Hydrogen is the clean energy we’ve always dreamed of: when consumed in a fuel cell, it only produces water, electricity, and heat.
But a new study looked at how hydrogen is produced today and got a completely different conclusion. Most of the hydrogen used today is extracted from natural gas in a process that requires a lot of energy and emits large amounts of carbon dioxide. Natural gas production also releases methane, a particularly powerful greenhouse gas.
And although the natural gas industry has proposed capturing that carbon dioxide, creating what it promotes as “blue” hydrogen — without emissions, in fact, that fuel emits even more greenhouse gases along the entire supply chain than simply burning natural gas, according to the new research.
“To call it a zero-emission fuel is totally wrong,” said the study’s lead author. “What we found is that it’s not even a low-emission fuel.”
The key point is that there are different types of hydrogen. Green hydrogen is produced by renewable energies such as electricity obtained from photovoltaics; the blue one, which is produced starting from methane and trapping the waste CO2 in the subsoil; the gray one, obtained from oil, natural gas, or coal without the waste CO2 being trapped and finally the purple one, obtained using nuclear energy. Of all these types it is evident that only some are truly sustainable in terms of climate-altering gas emissions and environmental impact. Others are only passed off as green solutions.
Blue hydrogen, as Nicola Armaroli, research director of the ISOF Institute of the CNR of Bologna, argues in this video interview, is the perspective that large European and world energy companies (which have large quantities of natural gas and methane that they do not want to give up) propose, arguing that trapping the waste CO2 is feasible.
In reality, all large CO2 storage projects in the world have been soaringly unsuccessful. So the blue hydrogen prospect is not realistic at the moment, and maybe it never will be. The only way is green hydrogen from renewable sources. However, according to Armaroli, even this road is not without pitfalls:
“To produce green hydrogen in significant quantities we would have to have a huge surplus of renewable electricity that we don’t have at the moment,” he points out. “If we want to get to hydrogen in heavy transport, for example, we must greatly increase the production of renewable electricity, in particular photovoltaics that lend themselves perfectly, because in the daily peaks I produce hydrogen, then I keep it there in the large production centers and maybe in the evening when the buses come back I fill them. The same applies to heavy industry. In Italy, renewable sources already cover almost 40% of electricity demand, but we should quintuple it to make sure we have an excess of electricity with which to produce the hydrogen we need and that would certainly be a good prospect”.
Here you can read the (sometimes behind a paywall) NYT article
Here the article published on the blog of the University of Padua with the video interview to Armaroli
Photo by Zbynek Burival