Magazine article National Defense

Powering Up: Fuel Cell Technology Positioned as Viable Alternative to Generators

Magazine article National Defense

Powering Up: Fuel Cell Technology Positioned as Viable Alternative to Generators

Article excerpt

Supplying electricity to military bases in austere combat zones can present huge logistics and transportation challenges. During a recent deployment to Iraq, Army Lt. Col. Rich O'Connor, who commanded the support squadron for the 3rd Armored Cavalry Regiment, required many large generators to supply electricity to the unit's base camp there.

"To power a grid is astronomic," he told an industry conference. "We need to start moving towards alternative fuel capability."

Developers of fuel cell technologies are confident that they can answer the call.

One company currently trying to garner attention from military energy planners says that molten carbonate fuel cells could produce enough electricity at highly efficient rates and with low emissions, which would make them suitable for powering military bases in remote locations.

Molten carbonate fuel cells have been developed for natural gas and coal-based power plants for electrical utility, industrial and military applications.

Ansaldo Fuel Cells, based in Genoa, Italy, has produced a molten carbonate fuel cell that fits on a flatbed truck and can generate one megawatt of electricity on natural gas. A 1-megawatt capacity power plant produces enough electricity to power 750 households. Work is in progress to increase that generating capacity to 4 megawatts and above by using fuels rich in hydrogen and carbon monoxide, said Ansaldo officials during a recent briefing.

The technology has a 50 percent electrical efficiency rate, they said. If the waste heat is also utilized by the system, the efficiency can reach 85 percent.

Fuel cells, on a basic level, produce electricity through a chemical reaction that takes place at two electrodes--the positively charged cathode and the negatively charged anode. Hydrogen atoms enter the anode and are stripped of their electrons, becoming ionized hydrogen atoms. The electrons are routed through wires to provide electrical current as the hydrogen ions pass through an electrolyte to the cathode, where the ions and the electrons combine with oxygen to form water--the emission that makes such power generators "greener" than conventional electricity plants.

There are several types of fuel cells. Molten carbonate fuel cells, as the name implies, use compounds of lithium-potassium carbonate salts as the electrolyte. When heated to approximately 1,200 degrees Fahrenheit, the salts melt into a liquid state. Though the nickel catalyst that these systems use are less expensive than others, the fuel cells require additional carbon dioxide to replenish the carbonate ions that are used up in the reactions.

Ansaldo officials said what sets their fuel cell design apart from the competition is the company's "twin stack configuration." Such an arrangement separates critical components and cuts down on costs, they said.

To derive pure hydrogen from fuel requires a reformer. The reforming process can occur within or outside the fuel cell stack. Internal reformers benefit from the heat generated from inside the stack while external reformers give operators the flexibility to change catalysts without altering the stack design to accommodate different types of fuels.

Ansaldo claims that its "modular integrated reformer" combines the advantages of both designs. Because it is internal to the vessel that contains the stack, the reformer uses the fuel cell's generated heat to sustain the reforming process so external heat is unnecessary. But it still permits catalysts to be exchanged without impacting the stack design.

"We can easily replace the reforming catalyst, so that we can reconstitute the power plant to be able to run on different fuel," said Bartolomeo Marcenaro, business development manager for Ansaldo.

"This is one of the major technical issues that allow us to say we can run on many, many different types of fuels."

The fuel cell can operate on the hydrogen and carbon monoxide obtained from natural gas. …

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