If we want to decarbonise our economy (which we do), then we have to decarbonise the way we heat our built environment.
In the effort to find ways to do this, policymakers have looked at various technologies, from biomass to solar to hydrogen gas to heat pumps. All of them have potential merits, but not all are viable or desirable. In order to validate whether a technology can truly aid our efforts to reach net zero by 2050, we need to consider three primary parameters:
-Availability. Is the technology going to be widely available quickly enough? We’re behind the pace if we want to decarbonise our energy supply, so we can’t go for a technology that is not yet fully ready, or does not work across different sizes and scales of buildings.
-Cost. How difficult and costly will it be to deploy the technology widely enough to have the desired impact?
-Effectiveness. How does it compare to what we have now, and will it truly aid us in reaching net zero?
Heat Pumps are at the heart of this debate. Any discussion about green heating and cooling will feature heat pumps prominently, and for leading experts and researchers they’re widely considered a ‘no brainer’ solution. Heat pumps are not new (they were first invented in the mid 19th century, and first deployed commercially in the mid 20th century) but due to improvement in the technology and in the renewable power supply, they are now an extremely viable way for us to heat our buildings efficiently, and with zero carbon emissions.
But there are alternatives, and foremost in terms of press coverage and policymaker discussion is hydrogen gas.
What is hydrogen heating?
When we talk about hydrogen in the context of green heating, we are essentially referring to burning hydrogen instead of methane in natural gas boilers.
The idea is rather than have to drastically change the way we build, as well as enhance the buildings we have, we put hydrogen through the existing system. Burning hydrogen does not release carbon into the atmosphere, provides instant heat, and because it comes from water it can essentially be considered ‘unlimited’.
How does hydrogen compare to heat pumps?
Hydrogen has been promoted heavily as the energy source of the future by lobbying interests (the major oil and gas companies). It’s found its way into public conversation, and into the UK government’s policy agenda, but its usefulness in hitting net zero is heavily disputed by UK climate scientists and energy experts. Let’s go back to our three parameters: availability, cost and effectiveness.
Availability. Hydrogen boilers are not currently commercially available, other than in small scale localised experiments like the H21 project in the North of England. A LOT of work would need to be done to make hydrogen heating a viable option – some of the current pipes and infrastructure are suitable but there would need to be significant network upgrades. We would need to increase network capacity because there is a lot less energy in hydrogen compared to methane, we would need to change the pressure management equipment in the system, and everyone would need a new gas meter, boiler and potentially internal piping. We would also need to build a huge amount of hydrogen production capacity, and plan for area-by-area complete switches from methane to hydrogen (you can’t just gradually change the supply from methane to hydrogen). That’s not to say installing heat pumps at the volume required will be easy – it will also be difficult and hugely resource-intensive. But so would hydrogen roll-out, and potentially more so.
Cost. The most cost effective way of producing hydrogen, blue hydrogen, creates residual emissions. If we were aiming for an 80% reduction in carbon emissions, that wouldn’t matter so much. But we’re aiming for 100%, so those residual emissions simply won’t do. And there is currently no carbon emission-free method of producing hydrogen that is at all cost effective (more on this in the next section). What’s more, the costs of getting the network ready for hydrogen would be substantial. Analysis for the UK government done by Element Energy suggested that the cost to make the existing gas network suitable for hydrogen would be in the region of £22bn. All net-zero solutions will have short term costs associated with them, but hydrogen will cost more in the short and long term.
Effectiveness. Okay. So we’ve established hydrogen deployment would be difficult and expensive. But the goal is saving the world – so how sustainable would hydrogen heating be? Would it be worth the cost?
The most common way of producing hydrogen is ‘blue hydrogen’. This process turns methane into hydrogen and ‘captures’ the waste carbon and stores it in the ground or under the sea. This process has problems associated with it – you still need to source methane, which would most likely be imported or fracked, and there are significant emissions associated with the production and transportation of methane. Once you have the methane, there are still residual emissions in the carbon capture process.
The alternative is ‘green hydrogen’. This is the process of passing electricity through water to split it. But that process is inefficient – one unit of electricity used to split the water produces around half a unit of hydrogen. Heat pumps are FAR more efficient, and the end result is you need about 6 times more energy from electricity for green hydrogen production than you do to run heat pumps. If we heat our homes with hydrogen produced this way it’s likely energy bills would double, triple or more. Plus, if we are trying to use only renewable electricity to split the water, we’d need six times the number of wind turbines or solar panels or or nuclear power stations than we would to power heat pumps.
Even in terms of emissions, hydrogen just can’t compete with heat pumps. Even if we were able to produce all the hydrogen needed using the ‘green hydrogen’ process, the inefficiency of the system and the carbon emissions in the electrical grid mean that any hydrogen boiler installed today would be responsible for 50% more carbon emissions than a conventional methane boiler. They wouldn’t drop to the same level as conventional boilers until 2030 at best.
That’s astonishing when you consider that heat pumps, right now, drop emissions by 75% when compared to conventional boilers. And they’ll only get better as the power grid becomes greener.
Heat pumps are the future and hydrogen isn’t. Hydrogen just can’t compete in terms of availability, cost or effectiveness. You might wag your finger and say ‘ you make heat pumps, you would say that’. Well, you don’t need to take our word for it. Jan Rosenow, Principal and Director of European Programmes at the Regulatory Assistance Project (RAP), modelled the least cost pathway to net zero emissions in the heating sector, as you can see below. The main tools are heat pumps, district heating and energy savings.
As you can see in the chart, widespread heat pump deployment, along with district heating networks and energy savings, would get us to net zero by 2050. But at the current rate of heat pump deployment it would take 700 years to hit net zero.
So, we need to invest in our future by building more heat pumps. Clade’s mission is to do our part to achieve a carbon neutral world, and that means heat pumps. You can read more about our heat pumps for commercial buildings or get in touch to talk to us directly.