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Could Fuel Cells Change the Energy Game?

Wednesday, August 17, 2016

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From the early days of the space program to the emergence of a variety of commercial applications over the last decade, fuel cells have become an increasingly promising energy technology. Growing appetite for clean energy has combined with advances in engineering and materials science to propel fuel cells to the precipice of significant commercial success.

Fuel cell systems are much more efficient and environmentally friendly compared with conventional technologies.

Fuel cells utilize hydrogen or hydrogen-rich fuels to generate electricity via an electrochemical reaction instead of combustion. Fuel cell systems are much more efficient and environmentally friendly compared with conventional technologies, while also being scalable, modular, and reliable.

Fuel cells can be used for a large variety of applications in transportation, stationary, and portable power.

What is a Fuel Cell?

How a Fuel Cell Works

There are several types of fuel cell systems, with varying structures and energy generating processes. However, the cells within these modular systems have the same basic anatomy:

Anode, Cathode, and Electrolyte: Hydrogen is channeled into the fuel cell, where it comes in contact with the anode, or positively charged post. From there, the hydrogen moves across the electrolyte membrane. The electrolyte membrane only allows the hydrogen molecule’s protons to pass through, while the electrons are diverted to create an electrical current. At the cathode, or negatively charged post, the protons react with oxygen from the air and the electrons that have passed through the electrical circuit to create the fuel cell’s byproducts: water and excess heat.

Proton Exchange Membrane Fuel Cell Diagram (Source: Wikimedia Commons)

Components of a Fuel Cell System

While all fuel cells utilize hydrogen as the key power source for the electrochemical process, the structure of fuel cell systems varies based largely on how hydrogen is provided to the cell. Whether the system intakes hydrogen in its pure form, as part of a chemical solution, or as a byproduct of methane or other fossil fuels, all fuel cell systems utilize the same basic components:

  • Fuel Cell Stack: The fuel cell stack is the core component of any fuel cell system. A single fuel cell produces little electricity. However, fuel cell stacks often consist of hundreds of fuel cells that work in concert to provide an efficient and effective source of energy.
  • Fuel Processor: The fuel processor converts the intake fuel into a fuel that can be utilized within the cell.
  • Power Conditioners: The power conditioner controls the electrical current to meet the requirements of the specific application. This component can also convert direct current into alternating current, which is the form of electricity used in homes and buildings.
  • Air Compressor: In order to run as efficiently as possible, the inlet air must be received at a high pressure. The air compressor is responsible for raising air pressure to improve the efficiency of a fuel cell.
  • Humidifiers: Because some types of fuel cells do not work well when dry, humidifiers are often used to maintain a small amount of water within the fuel cell.

Fuel Cell Applications

The uses of fuel cells are numerous and each carries with it a distinct set of advantages.

Transportation and Material Handling

Fuel cells can be used to power light duty and commercial vehicles, and are being examined for various maritime and aeronautical applications.

Fuel cell-powered forklifts are already replacing existing battery-powered and combustion equipment. These forklifts are seen as a potential upgrade from their battery-powered counterparts because they have significantly greater ranges and shorter refueling times.

Meanwhile, Toyota, Hyundai, and Honda are leading the way in U.S. production of fuel cell-powered automobiles. Toyota began sales of its Mirai in western California in October 2015 and plans to sell 3,000 of the fuel-cell vehicles by 2017.

Fuel cells can be used to power light duty and commercial vehicles, and are being examined for various maritime and aeronautical applications. 

Stationary Power

Fuel cell stacks can provide reliable on-site and on-demand electricity generation in buildings ranging from small homes to large factories. Many companies seeking to increase their use of clean energy, including Wal-Mart, FedEx, and Apple currently utilize fuel cell systems at select facilities around the country. Several utilities, data centers, and other critical operations are also installing large-scale fuel cell systems to ensure access to a constant power source.

Portable Power

As an alternative to fossil fuel-burning portable generators, fuel cells are capable of providing reliable and clean off-grid power. Portable fuel cells can be used as back-up electric generators and have a variety of military applications, including battlefield generators. Small portable fuel cells can also be used to charge phones and other electronic devices.

The Future of Fuel Cell Technology

Through a number of public-private partnerships such as the H2USA program, the Department of Energy has made significant investments in the advancement of fuel cell technology. These programs have improved durability, driven down cost, and encouraged market growth. However, the future of each fuel cell application will rely on continued progress.

Transportation and Materials Handling

Driving range for fuel cell-powered automobiles and materials handling equipment is competitive with combustion engine-powered vehicles and exceeds that of their electric counterparts. However, hydrogen fuel must be compressed to be stored, which creates cost challenges. Widespread deployment of fuel cell vehicles also relies on significant expansion of hydrogen fueling infrastructure.

While the cost of fuel cell vehicles has substantially decreased, they are still more expensive than conventional vehicles and hybrids. Durability has improved 129 percent since 2006-2007, yet further gains are needed to match conventional light-duty vehicles. DOE’s 2020 target for fuel cell operation time—5,000 hours—Is roughly 20 percent higher than the current maximum fuel cell fleet average of 4,130 hours.

Fuel cells hold considerable promise for both the transportation and power sectors.

Stationary Power

Stationary power has been the primary application of fuel cell technology to date, providing a fuel-flexible power source that is scalable, reliable, and efficient. However, these systems are expensive compared with conventional electricity generation. Continued improvements in durability are also needed.

Portable Power

Portable fuel cells provide off-grid power for a variety of applications. However, portable fuel cells have not yet achieved resounding commercial success and have yet to reach targets for cost and durability. Portable fuel cell generators also face hydrogen storage challenges similar to those for fuel cell vehicles.

Fuel cells hold considerable promise for both the transportation and power sectors. To take advantage of this potential, support for commercialization efforts and research that addresses the remaining technical challenges must be priorities.

Matt Perdue served as an intern for BPC’s Energy Project.

1 As much as 95 percent of the hydrogen produced in the United States today comes from natural gas reformation.