ARTICLES
Hydrogen fuels Rockets, but what about Power for Daily Life? (continued)
A further option being explored (but needing further development)
is to combine hydrogen with other elements, and then release it
when required for use.
Impact on the environment
From an environmental perspective, the ideal cycle in a hydrogen
economy involves:
Currently, most hydrogen fuel cell cars use carbon-fibre
reinforced tanks to store highly compressed hydrogen gas. The
cost of these tanks will need to be reduced to make this option
more economic (currently several thousands of US dollars per
unit).
• hydrogen production through using electrolysis to split water;
• hydrogen consumption via reacting it with oxygen in a fuel
cell, producing water as a by-product;
If the electricity for electrolysis is generated from renewable
sources, this whole value chain has minimal environment impact,
and is sustainable.
Using hydrogen as a fuel
There are two main ways to convert the chemical energy in
hydrogen into usable energy (electrical energy or heat energy).
Both of these approaches produce water as the by-product.
Moving closer to a hydrogen economy
Cheap electricity from renewable energy resources is the real
key in making large-scale hydrogen production via electrolysis a
reality in Australia. Internationally it’s already clear – for example,
in Germany and Texas – that renewable hydrogen is cost
competitive in niche applications, although not yet for industrial-
scale supply.
A primitive and straightforward way of using hydrogen is to simply
burn it to generate heat – just like natural gas is used for cooking
and heating in peoples’ homes.
A trial planned for South Australia aims to generate hydrogen
using renewable electricity, and then inject it into the local gas
distribution network. This way of “blending” gases can avoid
the cost of building costly delivery infrastructure, but will incur
expenditures associated with modifications to existing pipelines.
Extensive study and testing of this activity are required first.
Techniques for storage and delivery need to be improved in
terms of cost and efficiency, whilst the manufacture of hydrogen
fuel cells requires improvement.
Hydrogen is a most desirable source of energy, since it can be
produced in large quantities and stored for a long time without
loss of capacity. Because it’s so light, it’s an economical way to
transport energy produced by renewables over large distances
(including across oceans).
When used in hydrogen fuel cells, energy is produced when
hydrogen reacts with oxygen. This is the technology used
by NASA and other operators in space missions, and by car
manufacturers in hydrogen fuel cell cars. It’s the most advanced
method for hydrogen use at the moment.
Underpinned by advanced technologies, with strong support by
governments, and commitment from many multinational energy
and automobile companies, hydrogen fuel links renewable
energy with end-users in a clean and sustainable way.
It does work, but will we accept it?
Safety considerations
Let’s see if hydrogen takes off!
As a fuel, hydrogen has some properties that make it safer to
use than the fuels more commonly used today, such as diesel
and petrol. Hydrogen is non-toxic. It is also far lighter than air,
allowing for rapid dispersal in case of a leak. This contrasts with
the build-up of flammable gases in the case of diesel and petrol
leaks, which can cause explosions.
This article was originally published in ‘The Conversation’ on
11th March, 2019, and according to its generous policy that
encourages republishing of its articles, ‘Science Education
News’ is very pleased to include this important report. SEN
also thanks the author, Zhenguo Huang, for his work and
for the implicit permission to allow us to republish it for our
members. – Editor
However, hydrogen does burn easily in air, and ignites more
readily than petrol or natural gas. This is why hydrogen cars must
have such robust carbon fibre tanks – to prevent leakages.
Where hydrogen is used in commercial settings as a fuel, strict
regulations and effective measures have been established to
prevent and detect leaks, and to vent hydrogen. Household
applications of hydrogen fuel would also need to address this
issue.
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SCIENCE EDUCATIONAL NEWS VOL 68 NO 1