Page 16 - PEN eBook February 2024

SMART ENERGY SMART ENERGY

is a rarity, it’s abundantly found all around us, bonded hydrogen and oxygen, with the electricity required While green hydrogen can be produced with minimal or platinum alloy catalyst. PEM fuel cells offer a quick
with other atoms—as water, as biomass like wood and coming from renewable energies like wind, solar and emissions, it then needs to be transported to where startup time, low operating temperatures and electrical
in hydrocarbons like petroleum, gas and coal. hydropower. This means it has a minimal carbon it will be consumed. To limit the emissions footprint efficiency of about 45% to 65%, and they are smaller
footprint, so it is the best choice to reduce emissions, as much as possible, the locations of production and and lighter than other fuel cells.
Today, hydrogen is used in many industrial processes, but it also means that large-scale production is consumption should be physically close together, which
such as fertilizer production and petroleum refining. constrained by the limited availability of electricity may not be practical. KOHLER HYDROGEN SYSTEMS
It’s also used as a rocket propellant, as well as in fuel from renewable sources. We’re going to see hydrogen Kohler’s power systems business is focused on
cells in vehicles and electricity generation. production, therefore, scale at the same speed, or These challenges mean that today, we’re not yet providing its customers with sustainable energy
maybe slightly behind, the pace of the adoption of seeing high adoption rates of hydrogen, but the resilience. Hydrogen fits with that product portfolio,
To use hydrogen as a fuel and release the energy renewables. potential is there. For example, hydrogen fuel cells are providing reliable power with zero carbon emissions at
it stores, we can burn it through a process like starting to be used to power cars, but it’s early days— the point of use.
combustion in an engine or we can use it in a fuel White hydrogen, defined as hydrogen that is naturally and there are still very few hydrogen fueling stations.
cell. Using hydrogen can greatly reduce greenhouse produced or present underground, is another attractive U.S. government figures say there are only 58 hydrogen Kohler’s hydrogen power system uses a PEM fuel cell
gas emissions compared with traditional fossil fuels, option and is starting to create a lot of interest. fueling stations open, and 57 of those are in California. for high-efficiency energy conversion and is modular,
which are made of hydrocarbons, and thus release The technology to extract it is not yet commercialized, If you are lucky enough to find somewhere to fill up flexible and scalable to suit a broad range of mission-
CO when burned. Importantly, hydrogen’s waste but the potential is enormous for large-scale, low-cost with hydrogen, however, it is much quicker than waiting critical power users, including hospitals, data centers
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product is only water when it is used in a fuel-cell production. for your electric car to recharge, typically taking five and water-treatment plants. The system can be used
system. minutes or less. as a prime or backup power source, for peak shaving or
WORKING WITH HYDROGEN as part of a distributed energy network.
HYDROGEN PRODUCTION Compared with traditional fuels, hydrogen’s energy HYDROGEN FUEL CELLS
About 10 million tons of hydrogen are produced density is very low at atmospheric pressure. This Fuel cells are more energy-efficient than combustion The power system can operate in an extended range
in the U.S. each year. Typically, hydrogen is defined means that we must store a lot of it to get the same engines and can achieve more than 60% efficiency of temperatures, from –30°C to 45°C. It is designed
with a color that indicates both its source and the kind of power output as from fossil fuels. Storage is in converting the chemical energy in their fuel into for low-maintenance operation and reduced through-
technology used to make it. There are many colors therefore a challenge, and it requires high pressure to electrical energy. They have zero CO emissions, with life costs, with a 20-year design life. It has a compact,
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used today, including black, brown, gray, purple, pink, compress the hydrogen to occupy a reasonable space. their only waste product being water. durable steel housing featuring lockable access doors
blue, white and green. and a textured paint finish for corrosion and abrasion
However, if we consider energy stored per unit mass, Figure 1 shows a conceptual overview of how a fuel protection.
Black and brown hydrogen are the least attractive hydrogen has a high energy content—almost 3× that of cell works. Hydrogen molecules enter at the anode (the
options from an emissions perspective. They use gasoline. This means that if we compress hydrogen, it negative electrode) and oxygen molecules enter at the With this robust, scalable power system, hydrogen
gasification technology to create hydrogen, typically can be an effective energy store. cathode (the positive electrode). The hydrogen atoms fuel-cell technology for power generation will enable
using coal, which leads to a very high carbon in the hydrogen molecules split into electrons and Kohler’s customers to achieve the emissions reductions
footprint. If the CO produced in this process were Hydrogen is 14× lighter than air. This means that it positively charged hydrogen protons. they need without compromising their mission-critical
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to be captured and stored, the hydrogen would be likes to escape and go wherever it can through the power supplies.
described as blue hydrogen. smallest gap or defect, so we must consider what The electrolyte membrane allows only hydrogen
types of materials we’re using for the compression protons to pass through. The electrons are forced
At the opposite end of the spectrum, green hydrogen vessel. Also, when we make connections with pipes through an external circuit, thus generating an electric
is the cleanest option. Green hydrogen is made by and connectors, we must make sure that they’re all current. This flow of electrons reaches the cathode,
using electrolysis to separate water molecules into effectively sealed. where the negatively charged electrons combine with
the positively charged hydrogen protons and oxygen
from the air to form water. This process also dissipates
heat.

Different materials can be used as the electrolyte,
leading to different characteristics of the fuel cell and
making it suitable for various applications. For example,
polymer electrolyte membrane (PEM) fuel cells use an
acid membrane and a solid polymer as an electrolyte,
with porous carbon electrodes containing a platinum
Figure 2: Kohler hydrogen fuel-cell power system

References

▶ For more information, visit sustainablefuture.kohlerpower.com.
Figure 1: How a fuel cell works

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