Madrid - On a grim industrial park on the edges of Barcelona lies a shiny new depot that could hold the key to a future free of greenhouse gas emissions.
In this inauspicious location is a gas station for buses that fill up at night with green hydrogen, a 'clean' energy source for transport as well as other niche industries like fertilizers, steel or even whisky makers.
So far eight buses use the depot in a project run by the Spanish energy giant Iberdrola and the city bus company, but the project is set to expand to 64 vehicles. Each can travel up to 200km on a full tank of gas.
As Europe seeks to ditch fossil fuels, projects like this are springing up across the continent and beyond.
Spain is racing ahead in developing green hydrogen, helped by a growing wind and solar power sector as well as abundant space to house enormous plants needed to make green hydrogen.
Spain accounted for 20% of the world's green hydrogen projects in the first quarter of 2022, making it second only to the United States, according to Wood Mackenzie consulting firm.
The war in Ukraine has forced Europe to look for other sources of energy than Russian gas with the European Union doubling its production goal for 2030.
"Spain has become a very attractive country for green hydrogen. A shift is happening to mass-scale competitive hydrogen," EU chief Ursula von der Leyen said in May, the Agence France Press news agency reported.
The sector is in its infancy, but experts believe it could help solve the world's race to reach a net-zero future.
Green hydrogen is produced by passing an electric current through water to split it between hydrogen and oxygen, a process called electrolysis. It is considered green because the electricity comes from renewable sources of energy which do not create any harmful emissions.
"Spain has a series of advantages in comparison with other countries. It has a renewable energy structure. We have more sun and wind than other countries in northern Europe as well as more space [than other countries]," Rafael Cossent, professor of energy economics in Comillas Pontifical University in Madrid, told VOA in an interview.
In contrast, Germany, which has long been a leader in solar energy in Europe, is 1.4 times smaller than Spain and has a higher population - at 84 million - than Spain whose population is 47m.
Cossent said Spain has another advantage over other European countries as it has a large natural gas network and Liquefied Natural Gas (LNG) terminals that could be used to transport hydrogen.
A general view shows Enagas liquefied natural gas (LNG) terminal at Zona Franca in Barcelona, Spain, March 29, 2022.
At present, a drawback has been the high cost of producing green hydrogen which means natural gas is cheaper. But this could be about to change quickly, analysts say
'Blue' hydrogen, which uses fossil fuels, is cheaper now than its green version but the situation should reverse by 2030, according to an analysis by Bloomberg NEF, a research organization.
The Spanish government, which has made renewable energies its priority, last year launched a $1.56 billion project to promote hydrogen over the next three years using EU pandemic recovery cash. With private investments, it will boost the fund to nearly $9bn.
Iberdrola, like its competitors Enagas, has launched a series of projects to get in on the 'green hydrogen' boom.
Beacon of change
The Barcelona bus depot, which is roughly the size of a soccer field, is part of a ten-year project which is the first of its kind in Spain.
A green hydrogen bus depot on an industrial estate of Barcelona, which is the first of its kind in Spain. (Graham Keeley/VOA)
Similar public transport systems started in London and Aberdeen. Other projects in the United States include a planned ammonia plant.
Whisky producers in Scotland are keen to get in on this clean source of energy.
The Cromarty Green Hydrogen Project in Scotland will have the potential to produce 20 tons of the gas per day from 2024.
Major whisky distillers Diageo, Glenmorangie and Whyte & Mackay want to meet carbon reduction targets so the use of green hydrogen will help make Scotland's national drink greener.
"Green hydrogen is one of the solutions (to getting rid of emissions). It is not the solution. It is never going to compete with direct electrification," Millan Garcia-Nola, world director of green hydrogen for Iberdrola, told VOA.
"You cannot find hydrogen in the ground. It is not like natural gas. This process of converting electricity to hydrogen is expensive."
Garcia-Nola said what mattered for the future of green hydrogen was the commitment of industry to use it to drive down prices.
"If you use this green hydrogen in (the parts to make) a premium car like a Mercedes Benz maybe tomorrow it will be used in a cheaper car like a Renault," he said.
He warned the race to develop green hydrogen must speed up to meet the EU target of 2030.
"We are on the same page as renewables were 20 years ago, but we don't have 20 years to make this happen. We cannot wait over 20 years to make this happen. 2030 is only eight years away," Garcia-Tola said.
Some information for this report was provided by Agence France-Presse.