In his latest column Mark Venables, editor of Connected Energy Solutions, looks at the part that hydrogen will play on the path to a net-zero future.
It is well recorded that the Paris climate accord committed the world to limit global warming to well below 2°C above pre-industrial levels while striving to limit it to 1.5°C. Despite a great deal of rhetoric, the political will has never been fully supportive of this goal. Still, with evidence mounting, scepticism diminishing and the urgency of action increasing, times are changing.
The COP26 meeting to be held in Glasgow later this year is seen as a watershed, the last chance for a concerted push. That said, the same image was painted at the past three annual COP meetings in Fiji, Katowice, and Madrid, but this time around, there is an acknowledgement that the time for action is running very short. The hope and belief that this year may see some serious commitments are supported by recent proclamations from the United States and China.
Clean electrification must be at the heart of the global decarbonisation strategy, electrifying as much as possible while fully decarbonising the electricity supply. Even if that is achieved, there are sectors where this strategy is not feasible, and that is where there is a crucial role for hydrogen to play. A prime example is steel production, where it can replace the heavily polluting traditional medium of coking coal as the energy source and reduction agent. When it comes to long-distance shipping and significant grid-scale electric storage, it can play a vital role in the form of ammonia.
The problem is that not all hydrogen is equal; it comes in a rainbow of colours, each with its own carbon footprint and associated cost. The traditional form of hydrogen is grey. This has been produced for many years. Natural gas is split into hydrogen and CO2 either by Steam Methane Reforming (SMR) or Auto Thermal Reforming (ATR), with the CO2 produced not being captured and released into the atmosphere. Next up is blue hydrogen, produced in the same way as grey, but the CO2 is captured and then stored. As the greenhouse gasses are captured, this mitigates the environmental impacts on the planet. Of the three prime colours, green is the best ecological solution by far, although it comes with its cost challenges. Here hydrogen is produced by splitting water by electrolysis. This produces only hydrogen and oxygen. The hydrogen can be used, and the oxygen simply vented to the atmosphere with no negative impact. This process to make green hydrogen is powered by renewable energy sources, such as wind or solar. That makes green hydrogen the cleanest option – hydrogen from renewable energy sources without CO2 as a by-product.
It goes without saying that hydrogen utilised in 2050 must be produced in an almost zero-carbon fashion. This can be achieved either through green hydrogen production via the electrolysis of water or blue hydrogen production, deriving hydrogen from natural gas, with carbon capture and storage (CCS) applied. This can result in low but not zero-carbon hydrogen, with the size of residual emissions determined by the completeness of the carbon capture process and the scale of methane leaks in natural gas extraction, transport, and use.
But despite the urgency of climate change mitigation, any adoption will be dependent on cost. In its recent report, The Energy Transitions Commission (ETC) predicted that the green production route will be the significant production route in the long term, though with a substantial role for blue in transition and in specific locations where gas costs are meagre. The report estimated that by mid-century, 85 per cent of the 500-800 Mt of annual production could be produced via the green route. This would require about 30,000 TWh of electricity input on top of the 90,000 TWh potentially required for direct electrification.
It is hoped that clean hydrogen is likely to be cost-competitive with grey hydrogen in some locations by the end of the decade. However, end-use applications of hydrogen, and therefore the demand, may not grow fast enough to facilitate a credible path to the volume required.
Therefore, government support, both financial and regulatory, will be urgently required. Policies must be enacted to drive rapid decarbonisation of all existing hydrogen production and accelerate rapid technology development and sufficient early adoption of hydrogen in other vital sectors. This is particularly crucial with sectors with lower technology readiness but significant potential demand, like steel production and ammonia in shipping, to ensure that rapid adoption in the next decade can be achieved.
