Fiery rockets slowly lifting off the launch pad might be what people initially think of when considering what powered the first trips to the moon. But fuel cells also played a pivotal role as the primary source of electricity for the Apollo Command Module. Granted, they won't be found orbiting the moon these days, but they're currently used in a wide range of applications here on Earth.

Although the creation of hydrogen generates carbon dioxide, the pollution is produced at a single point, making it easier to trap. For this reason, and the fact that fuel cells primarily generate electricity, water, and heat as byproducts, environmental advocates tout them as a cleaner-energy solution.  But they're not the only ones excited about the prospects of this technology. Here are five reasons for the enthusiasm.

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1. Things may be looking up thanks to some help from Down Under

Almost all of the electric vehicles you see in traffic rely on lithium ion batteries. Yes, the Honda Clarity is available in a fuel cell model, and Toyota's Mirai is hydrogen powered, but the popularity of these vehicles pales in comparison to their lithium battery brethren. Scientists in Australia, however, think they're a step closer to changing that.

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) has announced the development of a fuel cell membrane that separates ultra-high-purity hydrogen from liquid ammonia. It believes that this new technology addresses two formidable obstacles to greater adoption of fuel cell electric vehicles: the transportation and storage of hydrogen.

Larry Marshall, CSIRO chief executive, said, "This is a watershed moment for energy, and we look forward to applying CSIRO innovation to enable this exciting renewably sourced fuel and energy-storage medium a smoother path to market."

2. Breaking ground to break a record

South Korea has very big plans for fuel cells in the near future. Daesan Green Energy recently held a groundbreaking ceremony for what will be the world's largest hydrogen fuel cell power plant. Located in Seosan, South Korea, the Daesan Green Energy Fuel Cell Power Plant will use a 50 MW Doosan fuel cell system. The plant, expected to begin operation in June 2020, will power about 170,000 homes. According to Doosan's press release, the facility "will be the world's first large-scale fuel cell utilizing hydrogen byproduct during operation."

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3. Powering defense

The military is using fuel cells in a variety of applications. Ballard Power Systems (BLDP -1.10%), for example, reported that in the first quarter 2018, it received two orders, totaling $3.5 million, from the U.S. military for the company's Power Manager product, which powers communication systems, medical equipment, and other devices used by soldiers in the field. Subsequently, the company reported that the U.S. Navy placed an order in the second quarter for 13 fuel cell propulsion systems for use in unmanned aerial vehicles.

Besides Ballard, General Motors is also partnering with the U.S. military. Earlier this year, the Army field-tested the Chevrolet Colorado ZH2 fuel cell electric vehicle. Lt. Col. Tim Peterman was quoted as saying that the ZH2 is "really a leap ahead as we look at solutions we're trying to get on the battlefield particularly applicable to reconnaissance and security organizations." Besides the Army, GM has partnered with the Navy in developing an unmanned submarine powered by a fuel cell.

4. Capturing a new opportunity

One of the notable advantages of fuel cells is that they produce very little pollution. FuelCell Energy (FCEL -6.93%), however, believes that it could leverage the power of fuel cells in another way to fight pollution -- by capturing it. Partnering with ExxonMobil and Southern Company, FuelCell Energy is developing a carbon-capture solution to be used at gas-fired power plants. The pilot project is under development at a power plant in Alabama.

Shortly after announcing the partnership with ExxonMobil, FuelCell CEO Chip Bottone said on the company's Q2 2016 conference call that "ExxonMobil is measuring the size of this global market in gigawatts, bearing in mind that a single gigawatt is equal to 1,000 MW. One thousand MW of projects will translate into multibillion dollars of revenue for FuelCell Energy." Not too shabby for a company that reported $96 million in revenue for 2017.

5. A little goes a long, long, long way

The Guinness World Records organization has confirmed that in July, students from Duke University broke the record for the world's most fuel-efficient vehicle. Duke Electric Vehicles designed and built a hydrogen fuel cell vehicle that got the equivalent of 14,573 miles per gallon. 

Fuel cells have come a long way from their discovery by William Grove nearly 180 years ago. Recently, fuel cell stocks have gained renewed interest following the IPO of Bloom Energy. But they might have a long way to go before they power investors' enthusiasm, since profitability continues to elude fuel cell companies.