In a world with an increasing human population, energy is one thing amongst others like food and housing, which will continually be in high demand. Over the years, energy has been sourced through man's ingenuity from various sources like coal, wood, biomass, petroleum, oil shale, tar sand, wind, sunlight, water dams, etc. Though all of them have contributed remarkably in various degrees to the global energy mix, some of them have turned out to be prime contributors to climate change. Energy sources like crude oil/petroleum, coal, wood, oil shale, tar sand, etc. are non-renewable. That is, these sources when exhausted cannot be regenerated, hence, the reason why the call for renewable and sustainable sources of energy has taken the centre stage.
Types of Energy
Renewable energy come from sources or processes which are constantly or naturally replenished. These sources include solar energy, wind energy, biomass energy, tidal power, geothermal energy and hydroelectric power. Renewable energy is often associated with green energy and clean energy, but there is a subtle difference between the three. While renewable sources are those that are recyclable, clean energy is the form of energy which does not release pollutants like carbon dioxide and carbon monoxide. Green energy on the other hand, comes from natural sources. Though these energy types are intertwined, renewable energy is not always fully clean or green. All green energy sources can be said to be renewable, but not fully clean. For instance, some hydroelectric projects or processes can actually damage natural habitats and cause deforestation. In this case, it is not green, though clean. Also, energy derived from biomass can be said to be green, but not clean as the process reduces air quality.
What is Hydrogen?
Hydrogen is a colourless, odourless, non-toxic and highly combustible chemical element with symbol H. The element which was discovered in 1671, when Robert Boyle reacted iron fillings and dilute acids, is found in the first group and first period in the periodic table. It is the first and the lightest (in weight) element known to man. With a weight less than air, hydrogen often rises into the atmosphere and is therefore rarely found in its pure form. It is the most abundant chemical substance in the universe, constituting approximately 75% of all normal matters.
What Prospects does Hydrogen hold as a future fuel?
While in theory hydrogen is the dream fuel or fuel of the future, in practice, things are trickier than they seem. But this does not rule out the fact that hydrogen in many ways has been proven as the perfect fuel for the future. Derived from the most abundant element in the universe, hydrogen fuel is the cleanest burning and most efficient fuel, creating an energy value chain that is renewable and eco-friendly.
Following current projections, by 2030 the hydrogen economy could be worth $500 billion dollars. And many billionaire investors, technology firms and automotive companies have announced their intentions of staking huge amounts of dollars in the market. But one thing is noteworthy, the energy efficiency and environmental impact of hydrogen fuel as a viable future replacement greatly depends on its production process.
Forms of Hydrogen Fuel
Industrially, production of hydrogen is usually classed in terms of colour, hence, there are three types of hydrogen sourced differently that are known to exist; grey hydrogen, blue hydrogen and green hydrogen. Grey hydrogen is produced or extracted as a by-product of the processing of natural gas or other fossil fuels, with the resultant emission of CO2 and CO - greenhouse gases (GHGs) in the process. Blue hydrogen is extracted from natural gas but where CO2 released in the process is captured and stored underground. And green hydrogen is the one produced from the electrolysis of water, an entirely renewable source. Though blue hydrogen is not as clean as the green type, it is often cheaper.
Today, about 95% of all hydrogen in global usage is produced from steam reforming (Bosch process) or partial oxidation of natural gas. Only a small percentage is made by alternative routes such as biomass gasification or electrolysis of water or solar thermochemistry; a process which produces solar fuel with zero emissions. The steam reforming of natural gas to yield hydrogen releases CO2 and CO exogenous to the natural carbon cycle, thus contributing to climate change. Such a type of hydrogen is not good for a world already facing a climate emergency, which is the reason some countries and Environmentalist groups are already out on the frontline clamouring for commercial production of green hydrogen. Green hydrogen is a clean or zero-carbon fuel that when consumed in a fuel cell, produces only water. It can be produced from the catalytic reforming of natural gas (methane), gasified coal or gasified biomass, and of course from the electrolysis of water.
Which Sector Will Use Hydrogen Fuel the most?
The transportation sector generates 23% of global CO2 emissions. And many automotive makers see huge opportunity in a transition to electric vehicles which at the moment appears to be the best way to achieve a long-term commitment to climate change. But battery electric vehicles have two limitations: the down time required for a full charge, and their short traveling range (100 – 300km depending on usage). After being a major focus of fuel cell research and developments in some countries, hydrogen fuel cells have recently been introduced in the tech scene to solve these two issues (that is, limited traveling range and longer charging time). A hydrogen fuel cell electric vehicle (HFCEV) can cover 500-600km, a distance comparable to that covered by a conventional vehicle, and recharging at a station takes three to five minutes. The time investment of battery charging and the effective storage/carrying capacity, among others make hydrogen fuel cells an attractive alternative in the bid to decarbonize the global vehicle fleets. This indeed makes much sense and will save cost. With these possibilities already in sight and practicable, hydrogen can for sure be the alternative fuel for the automobile industry. The US and the UK have hydrogen refueling stations already. The UK government recently disclosed in its Hydrogen Strategy; a twin track approach aimed at delivering 5GW of hydrogen production capacity by 2030. It promises to provide sufficient carbon capture systems as it is bent on producing more blue hydrogen, a type not so good but at least better off when compared with its grey counterpart.
Early adopters of the Hydrogen fuel technology
Hyzon Motors, based in Chicago, US has already begun shipping hydrogen trucks to customers. It is right on track to deliver 85 hydrogen fuel cell vehicles before the year 2021 runs out. Also, nine of the major global automotive manufacturers are currently developing hydrogen vehicle models like Toyota Mirai, Honda Clarity, Hyundai Nexo, BMW, etc. The Japanese engineering firm-Mitsubishi Heavy Industries (MHI) has completed tests of its first hydrogen-fuelled engine for cogeneration systems, as part of its efforts to decarbonize its engine business. Also, in recognition of the huge energy potentials in hydrogen fuel, Japan made history when it launched the controversial 10MW world’s largest facility-Fukushima Hydrogen Energy Research Field (FH2R), for hydrogen fuel production in March 2020. By the way, outside its wide usage in the automotive industry, the versatile fuel could also be used for heating homes and for generating power needed for industrial processes such as steel production and more.
Why we should worry about Hydrogen Fuel
Despite the fact that hydrogen as a prospective fuel holds much in stock for future generations, it can only get better for the world if the hydrogen sourced for use as fuel in these industries is green. Only this type can be said to be sustainable since it is produced largely through electrolysis; a process where electricity is run through water to separate it into hydrogen and oxygen atoms. The conventional logic here is that, if this separation/decomposition of water to yield hydrogen is not powered by fossil fuel but rather by renewable powers like solar and wind, then the resulting hydrogen will be considered green or renewable. Recently, photo-electrocatalytic and photo-electrochemical water-splitting methods have been identified as efficient approaches for the scalable generation of green hydrogen. These methods when fully developed and commercially scaled will not only be sustainable means but viable ways to commercially produce green and renewable hydrogen for industrial and domestic use at a low cost.
Challenges facing Hydrogen as a sustainable fuel
As an innovation which has made its way into the global technology scene, hydrogen fuel is likely to face some challenges before it gets widely adopted. Some of the drawbacks which may militate against the widespread adoption of hydrogen as a fuel are enumerated as follows. Firstly, is the fact that the commercial extraction of green hydrogen through electrolysis is quite technologically tough to scale up, since hydrogen does not exist in a free state but in a combined state with oxygen. The process though is less carbon intensive, demands that the electricity used to drive the reaction should not come from fossil-fuel power plants but rather renewable or nuclear energy. Currently, the production of hydrogen from natural gas requires a significant amount of energy, and the ugly part is that the energy put into the process can be more than that gained from the hydrogen itself.
Secondly, the extraction of hydrogen from the electrolysis of water is not efficient. The efficiency of the process needs to be increased to over 80% from the current 60%, thanks to the Proton Exchange Membrane (PEM) electrolysers technology which makes this possible. Until this is achieved hydrogen may still not be deployed in fuel cells in sufficient amounts to run combustion engines in the transport sector. Also, the high cost of precious metals like platinum and iridium required as catalysts during the process of electrolysis, is a notable challenge in the extraction process. In fact, this high cost of raw materials has deterred some automotive companies from investing in hydrogen fuel cell technology. And until such costs are reduced, hydrogen fuel cells, an environmentally friendly alternative may cease to be a feasible fuel source for all.
Thirdly, the limited availability of hydrogen infrastructures has equally impacted the number of hydrogen-fueled vehicles on the road. The storage and transportation of hydrogen are more complicated in design than those required for fossil fuels. Large scale adoption of hydrogen fuel cell technology for automotive applications will require setting up adequate filling/refueling outlets, with enough funding to support it, though for long-range applications as is in heavy duty vehicles and delivery trucks, start-to-end refueling is often used. Fourthly, hydrogen fuel cell technology begs for the political will of many governments around the world in monetary investment and some form of subsidy in order to improve and mature the technology. Germany, for example, has subsidized hydrogen fuel for use in its rail system. In the next five years, there are indications that countries like Italy and France would join the bandwagon.
Why Hydrogen fuel will scale through
In the face of some of the drawbacks which have been enumerated above, the prospect of hydrogen as a sustainable and alternative source of renewable fuel for the near future seems too viable to be defeated. Already as a golden technology which cannot be hidden, its applications are critical for the environment, just as they are in meeting rising global energy demands. Because of this, researchers and innovative companies are on track to leverage novel and relevant technologies at their disposal to ensure hydrogen is available just as water is, for industrial and domestic use. This is important because a low-carbon global hydrogen economy could deliver emissions savings equivalent to carbon captured by billions of trees in a few years. It would help decarbonize industrial processes such as chemical production, oil refining and heavy transport. All these when achieved would leave us with a safe planet as carbon emissions would be greatly reduced.