What is green hydrogen?

The time is right to tap into hydrogen’s potential to play a key role in tackling critical energy challenges. The recent successes of renewable energy technologies and electric vehicles have shown that policy and technology innovation have the power to build global clean energy industries.

Hydrogen is emerging as one of the leading options for storing energy from renewables with hydrogen-based fuels potentially transporting energy from renewables over long distances – from regions with abundant energy resources, to energy-hungry areas thousands of kilometers away.

Green hydrogen featured in a number of emissions reduction pledges at the UN Climate Conference, COP26, as a means to decarbonize heavy industry, long haul freight, shipping, and aviation.

Governments and industry have both acknowledged hydrogen as an important pillar of a net zero economy.

In the same vein, the Green Hydrogen Catapult, a UN initiative to bring down the cost of green hydrogen announced that it is almost doubling its goal for green electrolysers from 25 gigawatts set last year, to 45 gigawatts by 2027.

The European Commission has adopted a set of legislative proposals to decarbonize the EU gas market by facilitating the uptake of renewable and low carbon gases, including hydrogen, and to ensure energy security for all citizens in Europe.

The UAE is also raising ambition, with the country’s new hydrogen strategy aiming to hold a fourth of the global low-carbon hydrogen market by 2030.

Japan recently announced plans to invest $3.4 billion from its green innovation fund to accelerate research and development and promotion of hydrogen use over the next 10 years.

Depending on production methods, hydrogen can be grey, blue or green – and sometimes even pink, yellow or turquoise.

However, green hydrogen is the only type produced in a climate-neutral manner making it critical to reach net zero by 2050.

Dr. Emanuele Taibi, Head of the Power Sector Transformation Strategies, International Renewable Energy Agency (IRENA), was asked to explain what green hydrogen is and how it could pave the way towards net zero emissions.

Green hydrogen technologies

What is green hydrogen? How does it differ from traditional emissions-intensive ‘grey’ hydrogen and blue hydrogen?

Hydrogen is the simplest and smallest element in the periodic table. No matter how it is produced, it ends up with the same carbon-free molecule. However, the pathways to produce it are very diverse, and so are the emissions of greenhouse gases like carbon dioxide (CO2) and methane (CH4), Taibi said.

Green hydrogen is defined as hydrogen produced by splitting water into hydrogen and oxygen using renewable electricity. This is a very different pathway compared to both grey and blue.

Grey hydrogen is traditionally produced from methane (CH4), split with steam into CO2 – the main culprit for climate change – and H2, hydrogen.

Grey hydrogen has increasingly been produced also from coal, with significantly higher CO2 emissions per unit of hydrogen produced, so much that is often called brown or black hydrogen instead of grey.

Unlike renewable power, which is the cheapest source of electricity in most countries and region today, electrolysis for green hydrogen production needs to significantly scale-up and reduce its cost by at least three times over the next decade or two.

Green hydrogen energy solutions

What are the merits of energy transition solutions towards a ‘green’ hydrogen economy? How could we transition to a green hydrogen economy from where we are currently with grey hydrogen?

Green hydrogen is an important piece of the energy transition. It is not the next immediate step, as we first need to further accelerate the deployment of renewable electricity to decarbonize existing power systems, accelerate electrification of the energy sector to leverage low-cost renewable electricity, before finally decarbonize sectors that are difficult to electrify – like heavy industry, shipping and aviation – through green hydrogen, Taibi added.

Future of Green Hydrogen

It is important to note that today we produce significant amount of grey hydrogen, with high CO2 (and methane) emissions: priority would be to start decarbonizing existing hydrogen demand, for example by replacing ammonia from natural gas with green ammonia.

We will need green hydrogen to reach net zero emissions, in particular for industry, shipping and aviation. However, what we need most urgently is:

Several governments have now included hydrogen fuel technologies in their national strategies.

Given the rising demands to transition towards decarbonization of the economy and enabling technologies with higher carbon capture rates, what would be your advice to policymakers and decisionmakers who are evaluating the pros and cons of green hydrogen?

1) energy efficiency;

2) electrification;

3) accelerated growth of renewable power generation.

Source: World Economic Forum