Canterbury project uses algae to make oil

DEAN KOZANIC/The Press

ENERGY FARM: Chris Bathurst's company, Solray Energy, is making oil by using algae grown in treated wastewater.

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One of the largest biofuel projects in the world will use Christchurch wastewater to make oil.

The $4.5 million demonstration project plans to make crude oil from algae grown in wastewater.

It could produce up to 550 barrels of crude oil a year – enough to power 45 cars a year.

The biofuel is carbon neutral, as the algae captures carbon from the atmosphere when it is grown and this is released when the fuel is burnt.

A five hectare oxidation pond at the Christchurch Wastewater Treatment Plant in Bromley has been cordoned for the project.

The algae will be grown in shallow wastewater ponds, with waste carbon dioxide from the treatment plant pumped through the ponds to boost growth. The algae will then be harvested. Christchurch company Solray Energy has designed a reactor that uses high pressure and heat to create oil.

National Institute of Water and Atmospheric Research (Niwa) scientist Dr Rupert Craggs said the project would test the viability of the oil-production method.

"No-one has built a plant at this scale before using the carbon dioxide and the algae ponds," he said. "The whole purpose of the study is to do a full economic analysis of the total system."

Chris Bathurst, of Solray, said the algae was converted into fuel using 6000 pounds per square inch of pressure and temperatures of about 400 degrees Celsius.

"It is exactly how nature created the oil we pump out of the ground today," he said.

The system uses 28 megajoules of energy to create a kilo of fuel that can generate 38 megajoules of energy, he said.

Christchurch City Council water and waste manager Mark Christison said the project could be the step to using all 230ha of oxidation ponds for algae production.

"If the economics of the project look good ... then the council would do more work on environmental assessments on converting them to algae ponds," he said.

The three-year study is funded by $2.5 million from the Foundation for Research, Science and Technology, $500,000 from Niwa and $1.5m from Solray.

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