Black gold

Imagine a substance so light and full of holes that a handful had more surface area than a rugby field.

Futuristic Blenheim company CarbonScape hasn’t just imagined it – they’ve created it, and won second prize (€100,000) in the world’s biggest sustainable technology competition by doing so. Chairman Nick Gerritsen says their ‘activated carbon’, with its incredible 800m² surface area per gram, has huge potential in several industries – especially steel manufacturing, which normally uses coking coal to make steel. Replacing coal with CarbonScape’s product, however, cuts a steel mill’s CO₂ emissions by 31 per cent, while being – drumroll – cheaper. And the secret to this wonder substance?

Sawdust. Basically wood waste from the milling industry (though any kind of woody material can be used) is fed into a special microwave oven, which zaps the sawdust, cooking off impurities and stripping out gases to leave behind pure carbon with a bizarre honeycomb-like internal structure.

“The big idea was about speeding nature up,” says Nick. “It takes a lot of heat and pressure to turn biomass into coal and gas, so we use microwaves to do the same thing. It’s a bit like switching coal mining from analogue to digital.”

Hungry for carbon, the world’s steel mills are using “gigatons” of coal every year, says Nick. He claims that if the industry switched to green coke, as activated carbon is sometimes called, global greenhouse gas emissions would drop by 2.5 per cent – not to mention reducing output of the pollutants sulphur and nitrogen.

These figures aren’t just pie in the sky either: the judges of the Postcode Lottery Green Challenge picked over CarbonScape’s entry with a fine-toothed comb before selecting them out of 509 entries from 79 countries for the runner-up prize.

Despite targeting the steel industry – and recently inking an agreement with a major international steel firm to provide 9000 tonnes of green coke annually – CarbonScape’s specialised microwave technology has many other uses. Sawdust waste can be zapped into a range of carbon products such as biochar, which is added to soil to improve its health. Burying biochar is also an impressive way of taking carbon out of the atmosphere (trees capture carbon from the air, turning it into wood) and locking it away in the soil indefinitely. Other products include carbon filters for removing pollutants from water, air or industrial smokestacks.

For now, however, the biggest challenge for this little-known but groundbreaking Kiwi company is finding funding. CarbonScape need to build the next level of technology to meet their agreed targets with the steel industry, and Nick says they would love to get that funding from within New Zealand and prevent a move offshore to be closer to investors. Basically, this country has an opportunity to keep the company New Zealand-owned by investing, says Nick.

“We’re not asking people to be a believer or a non-believer. We just offer a better product that’s better for the environment.”

Learn more about activated carbon at www.carbonscape.com.