ERC: Lesson - Hydrogen Fuel Cells (Topic 6.11) đź“–

⏳ Estimated Reading Time: 4 - 6 minutes

Learning Objective

Describe the use of hydrogen fuel cells in power generation and the effects of hydrogen fuel cells in power generation on the environment. 

 

Hydrogen Fuel Cells

hydrogen atom model with one electron
Hydrogen is the lightest of all elements, with only one proton and one electron.

Hydrogen has been used by NASA in rockets since the 1950s and hydrogen is used often in industrial processes.

Unfortunately, there is virtually no pure hydrogen gas on Earth due to the fact that this element is very reactive and likes to bond with other elements. As such, it is rarely found alone. This means that hydrogen must be separated from other elements prior to use. This also means that hydrogen fuel cells require an input of energy using current methods of hydrogen extraction.

Hydrogen gas can be burned in the presence of oxygen and when it reacts with oxygen in the air, water is the only product:

2H2 + O2 → 2H2O + energy

We can use an electrical current to separate water into hydrogen and oxygen. A hydrogen fuel cell is a device in which hydrogen is chemically recombined with O2, which produces electricity INSTEAD of burning the hydrogen. 

a diagram of a hydrogen fuel cell: Hydrogen gas enters the cell, where it is split into protons and electrons. The electrons travel through a circuit, generating electrical energy, before recombining with the protons and oxygen to form water, which exits the cell along with the produced energy.
Hydrogen fuel cells can be small enough to power a laptop or a cell phone or large enough to produce electricity.

This method is a more efficient source of energy transfer at around 45-60%. Hydrogen fuel cells work well as backup power in areas that might lose power due to hurricanes or other natural disasters. Fuel Cell Electric Vehicles (FCEVs) generate electricity through a fuel cell that uses hydrogen as its power source, instead of relying solely on a battery. While FCEVs could technically be designed to plug in and charge up like electric cars, most of them don’t work that way. Instead, they use their batteries to capture energy when you brake, give a boost of power when you’re speeding up, and help keep the power output steady. The fuel cell can even be paused or shut down when the car doesn’t need much power. 

an overhead diagram of a Hydrogen Fuel Cell Electric Vehicle.
The total amount of energy Fuel Cell Electric Vehicles (FCEVs) can carry depends on the size of the hydrogen tank, which is different from all-electric cars, which depend entirely on the size of their batteries for both their power and how much energy they can store.

Another method is to remove the hydrogen from methane (CH4).  This portion can be produced using solar and other renewables, so it does not require fossil fuels. Once the hydrogen is separated, it is transported in pipelines and held in tanks.

 

Essential Knowledge

Hydrogen fuel cells are an alternative to non-renewable fuel sources. They use hydrogen as fuel, combining the hydrogen and oxygen in the air to form water and release energy (electricity) in the process. Water is the product (emission) of a fuel cell.

 

Environmental Effects of Hydrogen Fuel Cells

There are currently many limitations associated with hydrogen energy, despite it having very little environmental impact, but there are significant advantages to hydrogen energy.

Let's explore a few of these advantages and disadvantages. After reading through the pros and cons, what do you think? Are the disadvantages of hydrogen fuel cells worth the benefits?

âś… Low Environmental Impact (click to reveal)
          • Hydrogen fuel cells have almost no impact on the environment. They do not release any air pollutants or greenhouse gases.
          • No noise pollution.
          • No visual pollution.

 

âś… Efficient (click to reveal)
          • Hydrogen fuel cells are much more efficient than traditional internal combustion engines that run off of fossil fuels so the interest in developing this renewable energy is high.
          • Fuel cell efficiency often exceeds 80% in combined heat and power systems.

 

âś… Renewable Energy Source (click to reveal)
          • Hydrogen is the most abundant element in the universe and can be produced from various renewable sources.
          • Hydrogen fuel cells are a clean, renewable energy source that can help reduce reliance on fossil fuels.
          • Hydrogen fuel cells are also non-depletable.

 

❌ Expensive (click to reveal)
          • Current fuel cell technology is expensive.
          • Raw materials for fuel cells are expensive.
          • FCEVs are expensive.
          • Transporting hydrogen is expensive.

 

❌ Difficult to Store (click to reveal)
          • Hydrogen requires high-pressure tanks for storage, which can be a safety concern.

 

❌ Lacking Infrastructure (click to reveal)
          • To power our vehicles with hydrogen fuel cells, we will need a hydrogen infrastructure similar to the infrastructure we currently have for gasoline–abundant fuel stations. 

 

❌ Not Yet Reliable (click to reveal)
          • Hydrogen fuel cells are not a reliable power source in the current stage.

 

As traditional energy prices continue to increase, interest in alternative fuel vehicles will continue to increase. Hopefully, hydrogen power will find a place among the reliable, safe, and clean fuels of the future.

 

Essential Knowledge

Hydrogen fuel cells have low environmental impact and produce no carbon dioxide when the hydrogen is produced from water. However, the technology is expensive, and energy is still needed to create the hydrogen gas used in the fuel cell.

 

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