Kiwis on to hot source of energy

Technology advances mean the use of magma for power is increasingly feasible. Photo / AP

Grant will help scientists check out the potential of magma.

Scientists have turned to an intriguing place to source cheaper, more efficient energy - blazing-hot magma kilometres below the ground.

The concept is being explored in one of 18 international research collaborations just awarded nearly $5 million in government funding.

At present New Zealand sources about 13 per cent of its electricity from its geothermal assets, drawing out water pre-heated to temperatures of up to 350C from hot rock deep beneath the Earth.

But Canterbury University volcanologist Dr Ben Kennedy said it was possible much more energy could be found from sourcing even hotter fluids at the margins of magma chambers, where temperatures run from 700C to 1200C.

It would mean drilling several kilometres into the Earth with equipment that could withstand the "acidic and supercritical fluids" that would be produced when magma was struck, he told the Herald.

"This concept has long been laughed at by geologists and engineers as science fiction, or a little crazy, but technology is evolving," he said.

"At least two times recently, magma has accidently been intercepted by geothermal drilling, and this did not trigger a catastrophic eruption."

The university is working alongside Victoria University and several international organisations, including Icelandic power company Llandsvirkjun, in a new consortium.

It follows the Krafla Magma Drilling Project in Iceland, where scientists deliberately tried to drill into a magma chamber after a borehole accidentally hit one in 2009 and briefly created the world's most powerful geothermal production well.

"New Zealand generates more suitable magma than anywhere else on the planet so it is the ideal location. And like Iceland New Zealand has a long and proud history of geothermal energy," Dr Kennedy said. "There are still plenty of technological hurdles, so we probably won't be drilling into magma chambers in New Zealand for commercial energy in the next 10 years, but the Icelanders have shown it is possible, and we need energy solutions so it could be a realistic prospect for the future."

Technologies developed in the project, which has had a $450,000 grant from the Ministry of Business, Innovation and Employment, would be shared as Kiwi power firms drilled into hotter rocks and eventually magma, he said.

Other programmes in the Government's new $4.75 million Catalyst fund included a collaboration with teams in Korea and Singapore working towards a 5G network, a search for new technologies to eradicate invasive species, and a project that could potentially improve future housing for ageing populations.

Magma: our next renewable energy source?

• A new government fund has put $450,000 towards an international project to explore magma as a source of electricity generation.

• It would investigate whether fluids even hotter than those sourced in current geothermal energy production could be retrieved from the margins of magma chambers.

• The potential was identified when geothermal drilling in Iceland accidentally hit a magma chamber, briefly creating the world's most powerful geothermal production well.