While the importance of electrification to decarbonising commercial buildings has been well established in recent years and supported by various bodies such as ASBEC, GBCA, NABERS and governments at different levels, the challenge to actually electrify existing building stock remains immense.
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We are seeing more and more new buildings being built gas-free, which is fantastic, however, a number of obstacles are preventing electrification retrofits en masse.
We (Australian Alliance for Energy Productivity) estimate Australia has approximately 5,000 large commercial buildings which together are using more than 40 petajoules of fossil gas annually.
To decarbonise, almost all of these buildings, most of which will not have major refurbishments for decades, need to transition from gas boilers to heat pumps for water heating – both for heating and for domestic hot water.
While we are seeing some of these necessary retrofits, it is not happening fast enough. The current retrofit rate is about 10 to 20 per year across Australia, but to make an impact on emission reduction targets, we need to ramp this number to more than 500 a year. So what’s standing in our way?
Of course, to achieve this kind of scale of change a number of things need to come together to make this happen. We need skills development to increase the number of service providers with the right know-how, we need industry development for a greater number of products and of course more financial support from governments would be helpful. However, this is not what is holding projects back.
We are aware of dozens of buildings that have investigated electrification of their gas boiler-based heating systems over the last five years, only to receive project reports with very poor return on investment (ROI), resulting in these projects being shunted to the back of the queue (or off a cliff).
Not all hot water systems are created equal
The reason for this is most of those studies were investigating a like-for-like retrofit, by replacing the existing gas boiler with a heat pump with a similar capacity and the same delivery temperature, which for heating hot water (HHW) is usually 75 to 80 degrees. On the capital expenditure (capex) for this it is virtually impossible for a heat pump to compete with traditional technologies.
From A2EP’s research and working with our members and advisors such as Michael Snow from RMIT University and Dale Gartshore from Monash University, we believe lowering the temperature for HHW systems to 60 degrees (or lower) is the key to lowering heat pump costs, improving their performance and removing this obstacle to full building electrification.
Last year I was impressed to tour a facility where this had been implemented. Under the management of Michael Snow and Brad Costello, RMIT’s striking Building 80 has implemented a textbook, best-case heat pump retrofit.
Of course, the building benefited from already having good energy efficiency performance (for example double-glazing, LEDs, VSDs, smart controls and so on).
However, the key enabler was the reduction or the HHW loop to 55 degrees. From this they were able to determine the heat pump sizing according to the maximum loads.
The heat pump was 50 per cent of the nameplate capacity of the boilers they replaced so did not trigger an electrical system upgrade (but did need new cabling).
The capex was about $2,000 per kilowatt which is a fraction of what some consultants are estimating for such retrofits (and this was a high specification/high-quality build).
The system also incorporated thermal storage to enable load-flexing and the four-pipe system design allows for the “waste cold” created by the heat pumps to be utilised elsewhere.
Lowering HHW temperatures isn’t always easy, but if electrification and decarbonisation are your aim, it is absolutely worth doing as it can change the ROI dramatically.
A2EP is hosting a workshop on this topic. See website for more details.
