Hydrogen fuel cells use hydrogen as a fuel in an electrochemical process where hydrogen and oxygen create electrical energy and water. The opposite process, electrolysis, produces ‘green’ hydrogen and oxygen from water and can draw on many renewable energy sources (wind, wave, solar) to make hydrogen as a fuel for intermittent power generation.
There is also considerable interest in hydrogen power because it is uniquely ‘clean’, as it can produce heat (with it’s only by-products being water).
Nevertheless, green hydrogen produced from electrolysis (which is an energy-intensive process), and which draws on renewable energy sources, has high production costs, currently accounting for about 5% of total H2 production.
Currently the vast majority of the world’s hydrogen production is associated with fossil fuels (methane gas reforming) and will be for a number of decades into the future.
However, as the manufacturing capacity of more efficient and cheaper electrolysers becomes greater, and together with the roll-out of more mature renewable power generation technologies and the resulting capacity, the costs of producing hydrogen will reduce markedly.
In order to develop a stable, resilient and decarbonised energy system, the production and bulk storage of hydrogen will be key to balancing the intermittent supply of energy from renewable energy sources with end-user demand (i.e. for grid electricity, residential and industrial heating and fuel for transport).
The dialogue regarding the advantages and disadvantages of hydrogen fuel cells is ongoing, but while the current limitations exist, hydrogen is still a clean, green substitute for fossil fuels and can provide flexible and high-density power and propulsion through hydrogen fuel cell technology for a wide range of industries and transportation modes.
What are the Advantages Of Hydrogen Fuel Cells
#1. Renewable and Readily Available.
Hydrogen is the most abundant element in the Universe and notwithstanding the issues related to the extraction from water. It is uniquely abundant and renewable which can meet all of our future zero carbon requirements for combined heat and power supplies.
#2. Hydrogen is a Clean and Flexible Energy Source to support Zero-Carbon Energy Strategies.
Specifying hydrogen fuel cell technology provides a renewable and clean source of energy and does not cause harm to the environment in its operation because the byproduct of this technology is simply heat and water. Additionally, hydrogen in contrast to biofuel or hydropower does not require a vast footprint of land to produce and be used.
NASA has even been studying the use of hydrogen as a resource as the water produced as a by-product can be used as potable water for astronauts.
This example demonstrates that hydrogen fuel cells are a non-toxic fuel source and therefore, in this respect they are superior to coal, natural gas and nuclear power which are all either potentially dangerous or have limited availability.
The production, storage, and utilization of hydrogen will facilitate the continued evolution of renewable energy, allowing for renewables to be utilized efficiently and effectively while bypassing massive upfront investments in grid infrastructure upgrades to meet evolving energy demands from end-users.
#3. Energy Source that is More Powerful and Efficient than Fossil Fuels.
Hydrogen fuel cell technology is a high-density energy source, with consumption efficiencies typical of many fuel sources. Hydrogen has a higher energy content than any other common fuel by weight.
High-pressure gaseous and liquid hydrogen has approximately three times the gravimetric energy density (approximately 120MJ/kg) of diesel and LNG, with a volumetric energy density that is similar to natural gas.
#4. More efficient compared to other energy sources.
Hydrogen fuel cells are more efficient than most other energy sources, including many green energy alternatives. This efficiency in fuel conversion means more energy is produced per pound of fuel converted.
For example, a conventional combustion-based plant produces electricity at 33-35% efficiency while hydrogen fuel cells convert up to 65% of the fuel energy into usable energy. The same applies to vehicles, which use 40-60% of the fuel energy while decreasing fuel consumption by 50% as well.
#5. Near-zero emissions.
Hydrogen fuel cells do not produce greenhouse gas emissions, or as with fossil fuel sources, only very limited greenhouse gas emissions, which leads to decreased pollution and improved air quality.
#6. Reduce carbon footprint.
As hydrogen fuel cells have almost no emissions, there are no greenhouse gases released, which means that there are no carbon footprints, while being utilized.
#7. fast Charging Times.
The charge time for hydrogen fuel cell power units is extremely rapid, similar to internal combustion engine (ICE) vehicles, and dramatically shorter than battery-powered electric vehicles.
Electric vehicles take anywhere from 30 minutes to several hour to charge. Hydrogen fuel cells can charge in less than five minutes. The rapid charge time means that hydrogen powered vehicles have the same flexibility as conventional vehicles.
#8. Noise Pollution.
Hydrogen fuel cells do not produce noise pollution like some other renewable sources, such as wind energy. Like electric vehicles, hydrogen powered vehicles are generally quieter than vehicles with internal combustion engines.
#9. Visual Pollution.
Some of the low carbon energy sources like wind energy and biofuel power plants, can be ugly, however, hydrogen fuel cells do not take up as much space thus lowering the chance of visual pollution.
#10. Usage Times.
Hydrogen fuel cells are much more efficient when it comes to usage times. A hydrogen vehicle has as much range as fossil fuel vehicles (about 300 miles). This is better than that of battery powered electric vehicles (EVs), which are being built with fuel cell power units as ‘range-extenders’.
Hydrogen fuel cells do not lose efficiency because of external temperatures and do not lose power in cold temperatures like EVs. This is further supported by their short charging times.
#11. Ideal for Utilization in Remote Areas.
Where local conditions permit, the availability of hydrogen through local generation and storage may represent an alternative to diesel-based power and heating for remote locations.
This can not only eliminate the need to transport fuel but also enhance the quality of life for citizens living in remote places with a non-polluting fuel obtained from a fundamentally available natural resource.
#12. Diverse Applicability of Use.
As the technology develops, hydrogen fuel cells will expand to provide energy for a range of stationary and mobile applications. Hydrogen powered vehicles are one instance but can also extend downwards to small applications such as domestic applications and larger applications such as heating systems.
As with IC engines, power (applicable power) is decoupled from energy storage capacity (generally, the fuel tank) and defined by engine size (as opposed to battery – which has linear scaling), so versatility in size/dimensions is apparent.
#13. Democratic Distribution of Power Supply.
Hydrogen fuel cells bring possibilities to reduce a nation’s dependence on fossil energy sources, creating more democratic energy (and power) supplies in many places in the world.
This shift towards diminished dependence will benefit nations who rely on fossil fuels, but equally will will alleviate the issue of the rising fuel costs as reserves or access decreases.
What Are The Disadvantages Of Hydrogen Fuel Cells?
Although hydrogen fuel cells enjoy many advantages, there still some disadvantages and challenges to overcome:
#1. Hydrogen Extraction.
While hydrogen is the most abundant element in the Universe, it is not found alone and so is removed from water via electrolysis or extracted from carbon fossil fuels. Both of these processes take a lot of energy.
The extraction process can require more energy than what can be gained from the hydrogen itself, and it can also be cost prohibitive. Moreover, extraction also usually involves fossil fuels, which without CCS compromises the green credentials of hydrogen.
#2. Investment Is Required.
Hydrogen fuel cells will need development investment to become a serious source of energy. This will take a political commitment both to provide the time and money in development in order to grow and develop the technology.
In short, the global challenge to further develop hydrogen energy is how best to incrementally create the ‘supply and demand’ chain as quickly and cost effectively as possible.
#3. Cost of Raw Materials.
With precious metals required as catalysts in fuel cells such as platinum and iridium, and some form of water electrolyser, the initial cost of equipment for fuel cells (and electrolysers) would be significant.
High costs have dissuaded some parties to pursue investing in hydrogen fuel cell technology. Higher costs must be lowered in order to make hydrogen fuel cells available from a fuel perspective for every one.
#4. Regulatory Barriers.
There are also barriers around regulatory issues regarding the framework that outlines commercial deployment models. Without regulatory frameworks available for commercial projects to understand their cost and future revenue model, commercial projects can often find themselves struggling to reach a financial investment decision (FID).
#5. Overall Cost.
Currently, to obtain a unit of power from hydrogen fuel cells has a greater cost overall than other energy sources such as solar panels, which may progress as development occurs, all though at present, this is higher than what a hydrogen fuel cell would be worth providing compared to other energy sources.
This cost currently prohibits hydrogen from being considered a legitimate energy source, regardless of higher efficiency after production. The cost also affects those downstream again, such as hydrogen operated vehicles, as the sums for feasibility just don’t justification widespread uptake at this point.
#6. Hydrogen Storage.
For storage and transportation, hydrogen creates a greater complexity compared to fossil fuels, which creates additional costs to consider for hydrogen fuel cells as a viable source of energy.
#7. Infrastructure Beginnings.
Fossil fuels have been used for decades with adequate infrastructure for supply and transport, while hydrogen fuel cell technology during commercial implementation for deployment will require the installation of new refuelling infrastructure to support hydrogen utilization.
Although this could more likely appear in long-range applications such as for HGVs or delivery trucks where it could be possible to utilize start-to-end refuelling if hydrogen fuel cell tech is adopted.
#8. Highly Flammable.
The highly flammable nature of hydrogen creates understandable safety concerns. Hydrogen gas will ignite in air ranging from 4 to 75% gas concentration.