The moment has arrived to leverage hydrogen's potential for addressing urgent energy challenges. Recent advancements in renewable power and electric transport have exhibited that strategic policies and technological innovations can construct global clean energy sectors.

Hydrogen is rising as a premier solution for amassing renewable energy, with hydrogen-based fuels potentially conveying energy across vast distances – from regions abundant in resources, to areas thousands of miles away requiring copious energy.

Green hydrogen was prominently featured in emissions reduction pledges at the UN Climate Summit, COP26, as a technique to decarbonize heavy manufacturing, long-haul freight, maritime shipping, and aviation. Governments and enterprises have recognized hydrogen as a foundational pillar of a net zero economy.

The Green Hydrogen Catapult, a United Nations drive to decrease green hydrogen costs, nearly doubled its electrolyzer target from 25 gigawatts last year to 45 gigawatts by 2027. The European Commission has adopted legislative proposals to decarbonize the EU gas market by enabling renewable and low carbon gases like hydrogen, ensuring energy security across Europe. The United Arab Emirates has also elevated its ambition, with the national hydrogen strategy striving to capture a fourth of the global low-carbon hydrogen market by 2030. Japan recently declared a $3.4 billion investment from its green innovation fund over the next decade to accelerate hydrogen research and deployment.

You may encounter the terms 'grey', 'blue', and 'green' when describing hydrogen technologies. Production methods determine the color. Hydrogen only emits water when combusted but manufacturing can be carbon-intensive. Hydrogen can be grey, blue or green – sometimes even pink, yellow or turquoise. However, only green hydrogen is climate-neutral, making it essential for net zero emissions by 2050.

We consulted Dr. Emanuele Taibi, Head of Power Sector Transformation Strategies at the International Renewable Energy Agency, to elucidate green hydrogen and its role in reaching net zero. Based in Germany, Dr. Taibi assists member countries in power sector transformation strategies, managing efforts on system flexibility, hydrogen and storage. He co-curated the World Economic Forum’s transformation map on hydrogen.

Green hydrogen technologies

What motivated your expertise in energy technologies, and how does your role at IRENA contribute?

My master's thesis ignited my passion. An internship at the Italian National Energy and Environment Agency enlightened me about sustainable energy's nexus with development. My thesis channeled this interest, cementing my career trajectory. With almost 20 years of energy and international cooperation experience, a PhD in Energy Technology and time in the private sector, research and intergovernmental agencies, I now lead IRENA’s power sector transformation team since 2017.

At IRENA, I contribute with colleagues and partners like the World Economic Forum to assist our 166 member countries in the energy transition, concentrating on renewable power to decarbonize energy through green electrons and molecules like hydrogen.

How does green hydrogen differ from conventional carbon-intensive ‘grey’ hydrogen and blue hydrogen?

While hydrogen contains no carbon, production methods and emissions vary drastically.

Green hydrogen is produced by splitting water into hydrogen and oxygen using renewable electricity – a very different process from grey and blue.

Grey hydrogen stems from splitting methane into carbon dioxide and hydrogen. Coal-based grey hydrogen has even higher emissions, often called brown or black. Massive scale grey hydrogen today emits as much as the UK and Indonesia combined. It has no energy transition value.

Blue hydrogen uses carbon capture and storage to reduce emissions from grey production, but cannot eliminate all carbon dioxide. Capture rates and storage effectiveness vary greatly. Still, large-scale carbon capture significantly lowers climate impacts versus grey.

Emerging methane pyrolysis can potentially capture over 90% of emissions in solid form, deserving its own “turquoise” designation. But the technique remains in the pilot phase, while green hydrogen is rapidly scaling up using renewables and electrolysis.

Green hydrogen solutions

What merits do green hydrogen energy transition solutions hold? How can we make the shift from grey hydrogen?

Green hydrogen has an important transitional role, but other steps take precedence: deploying more renewables to decarbonize electricity, electrifying energy end-use sectors to capitalize on low-cost renewables, and finally green hydrogen for hard-to-electrify sectors like heavy industry and transport.

A priority is decarbonizing existing grey hydrogen demand, for example by substituting green ammonia for grey.

How would green hydrogen become cost-competitive with blue? What strategic technology investments could enable this?

Pricing carbon creates incentives for companies to switch from grey to blue or green. But with a net zero commitment, blue hydrogen's residual emissions will necessitate offsets. Gas price volatility also leaves blue hydrogen exposed.

Like solar PV, green hydrogen requires upfront capital investment. Scaling up renewable and electrolyzer manufacturing while securing low-risk offtake agreements can decrease costs. This stable trajectory can make green hydrogen economical within the next decade - faster than piloting complex blue hydrogen projects.

Where do you foresee hydrogen technologies by 2030? Could we see hydrogen-powered commercial transport?

By 2030 green hydrogen can decarbonize existing industrial demand like ammonia and steel production. It can also create synthetic fuels to reduce emissions from ships and planes. But truly zero-emission solutions like green ammonia maritime vessels and hydrogen aircraft will take longer.

The way forward is quickly expanding renewables, electrification, bioenergy and scaling up green hydrogen – enabling deep decarbonization by mid-century.