The hydrogen future
Hydrogen is the most abundant element in the universe. When compared to fossil fuels as an energy source, hydrogen energy generation technologies are much safer for the environment as many only produce pure water as an emission.
As a result of hydrogen’s potential to mitigate the effects of global warming as a clean and renewable energy source, and specifically green hydrogen’s potential, finding new ways to either reduce the cost of hydrogen manufacturing or to increase the efficiency of hydrogen as a fuel source have been major areas of research focus around the world for many decades.
Much progress has occurred on both of these fronts because of technology developments as well as the global energy crisis initiated by the war in Ukraine. As the cost of oil and gas has increased over 300% during 2022 due to international supply issues, the EU and the US have poured billions in new investments into hydrogen research and development. Moreover, recent technological breakthroughs open the door to future mass adoption of hydrogen fuel as a replacement for fossil fuels by providing it cheaper, cleaner, and more efficiently than ever before.
Sources of hydrogen
Main sources of hydrogen include coal, natural gas, oil, and electrolysis. Because hydrogen can be sourced in numerous ways, scientists differentiate among each type using the following color names.
- Blue hydrogen: Made from natural gas through steam reforming.
- Grey hydrogen: Created by converting natural gas to hydrogen without attempting to separate out CO2.
- Pink hydrogen: Created by electrolysis using nuclear energy.
- Yellow hydrogen: Produced by the electrolysis of electrical grids.
- Brown and black hydrogen: Made from brown and black coal. These types of hydrogen are produced via gasification in many industries that convert carbon-rich materials into hydrogen and carbon dioxide.
- Turquoise hydrogen: Obtained by pyrolysis of methane.
- Green hydrogen: Sustainable hydrogen created via electrolysis using renewable sources like solar or wind energy.
Only green and pink hydrogen are counted as renewable sources of hydrogen. Green hydrogen, or that which uses solar or wind energy to power electrolysis, is the cleanest source of hydrogen production. However, currently less than 1% of total hydrogen produced globally is considered green hydrogen. For hydrogen to replace fossil fuels as a sustainable energy source, only green and pink hydrogen must be used, instead of other color sources.
Historically, a main obstacle to mass adoption of hydrogen over fossil fuels is the relative inefficiency of traditional hydrogen production methods. Currently, steam reforming, the main method of grey and blue hydrogen production, is only 65% efficient. Electrolysis, the main method for yellow, pink, and green hydrogen production, is typically only between 70-80% efficient.
In March 2022, a paper published in Nature Communications describes a breakthrough by the company Hysata that has demonstrated a remarkable 98% efficiency for its novel electrolysis fuel cell design. Using a unique capillary-fed electrolysis cell, Hysata has achieved electrolysis performance exceeding current commercial electrolysis cells by more than 15-20%, achieving a cell voltage of 0.5 A/cm−2 at 85 °C and only 1.51 V, equating to an energy consumption of just 40.4 kWh/kg hydrogen.
A proton exchange membrane water electrolyzer (PEMWE) is the current standard fuel cell type used in hydrogen electrolysis systems, but is considered costly due to use of expensive noble metal-based catalysts and perfluorocarbon-based proton exchange membranes. As a result, for hydrogen to be more competitive with the cost of fossil fuels, cheaper alternative fuel cells must be developed which lead to lower costs of hydrogen manufacturing.
Fortunately a recent breakthrough was made by the Korea Institute of Science and Technology, or KIST, which created a cheaper and more efficient new type of fuel cell, AEMWE. These fuel cells work with an anion exchange membrane and electrode binder and do not need expensive platinum group-metal electrodes or titanium separator plate materials common in PEMWE fuel cells, leading to lower possible future hydrogen production input costs.
Although this new fuel cell type has been shown to achieve record cell performance (6 times that of existing anion exchange materials and about 1.2 times more than PEMWE) and lower costs, in order to fully replace PEMWE, its longevity must be improved.
Ammonia and solid hydrogen storage
Because hydrogen is the lightest element in the universe, it forms as a very low density gas at standard temperatures and pressures. Such low density, in fact, that it easily escapes from Earth’s atmosphere. As a result, a key challenge to improving the practicality of hydrogen as fuel is improving storage of the hydrogen itself.
Currently, hydrogen storage requires extreme conditions of high-pressure tanks at 350-700 bar (5,000-10,000 PSI) when stored as a gas or cryogenic temperatures as low as -252.8 °C at 1 ATM when stored as a liquid.
As a result, researchers have developed new ways to store and use hydrogen. One such proposed storage technique involves conversion to ammonia. Relative to gas or liquid hydrogen storage, ammonia storage offers advantages of a higher hydrogen density, an easier distribution network, and easier catalytic decomposition. Just as hydrogen but differently from hydrocarbons and alcohols, ammonia produces no CO2 emissions. In this system, hydrogen is stored as ammonia which is either used directly as a fuel source itself or simply turned back into hydrogen when ready to use.
A possible turning point in hydrogen energy storage is solid hydrogen. Rather than using liquid or gas hydrogen that each require extreme conditions, solid hydrogen is stable at standard conditions. A team based at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) in Dresden recently developed a “powerpaste” that uses magnesium hydride to store hydrogen. This new material is stable up to 250°C and carries 10 times the energy of a similar weight in lithium batteries, substantially more than a same weight 700-bar H2 tank. As a result, the range of future hydrogen fuel cell vehicles can be expanded beyond that of gas-powered vehicles, up to over 1000 miles per potential charging.
An exciting aspect of the future of hydrogen relates to new major investments in the US and EU.
Inflation Reduction Act
In August 2022, the US signed the Inflation Reduction Act, which provides $370 billion over 10 years towards renewable-energy measures. Earmarked in these provisions were major investments in hydrogen. In addition to research funding, the bill provides tax credits to producers of low-carbon hydrogen, incentivizing further adoption.
The IPCEI Hy2Tech initiative
In July 2022, the EU Commission approved up to €5.4 billion in public support from 15 member states and a likely additional €8.8 billion in the form of private investments for the IPCEI Hy2Tech project, an Important Project of Common European Interest (IPCEI) related to the hydrogen technology value chain. These types of investments will lead to future technology breakthroughs and a better supply chain for future mass adoption of hydrogen.
As a result of these investments, the future of hydrogen as a fossil fuel alternative is brighter than ever before. Due to aforementioned technological advances, green energy can be produced at $1.5/kg or less, a key benchmark needed to replace fossil fuels as a primary energy source. Future investments will further lower future costs and help to develop the infrastructure for more mass use of hydrogen as a fuel.
Hydrogen flow and pressure control
Alicat’s pressure and mass flow controllers are important components for hydrogen research, including electrolyzer system testing and regulation, fuel cell testing, leak checks, and more. As hydrogen becomes increasingly competitive compared to conventional fuels, pressure and flow optimization during hydrogen applications becomes even more critical.