Hydrogen is an energy source that emits zero greenhouse gases when burned. The only waste product is water vapor. That makes it a cleaner alternative energy source than fossil fuels like natural gas, oil, and coal.

The drawback to hydrogen as a fuel source is that we rarely find it in a gaseous form. And although we can produce hydrogen from a variety of sources, some of those methods emit greenhouse gases. On top of that, we don't yet make it at the scale needed to be economically competitive with fossil fuels.

However, that could change in the coming years. Several companies are working hard to tap into the enormous potential for this potentially emission-free fuel. 

Here's a look at some of the leading hydrogen stocks.

A hydrogen energy storage system near solar panels.

Image source: Getty Images.

What to know about investing in hydrogen

There are several ways to produce hydrogen. Some methods result in the production of carbon dioxide as a byproduct. The industry labels these forms "blue hydrogen." Using this form of hydrogen requires carbon capture and storage to trap and store the associated carbon dioxide underground for it to achieve zero greenhouse gas emissions. Another method uses renewable energy to power an electrolyzer that splits hydrogen from water molecules. This process produces green hydrogen, which creates no carbon emissions.

Green hydrogen energy has almost limitless potential. Hydrogen fuel cells work much like batteries, generating electricity from an electrochemical reaction. Instead of recharging them like a traditional battery, we refuel hydrogen fuel cells with more hydrogen. We can use hydrogen fuel cells to motorize vehicles (cars, trains, buses, maritime vessels, and trucks) and as a stationary power source. Hydrogen might also replace natural gas in the pipeline system with some modifications. We can then use it in power plants to generate electricity and as a fuel source for our homes. Because of its potential, some forecasts peg the future value of the green hydrogen market to be as much as $10 trillion

Although green hydrogen holds great promise as a potential emissions-free fuel source, it's costly to produce. It cost between $18.58 and $33.44 per dekatherm to produce green hydrogen in 2020. For comparison's sake, natural gas production costs were between $1.00 and $4.50 per dekatherm. Costs, however, are falling, making green hydrogen more competitive with natural gas. 

Top hydrogen stocks to watch

Given the potential of green hydrogen, a growing number of companies are getting into the sector. Many energy and industrial companies are in the early stages of exploring the possibility of hydrogen energy. However, a handful of companies are already starting to emerge as early leaders in the sector. Here are five leading hydrogen companies to keep an eye on as the industry matures: 

Hydrogen Stock

Ticker Symbol

Market Cap

Air Products

(NYSE:APD)

$50.4 billion

Plug Power

(NASDAQ:PLUG)

$13.3 billion

Bloom Energy

(NYSE:BE)

$3.8 billion

Ballard Power Systems

(NASDAQ:BLDP)

$2.9 billion

FuelCell Energy

(NASDAQ:FCEL)

$2 billion

Data source: YCharts. Market cap data as of March 4, 2022.

Here's a closer look at some of the best hydrogen stocks to watch as the sector starts taking center stage in the coming years.

Air Products

Air Products is one of the world leaders in supplying industrial gases. It's a global leader in liquefied natural gas (LNG) processing technology and equipment. It's also one of the world's largest suppliers of merchant hydrogen and a leader in hydrogen fuel infrastructure.

Air Products dreams of being a leader in providing solutions to the world's energy and environmental challenges through gasification, carbon capture, and clean hydrogen. It has several major hydrogen projects underway that it expects to complete in the coming years. These include a $4.5 billion blue hydrogen project in Louisiana, a $7 billion carbon-free hydrogen joint venture in Saudi Arabia, and a $1 billion net-zero hydrogen project in Canada that should enter service between 2024 and 2026. The trio and future projects position Air Products to remain a leading global hydrogen energy company.

Plug Power

Plug Power is a pioneer in the hydrogen fuel cell industry. It created the first commercially viable market for hydrogen fuel cell technology. It has deployed an industry-leading 50,000 fuel cell systems for the e-mobility market (using electric powertrain technologies to power vehicles and fleets). It's one of the world's largest hydrogen buyers and operates a leading hydrogen refueling network in North America.

Plug Power is building out a green hydrogen generation network in North America. It has several hydrogen plants under construction that should start production in 2022. It expects to begin construction on several more that should start up in the coming years. The company aims to build the world's first green hydrogen ecosystem, positioning it as the category leader in this massive market opportunity. 

Bloom Energy

Bloom Energy's mission is to make clean, reliable, and affordable energy. The company has developed the Bloom Energy Server, an on-site electric power generation platform. In 2021, it unveiled the Bloom Electrolyzer, using the same solid oxide technology as its Bloom Energy Server to produce clean hydrogen 15% to 45% more efficiently than other products on the market.

Bloom Energy believes the Bloom Electrolyzer, which it expects to start shipping in the fall of 2022, is a major leap forward for hydrogen. It believes the technology will enable heavy industries like steel, chemicals, cement, and glass manufacturing to decarbonize. Notably, Bloom Energy can pair its Bloom Electrolyzer with solar energy and wind energy to generate green hydrogen, which it can store and eventually turn back into electricity for future usage. 

Ballard Power Systems

Ballard Power Systems developed a zero-emission proton exchange membrane (PEM) fuel cell that runs on hydrogen. It enables the electrification of buses, commercial trucks, trains, marine vessels, passenger cars, and forklifts.

The company is also working on new technologies that use hydrogen energy. In early 2022, it partnered with Swiss industrial giant ABB (NYSE:ABB) to develop fuel cells to power ships. It also has partnered with Indian company Adani Group to evaluate investing in the commercialization of hydrogen fuel cells in India. In addition, it announced a successful test with Chart Industries (NYSE:GTLS) to power fuel cells with liquid hydrogen. The investments position Ballard Power Systems to emerge as a leader in the budding hydrogen industry. 

FuelCell Energy

FuelCell Energy is a leader in producing hydrogen through its proprietary fuel cell technology. Its SureSource products enable customers to generate ultra-clean power on-site. It can help large-scale facilities like wastewater treatment plants, manufacturing facilities, hospitals, and universities produce clean and affordable electricity for their operations.

FuelCell Energy wants to become a global leader in decarbonizing power. It's working on producing low-to-zero-carbon power, capturing carbon and other greenhouse gasses while producing power, and supplying green and blue hydrogen power. It also wants to store energy from intermittent renewable energy by converting it to hydrogen, which it can convert back to electricity when needed. It's investing in expanding its power generation portfolio and manufacturing capabilities so that it can compete and meet the energy market's needs in the coming years.

Hydrogen is one of the most promising alternative fuels

Hydrogen energy has enormous potential. The emissions-free fuel could help decarbonize heavy industry, replace natural gas, and store renewable energy, paving the way for a truly net-zero world. As such, it represents a multitrillion-dollar market opportunity. 

However, hydrogen is still emerging as a commercially viable fuel source. The industry needs to scale and reduce costs to become competitive with fossil fuels and other emerging technologies like battery storage. Because of that, investors might want to watch the sector for a while as they seek to gauge which companies have the best chances of emerging as long-term winners.