A Side-By-Side Comparison of Propane & Hydrogen
When a severe storm hits, or the local grid faces an overload, it’s essential that local transportation systems stay up and running.
The standby power systems supporting rail lines, traffic lights, and other transportation signals need to be reliable, low-maintenance, and cost-effective. As the transportation sector embraces the challenges of cutting overall carbon emissions, industry leaders also need to consider the sustainability of their standby power fuel sources.
Fuel Source Advantages & Disadvantages
While the majority of RedHawk Energy’s fuel cells rely on propane, we also supply and service fuel cells that run on hydrogen gas, a fuel source that has recently drawn national attention. We’ll discuss each fuel source’s unique advantages and disadvantages and consider the attributes that most impact the railway sector.
Accessibility
How easy is it to find the fuel in your area?
Propane
Propane is a widely available fuel source that’s used across a variety of industries, including agriculture, manufacturing, transportation, and everyday recreational use. The gas can be purchased at major retailers in transportable, consumer-friendly 20-pound tanks or larger quantities from a local commercial propane provider. The majority of RedHawk Energy’s standby power generators are run on propane. Our Solid Oxide Fuel Cells can provide 130-160 hours of run-time on just two BBQ-style propane tanks.
Hydrogen
Hydrogen is still an emerging part of the energy sector in the United States. Most of the existing and planned hydrogen stations in the United States are in California. Only five are planned for the northeastern states, creating challenges for many transportation sectors around the country aiming to embrace this alternative fuel source. To solve this infrastructure challenge, the U.S. Department of Energy launched H2USA, an initiative focused on advancing hydrogen energy infrastructure. However, it will likely take years until hydrogen energy is widely available in local marketplaces.
Cost
How does it impact your bottom line?
Propane
Propane is known as one of the most cost-efficient fuel sources. According to the U.S. Department of Energy’s Alternative Fuel Price Report, the average price of propane in the United States between April 1-15, 2024, was $3.45 per gallon or around $0.91 per kilogram.
Hydrogen
Currently, hydrogen production is expensive and can be prohibitive for some industry consumers. “Gray hydrogen,” or hydrogen made from natural gas, costs between $0.98 and $2.93 per kilogram to produce. “Green hydrogen,” made by a carbon-zero process called electrolysis, costs $4.5 to $12 per kilogram to produce.
The U.S. Department of Energy has launched a new Earthsthot Initiative aimed at reducing the cost of “green hydrogen” energy to $1 per kilogram in one decade.
Efficiency
How does it perform?
Propane
The U.S. Department of Energy Fuel Properties Comparison tool tracks alternative fuel source’s Gasoline Gallon Equivalent (GGE), or the amount of fuel it takes to equal the energy content of one liquid gallon of gasoline. One gallon of propane has 73% of the energy in one gallon of gasoline due to the lower energy density of propane.
Hydrogen
Hydrogen gas has the highest energy per mass of any fuel. According to the Fuel Properties Comparison tool, 2.2 lbs. or 1 kg of hydrogen gas has the same energy as one gallon of gasoline.
However, hydrogen is challenging to transport as a gas and is typically stored and shipped in a frozen, liquid form, requiring careful maintenance. Because of these storage challenges, liquified hydrogen has a low volumetric energy density.
Safety
Does it pose a danger to people?
Propane
Propane is non-toxic has the lowest flammability range of any alternative fuel. The gas can ignite if exposed to a spark or open flame, but an odorant is added to help quickly detect leaks. Propane is an asphyxiating gas, so if inhaled in high concentrations, can cause difficulty breathing.
If spilled outside, propane biodegrades rapidly in soil, water, and air. When used properly, it is generally considered to be one of the safest fuel sources.
Hydrogen
Hydrogen is non-toxic and will not contaminate groundwater. Because hydrogen molecules are smaller than all other gasses, hydrogen can leak from tanks or other containers that are otherwise considered impermeable. This can lead to loss of ductility, which reduces overall performance.
Hydrogen is stored at extremely high pressures, creating a risk of projectiles if the tanks rupture. It is also more flammable than other gaseous fuel sources. The minimum ignition energy (MIE) of a hydrogen-air mixture is only 0.019 mJ, whereas that of other flammable gasses such as methane, ethane, propane, butane, and benzene is usually on the order of 0.1 mJ.
Sustainability
How does the fuel source impact the environment?
Propane
Propane is considered a low-carbon fuel option and emits a low level of carbon dioxide compared to gasoline or diesel fuel. In 2019, energy experts developed renewable propane, also known as biopropane, made from non-petroleum sources such as natural fats, vegetable oils, and various types of grease. It is chemically identical to conventional propane and can be used in all propane applications. In the United States, renewable propane is commonly used in California, Washington, and Oregon due to state-wide carbon emission incentives.
Hydrogen
Hydrogen is considered an abundant, near-zero carbon-emitting energy source. After hydrogen gas has been produced and contained, it emits no greenhouse gasses during use, only giving off water vapor and warm air.
Hydrogen gas is made by separating the hydrogen out of commonly found chemical compounds (such as (H2O) or methane (CH4). Around 95% of hydrogen gas production is done by natural gas reforming, a thermal process. However, gas can also be produced using pressure, and electricity. If the hydrogen gas is created using renewable energy sources, such as solar or wind, the hydrogen is considered to be entirely renewable. However, in the United States, the infrastructure for hydrogen gas is still underdeveloped, so carbon gas manufacturers may still need to rely on traditional energy sources for the production of hydrogen gas, leading to an increase in overall carbon emissions.