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Where your eyes don’t go
It's not just refrigerant emissions left when you decarbonise the energy in a building
Like a few people, I used the covid lockdown time to read stuff that was piled up waiting. In my case I ended up digesting stacks of reports and papers on all things f-gases. I’m certainly more informed for it, but my ukulele still sits forlorn.
The time spent digesting, also led me to think about what happens to our building emissions over time. Today I’m going to loop back to a topic I touched on a few weeks back. The idea that once we decarbonise the energy in our buildings, there are still some emissions sources left. I covered the one I think will be most prominent - refrigerants. But it’s not always alone…
Return to the The Morph
As a reminder, my thinking goes that as we decarbonise our grids, and move combustion heating to electric, the operational emissions profiles of our buildings will look very different. Once energy emissions are off the table, we are left staring at refrigerant and fluorinated gas emissions. And what appears as a small percentage today will grow in stature on the reporting inventory. Data centres, education campuses and chilled warehouses will be just some of the examples.
In simplifying the description, I did however leave out a few other GHG emission sources. To clarify, I’m just looking at ‘operational’ emissions here. There are lots more ‘embodied’ emissions in the building related to f-gases, which we’ll cover another day.
For starters, many people aren’t aware that HFCs (and other fluorinated gases) exist in insulation products. They are commonly found in rigid foams (the pink, grey or blue cladding boards) and spray foams used for wall cavities and hard to reach places. The HFCs 134a and 245fa are some common examples in use.
These f-gases are used in the ‘foam blowing’ process to expand the foam and make the bubbles. Along the lines of an aero chocolate bar (sans HFC).
The gas in the bubbles contributes to the insulation, which is important when it comes to energy efficiency (good). The chemical properties of HFCs (and the CFCs before them) are ideal for this job.
However, the f-gas doesn’t stay trapped in the foam forever, and will leak out over time (not so good). Some estimates suggest up to 2% a year. Not a lot you might think, but there is an argument to be made that this constitutes an operational emission in a building. It also means the insulating properties of the foam degrades over time. Given the longevity of most building facades, this is an important consideration on its own.
We have a scenario where the insulation leaking its f-gas over time, can then lead to increased energy use as its insulating properties degrade.
Emissions at the foam’s end of life are also significant. Throwing slabs of insulation cladding into landfill and rolling over it with heavy machinery, will inevitably release those gases out to atmosphere where they do their heat trapping work.
Side note for those old enough. It’s a factor why the foam burger containers are no longer used in your favourite fast-food joint, being made with ozone depleting f-gases. And by now you won’t be surprised to learn that replacement burger wrappings are often coated in fluorinated chemicals. That’s one for another day.
There are of course foam and insulating options that don’t use fluorinated gases. You will however find plenty of chemical industry marketing (featuring photos of flowers and cats) explaining why you wouldn’t want to use something other than their patented, synthetic products.
Next up, the electrical switchgear. Some of the larger buildings and campuses out there will have gas-insulated transformers or switchgear using the f-gas, SF6. I’ve come across a few in the field while doing energy management work. SF6 as I’ve mentioned before, is the biggie of the f-gases, with a GWP of 25,200. It works great as an electric insulator and is present in large parts of the electricity distribution grid. Including some equipment at the end of the line in larger properties.
The reported leak rates for SF6 filled equipment is low – for the most part less than 1% per year. However being long-lived assets, and with the high-GWP they still pose a significant climate risk and one that should be tracked carefully.
Replacing SF6 is another ‘battleground’ for fluorinated chemicals (fluoroketone and fluoronitrile) vs natural origin and one that deserves an edition on its own. In the meantime, there are some companies trying to avoid their use and you can get up to speed on some of the discussion here.
Lastly. Some buildings which have an in-house data centre or command control room, may also utilise gaseous fire suppression systems using HFCs (HFC-227ea with a GWP greater than 3000 being common). Hopefully they don’t need to get used that often, but here is another ‘operational’ source you might want to keep an eye on. Certainly when it comes to the maintenance and servicing.
So here’s a recap of the potential non-CO2 sources that are going to be part of our net-zero journey.
Insulating foams and cladding
Gas-insulated switchgear and transformers
Gaseous fire protection systems
Some of those emissions might be small during the building operation phase, and some are easier to mitigate than others. But keep in mind we are going for real zero here. And it might also lead folks to think hard about what goes into that next building project...
Have I missed any others? Let me know in the comments.
Where the F-gas hides
Each week I provide an example of where f-gases are utilised, or used to produce something. They are present in more things than most people realise…
Today it’s another example outside the refrigerant realm. Given we’ve just had the Australian Open in my homeland, I’ll fill you in about f-gases and tennis balls.
The challenge for tennis balls is they have a limited (professional) shelf-life. The pressurised air, or nitrogen, inside gradually permeates the rubber outer, and as a result the ball loses its rebound and playability. The balls don’t have a valve for re-inflation either. I’m guessing it’s why major tournaments can use more than 50,000 new balls per event.
Enter SF6. As a gas, it has a greater molecular weight compared to other ball fillers, and hence is less likely to leak from the ball. It is also chemically inert and doesn’t react with anything. Hence patents were filed, and it appears that it was used for a good while to overcome this problem of the balls slowly deflating. Keeping shape and performance, allowing the pros to consistently belt those forehand winners down the line.
The downside, however, is because SF6 doesn’t react with much, it doesn’t breakdown very quickly in the atmosphere. It can hang around for over 3000 years. Coupled with the very high GWP, it presents a real problem for when the balls are eventually disposed of.
As a result, I believe that SF6 is no longer used in tennis balls. Probably best given there are approximately 300 million tennis balls made annually, and with little recycling that I know of, likely most end up in landfill. That part is concerning enough, with some small consolation that they no longer release a potent f-gas in the process.
Right, that’s all for this week and ‘till next time,
p.s. the title track from last week was ‘Feel the Pain’ by Dinosaur Jr – an indie crowd favourite from the 90s.
Fixed stuff here for newcomers
There is lots of news every week from the cooling industry and plenty of newsletters that cover it well. The intention is to keep this newsletter focused on the most prominent f-gases (fluorinated greenhouse gases), the most common of which are refrigerants and importantly their environmental impact. That’s the lane I’ve chosen - I’ll do my best to stick to it.
Below is the seven (formal) greenhouse gases that countries and companies should track, report and hopefully reduce.
Carbon Dioxide (CO2)
Nitrous Oxide (N2O)
Sulphur Hexafluoride (SF6)
Nitrogen trifluoride (NF3)
There is also the still circulating, ozone damaging chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and the ‘new-generation’ hydrofluoroolefins (HFOs).
Hopefully you can spot the pattern.
Emissions from f-gases and refrigerants have been the fastest growing greenhouse gases over the past decade (more than CO2 and methane - check out IPCC WG3 summary for policy makers). They are also classed as super pollutants given their outsized global warming and other environmental impacts.
Some useful permalinks
The scale of the climate challenge can often feel daunting. This piece helps me take a step back and understand where we need to focus first - recommend a read.
There are plenty of technology solutions available to address the cooling and refrigerant challenge. You can find many of them here
Beware when the same entities who have contributed to the current f-gas problem propose you new solutions… This is a good place to get up to speed.