"Green hydrogen" produced using renewable energy will soon plunge in cost, becoming cheaper than natural gas in many areas, according to a study released Wednesday by the research group BloombergNEF.

Hydrogen is considered a leader in the race to develop sustainable energy sources and slash carbon emissions. But it is expensive to produce and the electricity needed generates a lot of carbon dioxide emissions or other pollutants.

Green hydrogen is produced via electrolysis -- an electrical current passing through water -- with wind, solar or hydroelectric power providing the electricity. BloombergNEF (BNEF) researchers forecast its cost will fall steadily in the future, in large part due to lower prices for solar photovoltaic power (PV).

"We now think that PV electricity will be 40 percent cheaper in 2050 than what we had thought just two years ago," BNEF specialists said in a report. "The costs of producing 'green' hydrogen from renewable electricity should fall by up to 85 percent from today to 2050," they concluded.

In the majority of 28 markets covered by the study, green hydrogen production could cost less than one US dollar per kilogramme by 2050. In 15 of those markets -- which represented one-third of global gross domestic product in 2019 -- it was forecasted to become cheaper than natural gas.

By just 2030, green hydrogen was projected to cost less than "blue hydrogen," which is produced with electricity generated by fossil fuels using a process that captures greenhouse gas emissions.

It is expected to cost less than even dirtier "grey hydrogen", which lacks that process, by 2050. "Such low renewable hydrogen costs could completely rewrite the energy map," BNEF hydrogen analyst Martin Tengler said.

In the future, "at least 33 percent of the world economy could be powered by clean energy for not a cent more than it pays for fossil fuels", he added. For that to happen however, "the technology will require continued government support," Tengler acknowledged.

One reason for strong interest in hydrogen technology is that when it is used to fuel motors, the only emission is water vapour. It has therefore raised hopes that it could help clean up heavy industry and transportation. However at present the process requires large amounts of energy generated using coal or natural gas.