What is hydrogen fuel (Part 1)
Future Fueled explains what hydrogen fuel is, the past, present, and future.
- History of hydrogen
- Hydrogen the element
- Where it is found & how we extract it
— end of part 1 —
- What hydrogen is used for
- Why we should consider hydrogen
- Is hydrogen our future fuel?
Chemistry brings us more than 100 known elements, just over 90 occur naturally. To refresh us from year 10 science an element is a molecule which can not be broken down into anything smaller. Hydrogen is the smallest and lightest of all known elements. We can think about hydrogen like the Tinkerbell of elements, it is light and will fly away when uncontained, it is non-toxic but can be very powerful when used correctly. Today it has been growing in hype and there has been a long history of discovery and use.
Early science and discovery of the element
Boyle that is Robert Boyle, not Susan Boyle, discovered Hydrogen gas in the 17th century whilst conducting experiments mixing iron and acid. Robert Boyle (25 January 1627 – 31 December 1691) is regarded to be one of the forefathers of modern chemistry.
Around a hundred years later Henry Cavendish (10 October 1731 – 24 February 1810) conducted further experiments with what he called ‘inflammable air’, where he observed hydrogen gas being ignited and then turning into water post. Later on, a guy called Antoine Lavoisier (26 August 1743 – 8 May 1794) reproduced the same experiments and named the element Hydrogen from the Greek words hydro “water” & genes for “forming.”
About hydrogen the element
Hydrogen makes up around 75% of everything we know in the universe and is considered in science to be the most important element.
In relation to hydrogen fuel it is important to know the following:
There are three different hydrogen isotopes (isotope = variants of a particular chemical element); first ordinary hydrogen ‘1H’ or (protium) which is the most commonly found and when we are working in the lab looks like the below image. It has a positively charged nucleus (proton) and a negatively charged electron. This accounts for more than 99.9% of all hydrogen.
The other hydrogen isotopes are deuterium & tritium, which have 1 and 2 negatively charged neutrons accompanying the proton respectively. See below:
At standard atmospheric pressure and ambient temperature, ‘H’ by itself does not occur 🙁 “ah so sad”. Instead, hydrogen decides to grab one of his brothers and buddies up to become H2, which is why whenever we read about hydrogen fuel it is referred to as H2. The bonding of the two same atoms creates the H2 molecule which looks like the below image:
H-H or H2 has two modifications; the first is call ortho-Hydrogen (o-H2) where the protons inside the atom rotate on an opposite axis and the second is para-Hydrogen (p-H2) where the protons rotate on a parallel axis.
Under standard conditions (Normal atmospheric pressure & ambient temperature) H2 is 72:25 ratio ortho-: para-hydrogen. Converting o- to p-hydrogen is an exothermic reaction (exothermic reaction is explained below) where energy is released in the process. So, even with isolated cryogenic liquid hydrogen, we will experience evaporation until all of the ortho-H2 is converted to para-H2.
This may prove to noteworthy when talking about liquifying hydrogen in energy storage and transport applications.
Where is Hydrogen (H2) found?
In the known universe H2 is massively abundant making up around 75% of all matter^ stated above, but here on earth where do we find the stuff?
Hydrogen is found in almost all living parts of the planet and is most obviously available in our lifeblood, water or H2O.
Hydrogen in water
- Water or H2O has about 11.2% of its mass made up from H2.
- Earths surface is made up of around 70% water.
Therefore the layman can pretty easily make the judgment that hydrogen is abundant on Earth. The problem now is how do we get it out of water an on its own… We will dive into this in further blog posts, but in short; it is done via a process called electrolysis or water splitting where a DC electrical current is applied to the water producing pure hydrogen gas on the cathode and pure oxygen gas on the anode. See below.
Hydrogen in hydrocarbons
As well as accounting for the makeup of water, hydrogen easily bonds with carbon making different hydrocarbons.
Methane made up of one carbon atom and 4 hydrogen atoms (CH4) is found organically in small quantities around the world’s atmosphere and is the simplest of the hydrocarbons.
Methane is a strong greenhouse gas and although it isn’t rich in the atmosphere it does play a significant role in capturing heat. Science tells us that the methane content in the earth’s atmosphere has risen by almost 150% since 1750.
Using a process called cracking heating methane to a temperature of around 750c we can split hydrogen from methane, technology is still developing in this field and we will write a piece on this in the future.
The most common way we currently get our H2 gas is via a process called “steam-methane reformation” where high-temperature steam (700°C–1,000°C) degrees is used to produce hydrogen from methane sources such as natural gas. I will expand on this process in future posts.
This is the end of part one, please stay tuned for part two of what is hydrogen fuel.