And other factors were at play. The site itself had been the subject of politicking. Blacktown City Council wanted to ensure the development would be sustainable, so being able to demonstrate that Fairwater would be a sustainable community with an innovative solution, applied on a scale unseen in the southern hemisphere, was important to the planning and approval process.
An initial misfire
We were aware of geothermal heating and cooling technology as it has been used for some time in colder northern hemisphere climates with success.
Our challenge was to apply it to a warmer southern hemisphere climate in a market generally unaware of its existence, and therefore with fewer potential partners and suppliers.
Initially we trialed geothermal in a display home in our Botanica community at Lidcombe. It didn’t really work as we’d hoped.
The display home had high ceilings, with insufficient distance between the ceiling diffuser and the return air, along with an ever-opening and closing door, which resulted in poor heating and cooling. Yet even in these less-than-perfect conditions, the reduced energy consumption was promising.
However, the system being trialled was from a North American supplier, which would be risky in terms of cost and supply in the context of a large-scale rollout. We knew from a risk perspective that we couldn’t rely on offshore suppliers and materials given the potential for both to be subject to volatile offshore pricing, and questionable reliability in terms of delivery and maintenance.
But we weren’t ready to give up on geothermal at Fairwater. To satisfy the business case, we had to show that geothermal would provide a net benefit to the environment as well as to our customers, at an affordable price to us, without increasing our risk exposure in the delivery phase.
Most importantly, it would have to save money for our residents, most of whom would never have heard of it.
We continued the learning process with further modelling and testing, this time with Actron Air, an Australian air-conditioning manufacturer which believed it could manufacture a more efficient system with standard off-the-shelf components at a cheaper cost in their factory in Sydney’s west.
What is geothermal?
Geothermal air-conditioning is common in the US and Europe but until Fairwater – and since – it’s rarely been used in a large-scale capacity in the south Pacific.
From a resident’s perspective, a geothermal system operates in the same way as a conventional air-conditioning system, with a wall mounted thermostat. However it uses the constant temperature of the ground to heat and cool as opposed to conventional external condenser and fans subject to fluctuating outside air temperatures.
Geothermal loops reach deep underground. Refrigerant is circulated through the loop down into the earth and then back to the surface, having taken on the stable 22-degree temperature of the earth below, which is warmer than the outside air in winter and cooler than the outside air in summer.
It means the heating and cooling system in the home has much less work to do. It can operate more efficiently, using less energy, in an environment of rising energy prices.
Geothermal can only be applied to low-rise buildings, generally up to three storeys. So at Fairwater, a low-rise medium-density community, geothermal was a good fit.
Local logistics
That geothermal had been used with success in other countries didn’t help us in terms of a low-risk, large-scale deployment of geothermal in western Sydney.
We knew we couldn’t rely on offshore materials and suppliers for a community-wide rollout. We had to go local – local suppliers, local parts and a locally manufactured solution.
We worked with Alinta Energy Geothermal and Actron Air to commence the research and development process, and credit goes to our partners for their design solution of a reliable geothermal system that looked and felt like any typical system with Australian warranties.
With a design in place, our attention turned to making on-site construction of the technology possible. The introduction of another service into an already restricted services design required detailed up-front planning and meticulous attention to detail by the construction team. Down to the millimetre, especially where the drilling rigs were concerned.
A drilling rig is not something you use on a typical house construction site. We found, for a stage of 30 homes, that it took around six weeks to install the geothermal loops to the required depth of up to 80 metres for each home site.
Absorbing this into our construction timelines was achieved through an overlap process between our civil and housing contractors that allowed us to cordon off work areas for the geothermal to be installed, while maintaining a safe work environment for everyone.
The placement of the geothermal loops was critical. Loops cannot be closer than six metres in distance from each other, so when integrating geothermal in a community like Fairwater, where some of the homes are as narrow as four metres wide, detailed planning is required.
Making the numbers fit
Unsurprisingly, the cost of installation for a geothermal air-conditioning system was always going to be a sticking point.
The extra services and infrastructure required was clearly going to add up and customers would rightfully be expected to question the merit of paying a premium for an air-conditioning system that delivered similar heating and cooling outcomes to a standard unit.
For a standard ducted air-conditioning system in a freestanding home in Blacktown, you’re looking at an installation cost of around $8,000 to $10,000. The original price for us to install a geothermal system with US-made equipment for a one-off home worked out to be around $23,000.
We had to concede we couldn’t get the cost to match a standard system. Each Fairwater home would require a drilling rig, copper tubing, a special cement mix with thermal properties to fill the hole created in the drilling process, and other additional costs.
It couldn’t be done for a comparable price, however double the cost was not feasible either.
We worked closely with Alinta Energy Geothermal and Actron Air over several months to develop a local solution which, coupled with a coordinated approach to the delivery, geared for mass production, drove the cost down by almost 50%.
To further mitigate the installation cost premium, we considered the payback in terms of cheaper energy costs. We had estimated the savings from geothermal in a typical home at Fairwater to be approximately $500 per annum, so on the basis of a five-year timeframe, we allowed an additional $2,500 in installation costs on average per home.
We managed to meet the target and bring the cost of a geothermal installation down to the ballpark level of a standard ducted system. It was a great story of Australian manufacturing and a solution that was designed for Australian conditions, with an Australian warranty.
Calculating the cost savings
Obviously, we’ve been very keen to understand and quantify the benefits of geothermal in real cost terms.
Initially, the technology was estimated to save residents around $500 per year. Early reports from residents indicated a 40 to 60 per cent decrease in energy costs compared to their previous home.
A 2017 study by Alinta Energy Geothermal provided greater insight. It found that higher average savings of between $600-700 per annum were achievable, based on the system being used 100-150 days per year.
Cheaper energy bills aside, residents who had never heard of geothermal now speak about the air-conditioning system in their home with great pride. For many it is the icing on the cake of their beautiful new Fairwater home.
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We acknowledge and thank our collaborators:
Alinta Energy Geothermal
Actron Air
Blacktown City Council
