Kenaf, the carbon-sequestering monster plant, provides food, shelter and carbon credits.
If someone were to tell you that they had a technology — a weed actually — that could sequester huge amounts of carbon permanently while lifting villagers out of poverty by providing both protein-rich food and super-insulated building materials, you might start to wonder if they were, well, smoking a different weed.
But it appears that one retired building contractor, Bill Loftus, has actually come upon a brilliant application of the fast-growing, carbon-sucking plant known as Kenaf. Kenaf is in the Hibiscus family and is thus related to both cotton and okra. Originally from Africa
, this 4,000-year-old crop was used for its fiber. It has the astonishing ability to grow up to 14 feet in one growing season, yielding 6-10 tons of fiber
per acre and making it a great source of pulp for paper.
But researchers have also discovered a corresponding ability of Kenaf to inhale huge quantities of our most abundant global warming
gas — CO2. We all now know we need to dramatically reduce our emissions, but even if we were to cut them by 50 percent in the next 10 years (an almost unachievable goal), we still have decades worth of CO2 that has yet to impact the climate. In other words, we need a technology that can actively pull CO2 out of the air and store it … permanently, now.
It turns out that Kenaf can absorb 3-8 times more CO2 than a tree. One acre of Kenaf can pull about 10 tons of CO2 out of the air per growing season, and in some parts of the world it can be cut back and regrown for a second season. With proper management, a single acre planted in Kenaf could absorb 20 tons of CO2.
But its not enough to simply absorb CO2. In order to create verifiable carbon credits, the CO2 must be sequestered permanently. This is where Bill Loftus comes in. Having worked for decades in the green building
industry, he realized the abundant fiber of the Kenaf plant would be perfect as a filler to produce light-weight, super-insulating, fireproof concrete blocks that permanently sequester the carbon.
He patented the block, which weighs under 9 lbs, and is currently using it in two pilot projects in Haiti and South Africa, areas that have been hard hit by natural disasters and famine. The plant leaves are rich in protein (34 percent) and much-loved by chickens. So early in the season, it makes perfect feed in areas where feed is often not even available. The chickens in turn fertilize the soil and provide food for the villagers.
Kenaf has been used as a cordage crop to produce twine, rope, and sackcloth for over six millennia (Dempsey 1975). Kenaf was first domesticated and used in northern Africa. India has produced and used kenaf for the last 200 years, while Russia started producing kenaf in 1902 and introduced the crop to China in 1935 (Dempsey 1975). In the United States, kenaf research and production began during World War II to supply cordage material for the war effort (Wilson et al. 1965). The war not only interrupted the foreign fiber supplies from countries such as the Philippines, but the US involvement in the war also increased the use of these fibers by the US. Once it was determined that kenaf was a suitable crop for US production, research was initiated to maximize US kenaf yields. Asa result, scientists successfully developed high-yielding anthracnose-resistant cultivars, cultural practices, and harvesting machinery that increased fiber yields (Nieschlag et al. 1960; Wilson et al. 1965; White et al. 1970). Then in the 1950s and early 1960s, as USDA researchers were evaluating various plant species to fulfill future fiber demands in the US, it was determined that kenaf was an excellent cellulose fiber source for a large range of paper products (newsprint, bond paper, and corrugated liner board). It was also determined that pulping kenaf required less energy and chemical inputs for processing than standard wood sources (Nelson et al. 1962). More recent research and development work in the 1990s has demonstrated the plant’s suitability for use inbuilding materials (particle boards of various densities, thicknesses, with fire and insect resistance), adsorbents, textiles, livestock feed, and fibers in new and recycled plastics (injected molded and extruded) (Webber and Bledsoe 1993).
Researchers from Burkina Faso and France have developed a low-cost construction material made of clay and sand mixed with fibres from the kenaf plant.
Kenaf is member of the cotton family, and its fibres are already widely used in Burkina Faso to make bags and ropes, as well as other products typically made from wood, like paper.
Jacob Sanou, of the Farako-Ba research station of Bobo-Dioulasso, in Burkina Faso, says he was inspired to try using kenaf to make building materials by the flax plant, which Europeans have used in a wide range of products including clothing, paper and industrial products.