01 Sep 2021
Neil Weaver

Hydrogen: blue vs. green - what’s the difference?

The UK's hydrogen strategy involves investment in both blue and green hydrogen production. But what's the difference? In this video explainer, Neil guides you through the differences between the two.

Hydrogen: blue vs. green - what’s the difference?

The current situation

Currently, almost all of the hydrogen produced in the UK is what we call ‘grey hydrogen’. Grey hydrogen is extracted from fossil gas, with the resulting CO2 emissions being released into the atmosphere. As such, a cleaner solution to hydrogen production is required.

The UK government’s hydrogen strategy forecasts that, by 2050, between 20 and 35% of the UK’s energy consumption will be met by low-carbon hydrogen. In order to achieve this, the government intends to take a twin-track strategy, investing in both blue and green hydrogen production. But what’s the difference, and why is this topic so controversial?

Blue vs. green

Blue hydrogen, like grey hydrogen, is extracted from fossil gas. The difference is this: when CO2 is produced, it is captured and stored underground. However, some CO2 does escape into the atmosphere during this process, and the success of blue hydrogen as a low-carbon solution ultimately depends on how much CO2 is actually captured.

Green hydrogen, on the other hand, is a zero-carbon alternative. Powered by renewable energy, green hydrogen is extracted from water using electrolysis, with oxygen being released into the atmosphere. The problem with green hydrogen lies in its cost - at the moment, it is thought to be around two to three times more expensive to produce green hydrogen than it is to produce blue hydrogen.

The future

It is impossible to know, at this early stage, how successful the government’s planned hydrogen production rollout will be. When we look at European hydrogen strategies, they favour the development of green hydrogen over blue, whereas the UK government’s plan is to invest in both simultaneously.

Many hope that blue hydrogen production will be a temporary measure, a bridge to widespread green hydrogen production. However, the UK’s hydrogen strategy appears to suggest that it is here for the long-haul in our journey towards net-zero. As such, you can expect to hear plenty about the pros and cons of blue and green hydrogen production in the coming years.