It’s the lightest, most abundant element in the universe. And when it burns, all it leaves behind is clean.
So, it’s puzzling why more people haven’t heard of hydrogen – and of the role it is earmarked to play in the shift towards a carbon-free energy mix.
One reason for the public’s lack of awareness is the way climate change is portrayed in the media. Invariably, discussions around the emissions behind climate change focus on ‘renewable energy’ and ‘electrification’.
What is often overlooked is the fact that a large percentage of greenhouse gas emissions originate from sectors that are difficult to de-carbonize – from activities such as heavy industry (steel, cement, and chemicals), transportation, aviation, shipping, and heating and cooling in residential and commercial sectors.
Batteries alone are not going to de-carbonize these sectors. And we just don’t have time to wait while businesses shift from fossil fuels to renewable energy sources. We require a fuel that is already known to be safe, emissions-free, and available on demand. The answer is hydrogen.
Hydrogen – the good and the bad
Hydrogen has long been recognized as a viable alternative to fossil fuels. The gas is, after all, abundant and highly reactive. It is also surprisingly benign. When burned, it does not produce any of the following:
- Greenhouse gas emissions
- Particulates, such as soot, dust, or dirt
- Sulfur dioxide (SO2) that contributes to environmental acidification
- Ground-level ozone
- Pollutants, such as nitrogen oxides (NOx) and volatile organic compounds (VOCs), which cause respiratory and cardiovascular problems in humans and damage vegetation and ecosystems
However, the incredible low density of hydrogen makes it technically challenging and expensive to store, either compressed or liquified. Both these methods have their drawbacks.
With compression, hydrogen must be kept at anything from 350 bar to 700 bar. Despite this, hydrogen stored under high pressure requires more storage space than liquid or solid fuels. The current alternative to compression is liquefaction, which is the process of maintaining the gas as a liquid at the extremely low temperature of -253°C (-423°F).
- Storage tanks have a limited capacity. For large-scale applications, such as power generation, an impossibly large number of tanks would be required
- Compression is energy intensive
- It is unlikely that compressed hydrogen storage can be used in portable applications, such as for transportation, outdoor activities, portable power, emergency power, and others, due to the small amount that can be stored in commercial-volume containers
- High-pressure tanks must be designed and built to exact specifications, driving up costs
- As with many compressed gases, there are safety concerns; a ruptured tank or a leak of pressurized hydrogen could result in an explosion or fire
Liquified hydrogen drawbacks
- Liquefaction is achieved at -253°C, a process that requires significant energy
- It is estimated that up to 40% of hydrogen’s available combustion energy can be lost due to boil-off during storage, shipping, and handling
- Insulated cryogenic storage tanks are expensive
- Current liquefaction systems consume more than 30% of the energy content in the hydrogen
- Liquid hydrogen is both extremely cold and flammable, posing serious safety risks in case of tank ruptures or leaks
The good news is a breakthrough hydrogen storage technology has been developed. Based on advances in reticular chemistry, it uses metal-organic frameworks (MOFs) to safely store hydrogen at low pressure and ambient temperature.
MOFs are composed of repeating arrays of cage-like building blocks, which are empty cells known as ‘voids’ or ‘pores’. Hydrogen gas molecules fill these voids and attach to their surfaces in a process called adsorption. Large volumes of hydrogen can be adsorbed in small amounts of MOF, due to their immense surface areas. In fact, if a single gram of MOF were rolled out flat, it would cover an area the size of a soccer field. Subsequent pressurization of the MOF releases the hydrogen as a gas.
The right technology at the right time
The maturing of MOF-based hydrogen storage technology comes just as enthusiasm for hydrogen is reaching an all-time high. And these commitments go far beyond promises or vague policy statements. Some recent highlights in hydrogen and hydrogen infrastructure investments and initiatives include:
- The announcement by the Chinese government that it will replicate its ‘Ten Cities’ program (that launched electric vehicles in the country) for hydrogen vehicles. The program is to be rolled out in Beijing, Shanghai, Chengdu, and seven other metropolises. China has also announced that Wuhan will become the first Chinese ‘Hydrogen City’, with up to 100 fuel cell automakers and related enterprises and up to 300 filling stations by 2025. The country has recommitted to reaching its target of 1 million FCEVs by 2030, plus 1000 refueling stations
- In the US, the California Fuel Cell Partnership has outlined targets for 1000 hydrogen refueling stations and 1,000,000 FCEVs by 2030, matching China’s targets
- A global increase in demand for hydrogen, forecast by the International Energy Agency, is set to rise from 94 million tons in 2021 to 200 million tons by 2030. The transport, industry, and power generation sectors are driving this growth as they increasingly de-carbonize and reduce their greenhouse gas emissions
- A commitment by the European Union to produce 10 million tons of green hydrogen in the EU by 2030. The EU has also announced the creation of a European Hydrogen Bank to support the uptake of renewable hydrogen by member states. A key objective of the bank is to reduce the cost gap in the EU between green hydrogen and that produced by fossil fuels. To this end, the EU Commission has earmarked EUR 800 million (USD 865 million) to its first auction of hydrogen subsidies
In 2015, the community of nations came together and agreed to implement measures to try and limit the rise in global warming by 2050 to 1.5°C above pre-industrial levels. Much has been achieved. Battery-powered cars are now common in many cities. The share of solar and wind in the energy mix is slowly increasing. But the fact remains that vast swathes of our basic economic activities – making things and moving them around the world – remain reliant on fossil fuels. And it is a reliance that will remain until such time as it becomes more cost-effective to store and transport hydrogen.
H2MOF is a company founded by two eminent chemists, each of whom have created new fields of chemistry. They and others have now pooled their intellect and research to achieve one objective: to realize the tremendous potential of MOFs as a cost-effective hydrogen storage technology.
H2MOF welcomes discussions with likeminded companies and individuals who are interested in helping to advance MOF-based hydrogen storage and realize its potential applications even further.