As the world grapples with ways to create a net-zero carbon economy, hydrogen is being touted as the new industrial fuel of choice. Can hydrogen live up to all the hype and become manufacturing’s preferred energy source? Possibly.
The industrial revolution was launched by unlocking the energy stored in coal. More than two centuries later, coal and other fossil fuels are still being used in steel and industrial processing.
One unanticipated consequence of the industrial revolution has been climate change. The carbon dioxide (CO2) emitted from burning fossil fuels is now at higher levels in the atmosphere than at any time in three million years – before humans even existed.
Can the industrial revolution still produce goods and products, but without emitting CO2? Hydrogen is being seen as a way out of this conundrum.
How can hydrogen be used by big emitters
The steel industry for example, uses coking coal in high-temperature blast furnaces. The high carbon-emitting coke provides both heat and the carbon necessary for making steel. Electric furnaces struggle to provide these needs. Injecting hydrogen into the furnaces however, can reduce carbon emissions while still meeting heat and carbon content requirements.
The cement industry also uses high-temperature furnaces – in this case, to produce clinker. Like the steel industry, there are few suitable electric replacements. However, cement furnaces can reach the needed temperatures by burning hydrogen instead of coal. Water is the only by-product.
The aviation industry uses fossil fuels for propeller engines or for propulsion. Switching to electric motors is not economical or practical. The batteries required for sufficient power are far too heavy. However, liquid hydrogen has sufficient energy density to either power fuel cells driving electric propellers or for combustion in jet turbines.
Can carbon emissions be eliminated in these, and other hard-to-abate industrial sectors? Hydrogen is tantalizingly attractive as a fuel choice.
Hydrogen is not entirely free of carbon emissions
It is true, that hydrogen does not produce emissions when burned. However, hydrogen is not entirely free of carbon emissions. CO2 can be emitted in the hydrogen production process.
“Gray hydrogen" comes from splitting natural gas (CH4) into CO2 and H2. This is currently the most common form of hydrogen production. Producing gray hydrogen emits carbon. In addition, fugitive upstream methane emissions are also commonly associated with natural gas extraction.
“Green hydrogen" is produced when renewable, non-carbon emitting electricity is used to split water (H2O) into oxygen (O2) and hydrogen (H2). The green hydrogen produced is widely considered to be free of carbon emissions.
“Blue hydrogen" is produced as gray hydrogen, but the CO2 by-product is captured and pumped underground for permanent storage. As a result, blue hydrogen is sometimes considered zero-carbon emitting. However, upstream fugitive methane emissions need to be eliminated from natural gas extraction for that to truly to be the case.
Can the industrial revolution continue, but without the carbon emissions? Hopes are riding on hydrogen as the solution. A green hydrogen revolution just may win the day.