One of the biggest tourist attractions in New Zealand – the Hanmer Springs Thermal Pools & Spa in Canterbury – is slashing its harmful greenhouse gas emissions with a micro turbine which converts waste methane gas into electricity.
By using the electricity generated by the turbine to power the business sustainably, the pools – which attract more than half a million visitors a year – are reaping significant savings as well. Already electricity costs have reduced by 14.5 per cent, a net saving of $35,000 per year.
The turbine has now been operating for five months and with these gains already achieved, the team has set their sights even higher.
Prior to the installation of the turbine, the gas was mostly burnt off – but some of it was still being released into the atmosphere.
General manager Graeme Abbot recalls his frustration: "I just found the whole thing wasteful watching this methane burning away. I thought there had to be a more productive and less harmful way we could use it and that was the key driver for us to get moving."
In 2006, Hanmer Springs, well known for its geothermal hot pools, giant water slides and award-winning spa, partnered with DETA Consulting to work out the feasibility of operating a methane generator. The Energy Efficiency and Conservation Authority (EECA) gave them the support and financial aid necessary to get the project over the line.
"Had the drive and leadership not been in place, along with a strategic focus on environmental outcomes, we may have thrown in the towel years ago," Abbot says. "EECA stuck with us the whole way, supporting us through the process of permits and other red tape."
"I'm so glad to see the turbine in operation now – the payback for us was worth the wait."
Dinesh Chand, EECA technology innovation manager has worked with the pools for many years. "What has struck me is how innovative, persevering and forward thinking they have been. We hope that the positive approach they have taken to lessen their own impact on the environment will inspire other businesses to do the same."
He says there is wide potential for replicating this technology – for example, large dairying operations with effluent ponds or industrial businesses and local authorities with their own waste-water treatment plants.
The geothermal water used in the pools is pumped from 200m under the ground via a bore in the centre of the complex. Methane gas occurs underground in a waterborne state under pressure.
When the water is pumped to the surface, this pressure is released, and the methane gas naturally bubbles upwards and separates from the water. This methane is now being captured, and directed through the 65kW Capstone micro turbine, saving 100,000 cubic metres of methane a year, the equivalent of 1385 tonnes of carbon dioxide, from being released into the atmosphere.
The turbine is able to seamlessly change its rate of production depending on how much thermal water is being pumped into the pools, and therefore, how much methane gas is available to be converted into electricity.
The park's biggest power consumption is pumping water – so in times of high water and energy use, there is a reciprocal increase in electricity produced by the turbine.
Where other gas generators require servicing every few hundred hours of operation, the Capstone turbine only needs to be serviced every 40,000 hours. The turbine is also significantly quieter – eliminating the need to build noise buffering structures at the complex.
The pools have also made other positive choices to reduce their impact on the environment - reducing chemical use, plastic consumption, and using discharge thermal water to heat the facility.
"Hanmer Springs has really put its environmental aspirations into action, by relentlessly pursuing a better way of using the methane resource they have," EECA's group manager market engagement Eddie Christian says.
"Innovations like this help move New Zealand towards a future of clean and clever energy use."
Abbot is enthusiastic about the potential for other businesses to take up this technology and says Hanmer Springs will gladly share its data and experience.
"My advice for other businesses wanting to be more environmentally responsible is to find people who can help you," he says. "What got this project over the line was expert consultation and support from EECA. To have that help was a huge advantage."
Find out more about technology demonstration project funding at eecabusiness.govt.nz