My relentless pursuit of all things green has recently led me to learning more about something that is actually green; hemp. I’ve always been aware that this plant existed and that we can put it to many uses, but since discovering that it’s the second fastest growing plant on the planet after bamboo, I have been prompted to look at it in greater detail. In today’s world where we are increasingly aware of the materials used to make the products we buy and the impacts they have on the planet, I thought that sharing my findings may help us all to save a little energy and carbon.
Hemp has always had that hippy vibe attached to it and a person wearing clothes made from hemp will often be stereotyped. However, I want to investigate whether there may be more significant uses to this plant other than supplying the clothes stalls at Glastonbury. If this is indeed the case, then is it being under used and why?
What is hemp?
Hemp (cannabis sativa) is a fast-growing herbaceous plant. Hemp plants take only 70 to 100 days to fully mature and can be between 2 and 5 metres in height. Although from the same family and almost identical in appearance to the marijuana plant, hemp has minimal quantities of the narcotic agent tetrahydrocannabinol (THC). Getting high on hemp has been likened to trying to get drunk on low-alcohol beer. Nevertheless, because of its association with marijuana, hemp has had a slightly chequered history. In the last hundred years or so, many countries banned farmers from growing the plant, but in light of prudent research and a number of myth-busting exercises, many have subsequently lifted the bans. In the UK, Defra has sanctioned the growing of hemp crops and cited in a report (2005) that it has many beneficial factors, such as providing habitats for wildlife and its ability to be grown with practically zero use of pesticides and herbicides [1]. Historically, hemp has been widely grown and used; Tomas Jefferson grew hemp and then went on to draft the US declaration of independence on hemp paper. For the following hundred years or so, 75% of the world’s paper was made from hemp [2] and Henry Ford even made a car from the stuff – and then powered it on hemp biofuel. Nevertheless, this was not enough to save hemp from decline. The discovery of oil, and consequently plastic, saw the virtual end of hemp as a construction material, sailing ships which used hemp rope and sails were replaced by steam ships, wood became the material of choice for making paper, and a global trade in cheap cotton saw hemp slowly disappear as a clothing fabric. However, we are now witnessing a revival of the hemp industry and I shall go on to explain how it is making a comeback.
Uses for hemp
Clothing – This is probably where most of us are familiar with the use of hemp. The fibres from the stalks of the plant are used to make a tough durable material that can easily be woven to make clothing fabric; the original Levis jeans were made from hemp canvas. Clothing made from hemp is stronger and more long lasting than that of cotton and it’s worth noting that almost half of the agricultural chemicals applied to US crops are used for growing cotton [3].
Plastic – Hemp has the capacity to be moulded into many forms of plastic, but it is currently very expensive. The world’s first hemp CD is available and it even comes in a hemp case – although with the imminent demise of the CD in the face of digital music, this may have come just a tad too late. If, however, you are still into CDs and like your new age music for relaxation and well-being, then please do seek one out online and order yourself a copy. On a more serious note; plastic is a menace to the environment, causing a massive build up of non-biodegradable waste and consuming a finite fossil fuel (oil) in its manufacture. If a naturally grown material can be used to replace some of this plastic, then the environment could really benefit.
Food – Hemp is an unsung hero when it comes to nutrition, albeit that it generally only finds its way on the shelves of health food shops. The seeds from hemp can be used as a beneficial nutritional supplement and contain fibre, protein and essential fatty acids (EFAs). In fact, they contain a higher total of EFAs than any other seed oil [4] and are widely hailed as being superior to even the soybean. Has anybody told the Chinese this?
Building – A relatively new use for hemp is to mix it with lime to form a lightweight construction material similar to concrete. This eco-alternative can be used to form solid non-load bearing panels or bricks and has been successfully used in the construction of buildings [5]. Although given a rather uninspiring name, Hemcrete, the manufacturers claim that it:
- Produces 130kg less carbon per square metre of wall than traditional materials and being a natural product, also absorbs CO2 during the plant’s growth.
- Is made from UK grown hemp.
- Has excellent insulation properties. [6]
There are a wealth of articles and papers online to support these claims, as well as other brands of hemp masonry, which I would assume perform to a similar level. This being the case, it would appear that in hemp we have a genuine eco-building material. To put that into context; the average intensity of global carbon emissions from cement production is 222kg of carbon per tonne of cement, with the industry accounting for 5% of global anthropogenic (manmade) carbon emissions [7].
Car parts – Many car manufacturers are looking into using hemp – and other plant-based materials – to make various different car components [8]. This will affect every aspect of a car’s life cycle, from replacing man-made parts used in manufacture, to the end of the car’s life when biodegradable products can have a huge impact on the waste produced from old cars. This material is tough too. When Henry Ford took an axe to his hemp-made car, the vehicle shrugged it off as if it had been tickled. Amazing.
Henry Ford whacks his 1941 car to show the strength of the hemp-made boot panel.
Paper – Paper made from hemp is widely hailed as being far more environmentally friendly than paper made from wood. The yield from hemp is 4 times as high as that from trees and its low lignin content (cell binding fibre) removes the need for acid to be used in the pulping process, lowering waste water contamination. The paper is generally of a better quality than wood-based paper and will not turn yellow over time.
Biofuel – Hemp can easily be turned into a biofuel to power our cars, buses and lorries. However, biofuels are a contentious subject, and I’m not going to dwell too much on this potential use for the crop. Although a wonderful thing about hemp-derived biofuel is that it’s green…no really; I mean it’s actually green. Nice touch. As it currently stands, however, it is not commercially viable to grow hemp as a biofuel crop because it’s too expensive in relation to the alternatives [9].
Alongside all of the uses and products hemp can bring us, we must also consider the fact that as a spring crop it’s beneficial to wildlife, its deep roots aerate the soil and, because it replaces soil nutrients, hemp is a perfect rotation crop, so can be grown within a wider agricultural operation. Searching online for hemp products will turn up an almost never-ending list of different things that we can do with this crop (I have only touched the surface in this article). It may not be the solution to all of our environmental problems, but if this plant can be used to replace some of the more damaging products and processes currently employed by us to sustain our everyday lives, then surely that’s a start.
In summary then…
It would appear that far from being consigned to the depths of history or simply being a niche product, hemp is actually making a comeback. But what can you do with this information with regards to saving energy and carbon? Well, to begin with, I hope that I may have dispelled the image of sandal-wearing hippies that seems synonymous with hemp and that you can see it’s a versatile crop that is most definitely undervalued. I remember a time when organic food was seen as the choice of vegans and health freaks only – look at it now. Perhaps the same can happen for hemp and bring with it a host of environmental benefits. If you are looking for eco alternatives whether just for something as simple as a dietary additive or you are considering building an eco home, do add this to your list of potential purchases.
I have to admit that I am now a complete hemp convert. Should you be out and about one day and happen to see a hemp-dressed man, driving a hemp-built, hemp fuelled car, up the driveway of his hemp-built house, bringing in his hemp food which is packed in hemp shopping bags… that’ll be me. Peace out man.
References
[1] http://www.defra.gov.uk/foodfarm/growing/crops/industrial/pdf/flaxhemp-report.pdf
[2] http://hemporganic.com/whyhemp.html
[3] http://www.azhemp.org/Archive/Package/Facts/facts.html
[4] http://www.hemp.co.uk/Hemp_UK/Hemp_Food.html
[5] http://opus.bath.ac.uk/16170/1/papers/Paper%20123.pdf
[6] http://www.limetechnology.co.uk/
[7] http://www.annualreviews.org/doi/abs/10.1146/annurev.energy.26.1.303
[8] http://www.eeda.org.uk/3319.asp
[9] http://biodieselmagazine.com/article.jsp?article_id=1434
