Page 49 - Energize October 2022

VIEWS AND OPINION

Green ammonia - the fossil-free “crude”

of the hydrogen economy

by Collin Hamilton, Verano Energy

Hydrogen has the potential to decarbonize a wide range of heavy industries including energy,
chemicals, steel and cement, which means demand is going to be huge. In its Net-Zero Emissions
scenario the IEA expects demand to increase fivefold from 2020 to 2050.

owever, there are a few important limitations to overcome for hydrogen to
become competitive. The first challenge is to produce sufficient supply of
Hrenewable “green” hydrogen; the next is to be able to store it in large quantities;
and then to establish the required infrastructure to trade and transport hydrogen. This
is where ammonia comes into play. Consisting of one nitrogen and three hydrogen
atoms, the ammonia molecule (NH3) has the potential to support the hydrogen fuel
economy in all three domains.
Making hydrogen competitive

Today, most hydrogen is produced from fossil fuels through steam methane reforming,
generating 830 Mt of annual CO 2 emissions. Carbon-free “green” hydrogen is produced
using electrolysers to split water molecules to separate the hydrogen from the oxygen.
It is an expensive and energy intensive process, but when the energy used is from
renewable sources, hydro, wind or solar, then it provides a versatile, fossil-free energy
carrier.
How can hydrogen be made more competitive? Firstly, by using renewable energy
rich sources such as solar PV in Chile, Saudi Arabia and Australia, where it will be Collin Hamilton
extremely competitive to produce. And secondly, by ramping up renewable energy
production and deploying electrolysers to produce hydrogen with “excess” or “curtailed”
renewable energy. In other words, it will allow for a higher percentage of renewable Hydrogen could also play a useful
energy to enter the market by reducing renewable curtailment. complementary role to current energy
storage solutions. Batteries are a
Reducing renewable energy curtailment cost-effective way to store energy on
The intermittence of renewable energy means that there are periods of very high a daily or potentially weekly basis but
energy production which do not match demand. The supply from renewables, because curtailment is usually seasonal,
particularly solar, becomes so high that the amount of electricity generated threatens it will never be cost effective to store
to overwhelm the grid capacity. Although battery energy storage systems are being six month’s worth of energy in the
developed, they are not yet capable of capturing and storing this amount of excess batteries, at least the ones we know
energy. The result is curtailment. This is where grid operators shut down access to the exist today. If renewable energy is going
grid or adopt pricing mechanisms to generate negative pricing to reduce production. to replace fossil fuels, we will need
Some estimates put renewable energy curtailment as high as 20% of capacity. seasonal or even annual storage as well
Rather than curtailing excess renewable energy, the solution would be to use this as international trade of renewable
excess to produce green hydrogen. By installing electrolysers at major substations energy. Green molecules are perfect
which are connected to renewable plants, green hydrogen production can act as a load for this.
balance. It would be cost competitive, because the renewable energy would otherwise
be wasted, and it allows renewable operators to be paid for every megawatt hour they Green ammonia as a key
produce. No energy is lost. enabler of the hydrogen
In this way, green hydrogen production would incentivise further growth in revolution
renewables. However, it must not detract from the availability of electricity for other While most of the hydrogen produced
essential and more effective uses – it must be additional. The transition to green will be fed into existing pipelines and
hydrogen and the acceleration of renewable energy generation must work together. traded regionally, some regions such

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