Hydrogen fuel cells: A look into the future
Hydrogen fuel cells are one of the most important technologies that will help us to reach a zero-emissions future. Producing electricity from the chemical energy of hydrogen, hydrogen fuel cells provide clean energy while producing only heat and water as by-products. Crucially, no carbon is emitted during their use.
Here, we’re taking a look at how hydrogen fuel cells work—and what we can expect from them into the future.
What are hydrogen fuel cells used for?
The promise of hydrogen fuel cells is impressive, with the technology expected to be used in the transportation, heating, and power sectors.
- Transportation. Fuel cells can be used in various modes of transport, including cars, buses, motorbikes, trucks, trains, and ships.
Figure 1: Project Evolution – the first cruise ship to use fuel cells for 100% of power while at port.
- In the heating sector, combined heat and power (CHP) systems can generate heat and electricity using hydrogen fuel cells. Due to their low temperature, they are suitable for heating individual buildings.
- Power. In the US, power-only fuel cells are already being used to produce cheap electricity (by Bloom Energy Corporation).
How Hydrogen Fuel Cells Work
Fundamentally, fuel cells work in three main steps:
- A fuel cell consists of two electrodes (one positive and one negative) surrounding an electrolyte. The negative electrode is called the anode and the positive electrode is the cathode.
- During operation, hydrogen is fed to the anode and air (containing oxygen) is fed to the cathode. A catalyst which is placed at the anode separates the hydrogen molecules into protons and electrons and these take different paths to the cathode.
- The electrons move through an external circuit to the cathode creating electricity in the process. Meanwhile, the protons move through the electrolyte to the cathode. There, they combine with oxygen and the electrons to produce water and heat.
Figure 2: Illustration of Hydrogen Fuel Cell
There are different types of fuel cells, based on the kind of electrolyte they use: polymer electrolyte membrane fuel cells (PEMFCs), direct methanol fuel cells (DMFCs), alkaline membrane fuel cells (AMFCs), phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), solid oxide fuel cells (SOFCs), and reversible fuel cells.
What are the benefits of using fuel cells?
Why is this technology so attractive? There are many good reasons:
- Carbon-zero. Attention has turned to this new technology due to efforts to decarbonize many sectors with clean and renewable energy. Fuel cells have zero emissions, since no carbon dioxide is emitted during the operation of these cells.
- Ease of use. The fact that electricity generation is possible without the use of cumbersome mechanical parts has made the fuel cell attractive.
- Demand for energy security. Discontent with dependence on oil and gas producing nations has made alternative forms of energy attractive. Fuel cells are one of the most compelling alternatives.
- Quiet operation. The fact that the fuel cells make little noise means that they can be used within challenging contexts, such as in hospital buildings.
- Easier scaling. Operation times of fuel cells are longer than those of batteries. With fuel cells, only the amount of fuel needs to be doubled to double the operation time, while batteries require the capacity of the components to be doubled to achieve the same.
- Lower costs. Greater investment has gone into this technology, with a focus on fuel cell performance and simplification. This has been able to reduce the costs of the membrane, allowing competition with the combustion engine.
Obstacles affecting the hydrogen fuel cell industry
While the science behind hydrogen fuel cells is well-established, there are some challenges—both technical and commercial—that are facing the industry:
- Safety. Due to its highly flammable nature, hydrogen does come with safety concerns for many people.
- Cost. Fuel cells are expensive, primarily due to the high cost of the catalyst (platinum is the main catalyst in use and it is very expensive).
- Limited infrastructure. The current infrastructure for the growth of hydrogen fuel cells is limited.
- Different hydrogen sources affect cleanliness. The type of hydrogen used for the fuel cell application can undermine the overall net zero ambition. For example,… If the hydrogen used is not from renewable sources, then the net-zero benefit is obfuscated.
Is the future bright for hydrogen fuel cells?
The future of hydrogen fuel cell does indeed look bright:
- By 2030, the cost of green hydrogen is projected to be competitive with blue hydrogen, according to research by IHS Markit.
- Oil and gas giants are jumping into the hydrogen fuel cell space, with Baker Hughes, for example, joining forces with Plug Power.
- Cheaper fuel cell technologies are expected, as production scales. The cost of catalysts is expected to decrease, through decreasing platinum prices or the use of cheaper alternatives.
- New and ground-breaking applications serve as an incentive for venturing into this space.
- The rate at which governments have rallied behind this technology is only predicted to increase. The UK government has planned investments of over £4 billion in the hydrogen economy by 2030. Wrightbus in Northern Ireland has already benefited from over £8 million in R&D from the UK government which is a sign of commitment to this technology.
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