Geothermal heat pumps at western Sydney estate

An old technology is proving its potential at a new Sydney housing estate.

Residents in an 800 home development in western Sydney are saving energy and money by using geothermal heat pumps to provide heating and cooling.

In 2019, ARENA provided funding for Climate-KIC to undertake a three year study into the use of ground source geothermal heat pumps at Frasers Property Australia’s Fairwater development at Blacktown, New South Wales.

How do geothermal heat pumps work?

The technology works by exchanging heat between the surface and earth by piping a refrigerant solution through copper tubes that loop deep underground. This provides heating in winter and cooling during summer, as subsurface temperatures in the area hover in the low 20s year round.

The copper tubes were installed in holes excavated up to 90 metres beneath the earth’s surface before the houses were built, linked to individual pumps located in each home.

This type of geothermal heat pump technology is already popular in Europe, the US and some Asian countries, but has been slow to take off in Australia. The Blacktown development is the first large-scale deployment to date in Australia.

Climate-KIC’s trial is now in its final year, returning promising findings across its first two years.

A – B testing

Findings from the Fairwater Living Laboratory have been compared to another development at North Kellyville, also in Sydney’s west.

The study has assessed the impact the geothermal heat pumps have had on peak demand for energy, finding the Fairwater houses consistently consume less electricity than those at North Kellyville, which use conventional air conditioning.

Remarkably homes in the Fairwater Estate have been found to consume 37 per cent less electricity, saving $691 over the course of a year. Researchers at the University of Technology Sydney (UTS), who are partnering on the project, say that even using a conservative measure that corrects for house size shows Fairwater houses consumed 19 per cent less over the year, saving $282 annually on the household’s electricity bills.

They found that on average, air conditioning accounted for 42 per cent of household annual electricity usage, but that could reach as high as 76 per cent during summer.

What are the benefits of geothermal heat pumps?

The researchers scoped residents’ experiences with the heat pumps, finding a satisfaction rate of 85-87 per cent.

Approximately 60 per cent said the system had met or exceeded their expectations, but some were less convinced. Twenty per cent of respondents were unsure of the effectiveness, cost savings and maintenance needs.

The cost benefit research is still underway, but analysis has revealed that Fairwater properties attract a premium of $62,871 compared to non-Fairwater properties with similar attributes located in Blacktown. A more detailed analysis of the costs associated with construction, maintenance and operation and benefits is underway.

Early results have found that reductions in peak demand events on the electricity distribution grid is helping to avoid the need for upgrades, and the technology could help to avoid the need for emergency market actions at a NEM level.

Climate-KIC believes the value from the benefits to the network at peak times are potentially even greater than the savings for consumers, creating opportunities to explore different pricing arrangements if the technology is included in new developments.

The geothermal heat pump project is assessing the impact of vegetation on the heat island effect
The geothermal heat pump project is assessing the impact of vegetation on the heat island effect. Image: Frasers Property

The project also set out to quantify benefits in the urban heat island effect from reducing the need to exhaust waste heat into the local area. While lighter coloured roofs and vegetation are helping to lower temperatures, researchers aim to investigate waste heat impacts in more detail in the next stage of the study.

Overall, the objectives set at the beginning of the project for economic benefits for residents, developers and local electricity distributors are on track to being met.

Flexible geothermal heat pump technology

According to Climate-KIC, geothermal heat pumps like those used in the Fairwater estate are suitable for all types of houses, with their study including a mix of small and large homes. Benefits will be greatest in climates where extreme summer and winter temperatures require large amounts of energy to be used for heating and cooling.

Findings to date show the costs associated with drilling and installing copper pipes makes the system best suited to large-scale developments, like that undertaken by Frasers at Blacktown.

At the completion of the project, results will be shared with property developers to encourage the use of the technology, and also feed into policy development underway by the New South Wales Department of Planning, Industry and Environment.