But perhaps hydrogen’s greatest potential lies in its ability to store energy for rainy days. Fossil fuels store the energy of prehistoric sunlight, while hydrogen can be used to store solar energy from the past 12 hours. “You need green hydrogen to continue to increase the amount of renewable energy,” Mowill said. Once the grid receives a critical mass of renewable energy input from sources such as wind and solar, steps must be taken to stabilize and smooth out supply and demand peaks and troughs. “You can’t solve this problem with batteries; it’s impractical to scale,” Mowill said. “Hydrogen is a great way to balance that.”
Unlike batteries, hydrogen can be transported efficiently. It can be compressed into liquid hydrogen, which does require some energy, or converted into ammonia, which has been shipped around the world and then “cracked” back into hydrogen and nitrogen at its destination.
Countries such as Japan and South Korea, home to energy-intensive industries such as steel and car and shipbuilding, but lacking the renewable resources to sustainably power these industries, are eagerly importing hydrogen from countries with a surplus of renewable energy, such as Australia .
“The idea is basically to produce these hydrogen molecules or direct derivatives of hydrogen in countries with abundant renewable resources,” said Carlos Trench, head of Engie’s Australia and New Zealand hydrogen project. “Then you transport those molecules — whether it’s ammonia or any other derivative — and then you convert that molecule back into green energy at a destination where renewable energy cannot be directly exploited.”
As part of its carbon neutrality strategy, Japan has announced its intention to become a world leader in the hydrogen economy. South Korea hopes hydrogen will supply about a third of its energy by 2050.
But Percy stresses that, despite its excitement, green hydrogen is currently a small player in the global decarbonization game. “It’s really very small right now,” he said. But it is on the rise.
Chinese state-owned energy company Sinopec has begun construction of the world’s largest green hydrogen facility. After completion, it can produce 30,000 tons of green hydrogen per year. (Currently, less than 1 million tons of low-carbon hydrogen are produced annually, much of it using fossil fuels and then capturing the resulting carbon.)
Spain is also making strides in terms of production, and in 2020 announced plans to become a major hydrogen producer. It set a target of producing 4 gigawatts of green hydrogen per year by 2030, but it has already surpassed that target by four times and plans to build more production facilities.
Cost remains an issue. About 60 percent of the cost of green hydrogen is the cost of the renewable energy used to produce it, Percy said, so as renewable energy gets cheaper, so does hydrogen. The cost of electrolyser technology is another major factor in the relatively high price of hydrogen, but Mowill said electrolysers are becoming more efficient. There are also the logistics of storage, compression and transport, further driving up the price of green hydrogen molecules.
But those costs will inevitably come down as the hydrogen star rises, Percy said. “If you look at what’s happened to solar, both solar and battery systems have declined by about 80% in about 10 years,” he said. He predicts the same will happen to hydrogen once it finds a firmer technological footing. “The trials that are going on now are very important for industry to learn from,” he said. “While today is a pilot scale, five years from now they may be ready for a larger scale.”