If we are to have any chance of keeping global warming below two degrees, we have to wean ourselves of gas. So at face value the plan to convert Leeds to a hydrogen city looks like a great idea. However, since hydrogen does not naturally exist anywhere on Earth, whenever someone proposes it in relation to climate change, we need to be very sceptical.
The environmentally friendly way of producing hydrogen is to use electricity generated from renewables to separate water into hydrogen and oxygen. More electricity can then be used to compress the hydrogen into a liquid for storage and transportation. There is a reason that nobody does this on a commercial scale – it provides far less energy than it takes; and this makes it unprofitable. Put simply, we are better off using electricity directly to do the things we might do with hydrogen.
The Leeds proposal is less green. It aims to create a hydrogen processing plant and insert this into the existing gas infrastructure. Natural (methane) gas will be separated into hydrogen and carbon dioxide at the processing plant. The hydrogen will be pumped into people’s houses through the existing gas pipelines. The carbon dioxide will then be captured and stored.
As with hydrogen, when someone mentions carbon capture and storage (CCS), we need to be sceptical – in this case, because CCS is a future technology. We understand in theory how CCS might be done, but in practice, the storage component is a nightmare since we need to find a means of storing a gas (always a problem due to diffusion) in a sealed containment where it needs to stay for centuries to come. Nobody knows how to do this profitably.
There are also questions about the way methane gas is obtained. Although the UK government has wishfully described methane gas as a clean fuel (methane is actually a far more potent greenhouse gas than carbon dioxide), if it leaks – and it often does – its impact is worse than coal. NASA satellites recently located a much larger than expected concentration of methane gas above the central USA – broadly above the areas where fracking has been concentrated. Whether this is a direct result of fracking or whether it is due to leakage from pipelines and railway tanks is unclear. However, this kind of leakage raises questions about the green credentials of any process that depends upon natural gas, since leaking methane into the atmosphere is worse than burning it!
The Leeds proposal is an exercise in “prior investment”. What we actually need to do is to write off the UK’s domestic gas infrastructure – not least because, following the collapse of North Sea gas production, imported gas is going to get expensive, and what gas we can afford will be needed for electricity generation. However, because the infrastructure is already in place, and thousands of homes and businesses are connected to it, scrapping it would be highly disruptive. So, instead, we seek to dream up ways of making the existing infrastructure do things it was never designed to do – in this case attempting to convert an environmentally toxic infrastructure into a clean one. Inevitably this costs a lot of money – the Leeds scheme claims £2bn; but the carbon storage component (if doable at all) is likely to be much higher – and takes time and resources that would be better employed elsewhere.
For the £2bn in the Leeds proposal, we could provide at least 150,000 homes (probably a lot more given the economies of scale) with rooftop solar pv and solar thermal systems, an air source heat pump system, and a halogen electric cooking hob – removing the need for gas altogether. Alternatively, by using the £2bn in the form of means tested grants for these alternatives to gas, we could rapidly wean an entire city off gas and onto clean electricity. And crucially, we could do it using technologies that are already in existence and for sale today.