medium- and heavy-duty vehicles within the next few years. Refueling options for passenger cars, light trucks and buses are already established and in operation. Technology for hydrogen refueling stations for heavy vehicles is still under development as they require high compression (350 bar or 5000 PSI) for rapid refueling.

For logistics companies looking to shift towards zero emission alternatives, the most important factors to consider are convenient refueling times, payload, range, and costs related to their specific use cases. For example, long-haul use cases usually require 500 km or more per tank fill. By comparison, today’s long-haul trucks can travel 1,000+ km without refueling. With an average consumption between 7 and 8 kg hydrogen per 100 km for heavy trucks, a minimum of 40 kg of onboard hydrogen storage is required to avoid frequent refueling.

Where can we expect the fastest transformation?

1. The simplest transformation is in industry: The number of users is limited (perhaps to just several hundred per country), and hydrogen works wherever coal or natural gas has been used prior.
2. The most popular application for green hydrogen though is mobility: It is simple to explain, the investments are focused (although sometimes technologically challenging such as planes, which have complex safety procedures). Public acceptance might be high, and it is a media-friendly subject, particularly because exhaust from any well-designed hydrogen machine is merely water vapor.
3. When it comes to widespread implementation, the cost of green hydrogen and the current lack of ample renewable energy are limiting factors. While prices have been dropping, green hydrogen still is, for instance in Germany, about twice as expensive to produce per unit of energy as gasoline for cars, even including taxes. But technological advances could cut those costs significantly.

Acknowledgement: This piece of research was produced with input and advice from Prof. David Novak, for which we are grateful.