From grey, to blue, to green hydrogen

Different this time?

As the world shifts away from burning fossil fuels to a low-carbon future, hydrogen is key to decarbonising heavy industry, long-haul transport and heating systems.

It is also a solution to balancing supply and demand from intermittent sources of electricity generation.

Steelmaking, cement manufacture and other industrial processes need high temperatures and hydrogen, in some cases, is better able than electricity to deliver it. The Committee on Climate Change, the independent body advising the UK government, believes that hydrogen will be the cheapest or only way to replace fossil fuel energy in heavy industry over the next 20 years.

On the roads, hydrogen fuel cells will power trucks and buses for long distances and can be refuelled as quickly as diesel engine vehicles. In the not too distant future, hydrogen and captured carbon dioxide will be turned into carbon-neutral liquid fuels for aircraft, while hydrogen fuel cells will be common in planes flying short-haul routes.

In the built environment, a combination of hydrogen, electric heat pumps and district heating networks will provide heating in the future. Countries with extensive gas networks must repurpose and modernise their systems for hydrogen, first blending it with natural gas before switching entirely. In the UK, the National Grid is currently testing the conversion of the gas network to hydrogen, possibly completing the transition by 2035.

Hundreds of terawatts of surplus renewable electricity a year can be stored in the form of hydrogen to manage seasonal fluctuations and provide electricity at peak times when the wind isn’t blowing, or the sun isn’t shining. By utilising the existing gas grid infrastructure as well as salt caverns and depleted gas fields, large-scale, low-cost, long-term hydrogen energy storage is cost effective. Europe is already beginning to exploit its 18Bnm³ of salt caverns to store about 40TWh of hydrogen, while a project is underway in the US state of Utah to build the world’s largest salt cavern hydrogen storage facility.

Scaling up, cutting costs

There are three main types of hydrogen production pathways and these are generally colour coded – grey, blue or green.

Hydrogen is already used in huge quantities to refine oil and to produce methanol, ammonia and other chemicals, and is produced mostly from natural gas. But the carbon emissions from the process – called steam methane reforming (SMR) – contributes to global warming. Hydrogen from natural gas is known as grey hydrogen.

Capturing the carbon dioxide from the SMR process and utilising it to produce sustainable fuels or chemicals, or storing it in depleted gas fields offshore is called blue hydrogen.

Green hydrogen is produced using renewable sources or nuclear power in an electrolysis plant to split clean water into hydrogen and oxygen.

Up to now, cost has been the main obstacle to the widespread use of either blue or green hydrogen. But, given the scale of current investment in hydrogen, that is about to change. The Hydrogen Council is forecasting a 60% reduction in the cost of producing hydrogen by 2030.
Scaling up production of both blue and green hydrogen is key to reducing costs and a creating virtuous circle of growing demand fuelling lower component and distribution costs. And, as more production facilities open, shorter supply lines will cut costs further, while the huge global expansion of renewable power over the next decade will see the cost of electricity decline and make green hydrogen cost competitive.

Moving forward

Solar and wind required government support in the form of incentives and subsidies to reach scale to trigger plummeting costs.

The rollout of hydrogen generally, and carbon capture technology to enable the production of blue hydrogen, will also need government backing.

The potential benefits of doing so are huge, and not just in reducing carbon emissions. Decarbonising heavy industry will safeguard high-skill, high-value jobs in industrial heartlands, while thousands of new jobs will be created in the fuel cell, carbon capture and hydrogen infrastructure and equipment supply chains.

A cleaner energy system in which hydrogen is a core component will also improve health outcomes in many communities, particularly in congested urban areas and industrial regions, where poor air quality is a major cause of respiratory ill health.

The shift to hydrogen – both blue and green – must come quickly. If not, countries’ 2040-2050 net-zero ambitions will amount to nothing but ‘hot air’.