Geothermal technology - isn’t it time we got brownie points for energy rating?

In 2010 Alison Dodds Architect started a project on a large block of land on the Mornington Peninsula. Our interest had been stirred in sustainability and alternative sources of energy and we had a client who was open to exploring the use of geothermal technology—which very simply explained is heat stored in the earth that results through the decay of radiogenic elements such as uranium, potassium etc. Energy can be extracted from the resultant heat that is stored in either hot sedimentary rocks or deep hot aquifers and turned into electricity as a useable energy source above the ground. In 2010 there were very few residential projects that had actually tapped into such sources and had functioning systems and the whole concept, whilst not new on a world stage, was in its infancy in Australia despite there being a huge natural potential. We went right through the gamut of research, viability for our project and costing. The cost of installation even with using a system that lay only a short distance below the surface to gain its heat exchange potential was prohibitive as a one off cost at $230,000, which even amortised over an extended period of time saw probably only our clients children reaping the benefit of sustainable cheap power (if the house was still in the family at that stage) and primarily for that reason it didn’t proceed. However, another major stumbling block, had it proceeded, was that the energy efficient status of the project gained zero points against the mandatory energy rating system. We were disappointed as we hoped to be in the forefront of using a new technology that made huge sense on all fronts.

Fast forward to 2018 and the Institute of Architects held a professional development two part course called ‘Going Underground’ which again stirred our interest and we attended. They provided a very interesting mix of presentations which covered a whole range of related topics as well as showcased energy management in particular buildings both residential and commercial. It is commendable that state governments as well as local councils are turning their attention to and putting their money into sustainable energy implementation in projects they have a financial say in. The two questions that most interested us were:

  • What are the current costs for installing geothermal technology in a medium sized residential project?
  • Is geothermal technology now recognised as part of an energy rating assessment?

The answers were both very encouraging as well as extremely disappointing as the bottom line is that if we were looking at achieving a similar result in a project today it would cost approximately $60,000—but there is still, eight years down the track, no recognition in terms of energy rating!

Governments need to get on board with this aspect of sustainable energy and do everything they can to enable and encourage installation in projects moving forward.

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