Thermal pools turn waste gas into power
Hanmer’s Thermal Pools have harnessed the greenhouse gas methane as a resource to generate electricity to put back into their business - saving on their costs, and the cost to the environment.
Bringing in more than half a million visitors a year, Hanmer Springs Thermal Pools & Spa is a leading tourist attraction in the Canterbury region. Boasting geothermal hot pools, giant water slides and an award-winning spa, the popular destination is now committed to becoming one of the most environmentally responsible tourist attractions in the country. Their most recent eco-friendly innovation is the installation of a micro turbine, which converts waste methane gas into something useful – electricity they can use to power their business sustainably. The geothermal water used in the pools is pumped from 200 metres under the ground via a bore in the centre of the complex. Methane gas occurs underground in a waterborne state under pressure.
Hanmer Springs has really put its environmental aspirations into action, by relentlessly pursuing a better way of using the methane resource they have Eddie Christian
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 a 65 kilowatt Capstone microturbine. 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. That was the key driver for us to get moving.” In 2006 they 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. 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.” On his involvement with the project, EECA technology innovation manager Dinesh Chand said: “Through my years of working with Hanmer Pools, what has struck me is how innovative, perseverant 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. The potential for replicability of this particular technology is wide – for example, for large dairying operations with effluent ponds, or industrial businesses and local authorities with their own wastewater treatment plants.” 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 pools complex. The turbine has now been operating for 5 months, and the business is already reaping the rewards of generating their own electricity by saving 14.5 per cent on their electricity costs, a net saving of around $35,000 a year. The turbine will also save 100,000 cubic metres of methane from being released into the atmosphere a year, the equivalent of 1385 tons of carbon dioxide. With impressive gains already achieved, the ambitious team has set their sights even higher – the next phase of their project is to capture the heat released while the turbine is operating, and use it to further power their business. Hanmer Springs Thermal Pools & Spa 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, which sees the park becoming a major eco-friendly tourist destination. “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 said. “Innovations like this help move New Zealand towards a future of clean and clever energy use.” Abbot is enthusiastic about the potential for replicability of this project for other businesses; “We encourage other organisations with potential for similar resource generation to visit us, we will gladly share our data and our experience with them. My advice for other businesses wanting to be more environmentally responsible is: find people who can help you. What got this project over the line was expert consultation and support from EECA; to have that help was a huge advantage.”