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Green hydrogen: an alternative that reduces emissions

As the world grapples with the urgent need to reduce greenhouse gas emissions and combat climate change, finding clean and sustainable energy sources has become paramount. In this quest, green hydrogen has emerged as a promising alternative. Produced through renewable energy sources and water electrolysis, green hydrogen offers a pathway to significantly reduce emissions while providing a versatile and clean energy solution. In this article, we will explore the concept of green hydrogen and its potential to revolutionize various sectors and contribute to a greener future.

 

The latest estimates by the International Energy Agency (IEA), published at the end of 2019, predict that global energy demand will increase by between 25 % and 30 % by 2040, which in an economy dependent on coal and oil would mean more CO2, exacerbating climate change. However, decarbonising the planet suggests a different world in 2050: one that is more accessible, efficient and sustainable, and driven by clean energies such as green hydrogen.

 

Decarbonising the planet is one of the goals that countries around the world have set for 2050. To achieve this, decarbonising the production of an element like hydrogen, giving rise to green hydrogen, is one of the keys as this is currently responsible for more than 2 % of total global CO2 emissions. Find out how this is achieved and what its impact will be in the coming decades.

 

Understanding Green Hydrogen:

Hydrogen, the most abundant element in the universe, has long been recognized for its potential as a clean energy carrier. However, traditional methods of hydrogen production rely on fossil fuels, resulting in significant carbon dioxide emissions. Green hydrogen, on the other hand, is generated through electrolysis, a process that splits water molecules into hydrogen and oxygen using renewable electricity, such as solar or wind power. The resulting hydrogen is completely free of carbon emissions, making it a vital tool in the fight against climate change.

 

This technology is based on the generation of hydrogen — a universal, light and highly reactive fuel — through a chemical process known as electrolysis. This method uses an electrical current to separate the hydrogen from the oxygen in water. If this electricity is obtained from renewable sources we will, therefore, produce energy without emitting carbon dioxide into the atmosphere.

 

As the IEA points out, this method of obtaining green hydrogen would save the 830 million tonnes of CO2 that are emitted annually when this gas is produced using fossil fuels. Likewise, replacing all grey hydrogen in the world would require 3,000 TWh/year from new renewables — equivalent to current demand of Europe. However, there are some questions about the viability of green hydrogen because of its high production cost; reasonable doubts that will disappear as the decarbonisation of the earth progresses and, consequently, the generation of renewable energy becomes cheaper.

Producing green hydrogen by electrolysis from renewable sources involves breaking down water molecules (H 2O) into oxygen (O 2) and hydrogen (H 2).
1. The water used in the electrolysis must contain salts and minerals to conduct the electricity.
2. Two electrodes are immersed in the water and connected to a power source and a direct current is applied.
3. The dissociation of hydrogen and oxygen occurs when the electrodes attract ions with an opposite charge to them.
4. During the electrolysis, an oxidation-reduction reaction occurs due to the effect of the electricity.
Green hydrogen has significantly lower carbon emissions than grey hydrogen, which is produced by steam reforming of natural gas, which makes up the bulk of the hydrogen market. Green hydrogen produced by the electrolysis of water is less than 0.1% of total hydrogen production. It may be used to decarbonize sectors that are hard to electrify, such as steel and cement production, and thus help to limit climate change.

For in depth understanding on Green Hydrogen   technology and applications please visit:  Green Hydrogen: Clean Energy from Water and Renewables

HYDROGEN AS CLEAN ENERGY

Hydrogen is the most abundant chemical element in nature. As noted by the IEA, the global demand for hydrogen for use as a fuel has tripled since 1975 and reached 70 million tonnes a year in 2018. In addition, green hydrogen is a clean energy source that only emits water vapour and leaves no residue in the air, unlike coal and oil.

 

Hydrogen has a long-standing relationship with industry. This gas has been used to fuel cars, airships and spaceships since the beginning of the 19th century. The decarbonisation of the world economy, a process that cannot be postponed, will give hydrogen more prominence. In addition, if its production costs fall by 50 % by 2030, as predicted by the World Hydrogen Council, we will undoubtedly be looking at one of the fuels of the future.

 

Green Hydrogen Impacts

 

Reducing Emissions Across Industries:

One of the significant advantages of green hydrogen lies in its versatility and potential to replace fossil fuels in various industries. The transportation sector, for instance, heavily reliant on gasoline and diesel, can transition to hydrogen fuel cells, which convert hydrogen into electricity to power vehicles. This shift would result in zero tailpipe emissions, significantly reducing air pollution and mitigating the sector’s environmental impact.

 

Similarly, industries such as steel, cement, and chemicals, which account for a large portion of global emissions, can employ green hydrogen as a clean energy source in their production processes. By replacing fossil fuels with hydrogen, these industries can substantially reduce their carbon footprint and contribute to a more sustainable future.

 

Green Ammonia

Green hydrogen can be blended into existing natural gas pipelines, and also used to produce green ammonia, the main constituent of fertilizer production. It is suggested by hydrogen industry bodies that green ammonia will be cost-competitive with ammonia produced conventionally (gray ammonia) by 2030

Electricity and drinking water generator

These two elements are obtained by reacting hydrogen and oxygen together in a fuel cell. This process has proved very useful on space missions, for example, by providing crews with water and electricity in a sustainable manner.

Renewable Energy Storage:

One of the biggest challenges of renewable energy sources like solar and wind power is their intermittent nature. Green hydrogen provides an elegant solution by acting as a form of energy storage. Compressed hydrogen tanks are capable of storing energy for long periods of time and are also easier to handle than lithium-ion batteries because they are lighter.

Excess electricity generated during peak periods can be used to produce hydrogen through electrolysis. This hydrogen can then be stored and converted back into electricity when demand exceeds supply. By integrating green hydrogen into the energy grid, we can create a more stable and reliable renewable energy system.

 

Heating

Hydrogen can be used for cooking and heating within homes. Hydrogen heating has been proposed as an alternative to power most UK homes by 2050. The British government intends to launch demonstration projects to show how the fuel can power regions containing hundreds of home

 

Transport and mobility

Hydrogen can be used as a hydrogen fuel for fuel cells or internal combustion engines. Hydrogen vehicles are not limited to automobiles, with trucks also being designed to run on green hydrogen.

Hydrogen’s great versatility allows it to be used in those consumption niches that are very difficult to decarbonise, such as heavy transport, aviation and maritime transport. There are already several projects under way in this area, such as Hycarus and Cryoplane, which are promoted by the European Union (EU) and aim to introduce it in passenger aircraft.

 

Adoption of  Green Hydrogen

Hydrogen as a fuel is a reality in countries like the United States, Russia, China, France and Germany. Others like Japan are going even further and aspire to become a hydrogen economy.

China Southern Power Grid has started using solid hydrogen for electricity generation in two power stations in Kunming and Guangzhou, China. “This is the first time that my country has used photovoltaic power generation to produce solid-state hydrogen energy and successfully applied it to the power system,” said the Chinese state-owned utility. The company implemented a storing solution at room temperature, instead of liquefaction. “Its principle is to attract hydrogen atoms into the metal voids through a chemical reaction between hydrogen gas and new alloy materials to achieve storage purposes. At this time, if the ambient temperature of the alloy is raised, the hydrogen in it will be released, converted into electrical energy through the fuel cell, and can be incorporated into the grid.”

 

The European Parliament and the European Council have agreed to expand the number of publicly accessible electric recharging and hydrogen refueling stations across the European Union’s main transport corridors. “Hydrogen refueling infrastructure that can serve both cars and lorries must be deployed from 2030 onwards in all urban nodes and every 200 km along the TEN-T core network, ensuring a sufficiently dense network to allow hydrogen vehicles to travel across the EU,” said the European Commission. The political agreement reached this week must now be formally adopted.

 

Germany and Denmark have agreed to further integrate their energy systems. They will cooperate on advancing the rollout of transmission infrastructure for green hydrogen between western Denmark and northern Germany from 2028. The two countries have also agreed to support coordination between the national regulatory authorities in the hydrogen sector.

 

Algeria’s commissioner for renewable energy and energy efficiency, Noureddine Yassaa, and Minister of Energy Mohamed Arkab presented a national strategy for the development of hydrogen. The North African country wants to produce 40 TWh of hydrogen by 2040. It intends to sell most of the produced hydrogen to European markets. Algeria also sees hydrogen as an instrument to improve energy security.

 

India’s NITI Aayog report highlights that green hydrogen can substantially spur industrial decarbonization and economic growth for India in the coming decades. Shri Amitabh Kant, CEO NITI Aayog, made a brief presentation on the report.  He remarked that, given the right policies, India can emerge as the least cost producer and bring down the price of green hydrogen to US$ 1 per kg by 2030.

 

While hydrogen can be produced from multiple sources, India’s distinct advantage in low-cost renewable electricity means thatgreen hydrogenwill emerge as the most cost-effective form. The report concludes that hydrogen demand in India could grow more than fourfold by 2050, representing almost 10% of global demand. Given that the majority of this demand could be met with green hydrogen in the longterm, the cumulative value of the green hydrogen market in India could reach US $8 billion by 2030.

 

Highlighting the opportunity, Clay Stranger, RMI Managing Director, said that there is significant global interest in green hydrogen and countries are in the first stages of formulating a strategy and this will ultimately decide the winners and losers of the hydrogen economy. A globally competitive green hydrogen industry can lead to exports in green hydrogen and hydrogen-embedded low-carbon products like green ammonia and green steel that can unlock 95 GW of electrolysis capacity in the nation by 2030.

 

ROLLS-ROYCE AND EASYJET TEST HYDROGEN PROPULSION SYSTEM

Rolls-Royce and EasyJet have completed ground tests with an early concept demonstrator for a hydrogen propulsion system that they hope will eventually be capable of powering narrowbody airliners. The partners announced on November 28 that they recently ran a modified Rolls-Royce AE 2100 A turboprop airliner engine on green hydrogen made from wind and tidal power inspired by the United Nations-backed Race to Zero campaign to achieve net zero carbon emissions by 2050.

A series of ground tests conducted during November 2022 with the concept demonstrator at the UK’s Boscombe Down defense research facility has prepared the way for full-scale ground tests using the Pearl 15 turbofan engine that Rolls-Royce developer for Bombardier’s Global 5500 and 6500 business jets. Eventually, the engine maker intends to scale up the technology to work with large turbofans needed for aircraft such as the Airbus A320 family operated by Easyjet across Europe.

The low-cost airline and Rolls-Royce embarked on their partnership to develop hydrogen propulsion for commercial flights as part of the H2Zero program. EasyJet is also involved in parallel work with GKN Aerospace to develop both direct hydrogen combustion technology under the H2JET program and hydrogen fuel cells through a project called H2GEAR.

The AE 2100 engine powers the 50-seat Saab 2000 regional airliner, as well as various military aircraft such as the Lockheed P-3 Orion surveillance platform and the C-130 troop carriers. For larger commercial aircraft, like the 150-seat A320s, the direct combustion technology would need to work with more powerful engines like the CFM International Leap family.

Rolls-Royce and EasyJet aim to be ready to deploy hydrogen propulsion for commercial flights in the mid-2030s, a target aligned with the objectives of Airbus’s own Zero E program to produce new hydrogen-powered airliners.

The green hydrogen used for the first test with the concept demonstrator was provided by the European Marine Energy Centre at its facility in Eday in the Orkney Islands off the north coast of Scotland. The organization runs a hydrogen production and tidal test facility at that location and participates in early work to establish the infrastructure needed to supply hydrogen for air transport.

The renewable electricity generated by wind and tidal power runs an electrolyzer to produce green hydrogen through electrolysis. The hydrogen is then “squeezed” to compress it from 20 bar to 200 bar pressure to maximize the amount available in an aircraft fuel tank; the engine then combusts the hydrogen in place of Jet-A fuel.

Easyjet and Rolls-Royce are now preparing for a second set of ground tests with a full-scale powertrain. At some point, they intend to be ready to evaluate a hydrogen powerplant in flight tests using still unspecified aircraft.

“The success of this hydrogen test is an exciting milestone,” commented Rolls-Royce chief technology officer Grazia Vittadini. “We only announced our partnership in July and we are already off to an incredible start with this landmark achievement. We are pushing the boundaries to discover the zero carbon possibilities of hydrogen, which could help reshape the future of flight.”

 

ADVANTAGES AND DISADVANTAGES OF GREEN HYDROGEN

This energy source has pros and cons that we must be aware of. Let’s go over some of its most important good points:

  • 100 % sustainable: green hydrogen does not emit polluting gases either during combustion or during production.
  • Storable: hydrogen is easy to store, which allows it to be used subsequently for other purposes and at times other than immediately after its production.
  • Versatile: green hydrogen can be transformed into electricity or synthetic gas and used for commercial, industrial or mobility purposes.

However, green hydrogen also has negative aspects that should be borne in mind:

  • High cost: energy from renewable sources, which are key to generating green hydrogen through electrolysis, is more expensive to generate, which in turn makes hydrogen more expensive to obtain. Nonetheless, the United States Department of Energy forecasts that the hydrogen market is expected to grow, with the cost of hydrogen production falling from $6/kg in 2015 to as low as $2/kg by 2025. The price of $2/kg is considered a potential tipping point that will make green hydrogen competitive against other fuel sources.
  • High energy consumption: the production of hydrogen in general and green hydrogen in particular requires more energy than other fuels.
  • Safety issues: hydrogen is a highly volatile and flammable element and extensive safety measures are therefore required to prevent leakage and explosions.

 

The Road Ahead:

While green hydrogen holds immense promise, there are still obstacles to overcome before it becomes a mainstream energy source. One of the primary challenges is scaling up production and reducing costs. Currently, the electrolysis process is energy-intensive and expensive. However, with advancements in technology and increased investment, the cost of green hydrogen production is expected to decline, making it more economically viable.

Additionally, building the necessary infrastructure for hydrogen transportation and storage is crucial for its widespread adoption. Collaborative efforts between governments, industries, and research institutions are needed to establish a robust hydrogen ecosystem that supports production, distribution, and utilization.

 

Conclusion:

Green hydrogen represents a transformative alternative that can significantly reduce emissions and accelerate the transition to a low-carbon future. With its ability to decarbonize various sectors, provide renewable energy storage, and reduce reliance on fossil fuels, green hydrogen offers a pathway to a cleaner and more sustainable world. As we continue to invest in research, innovation, and infrastructure development, green hydrogen has the potential to revolutionize our energy systems and contribute to a greener and more prosperous planet for generations to come.

 

 

References and Resources also include:

https://www.futureflight.aero/news-article/2022-11-28/rolls-royce-and-easyjet-test-hydrogen-propulsion-system

https://www.pv-magazine.com/2023/03/28/the-hydrogen-stream-china-southern-power-connects-hydrogen-plants-to-grid/

 

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