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Hydrogen: Hype, hope or horror?

24 October 2019

The Government has just published its proposals for how it is going to make new homes fit for a net zero emissions economy. The programme is called the Future Homes Standard. It has two key elements – super levels of efficiency and low carbon heating.  

Now, this low carbon heating plan is interesting. The original proposal from the Committee on Climate Change (CCC) was to stop all new individual gas boilers. Basically, the CCC left room for heat pumps, heat networks and electric heating (like storage heating - I’ve written about the risks of electric panel heaters here - an issue that is being addressed in the future homes standard consultation) and said that individual gas was not the best way to go. However, this proposal hasn’t made it into the programme. So why does the new government document back away from banning individual gas boilers?  

I suspect one reason is the shiny new toy in heating – hydrogen.  

Hydrogen is hugely appealing. You can burn it in a boiler. It burns between 2000˚C to over 3000˚C, compared to Natural Gas at 1950˚C. You are not going to worry about getting enough hot water with that! Also, it is a gas so we can put it in pipes which we have a lot of. In fact, the UK is probably only beaten by the Netherlands for the proportion of homes on the gas network. And, last but not least it can be made cleanly. It can come from natural gas in an industrial process called steam methane reformation. If the CO2 made in the process is captured and stored it reduces the emissions compared to gas burning dramatically. Excitingly hydrogen can also be made from salt water and electricity – enough to get the net zero badge. Oh, and which country has the most power stations in the sea? That will be the UK.  Almost 8.5 GW of offshore wind turbines are in operation and, with more under construction, the UK is the world leader in offshore wind. And the price keeps falling. September’s auctions for offshore wind made it cheaper than new fossil generation so it’s the economic choice for power and then we can make hydrogen. 

Put these together and the appeal is immediate – potentially carbon free gas in the existing albeit modified network, that burns super-hot to make heating and hot water. So why don’t we just do that? 

The reason for caution on using hydrogen in homes is because it burns just quite so hot. Used directly as a fuel or as a feedstock to make another fuel (such as ammonia for ships), hydrogen presents a whole host of options. Hydrogen can drive a heavy truck, fly a plane, power a super tanker, run a flexible power station or heat an energy intensive industrial process like making paper or recycling metals.  The combustion temperature means that hydrogen can do all kinds of incredibly valuable work.  

Importantly, these tasks – heavy road air and sea transport, heavy industry and back-up power generation are the areas that are hardest to decarbonise. Replacing the aviation gas, diesel, shipping oil and natural gas that do these tasks is really hard. We have few options and hydrogen is one.  

Imagine a world where we manage to create abundant zero emissions hydrogen. The sectors that are going to hoover it all up are these hard to tackle areas. In fact, I imagine a stiff competition for them because we will probably have to build power stations just to meet their demand for hydrogen. Even a future abundant supply will be matched by an abundant demand from these five sectors. Sectors that have very limited choice.  

It is in this context that burning hydrogen just to make warm air (21˚C) and hot water (up to 60˚C) in homes seems unwise. In a world of high demand and limited supply, the result is a high price. These energy-hungry sectors with an obligation to decarbonise and limited options will probably keep hydrogen prices high. So to go on a programme of heating homes with hydrogen risks creating high heating bills for homes for years to come.  

The focus on hydrogen for heating also risks us thinking we can stop focussing on making homes more efficient and training up a new army of heat pump installers. Hydrogen can be presented as a guaranteed future solution which causes a state of inaction now.  

Hydrogen is an amazing fuel; the falling costs of renewable power and the electrolysis to produce it cleanly, along with the immediate option of carbon capture offer real hope for the hardest parts of our economy to decarbonise. But making hydrogen is not free from cost or environmental impact. The demand for its amazing properties is likely to always meet the ability to produce it. Seen from this perspective, using a valuable fuel with a several thousand degree flame to heat homes to 21 degrees is not the best path. We should focus on doing rather less exciting things like making homes efficient, installing well performing heat pumps and heat networks and capturing waste heat. These approaches may be comparatively dull and not attract the same excited attention, but they will ensure we can have low carbon affordable heating for the future. They will also assure we can have the hydrogen for the industries that need it most to give those living in these new homes the careers they need in a net zero world. 

This blog by Tim Rotheray first appeared in Business Green 16 October 2019

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