By Kay Kaiser

As governments around the world search for cheap, renewable energy, green hydrogen is becoming popular. Although hydrogen fuel is not new, creating it in an entirely clean process is a recent development. As huge fossil fuel companies begin to invest into green energy, we seek to answer the questions: Is it safe? Is it sustainable? And will hydrogen become the fuel that the world runs on? 

Hydrogen as Fuel

Right now, most things we use to create energy release pollutants into the atmosphere; burning coal, natural gas, oil, and petrol. In 2019, these destructive processes made up 84% percent of global energy use (Ritchie, Roser, 2022). 

Although strides have been taken to make electricity grids green, there are some processes that prove difficult to electrify. Namely, infrastructure that involves moving big, heavy things like lorreys, ships, etc. It can also be difficult to electrify more remote areas and to move them off of fossil fuel energy. That is where hydrogen fuel comes in. 

Since hydrogen is a gas, all the current gas-oriented infrastructure can more easily be adapted to include usable H₂ without the initial cost associated with electrification. Likewise, it can more easily be used to power large vessels without worrying about power cells or electricity storage. (Topolski et al., 2022). 

Why all the Colors?

Hydrogen gas is a fuel type which can be classified into grey hydrogen, blue hydrogen, and finally green hydrogen. Because hydrogen is rarely found as pure H₂, it normally exists in nature as a compound that has to be broken up. The colour of the hydrogen is based on how environmentally friendly its isolation process is. 

The only natural by-product of hydrogen gas as a fuel alternative is water (H₂O) as the pure hydrogen combines with oxygen in the air. The water created in the process can then be split to create more pure hydrogen and continue the cycle. That may sound like a perfect, infinite energy system, but the problem occurs with splitting the water into its separate components. Some extra energy needs to be added to split the compound. 

Grey

Historically, the pure hydrogen isolation process has been done using natural gases. Of 70 million metric tons of hydrogen produced world-wide, 99.6% comes from hydrocarbons and can be classified as grey (methane) or brown (coal) (Wood Mackenzie, 2020). 

Blue

To offset emissions, sometimes the carbon is captured and stored resulting in “blue” hydrogen. This carbon capture technology is imperfect and expensive, so blue hydrogen has not become particularly sought-after. 

Green

Green hydrogen is entirely renewable, produced through solar-powered electrolysis. Because the power used to jumpstart the electrolysis process produces no pollutants, this fuel is deemed “green.” 

Why is it Important Now?

As countries and companies all over the world initiate Climate Action Plans, many include clean energy deadlines and emissions reductions. As the world shifts to renewable energy, major fossil fuel companies have begun to look into clean energy that matches their current infrastructure and can be implemented cheaply: enter, green hydrogen. Major investors in green hydrogen projects include BP, Shell, TotalEnergies, Repsol, and Italy’s Eni. In Ireland, interest groups like Hydrogen Mobility have been formed, made up of BOC Gases, Bord Gáis Energy, Toyota Ireland, CIÉ Group, Hyundai Ireland and government departments. Hydrogen Mobility has goals to have 80 hydrogen fuel stations in Ireland by 2030 (Hydrogen Mobility Ireland, 2023). Currently, there are two; one in Dublin and one in Belfast.

Will Hydrogen fuel overtake Electric?

Although some groups would like most vehicles to run on hydrogen, this is likely not the case. Hydrogen gas may have a higher energy output than diesel, creating 33.6 kWh of usable energy per kg, as opposed to only 14 kWh per kg, but it also has to compete with electric vehicles (GenH2 Staff, 2022). 

As EVs become more common and more charging stations are put in place, it seems to be winning the sustainable energy race. Although hydrogen has its upsides, namely fuel cell range, gaseous infrastructure and short charging time, it may have gained traction too late in the face of an electrifying fleet. Compressing, storing, and transporting hydrogen also proves to be expensive in a way that electricity is not. Both fuels have the downside of requiring rare earth minerals in their fuel cells, increasing their carbon footprints. 

Will it Become the Golden Child of Renewables in Ireland?

The world energy economy is at a period of transition, investing globally over 1 trillion USD in renewables and grids in 2023 alone (IEA, 2023). Electricity can only take us so far–alternatives are needed. According to a report by Aurora Energy Research, Ireland is uniquely suited to become a “powerhouse” of green hydrogen. This is due to its offshore wind energy farms. (Aurora Energy Research, 2023). The Irish government has also come to recognize this advantage and possibility to provide the cheapest green hydrogen in Europe. In its 2023 Climate Action Plan, Ireland pledged to dedicate 2GW of its offshore wind energy to green hydrogen production. For Ireland, green hydrogen has the ability to achieve reduction goals while adding to the country’s energy export economy. With the financial backing and encouragement of oil and gas giants to reduce overall cost, green hydrogen could become a new favourite energy source. Will it take over every sector? Likely not. But, it will hopefully fill in the missing pieces of the renewable energy puzzle that electrification has left empty.