By Gulseli Kenarli
ISTANBUL (AA) — Hydrogen sulfide, a toxic chemical that exists in significant quantities in the depths of the Black Sea, has long been considered a risk to the local marine ecosystem. But some experts believe it could be used as a source of clean energy equivalent to over 850 million tons of oil, with added ecological benefits.
With the combined effects of climate change and increased pollution, the Black Sea ecosystem faces the danger of hydrogen sulfide rising from the oxygen-poor seabed to the much more biodiverse areas closer to the surface, where it can harm marine life.
Some scientists, like Ibrahim Dincer, think that through environmentally friendly methods, these vast reserves of hydrogen sulfide can be used to obtain energy-rich hydrogen, a clean fuel expected to play key role in the transition away from fossil fuels.
Highly flammable, hydrogen is the lightest and most abundant substance in the universe, according to Dincer, a faculty member of Ontario Technical University and Yildiz Technical University in Istanbul, who is also an expert in clean energy systems.
Hydrogen is found in many substances on the planet, including water. Through various methods, water molecules can be separated into their constituent hydrogen and oxygen. If the energy needed for this is produced using renewable and clean sources, like wind or solar, the resulting fuel is called green hydrogen.
Dincer explained that hydrogen sulfide, meanwhile, contains sulfur as well as hydrogen, and procedures such as electrolysis, thermal, catalytic, and photocatalytic separation can be used to produce the fuel. He added that for an energy type to be considered green, it needed to be produced without using fossil fuels and without emitting greenhouse gasses like carbon.
"These methods make it possible to separate hydrogen sulfide to obtain both hydrogen and sulfur. These emission-free projects are crucial for the health of the Black Sea. You will rehabilitate the Black Sea, improve the ecosystem, increase biodiversity; this is an unparalleled opportunity and chance," he said.
"We did the math, and if we separate it using electrolysis methods, there's the potential to obtain 270 million tons of green hydrogen and 4.3 billion tons of sulfur. The current annual consumption of hydrogen in the world is 118 million tons, and sulfur consumption is 85-90 million tons," he said.
The Black Sea is in a position to meet almost 50 years' worth of sulfur demand in the world, said Dincer, who is also the president of the Hydrogen Technologies Association, Coordinator of the Energy Working Group at the Turkish Academy of Sciences (TUBA), and a member of the Executive Board of the Turkish Energy, Nuclear, and Mining Research Institute (TENMAK).
Besides these end products, he said, this process would also involve added value production and economic income, while also helping rehabilitate the Black Sea.
"This issue is deeply important because many people still aren't aware of it, and they have not grasped this transformation," he said, underlining the need to adapt technologies to the hydrogen era.
In order to protect the Black Sea from pollution, the signatory countries of the Bucharest Convention signed in 1992, including Türkiye, declared Oct. 31 as "International Black Sea Day" in 1996.
- Less for more
Adnan Sozen, a faculty member at Gazi University in Türkiye's capital Ankara, told Anadolu that the Black Sea contained a hydrogen sulfide reserve of about 4.5 billion tons and obtaining green hydrogen from this reserve would create significant value.
Sozen, a member of Gazi University's Faculty Energy Systems Engineering, pointed out that there producing hydrogen from hydrogen sulfide requires less energy compared to water.
"To produce 1 mole of hydrogen from water, we need 66 watt hours of energy, whereas we need 20 watt hours to produce hydrogen from hydrogen sulfide," he explained.
"When processing 100 kilograms of hydrogen sulfide per hour, you can produce 5.8 kilograms of hydrogen, and the required energy amount is 75 kilowatt hours," he added.
"If you can produce hydrogen from the Black Sea's potential, this energy is equivalent to 851 million tons of oil, 766 million tons of natural gas. There's a significant energy source."
Also emphasizing that producing green hydrogen from hydrogen sulfide in the Black Sea would be highly beneficial for the marine ecosystem, he said: "There are not many living creatures in areas with hydrogen sulfide.
"The only issue here is to safely separate the sulfur released after obtaining hydrogen from hydrogen sulfide. It needs to be stored and can be widely used in industry."
- Delaying approach to surface
Ali Alkan, the deputy director of the Institute of Marine Sciences and Technology at the Karadeniz Technical University in Türkiye's Black Sea province of Trabzon, said the sea's hydrogen sulfide resided below an average of 150 meters (about 490 feet) from the surface varying by region, with its concentration depending on depth.
Alkan mentioned that theoretically, removing a large amount of hydrogen sulfide from the sea would delay its approach to the surface.
He said: "The problem under the first 150 meters of the Black Sea is, along with the presence of hydrogen sulfide, the low oxygen.
"We cannot use the sea from the point where the layer without oxygen begins," he said, adding that removing part of the sea's hydrogen sulfide would be an endeavor of massive scale.
"At this stage, it seems a bit utopian to me," he added.