Hydrogen Fuel Cell Technology
Hydrogen fuel cells work through a chemical reaction of hydrogen gas with oxygen inside a fuel cell, which generates electricity and water as by-products.
Hydrogen power was popular in the 1990s and early 2000s when many thought it would start a revolution of clean energy, but the imagined new world of hydrogen energy never materialized.
One major factor that stands in the way of most new forms of energy is infrastructure.
High manufacturing costs, less-than-optimal efficiency in production and manufacturing, and complicated storage and transport requirements have also held back hydrogen fuel cells from becoming a widely adoptable technology for consumer vehicles.
For industrial applications, however, the hydrogen fuel cell makes more sense for those who can afford the required infrastructure to support it. In this blog, we will cover the advantages and disadvantages of hydrogen fuel cells used to power material handling equipment.
Advantage: High Energy Density Improves Productivity
As many companies search for an emission-free alternative to internal combustion engines in their forklifts, some are turning to hydrogen fuel cell technology.
Hydrogen fuel cells do not produce any CO2 emissions during operation, even if their production is not necessarily carbon-free. This gives them an advantage over combustion engine vehicles, which can emit small amounts of poisonous carbon monoxide and require well-ventilated rooms for indoor use.
The refueling process for hydrogen fuel cells is easy and takes about three minutes, compared to the longer and more complex process of changing out a large, heavy lead acid battery when it needs to be charged.
In comparison to refueling a propane-powered forklift, the hydrogen fuel cell refueling process has an advantage. Because, the energy density of hydrogen fuel cells is very high, hydrogen-powered equipment can operate for longer times and with less frequent refueling than with a propane cylinder.
Hydrogen fuel cells and lithium-ion battery energy densities are very similar, making them great choices for busy operations who need equipment to last a full shift.
Disadvantage: The Use of Fossil Fuels in Hydrogen Production
While it is true that hydrogen fuel cells do not emit harmful gases during operation, the same is not true for the production process to make hydrogen fuel. In fact, hydrogen power is nearly energy-neutral - which means that it takes almost as much energy to produce as what it produces.
Hydrogen is one of the most abundant elements on earth, but it is typically bonded to other elements and must be isolated to be used for energy purposes.
A common way to isolate hydrogen is to extract it from natural gas in a process called reforming. This process is costly and emits carbon dioxide, which is counterproductive to using an emission-free energy source.
The other way to isolate hydrogen is through electrolysis, where it is extracted from water and separated from the oxygen molecule using an electrical current.
The source of this electrical current can be anything, but today, electricity is most commonly generated from natural gas-powered plants.
The only truly carbon-free way to use hydrogen fuel cell power is to use solar or wind power (which is not accessible in some areas of the world) to generate electricity for the electrolysis process.
Because the hydrogen fuel production process is so complicated, it makes using hydrogen fuel cells more costly than other forms of energy. When looking into what energy source to integrate into material handling equipment, fleet managers need to make sure that hydrogen fuel and infrastructure costs will be offset by the significant labor savings compared to lead acid.
Disadvantage: Hydrogen Storage and Transportation
Hydrogen can be stored as either gas in high-pressure tanks or as a liquid in cryogenic temperatures, but it must be in the gas form to be used for lift truck fuel cells.
Both methods of hydrogen storage involve an inherent loss of energy. Compressing the hydrogen requires about 13% of the total energy content of the hydrogen itself, and if it is liquefied it loses about 40%.
Hydrogen gas is highly flammable and can easily escape containment. If hydrogen gas escapes containment, it can corrode metals. This, in turn, can make these contaminated metals brittle and prone to breaking.
Organizations that currently use hydrogen power can either have hydrogen gas delivered to them via tube trailers for smaller quantities or if they need a higher quantity of fuel, they have to build a plant onsite to generate hydrogen gas.
Setting up the infrastructure to use hydrogen fuel cells requires a large capital investment. Organizations will have to work with their local government and fire department to get approval, as well as worry about costs that come with hydrogen gas deliveries or building an on-site plant to generate hydrogen gas.
Disadvantage: Fuel Cell Efficiency
Hydrogen fuel cells are more energy-efficient than internal combustion engines. However, lithium-ion batteries are still the most energy efficient and the highest performing energy source for forklifts.
A CE rating is a measure of battery energy efficiency that examines the number of electrons that are lost during a full charge-discharge cycle.
At its highest, fuel cell energy efficiency is around 60%. Typical internal combustion engines have 20-30% efficiency. Lithium-ion batteries have one of the highest CE ratings at 99%, while lead acid batteries are around 90%.
This comparison is in terms of the “tank-to-wheels” efficiency; when you factor in the losses from production to utilization, hydrogen fuel cells have significantly higher energy losses than batteries.
This comparison graphic from a Copenhagen Centre on Energy Efficiency study shows the cumulative energy losses.
Why Lithium-Ion is the Best Option for Electric Forklifts
When comparing hydrogen fuel cells to other energy sources, it is important to note the differences between different types of forklift batteries.
Lead acid is the oldest and most commonly used battery technology, but it has a much shorter service life and degrades in performance quickly throughout the discharge cycle.
Lithium-ion batteries keep a constant voltage level during the entire discharge cycle, so they are able to maintain consistent performance until they need recharging.
Hydrogen fuel cells deliver better performance than lead acid batteries, but they do not beat lithium-ion batteries when it comes to efficiency, costs, and safety.
When considering fuel cells to power your forklifts, make sure you understand all of their advantages and disadvantages.