Geothermal energy could provide electricity while capturing carbon emissions
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A University of Canterbury (UC) PhD student has identified a renewable and affordable energy source with the ability to remove carbon dioxide (CO2) from the atmosphere.
Using Geothermal-Bioenergy and Carbon Capture and Sequestration (BECCS) as an energy source could positively impact the environment, new research has shown.
Karan Titus, UC civil and natural resources engineering PhD student, has investigated this type of energy, and how it can be harnessed to remove carbon from the atmosphere.
The BECCS process involves taking hot water from geothermal reservoirs and burning forestry waste to superheat it – generating electricity. The geothermal water is then injected back underground along with the CO2 produced from the burning wood.
“We are creating more clean, renewable energy, while indirectly removing CO2 from the atmosphere," Titus said.
“We can also generate significantly more renewable energy using this process when compared to traditional geothermal power. The BECCS system is also more cost-effective per tonne of CO2 than other common climate change mitigation strategies due to decarbonisation on two fronts: more renewable power and the secure storage of CO2.”
According to the researcher, geothermal-BECCS plants have the capability to store one million tonnes of usable CO2 each year in underground geothermal reservoirs.
At the moment, a similar process of directly separating CO2 from the air and storing it in geothermal reservoirs is used in Iceland but is not yet used in Aotearoa New Zealand.
Karan’s research is the first to explore pairing CO2 with injection to boost geothermal energy production, which is created by burning biomass; a forestry by-product that includes slash, which caused widespread damage following Cyclone Gabrielle.
“A carbon-negative energy cycle would be very valuable to Aotearoa’s long-term energy and sustainability goals," said Dr Rebecca Peer, Titus's supervisor at UC.
"It is exciting to be a part of research at UC tackling a global issue like climate change with potential solutions that leverage our indigenous resources and provide a pathway to address national issues such as forestry slash,” she says.
Karan, who aims to graduate in mid-2024, says his interest in this area stems from his childhood.
“From when I was a child and watched 'An Inconvenient Truth’, climate change has always been on my mind. Hearing back then that excessive emissions will result in extreme weather events – such as droughts, wildfires, brutal hurricanes, and immense floods – and seeing that happen now, makes me want to do something to help protect people, animals and the environment,” he explained.
“This is my way of contributing at a local level. No single solution will save us; we need to be fast-acting to find the best fit solution for our community without wasting any more decades.”
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