Underground hot-water pool awaits drill rigs


IMAGINE a chilly May day such as the peninsula has been enduring, a decade or two into the future. The rain is, as now, hammering on roof and windows: the wind is keening through the trees. But you are snug, heater on day and night, with no great concern about the cost.

Your home has been retrofitted to deliver never-ending geothermal heating, with power bills far below what you would incur for gas and electricity. In summer a cooling liquid is fed to your house via the same pipes.

How will this be achieved?

Peninsula dwellers live above a giant hot water resource, captured in fractured rock, waiting to be piped to the surface as it is at the tourist attraction Peninsula Hot Springs. The water could provide cheap heating for homes, factories, shops – swimming pools that now cost a fortune to heat with gas – and any other building that requires heating and cooling.

The water can be piped to buildings half a kilometre from the bore, according to geothermal experts. And the heat can be used to create cool air for summer. After initial infrastructure costs, these benefits can be relatively inexpensive. The hot water is endless, as in thermal zones such as exist in New Zealand and Iceland.

Mornington Peninsula Shire Council took its initial step in this direction last November when councillors voted to commit to a carbon-neutral future.

Starting with sensible but unspectacular steps including more energy-efficient street lighting and better control of methane emissions from Rye tip, the shire will cut its carbon footprint to the practical minimum and buy carbon credits to offset the rest. The hot water comes later but work has already started.

The shire aims to become Australia’s first local government district with a landfill to become carbon neutral, and one of the first to achieve this goal, despite the Rye tip landfill emissions.

The strategy is set out in a 73-page report to councillors, ̔Carbon Neutral Options’, which states that becoming carbon neutral “proves to be a sound investment in long term financial savings”.

The target date is 2020. According to the report, it will require a $15.5 million investment in more efficient LED street lights and solar panels, as well as other measures – continuing to make shire buildings more energy-efficient and buying carbon offsets.

The savings from this would be realised by 2026-27, councillors are told.

Where do shire greenhouse gas emissions come from?

Well over 70 per cent is from two sources – methane from landfill (48 per cent) and street lighting (28 per cent). Gases associated with generation of electricity used by the shire is next, at 20 per cent. The remaining four per cent represents emissions related to water, gas and the shire vehicle fleet.

As well as saving money, key benefits of achieving carbon neutrality include reducing the local impact on climate change and becoming a member of the Carbon Neutral Network, enabling shire participation in global forums and networks.

Only two Victorian councils – Yarra and Moreland – are accredited as carbon neutral. The shire is among 22 aiming to become accredited. It began a program to reduce green house emissions in 2001, adopting an Energy Action Plan in 2005 that set an emissions target that was achieved by 2007, the report states, by installing solar, buying Greenpower for street lighting and upgrading some shire buildings.

Happily, some measures taken have had a double benefit. An upgrade to lighting at the Mornington Peninsula Regional Gallery also cut air conditioning costs: the LED globes don’t run as hot as the halogen globes they replaced, and produce better light into the bargain. Upgrading street lights will be a focus of the carbon neutral plan, along with using Greenpower for all all shire buildings.

The plan will also “maximise localised renewable energy for shire buildings”, with solar panels or geothermal for new buildings and solar panels retrofitted to existing buildings. Eighty-nine buildings have been deemed suitable for retrofitting.

Finally, carbon offsets will be bought, to cancel out, or “abate”, remaining emissions.

For some businesses and individuals, abatement can be achieved by growing trees and other foliage crops, which soak up carbon. Or, in the case of livestock, offsets must be bought to neutralise methane emanating from animal manure and produced “as part of [animals’] normal digestive process”, as the US Environment Protection Agency delicately puts it.

The peninsula is also well served by further carbon sinks, known collectively as “blue carbon”. They comprise such coastal and marine – “blue” – features as saltmarshes, mangroves and seagrasses.

In a recent lecture, ecologist Dr Paul Carnell of Deakin University said these have a far higher ability to capture and permanently store carbon than forests and offer a valuable resource as offsets for polluting industries.

The lecture was attended by David Gill, president of the Balnarring Beach Community Association. He noted that Dr Carnell pointed to Port Phillip, Lang Lang and Western Port / Yaringa Marine National Park near Hastings as “hot spots” for carbon capture.

This was because saltmarshes, seagrass and mangroves are relatively healthy despite dredging, development and run off from drains. They mop up plant structure with sediment: retention is permanent because the sediment continues to rise unless disturbed by humans.

Dr Carnell told the audience that the anoxic (oxygen depleted) conditions in mud favour carbon retention. Expansion of coastal vegetation in places such as Western Port adds to that stock and will be studied in future experimental plots.

Finally, the shire report returns to the potential for geothermal energy. Research is recommended, including studying existing data on rock fractures in the fault areas that lie under the peninsula; aerial magnetic imaging; and ground-level surveys to locate fracture systems with more accuracy.

Preliminary test bores should be the next step, followed by more intensive bores “should the project progress to this stage”, the report recommends.

The result could be the seasonally cosy-cum-cool home of the future, described earlier, courtesy of the shire’s hard-headed approach to, as CEO Carl Cowie puts it, “unlock[ing] maximum value for the community” from factors including “enhanced technology solutions”.

Geothermal is still a vision. The hot underground water waits to be unlocked.

First published in the Southern Peninsula News – 12 May 2015


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