Green Hydrogen and Fuel Cell Electric Vehicles (FCEV)

Green Hydrogen

Green hydrogen refers to hydrogen gas that is produced using renewable energy sources and environmentally friendly methods, emphasizing sustainability and low carbon emissions in the production process. Unlike traditional hydrogen production methods that often rely on fossil fuels, green hydrogen is generated through processes powered by renewable energy. The primary methods for producing green hydrogen include water electrolysis using electricity generated from renewable sources like solar, wind, or hydropower.

Key features of green hydrogen production include:

1. Renewable Energy Sources:
• Green hydrogen is produced using electricity generated from renewable sources, such as solar, wind, or hydropower. These sources ensure that the overall carbon footprint of hydrogen production is minimal or zero, contributing to environmental sustainability.
2. Water Electrolysis:
• The most common method for producing green hydrogen is through water electrolysis, a process that uses electricity to split water (H₂O) into hydrogen (H₂) and oxygen (O₂). The electrolysis reaction occurs in an electrolyzer, and when powered by renewable energy, it results in the creation of green hydrogen.
3. Carbon Neutrality:
• Green hydrogen is considered a carbon-neutral or low-carbon energy carrier because the electricity used in electrolysis is sourced from renewable energy, avoiding the carbon emissions associated with fossil fuels. The overall life cycle emissions of green hydrogen are significantly lower compared to hydrogen produced from fossil fuels.
4. Reduced Environmental Impact:
• The production of green hydrogen contributes to the reduction of greenhouse gas emissions, air pollutants, and dependence on finite fossil fuel resources. It aligns with global efforts to transition to cleaner and more sustainable energy systems.
5. Versatility:
• Green hydrogen can be used in various applications, including transportation (fuel cell vehicles), industrial processes, power generation, and as a storage medium for excess renewable energy. Its versatility makes it a promising candidate for a wide range of sectors seeking cleaner energy alternatives.
6. Energy Storage:
• Green hydrogen can serve as a form of energy storage. Excess electricity generated from renewable sources during periods of high availability can be used to produce hydrogen through electrolysis. The stored hydrogen can then be converted back into electricity when needed.

While the production of green hydrogen is gaining momentum as an environmentally friendly energy solution, it is essential to consider the overall energy efficiency and economic feasibility of the production process. Ongoing advancements in technology, cost reductions, and supportive policies are expected to further enhance the viability and adoption of green hydrogen as a key component of the transition to a sustainable energy future.

Electrolysis-Hydrogen Production:

Electrolysis is a promising option for carbon-free hydrogen production from renewable and nuclear resources. Electrolysis is the process of using electricity to split water into hydrogen and oxygen. This reaction takes place in a unit called an electrolyser. Electrolysers can range in size from small, appliance-size equipment that is well-suited for small-scale distributed hydrogen production to large-scale, central production facilities that could be tied directly to renewable or other non-greenhouse-gas-emitting forms of electricity production.

How Does it Work?

Like fuel cells, electrolysers consist of an anode and a cathode separated by an electrolyte. Different electrolysers function in different ways, mainly due to the different type of electrolyte material involved and the ionic species it conducts.

Polymer Electrolyte Membrane Electrolysers

In a polymer electrolyte membrane (PEM) electrolyser, the electrolyte is a solid specialty plastic material.

• Water reacts at the anode to form oxygen and positively charged hydrogen ions (protons).
• The electrons flow through an external circuit and the hydrogen ions selectively move across the PEM to the cathode.
• At the cathode, hydrogen ions combine with electrons from the external circuit to form hydrogen gas. Anode Reaction: 2H₂O → O₂ + 4H⁺ + 4e^- Cathode Reaction: 4H⁺ + 4e^- → 2H₂

Alkaline Electrolysers

Alkaline electrolysers operate via transport of hydroxide ions (OH^-) through the electrolyte from the cathode to the anode with hydrogen being generated on the cathode side. Electrolysers using a liquid alkaline solution of sodium or potassium hydroxide as the electrolyte have been commercially available for many years. Newer approaches using solid alkaline exchange membranes (AEM) as the electrolyte are showing promise on the lab scale.

Solid Oxide Electrolysers

Solid oxide electrolysers, which use a solid ceramic material as the electrolyte that selectively conducts negatively charged oxygen ions (O^2-) at elevated temperatures, generate hydrogen in a slightly different way.

• Steam at the cathode combines with electrons from the external circuit to form hydrogen gas and negatively charged oxygen ions.
• The oxygen ions pass through the solid ceramic membrane and react at the anode to form oxygen gas and generate electrons for the external circuit.

Solid oxide electrolysers must operate at temperatures high enough for the solid oxide membranes to function properly (about 700°–800°C, compared to PEM electrolysers, which operate at 70°–90°C, and commercial alkaline electrolysers, which typically operate at less than 100°C). Advanced lab-scale solid oxide electrolysers based on proton-conducting ceramic electrolytes are showing promise for lowering the operating temperature to 500°–600°C. The solid oxide electrolysers can effectively use heat available at these elevated temperatures (from various sources, including nuclear energy) to decrease the amount of electrical energy needed to produce hydrogen from water.

Fuel Cell-Converts Hydrogen into Electricity

A fuel cell is an electrochemical device that converts the chemical energy of a fuel directly into electrical energy through a chemical reaction known as an electrochemical process. The basic operation of a fuel cell involves the reaction of hydrogen with oxygen to produce electricity, water, and heat. The most common type of fuel cell is the proton exchange membrane (PEM) fuel cell, and its operation can be explained as follows:

1. Components of a PEM Fuel Cell:

a. Anode:

• The anode is the negative electrode where hydrogen fuel is supplied. Hydrogen molecules (H₂) are broken down into protons (H⁺) and electrons (e⁻) through a process called electrochemical oxidation.

b. Cathode:

• The cathode is the positive electrode where oxygen (usually from the air) is supplied. Oxygen molecules (O₂) combine with protons and electrons from the anode side.

c. Electrolyte (Proton Exchange Membrane):

• A thin, permeable membrane, usually made of a solid polymer material, separates the anode and cathode. It allows the passage of protons while preventing the direct mixing of hydrogen and oxygen gases.

d. Electrolyte-Catalyst Interface:

• Catalyst layers at the interfaces between the electrodes and the electrolyte facilitate the electrochemical reactions by providing sites for hydrogen and oxygen molecules to interact.

2. Electrochemical Reactions:

a. At the Anode:

• Hydrogen molecules (H₂) are split into protons (H⁺) and electrons (e⁻) in the presence of a catalyst:   
• H₂​→2H⁺+2e−

b. Through the Electrolyte:

• Protons move through the proton exchange membrane (PEM) to the cathode, creating an electric current.

c. At the Cathode:

• Oxygen molecules (O₂) from the air combine with protons (H⁺) and electrons (e⁻) at the cathode to form water:

                              O₂​+ 4H⁺+ 4e−→2H₂​O

3. Electricity Generation:

• Electrons that are released at the anode cannot pass through the proton exchange membrane. Instead, they are forced to travel through an external circuit, creating an electric current. This flow of electrons through the external circuit can be harnessed to do useful work, such as powering an electric motor or charging a battery.

4. Overall Reaction:

• The overall reaction combining the anode and cathode processes is the production of electricity, water, and heat:
• H₂​+O₂​→H₂​O + Electricity

5. Heat Generation:

• In addition to electricity and water, fuel cells produce heat as a byproduct of the electrochemical reactions.

Advantages of Fuel Cells:

• Fuel cells offer high energy efficiency.
• They produce electricity with lower greenhouse gas emissions compared to conventional combustion processes.
• Fuel cells provide a clean and quiet energy solution.

Fuel cells find applications in various sectors, including transportation (fuel cell vehicles), stationary power generation, and portable devices, contributing to a more sustainable and low-carbon energy future.

Fuel Cell Car

Fuel Cell Electric Cars (FCEV) in Market:

1. Toyota Mirai:
• The Toyota Mirai is one of the pioneering hydrogen fuel cell vehicles and has gone through several generations. It is available in select markets, and Toyota has been actively promoting hydrogen fuel cell technology.
2. Honda Clarity Fuel Cell:
• The Honda Clarity Fuel Cell is a midsize sedan that runs on hydrogen fuel cells. It has been available in certain regions, primarily in California.
3. Hyundai Nexo:
• The Hyundai Nexo is an FCEV SUV offering from Hyundai. It features a hydrogen fuel cell system and has been made available in some markets, including the United States and Europe.
4. Mercedes-Benz GLC F-CELL:
• The Mercedes-Benz GLC F-CELL is a plug-in hybrid that combines a hydrogen fuel cell with a battery. It has been introduced in limited markets to explore the potential of FCEV technology.
5. BMW i Hydrogen NEXT:
• BMW has been developing hydrogen fuel cell technology, and the BMW i Hydrogen NEXT concept car showcases the company's commitment to exploring different sustainable mobility options.
6. Riversimple Rasa:
• The Riversimple Rasa is a hydrogen fuel cell-powered car developed by the UK-based company Riversimple. It is designed with a focus on sustainability and efficiency.
7. Linde H2:
• Linde, a global industrial gas company, has developed the Linde H2, a hydrogen fuel cell vehicle designed for commercial fleet applications.
8. Daimler F-CELL:
• Daimler has developed various fuel cell vehicles under its F-CELL branding, including models like the Mercedes-Benz F-CELL.