With climate change and the environment becoming a big concern, many people are looking for green resources to replace pollution-heavy processes. One of these resources is “green hydrogen.”
Hydrogen is an abundant chemical element made of one electron and one proton, and in standard conditions it exists in molecular form as H2 gas. Hydrogen is a colorless, odorless and highly combustible nonmetal that is often stored in high-pressure tanks in its gas or liquid form.
Green hydrogen is formed through electrolysis, which uses electricity from renewable sources such as wind or solar power to split water into hydrogen and oxygen. Since the source is from renewable energy, the fuel is truly emission-free and clean, making it “green.”
Unlike the traditional method of natural gas reforming or gasification, electrolysis does not require coal, natural gas or other nonrenewable resources that harm the environment.
The History of Hydrogen
In 1671, British scientist Robert Boyle first discovered hydrogen when he placed a pure metal in acid, leading to a single-displacement reaction. The reaction combined hydrogen and oxygen to generate heat energy, while the leftover atoms in the process formed hydrogen gas.
In the beginning, hydrogen gas was used to lift things like balloons for transportation and large airships, as it is lighter than air.
However, it is also highly combustible, which led to tragedies such as the Hindenburg disaster, where an airship caught on fire and exploded.
For over 200 years, people have been using hydrogen in oil refining, the production of ammonia, methanol, and steel, as well as to power NASA’s Space Shuttles. In fact, it powered the first internal combustion engines.
Lately, there has been a keen interest in creating hydrogen fuel cell-powered cars as an eco-friendly option for battery-powered vehicles.
Hydrogen has also become an important factor in the modern refining industry since it is light, storable, and energy dense. The fuel also does not produce any direct carbon emissions or greenhouse gases.
The demand for hydrogen has tripled since 1975 and continues to rise today, starting more discussions about green hydrogen. Many government bodies have also invested in green hydrogen energy research and development.
Where We Stand Now
Green hydrogen aims to electrify some of the biggest sectors that contribute to climate change, such as aviation, marine shipping and heavy industry.
It can help lessen carbon emissions and other environmental impacts to avoid increasing global warming to the 1.5 °C threshold. If global warming surpasses the 1.5 °C threshold above preindustrial temperatures, there is an increased risk to health, livelihood, food security, water supply, human security and economic growth.
However, green hydrogen only accounts for less than one percent of total annual hydrogen production.
To help increase the use of green hydrogen, groups are currently researching green hydrogen fuel cell trucks, hydrogen-powered cars and hydrogen generators.
There is also research into how green hydrogen can be combined with existing natural gas networks and boilers to help reduce emissions, especially in multi-family and commercial buildings.
Many countries also have rules and regulations in place around green hydrogen.
Germany has recently invested a majority of its green stimulus funds into hydrogen along with Japan and Korea, which are providing hydrogen subsidies.
The European Union’s recently proposed hydrogen strategy is projected to kick-start a global hydrogen economy.
In the United States, the House Climate Action Crisis Plan proposed by Democrats in the U.S. Congress includes multiple policies to expand the hydrogen industry and increase the number of proposed green hydrogen projects.
Engineering Challenges
Since green hydrogen is produced from solar, wind or nuclear power, it is more efficient if the electricity stays in the form of electricity for as long as possible. The energy can be used in mechanical work by a motor with at least 90 percent efficiency. It can also produce heat with close to 100 percent efficiency or 200 to 400 percent efficiency with a heat pump. Thus, it is not beneficial to produce hydrogen for electric power as it requires a lot of energy.
For example, battery-powered cars are up to four or five times more efficient than a hydrogen-fueled vehicle, even though hydrogen takes a lot more energy to produce.
The process of electrolysis, in which an electric current is used to split water into hydrogen and oxygen, is not efficient. Even though there has been advancement in various electrolysis technologies, leading to a 90 percent increase in efficiency to produce hydrogen, the process is still less than half as efficient as a current battery vehicle.
To compete with battery-powered cars, manufacturers must also produce large quantities of green hydrogen for electric vehicles (EVs).
Hydrogen also has a low density, which means it is harder to store and more expensive to transport via road or ship compared to fossil fuels.
Economic Challenges
Multiple factors affect the economics of green hydrogen, namely, power prices, plant utilization rates, load factors and electricity prices. Hydrogen produced using the steam methane reforming process costs between $1 to $2/kg without carbon capture and storage, or 50 cents more when paired with carbon capture and storage, while green hydrogen costs around $4 to $5/kg.
The overall capital cost of the equipment needed to create green hydrogen is between $800 and $1,400/kW.
The price of the power purchase agreement for renewables is nearer to $50/MWh globally.
There also needs to be three to four times more storage infrastructure for hydrogen to replace natural gas in the global economy, which would cost $637 billion by 2050 to provide the same level of energy security.
For green hydrogen to reach $1/kg, there needs to be an increase in demand along with a decrease in transportation and storage costs.
There must also be new and cheaper materials that reduce the overall capital cost of polymer electrolyte membrane equipment.
Governments and large enterprises can help reduce the cost of producing green hydrogen by implementing national and corporate policies to decarbonize and help the environment. In fact, there will be around $150 billion worth of subsidies by 2030 for the production of green hydrogen. This will lead to further investments, technological improvements, further research and modifications in the power market.
Why It’s Better
There are many benefits of green hydrogen, from its environment-friendly factors to its economic opportunities.
Green hydrogen will make countries and companies more environmentally sustainable, as it does not emit polluting gases during combustion or production. It burns clean, leaving only water vapor behind.
It could be blended with natural gas to reduce carbon emissions in residential and commercial heating. Countries with low renewable energy potential could import green hydrogen to produce electricity and reduce their carbon footprint.
Green hydrogen can also create new revenue opportunities for solar and wind asset owners, since surplus electricity can be used to produce green hydrogen. It can be mixed with natural gas and can use the same gas pipes and infrastructure at smaller ratios.
Green hydrogen can create a $300 billion annual market by 2050 if manufacturers export around 200 million tons of fuel. This will also create up to 400,000 operations and maintenance jobs, with 300,000 jobs in renewable power generation and 100,000 jobs at electrolysis facilities.
The makeup of green hydrogen also enables it to be stored for long periods in large tanks for industrial use, gas networks or fuel cells, even though it would be expensive to create the storage infrastructure. Green hydrogen can also be turned into electricity or synthetic gas for domestic, commercial, industrial or mobility purposes.
What Happens Now
Now that the government has started implementing important policies and funding green hydrogen projects, there has been an increase in its use.
There are currently talks about passing a national, economy-wide net-zero greenhouse gas emissions target by 2050 as well as transitioning to zero-emission trucks and buses.
Many states are also establishing a mandate for gas utilities to blend green hydrogen with gas, which can help lower carbon emissions. There will also be an increase in “green” steel infrastructure projects and “green” fertilizer agricultural projects.
With the help of government incentives and research, it is estimated that there will be a 1,272 percent increase in green hydrogen production by 2025. During the same period, an additional 3,205 MW of electrolyzers will be dedicated to green hydrogen production, as the demand for the fuel reaches about 530 million tons. The aim is to replace 10.4 billion barrels of oil, equivalent to 37 percent of current global oil production by 2050.