New Zealand company converts wood to charcoal

By Anna Austin
In a bid to produce charcoal from biomass for the sequestration of carbon dioxide, Marlborough, New Zealand-based Carbonscape Ltd. has developed a microwave technology capable of converting 40 percent to 50 percent of wood debris into charcoal.

Dubbed "Black Phantom," the wood-nuking process was described by Chief Science Officer Forrest Tyrrell-Baxter as an "energy-efficient, high-yielding, microwave-assisted pyrolysis."
Carbonscape, established in 2006, produced its initial industrial-scale batch at its pilot plant on the South Island of New Zealand in early October. "We know from scientific studies that charcoal can store carbon for thousands of years," Company Director Chris Turney said. "Ancient fires preserved in archaeological sites show carbon can be stable for thousands of years. This is because charcoal is highly resistant to microbial breakdown. Once formed, the charcoal effectively keeps the carbon out of the atmosphere and ocean for virtually indefinite periods."

According to the company, the significance of its technology is that in spite of the energy used during production, the carbon captured during the process draws down significantly more carbon dioxide from the atmosphere than it produces; approximately one ton of carbon dioxide can be transformed into charcoal each day. The final charcoal product may be returned to the soil in the form of bio-char to improve plant productivity and further reduce greenhouse gases.

Tyrrell-Baxter said initial considerations have focused on converting wood waste from harvesting operations such as pruning and bark material, and common agricultural crop waste such as leaf and stalk byproducts from maize plantations, into charcoal. However, other biomass materials may be utilized in the future. "Farm manure and compost biomass are two other waste streams identified as likely viable source materials for biochar production," he said. "Both are currently planned for further examination by the company's research team and academic partners in the near future. Ultimately, we're open to considering any waste or byproduct source materials that are of primary sector origin, and demonstrated as viable in terms of energy balance and final charcoal.