Geology and data

Geothermal energy

Illustration depicting the flow of hot water from beneath the earth to above the ground
Geothermal information for landholders

Geothermal energy is clean, reliable and renewable. It comes from natural heat in hot rocks and groundwater below the earth’s surface.

Geothermal energy can be used for:

  • heating and cooling homes and buildings
  • spas and hot springs
  • agriculture
  • aquaculture
  • industrial processes
  • electricity generation.

Geothermal energy can be turned into electricity. This is common in places with active volcanic systems, such as Iceland and New Zealand, where geothermal temperatures can be higher than 150°C.

Electricity can also be generated at lower temperatures. Binary-plant technology can achieve this with geothermal temperatures as low as 85°C.

Geothermal energy in Victoria

Victoria has potential for geothermal energy.

Research and data collected from boreholes across the state indicate there may be geothermal resource potential.

Naturally occurring warm groundwater is already used in several parts of Victoria, including spas on the Mornington Peninsula, in Warrnambool and Mt Buller. It is also used at an abattoir in Warrnambool and fish farms in Robe, South Australia, just across the Victorian border.

Geothermal exploration

Geothermal exploration helps identify areas where underground heat may be appropriate for extraction and use.

Common exploration methods include:

Data review

Existing publicly available well temperature and thermal conductivity data are reviewed. This is used to model temperatures underground and identify areas of geothermal potential.

Gravity and magnetic surveys

Gravity and electromagnetic surveys measure the earth’s gravity and electromagnetic fields. These surveys help build a better picture of geothermal heat reservoirs below the surface.

Seismic surveys

Seismic surveys use sound waves to create images of rock layers underground. The sound waves travel into the ground and reflect back from different rock layers. Sensors record the signals.

The most common method is called ‘vibroseis’. It uses specialised trucks that vibrate the ground to generate the sound waves.

Drilling

Drilling may be used to measure underground temperatures and thermal conductivity. A geothermal well is created using a drilling rig, which may stay on site for several weeks. Once drilling is complete, the well is either temporarily capped or permanently sealed with cement. This usually leaves no visible trace on the surface.

Geothermal extraction

Geothermal extraction harnesses naturally occurring heat below the earth’s surface by accessing hot fluids or heated rocks beneath the surface.

The type of geothermal resource can vary, but most projects need 3 key things:

  • a heat source
  • rock that allows fluids to move through it
  • fluid that brings heat to the surface.

In some places, naturally occurring hot water or steam can be produced directly below the surface. In other places, water is pumped through deep, hot rocks. The water absorbs heat and returns to the surface.

Once the hot water is brought to the surface, it can be used for heating, industry or electricity generation.

Depending on the technology used, fluids are commonly returned underground. This helps maintain pressure and supports the long-term use of the resource.

Further information

Geothermal reports are available for free through Earth Resources Publications.

GeoVic is a free online mapping tool. It lets users create earth resources maps, search for information and access data.

Page last updated: 09 Jul 2026