RAS question
Blue hydrogen differs from grey hydrogen in that:
Correct answer: (A) It captures and stores the CO2 emissions from natural gas reforming.
Blue hydrogen differs from grey hydrogen because it is produced from fossil sources such as natural gas with carbon capture storage or carbon capture use technology to reduce carbon emissions.
Explanation
Grey hydrogen is hydrogen made through carbon-intensive fossil-fuel routes, including steam methane reforming of natural gas or methane. Blue hydrogen keeps that fossil-source base, but adds the key control step: the National Green Hydrogen Mission says it is produced through natural gas or coal gasification combined with carbon capture storage or carbon capture use technologies to reduce carbon emissions. The distinction is not the use of renewable electricity or water electrolysis; it is the addition of carbon capture, utilisation and storage to a natural-gas route that otherwise resembles grey hydrogen.
Why the other options are wrong
- (B) Solar-powered hydrogen production points to green hydrogen, not blue hydrogen, because the defining feature here is renewable electricity rather than carbon capture on a natural-gas route.
- (C) Wind energy is also a renewable-electricity route for green hydrogen, while blue hydrogen is identified by carbon capture attached to fossil-source production.
- (D) Hydrogen produced from water through electrolysis is classified as green or pink depending on the power source, whereas blue hydrogen remains tied to natural gas or similar fossil-source production with carbon capture.
Concept
Hydrogen colour categories are part of environment and energy-transition policy. RAS coverage includes them because policy debates on decarbonisation often turn on whether emissions are avoided by renewable electrolysis or reduced through carbon capture.