Make most of thermal power

The Bay of Plenty is already dominant when it comes to geothermal energy. Photo/GNS Science

Around half of New Zealand's geothermal energy use occurs in the Bay of Plenty, but there's scope for much more, including by Tauranga businesses. That was the message from a recent Energy Efficiency and Conservation Authority (EECA) workshop on direct use of geothermal energy for commercial use.

"Access to geothermal energy resources provides a real comparative advantage for the Bay of Plenty and Waikato regions," said Shaun Bowler, EECA renewable heat programme manager.

The Bay of Plenty was already dominant when it came to geothermal energy, with around half of the country's 300 geothermal applications located in the region, said Mr Bowler. Geothermal heat was available throughout the central North Island area and there was scope to develop a lot more of it, he said.

Direct use was the use of geothermal heat energy in applications other than the generation of electricity.

Most processes that needed the input of heat could successfully use geothermal energy directly, instead of, or as a supplement to, electricity and/or fossil fuels. Uses included hot houses, aquaculture, motel and accommodation providers, timber drying and spas.

Direct-heat applications allowed landowners and businesses to access geothermal energy without the high cost and risk associated with deep bore exploration typical of major geothermal power generation plants.

Brian Carey, a geothermal resource management specialist for GNS Science, based at the Wairakei Research Centre, said local businesses in the wider Tauranga area should be aware of the potential geothermal direct heat resources offered.

"They're actually sustaining a number of mid-sized New Zealand businesses," he said.

"There's a little bit of mapping been done in the Tauranga area, but it's not particularly well-developed. I think the primary thing is that people need to be aware of the potential and look around them and decide if there are other opportunities."

Direct heat from geothermal resources was a good fit with a number of mid-sized businesses, he said, citing the use of direct heat by the Arataki Honey facility at Waiotapu, which was visited by participants in the Rotorua workshop.

Mr Carey said that geothermal direct heating needed to be "pulled out of the closet" and looked at to see how it could enhance the renewable energy supply and the positioning of the fortunate communities who had those resources.

Mr Carey noted that even when assessments were done on the size of a resource, off-take could be constrained by other aspects such as local land use or what local owners want to undertake.

"Potential users have to balance the risk versus cost equation."

The keynote speaker at the workshop was Dr John Lund, an internationally acclaimed expert on geothermal energy.

"The region has the potential to significantly contribute towards the government's renewable energy goals - geothermal is a key component of these goals," said EECA's Mr Bowler.

(Further details on commercial direct heat use are at http://www.bayofconnections.com/geothermal.)