Hydrogen as a fuel
Is hydrogen fuel good for the environment?
When it comes to hydrogen, there are caveats around environmental impacts. Refining hydrogen requires electrolysis, which involves passing an electric current through a substance to effect a chemical change. As with all chemical reactions, you must put in more energy than you get out of the process. In the case of hydrogen, electrolysis is both energy intensive and inefficient, losing around 30% of the potential energy during the processing stage. Improving the efficiency of electrolysis is essential, and there has been a huge amount of innovation directed towards making electrolysers more efficient.
Platinum offers the lowest catalytic loss in terms of energy put in, but it is also very expensive, so a lot of research is focusing on cheaper catalysts. Industrialising the process would generate efficiencies, but it also requires substantial investment to achieve economies of scale.
To determine the environmental impacts of hydrogen production, you must pay attention to how energy is generated to undertake electrolysis. Currently, over 95% of the world’s hydrogen comes from coal (brown) and gas (grey) energy sources. Other sources include nuclear (pink), and renewable sources. Hydrogen generated via renewable sources is referred to as “green hydrogen”. “Blue hydrogen” refers to hydrogen generated from gas where carbon dioxide generated is captured and stored underground.
How much does hydrogen fuel cost?
Currently, around 70% of production costs for green hydrogen are energy costs. The relative costs of hydrogen production will depend on your location. Because the US has abundant reserves of natural gas, hydrogen from natural gas costs around $1.50 per kilogram. By contrast, it costs around $5 per kilogram to produce “clean hydrogen”. US policymakers are looking to address this, however. The US Department of Energy wants to get the cost of clean hydrogen down to $1.00 per kilogram over the next decade to make it a more competitive fuel source.
Will hydrogen fuel take off?
Hydrogen fuel has several challenges to overcome, including efficiency of production, cost, transportation, safety, and storage. It is explosive and because hydrogen lacks density, huge volumes are required, making storage potentially challenging. Moreover, hydrogen is prone to leaks and hydrogen leakage risks have been identified along the entire value chain of hydrogen.
How can hydrogen overcome its storage problem?
One way to overcome the challenges of transporting and storing hydrogen is to convert hydrogen into another fuel that is denser and easier to store and transport. This is known as the Power-to-X approach (also P2X and P2Y). Green ammonia is a popular option as it is easier to store and transport. The ammonia itself can also be used as a fuel source or converted back to hydrogen.
Again, caution should be exercised as convert hydrogen into ammonia it’s both expensive and energy intensive. Having said this, ammonia produced by renewable green hydrogen is becoming more competitive and is the closest to operating on an industrialised scale. With enough investment, it could reach industrial scale in 10 to 20 years, or sooner if the political will is there.