Hydrogen is the most plentiful and simplest element in the universe. When hydrogen burns, it produces energy in the form of heat as the only byproduct. That means hydrogen energy produces no greenhouse-gas-emitting carbon dioxide, making it one of several possible energy sources that might help decrease carbon emissions and moderate global warming.
However, producing hydrogen and converting it into a usable form necessitates the expenditure of energy, which is not always renewable. This method is both inefficient and costly when compared to other kinds of energy, whether renewable or not. Many detractors argue that the hydrogen business is a means for oil and gas companies to delay the adoption of pure renewable energy sources such as solar and wind, providing them with a “green” cover while still sustaining demand for their goods. Regardless of the dispute, businesses and the US government are both pushing for the ongoing growth of the hydrogen sector.
“In my travels around the globe, I can’t identify a country that hasn’t shown excitement in hydrogen,” said John Kerry, special presidential envoy for climate, last August at the Department of Energy’s Hydrogen Shot Summit. “From Saudi Arabia to India to Germany to Japan, we’re establishing hydrogen collaborations all across the world to promote this crucial technology that every government recognizes has the potential to play a major role in the clean energy transition.” According to Kerry, hydrogen might become a multitrillion-dollar global market, but China wants to control it.
What is the difference between green hydrogen, blue hydrogen, and so on?
It requires energy to produce hydrogen because hydrogen atoms do not exist on their own – they are usually always attached to another atom, frequently another element. (Hydrogen is particularly plentiful on Earth in the form of water, or H2O.) Breaking those molecular bonds is required to produce pure hydrogen. In the energy industry, hydrogen is referred to by a variety of colors as a shorthand for how it was formed.
One method of producing hydrogen is by electrolysis, which involves passing electricity through a substance to create a chemical change — in this example, splitting H2O into hydrogen and oxygen. When the energy used to power electrolysis originates from renewable sources such as wind, water, or sun, it is referred to as green hydrogen.
Blue hydrogen is hydrogen created from natural gas using a steam methane reforming method in which natural gas is combined with extremely hot steam and a catalyst. A chemical reaction takes place, resulting in hydrogen and carbon monoxide. When water is added to the mixture, the carbon monoxide is converted into carbon dioxide and additional hydrogen. If the carbon dioxide emissions are subsequently caught and stored underground, the process is considered carbon-neutral, and the hydrogen produced is referred to as “blue hydrogen.”
However, there is some debate over blue hydrogen since natural gas production necessarily results in methane emissions via fugitive leaks, which are methane escapes from the drilling, extraction, and transportation processes.
Methane does not persist as long in the atmosphere as carbon dioxide, but it is a considerably more potent greenhouse gas. According to the International Energy Agency, one ton of methane is equivalent to 28 to 36 tons of carbon dioxide over a 100-year period.
Grey hydrogen is created by reforming natural gas in the same way as blue hydrogen is, but without any effort to absorb carbon dioxide byproducts.
Pink hydrogen is hydrogen produced using nuclear-powered electrolysis, which emits no carbon dioxide. (However, nuclear energy generates radioactive waste that must be carefully kept for thousands of years.)
Yellow hydrogen is hydrogen produced by electricity grid electrolysis. Carbon emissions vary substantially depending on the sources of power used to power the grid.
Turquoise hydrogen is hydrogen created by methane pyrolysis, which is the process of breaking methane with heat into hydrogen and solid carbon in reactors or blast furnaces. Turquoise hydrogen is still in its early phases of commercialization, and its climate-conscious value is dependent on using clean energy to power the pyrolysis and storing the physical carbon.
According to Daryl Wilson, executive director of the Hydrogen Council, a group of industry CEOs, the color scheme is a bit basic and has to be upgraded and made more detailed.
“The color scheme isn’t useful in the sense that it doesn’t get to the main point, which is what the environmental qualities of the hydrogen being created are,” said Wilson. “The fundamental issue is that a mechanism for tracking and disclosing the exact CO2 intensity of whatever hydrogen you’re dealing with is required.”
Proponents argue that hydrogen is flexible yet costly
Hydrogen is already a critical component of chemical industrial processes as well as the steel sector. Making clean hydrogen for use in those industrial processes, according to Jake Stones of market research firm Independent Commodity Intelligence Services, is crucial to decreasing carbon emissions (ICIS).
According to Sunita Satyapal, who oversees hydrogen fuel cell technology for the Department of Energy, the main benefit of hydrogen as an energy source is its adaptability. “It’s sometimes referred to as the Swiss Army knife of energy,” she explains. According to Stones, clean hydrogen would be effective in decarbonizing industrial heavy transportation such as truckers, large industrial vessels, and planes.
It’s less appealing for smaller consumer vehicles, while battery-powered vehicles are becoming increasingly popular. However, larger cars need larger batteries, which increases their weight and, as a result, their energy consumption. Hydrogen might offer a solution to this dilemma.
Hydrogen may also be used to store energy from intermittent renewable sources, such as the sun, which isn’t always shining and the wind, which isn’t constantly blowing. Instead, as an alternative to battery storage, utilities can convert surplus energy into hydrogen and then use it for energy later on. “Hydrogen can be kept underground for as long as it needs to be, much like natural gas, and on a seasonal basis,” Stones explained.
The biggest disadvantage of hydrogen is its high cost. According to Satyapal, the cost of producing hydrogen from natural gas is roughly $1.50 per kilogram. The cost of clean hydrogen is roughly $5 per kilogram. The Department of Energy began the Hydrogen Shot initiative in June, with the goal of reducing the cost of clean hydrogen to $1 per kilogram within a decade.
At the Department of Energy’s Hydrogen Shot Summit, billionaire Bill Gates, founder of Breakthrough Energy Ventures, stated that lowering the price of clean hydrogen “would be a significant step toward tackling climate change.” “The objective of reducing premiums by 80% is great and ambitious,” he remarked.
The Department of Energy anticipates three main approaches to reduce the cost of clean hydrogen from roughly $5 per kilogram to $1:
- Improving electrolyzer efficiency, durability, and production volume.
- Satyapal’s goal is to improve pyrolysis, which produces solid carbon rather than carbon dioxide as a byproduct.
- “Advanced routes,” a catch-all term for experimental technology. A photoelectrochemical method (PEC) is one example, in which sunlight and specific semiconductors are utilized to split water into sunlight and hydrogen.
Skeptics argue that it is inefficient and unsustainable.
While green hydrogen might be crucial for decarbonizing heavy industries, powering ships and planes, and perhaps storing energy, it is not efficient for use as a general energy source, according to Cornell University’s Robert W. Howarth, professor of ecology and environmental biology.
Howarth is one of 22 members of the New York Climate Action Council, a committee tasked with devising a strategy for implementing the statute mandating New York’s decarbonization plan. In the summer of 2020, players in the natural gas sector proposed deploying blue hydrogen in the current natural gas pipeline system to heat houses.
However, in August, Howarth and Stanford professor Mark Jacobson produced a research study demonstrating that this was a lousy idea. “The main reason is that blue hydrogen emits a lot of pollution and can only be utilized in small amounts in the present gas system,” Howarth told CNBC. “It is significantly more cost effective to switch to electrically powered heat pumps for heating.” Other opponents argue that the issues with hydrogen are more basic.
According to Paul Martin, a chemical process development specialist and member of the Hydrogen Science Coalition, the process of creating hydrogen, compressing it, and then converting that compressed hydrogen back into electrical or mechanical energy is wasteful.
“It’s worth putting up with a battery’s flaws because for every joule you put in, you receive 90 percent of it back.” “That’s fantastic,” said Martin. Only 37% of the energy used in creating and storing hydrogen is returned. “So, according to you, 63 percent of the energy is gone. And that’s the best-case scenario.”
However, the concept of using hydrogen as a fuel is false, according to Martin, who describes himself as a lifelong environmentalist.
“The people who are actually driving this hydrogen push are the fossil fuel sector, because what are they going to do without it?” Without fossil fuels, the fossil fuel sector is primarily the petroleum chemicals and materials business, which accounts for around 25% of the existing business.”
Nonetheless, Martin believes that researching green hydrogen is critical for all of its other applications, such as industrial operations and the Haber-Bosch process, which transforms hydrogen and nitrogen to ammonia for use in fertilizer. Over the last century, the Haber-Bosch process is credited for dramatically expanding food output and assisting in feeding the world’s rising population.
“I don’t want people to think of me as anti-hydrogen.” “I believe that producing green hydrogen is critical,” Martin remarked. However, it’s equally critical to utilize it for the proper things and not for stupid things.”