Sep 09, 2021

How green is hydrogen?

Green hydrogen can play an important role in the energy transition, both in CO2 reduction in the industry or as a replacement for natural gas in the built environment. Hydrogen gas is a completely clean fuel, yet the production process is by no means always so. When is hydrogen gas green? And what are the developments?  


Hydrogen gas  

Hydrogen (H2) is the most abundant element in the universe. It does not occur in nature as a gas, though, so it needs to be made. The most common way is in a hydrogen system with electrolysis technology. Here electricity is added to purified water, creating oxygen and hydrogen gas.   

Grey, blue and green  

Hydrogen gas is only green if the electricity used for electrolysis is 100% green, too. There is also gray hydrogen, made from natural gas, which is not sustainable but is currently widely used in industry. This releases 13 megatons of CO2 per year, accounting for 8% of all Dutch CO2 emissions. Blue hydrogen is also produced from natural gas, with the difference that the CO2 released is captured in, for example, an old natural gas field or a salt dome. In the short term, this can be a solution. But to make real sustainable steps, green hydrogen is by far the best option.  

Local, sustainable generation  

The most direct way to produce sustainable hydrogen is through pairing up with a local wind farm or solar farm. A wind turbine has a more constant production, even in winter, and is therefore preferred to a solar farm. Because the wind does not always blow and the sun does not always shine, local storage of hydrogen is necessary.  

An ideal ratio of wind to solar energy is 70% wind and 30% sun. If hydrogen is used in the built environment, support for local sustainable generation is an important aspect. In a residential area a wind turbine is not placed just like that: think of the rules, permits or the support of residents. There is an alternative, though, and that is via a virtual connection with wind turbines at sea.  

Virtual power station  

In a virtual connection, a wind turbine at another location, for example at sea, is virtually connected to a hydrogen plant. If the wind turbine is turning, the hydrogen plant is operating. If it there is no wind, then the electrolyser is off. This concept was developed by TransitionHERO for the Green Whale project (see box below).  

Hydrogen full of potential   

The use of hydrogen gas is very promising. Currently, subsidies still ensure that it can be competitive with natural gas, but the technology is in full development. The energy losses during hydrogen production have already been reduced from 30 to 15%, and this is expected to fall rapidly below 10%. The investment costs in electrolysis will also fall rapidly, due to increasing market demand and further development of the technology.   

Worldwide developments are not standing still either. Australia, Japan (see box), Saudi Arabia, Morocco and Portugal, among others, are profiling themselves as hydrogen countries. And the EU also sees the potential of hydrogen gas, and a stronger trade flow can further reduce costs. Hydrogen can be shipped. By bonding it to liquid chemicals (LOHC, Liquid Organic Hydrogen Carriers), you can store it under pressure at room temperature in the same seagoing tankers that transport gasoline.  

Tokyo: The hydrogen games  

At the Tokyo 2021 Olympic Games, hydrogen is a major participant. The Olympic village (6,000 homes) will have an energy supply that runs entirely on hydrogen. Hydrogen-powered cars and buses must transport athletes to and from sports venues. And even the Olympic flame burns on hydrogen gas.  

The Green Whale  

The Green Whale Project (De Groene Walvis) wants to take Graft-De Rijp (a village in the municipality of Alkmaar) off gas, and make it completely sustainable with hydrogen and green electricity. TransitionHERO advises on the entire process: from research to realization. Eventually all 2,200 households should be 100% sustainable by 2030.