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Written by Sarah Kellett

Natural hot springs in England were considered by the Ancient Romans to be a gift from the gods. Their real source is water journeying thousands of years underground.

If you like your hot water brimming with history there’s nothing quite like Bath, England. Bubbling up through gravel along the bed of the River Avon, water emerges at 46 degrees Celsius. The water has been captured in constructed pools for bathing since Roman times.

Water surfacing today last saw the light of day thousands of years ago when it fell as rain. It’s difficult to follow its long journey, but geologists believe the rain slowly wove its way through fractures in the rock to a depth of about two kilometres. Here, hot rocks heated the water and pressure pushed it back to the surface.

As well as providing a muscle-soothing soak, hot rocks deep in the Earth are a potential source of energy. Groups around the world are researching areas where hot rocks are closer to the surface. If a site doesn’t already contain hot water, they can drill a hole to hot rocks and add their own water supply. Either way, they could use the natural heat to turn water to steam for powering turbines and producing electricity.

This is already being done in Birdsville, Queensland, where Australia’s only geothermal power station can be found on the edge of the Simpson Desert. A bore more than a kilometre deep draws up water naturally heated to almost boiling point. The water is used to heat another fluid called isopentane, which has a lower boiling point. The isopentane turns into gas and rotates an alternator to make electricity.

If you want to take in the waters in a more relaxing fashion, you don’t have to be in Rome to do as the Romans do. There are plenty of hot springs around Australia – maybe you could find one in your area.

More information

CSIRO, Potential of geothermal energy in Australia

Geothermal systems in New Zealand

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