Jan 20, 2021
A Hydrogen Fuelled Future
Just how important is hydrogen to build a carbon free civilisation
Hydrogen seems to be on the news all the time. Airbus has its project ZEROE to develop a short haul hydrogen powered flight; Hyundai and Toyota both have their plan designing cars with hydrogen fuel cell; Nikola Corporation has already been making and improving hydrogen fuelled lorries.
This hype is largely backed by the plans of governments to speed up the decrease in its price for manufacture, transportation and application. Japan, China, Britain and EU are all pouring in buckets of cash, racing to be the leader of the upcoming Hydrogen economy.
Because, in the long term, when we will only use green hydrogen, both its manufacturing process and usage will emit no carbon.
We can expect this lightest and the most abundant molecule in the universe to pay an important role to our combat against net carbon emission. However, there are some huge draw backs of Hydrogen that are casting doubts for some.
Elon Musk has made comments on hydrogen fuel cells technology on twitter since 2014 on various occasions as “Staggering dumb”, “mind-bogglingly stupid” and “fool sells”.
Although he is obviously biased towards battery power (given his company, Tesla, is a competitor to hydrogen powered cars manufacturer), his view is logical.
The major defect of hydrogen power is its source. According to Hydrogen Europe, natural hydrogen gas is rare on earth since it is very reactive and tends to “form covalent compounds with most non-metallic elements”. Water (H2O), for example, is a compound of hydrogen (H) and oxygen (O) atoms. To make use of hydrogen, unless we can find and understand more natural hydrogen, we first have to make it.
There are two ways to farm hydrogen in general: processing fossil fuels or electrolysis of water (splitting water molecules with electricity). Either way, it takes energy to extract hydrogen — the law of thermodynamics has dictated that we will always lose some energy in the process: the energy in the resulting hydrogen will always be less than the sum of the energy put in for manufacturing it.
At the moment, hydrogen harvested preserve roughly just 80% of the input energy. Not to mention, it will probably involve extra energy pressurising or liquifying it to compress its inconveniently enormous size (from a gas) for various applications.
Hydrogen is an energy storage medium just like battery, except that we would waste far less energy charging battery than making hydrogen.
So why are people still putting resources in investing in hydrogen as energy?
“If CCUS (Carbon Capture, Utilisation and Storage) is used to reduce the CO2 intensity of fossil fuel hydrogen production, that would enable some fossil fuel resources to continue to be used,” written in a 2019 IEA (The International Energy Agency) report.
Hydrogen produced with CCUS is what we call blue hydrogen, involving a low carbon emission. Instead of ignoring the seven tonnes of carbon dioxide released into our air for every tonne of hydrogen during the production, which results in “Grey Hydrogen”, it captures them with special equipments and stores them underground- despite some leakage.
For some countries, those who rely heavily on fossil fuels, blue hydrogen is the most realistic way to transition into a low and ultimately zero carbon emission economy- without sacrificing economic growth. The target is eventually to consume exclusively green hydrogen -made from electrolysing water with oxygen, emitting no carbon.
Even though critics say that blue hydrogen is “fossil fuel industry greenwash and won’t fix the climate”, this helps to pave the way to a greener future. We can get all the infrastructure ready (for industries that are suitable for hydrogen fuel), so the economy engaged will be green whenever we will produce sufficient green hydrogen.
It is worth noting that the price of green hydrogen is highly dependant to the price of the electricity used to manufacture it. As the price of solar and wind power comes down, and as the number of electrolyser facilities goes up, we can foresee it to come to a competitive price point soon.
According to BNEF (Bloomberg New Energy Finance), its price by 2050 will be “competitive with current natural gas prices… on an energy-equivalent basis.”
It will basically be the same price as the grey hydrogen now.
For the time being, blue hydrogen is taking the lead.
EU and UK for example, are now leaving a back door for blue hydrogen in their current carbon free policy making.
However, CCUS is expensive. At present, China is the world’s largest hydrogen producer, with annual output of 20million tons accounting for one-third the global production . They have been mostly grey hydrogen, if not all. Ironically, this is now giving China an edge over others over this race towards the number 1 hydrogen economy.
Despite being the biggest carbon emitter in the world, China has also been putting in a lot of effort in flourishing green hydrogen. Thanks to its devotion in promoting solar and wind technology, the country is rich of renewable energy power plants. Many of them, however, have not been connected to a grid for efficient usage — some energy generated is not used. It has hence given another strange advantage for China to move towards a hydrogen economy, this time with green hydrogen.
They can use part of these power plants to make Hydrogen instead. As said earlier, Hydrogen is an energy carrier like battery but with unique properties — some are advantageous.
Hydrogen can be transported with the current infrastructure built for natural gas with little modification. This makes it a particularly practical resource for countries like UK, where they use most of natural gas for heating.
The prevalent boilers can be converted to burn hydrogen quickly and easily. Furthermore, one-third of UK’s greenhouse gases come from home heating: usage of hydrogen can smoothly fill its place and largely reduce carbon emissions (if not zero for now) without having to build new infrastructure.
Incorporating in Hydrogen in its future renewable energy spectrum will make UK’s goal of net zero carbon emission by 2050 achievable, according to David Joffe, a member of the Committee on Climate Change, as cited in The Economist.
More than that, unlike battery, hydrogen in fuel-cell can power for freight industry, because of its higher energy density than even the best battery to date, meaning that it can offer a driving range and refuelling time comparable to current vehicles while battery cannot. To put into perspective, it will take a few minutes to refuel a hydrogen tank while it can take up to 12 hours to fully recharge a battery.
A hydrogen fuel cell operates just like green hydrogen production but in reverse- instead of splitting water molecules with electricity, it combines hydrogen and oxygen to generate electricity. Unlike traditional fuel, water is the only thing that comes out of the exhaustion pipe.
At this instant, sales of electric car is leading by far to hydrogen car, given that battery has a clear advantage of energy efficiency and hence price, by charging with electricity directly generated from the power plant.
That is true for short haul cars. Things are different for trucks that weight a few tonnes though- it is simply unimaginable to see lorries to stop for hours to recharge their battery every time they are out of juice.
To decarbonise lorries is imperative, right now they are producing about 2.5 tonnes of CO2 per year, which is about one-fourth of total emission of all transport. Hydrogen seems to be a suitable compromise between fossil fuel and battery. We should see an increasing number of hydrogen fuel cell lorries on the road soon.
The application of Hydrogen can be further to aviation and heavy industry, given that it has a combustion property like traditional fuel can generate an enormous amount of heat and hence drives a gas turbine.
Despite some technical difficulties that we still have to overcome, we can foresee hydrogen will take an increasingly important part in our daily lives.
