When it comes to energy, hydrogen is attracting plenty of interest relating to its development and how it could be used to decarbonise various sectors of energy systems, including transport, commercial, industrial and residential.
Most of the globe’s hydrogen is produced through a process of steam methane reforming fossil fuels – ie, natural gas, also referred to as “grey” hydrogen, which is predominately used for oil refining and ammonia production. But its applications can be expanded to wider industrial uses.
Grey hydrogen is highly carbon-intensive, responsible for millions of tonnes of CO2 emissions every year. Applying carbon, capture and storage (CCS) to the grey hydrogen process can reduce the emissions by 50–90 percent, an approach referred to as “blue” hydrogen.
Many companies are leading the way through technology and innovation in carbon capture for blue hydrogen through the use of carbon capture and storage.
Blue hydrogen is well placed to kickstart the rapid increase in the use of clean hydrogen for climate mitigation with both coal and gas industries operating in mature and well-established supply chains.
The most widely discussed and proposed alternative to grey hydrogen is to produce hydrogen through electrolysis, a process that involves passing an electrical current through an electrolyser to split a feedstock – ie water – and releasing only hydrogen and oxygen in the process, which is known as “green” hydrogen.
The method to produce green hydrogen requires significant quantities of renewable electricity relative to the volume of hydrogen produced, as well as the use of expensive materials to construct the electrolyser and associated infrastructure.
As we embark on the energy transition, we must ensure a balance from oil and gas to hydrogen and renewables. Our economy requires a significant amount of energy output, which is supported by an incredible energy density of oil and gas. It goes unappreciated how many wind turbines or solar panels need to be constructed to replace that.
Hydrogen as a commodity can also be used in chemical processes and as a low-emission source of heat and electricity, and in transport. It can also be used as a cost-competitive feedstock for ammonia, chemicals, petrochemicals, synthetic fuels, glass manufacture and metal processing, same as that of natural gas.
Hydrogen can most certainly play an important role in the energy transition through smart use of carbon capture and storage in combination with the development of hydrogen infrastructure.
For as long as electricity cannot be 100 percent sustainably generated, climate-neutral hydrogen will mainly be blue hydrogen and while the demand for solar and wind to develop into the mix increases, so will the integration to green hydrogen.
For the construction of hydrogen infrastructure (new pipelines, conversion of existing gas pipelines, storage, filling stations), it does not matter which hydrogen is used, meaning blue could certainly complement the pathway to green.