Though it is less sexy than it’s modern counterparts, industrial hemp has entered the conversation as a material with an exciting future. It is showing up in products with uses that range from ultra-specialized to everyday. But can industrial hemp compete in a world focused on high-tech solutions?
If you follow Amory Lovins (and the Rocky Mountain Institute) at all, you know Lovins’ new book “Reinventing Fire”
(which we’ve reviewed previously
) covers many exciting technologies that could help us reduce our reliance on fossil fuels and wean our economy off oil, coal and nuclear energy. Former U.S. President Bill Clinton said of the book “My friend Amory Lovins knows that the most important question of the twenty-first century is the “how” question–how we turn good ideas into working solutions. Reinventing Fire is a wise, detailed, and comprehensive blueprint for gathering the best existing technologies for energy use and putting them to work right now to create jobs, end our dependence on climate-changing fossil fuels, and unleash the enormous economic potential of the coming energy revolution.”
In a recent TED talk
(that has now been viewed over 300,000 times), Lovins discusses many technologies that are already well underway in terms of production and distribution. One of these is carbon fiber. Production of it (particularly polyacrylonitrile-based carbon fiber) is set to double in five years. It’s a product Lovins is obviously passionate about–the Rocky Mountain Institute’s hypercar concept, which utilizes it, dates back to 1994.
So just what is carbon fiber…? The technology involves drawing carbon polymers into very thin strands–they’re even thinner than human hair. The strands are then twisted into a yarn that can be woven together into a cloth-like material. The fabric, while super-strong, is also extremely light in weight. Designers and engineers in particular like it because it’s up to five times as strong–and two times as stiff–as steel, yet it weighs about two-thirds less. Its main drawback so far has been its price (around $22 a kg.). (Most steel, by way of contrast, costs under $1 a kg.) According to many experts, carbon fiber won’t be widely used until it drops in price to about $10 or $11 per kg. So far the auto industry has shown the most interest in using the material. German carmakers Volkswagen and BMW both plan to have models out, in the near future, featuring full carbon fiber-based bodies. They believe the carbon fiber will pay for itself because the cars, which are fully electric, will need fewer batteries. The replacement of steel components with carbon fiber equivalents is said to reduce the weight of most cars by 60 percent. That massive drop in weight would, in turn, reduce that car’s fuel consumption by 30 percent and cut greenhouse gas and other emissions by 10 to 20 percent.
It isn’t just in the auto industry, however, that consideration is being given to carbon fiber. Cradle to Cradle author and green architect William McDonough has talked about incorporating lightweight carbon nanotubes
into building structures as well. According to Wikipedia, carbon nanotubes are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. They’re potentially useful in everything from fuel cells, to electrical circuits and bulletproof clothing.
So if a product like carbon fiber is generating so much interest, in so many fields, can it be produced sustainably? Carbon fiber, like anything else, is not perfect. It can’t be melted down, for one thing; therefore it’s not easy to recycle. When it is recycled, the recycled fiber isn’t as strong as it was before recycling. Most carbon fiber is produced by using polyacrylonitrile, a synthetic resin obtained by reacting propylene with ammonia and oxygen. Since propylene is a petroleum product, its use as a resource isn’t helping us any in our quest to reduce our reliance on fossil fuels. Also, polyacrylonitrile is known to be carcinogenic; as such, its use is strictly regulated and includes prescriptions for safe handling and disposal. Fortunately, carbon fiber can also be produced from renewable and/or recycled materials; some of these include lignin, cellulosic fibers, routinely recycled petrochemical fibers, and blends of these components. Use of these resources is likely to be the most sustainable route, in the long term, for the production of carbon fiber composites.
And where does this leave industrial hemp? Can it compete, in tomorrow’s markets, with an influx of carbon fiber materials?
Well–not only does hemp lignin potentially constitute a renewable resource for the production of carbon fiber, but hemp fiber itself can be used to produce bio-composites. One Canadian company, Motive, has already conceptualized a prototype car made from hemp
fiber. This company’s research carries on from the work of Henry Ford, who experimented with the use of agricultural feedstocks back in the 1930s. But make no mistake,Motive’s car
is built for the 21st century! To make the vehicle’s resilient, lightweight body, hemp stalks are combed and rolled into a mat that is infused with a polymer resin. The hemp is what gives the biocomposite its flexibility, and a weight that is comparable to that of carbon fiber composites.
When it comes to buildings, the use–in construction–of bio-masonry materials based on hemp and lime
results in structures that are carbon-neutral, fire and mould resistant, as well as highly insulative. As a builder, you could choose the more traditional route, i.e. applying a temporary shuttering around a stick-frame and using a cast and tamp approach to create highly insulating bio-masonry walls. On the other hand, you might choose to go the prefabricated route, and have factory-made panels shipped to your jobsite. When using a building material that incorporates industrial hemp, you can rest assured that your building as sustainable a home as you could ask for. One of the most ancient crops ever cultivated, hemp has been grown for centuries–regardless of how much oil we’ve had access to, or how much industrial equipment we’ve had. According to one report “Assessments of industrial hemp, when comparing to hydrocarbons, show that, generally, industrial hemp requires substantially lower energy demands for manufacturing, is often suited to less-toxic means of processing, provides competitive product performance (especially in terms of durability, light weight, and strength), greater recyclability and/or biodegradability, and a number of value-added applications for byproducts and waste materials at either end of the product life cycle. Unlike petrochemical feedstocks, industrial hemp production offsets carbon dioxide emissions, helping to close the carbon cycle.”
Our assessment? Today or tomorrow, industrial hemp is more than a match for carbon fiber!