Bricks and fuel – Hemp a lean green alternative?

By Richard Shrubb

We’re aware of non psychoactive hemp as a food and fibre source. Hemp may well be a solution for two of the world’s major ills – pollution from transport and house building. Hemp oil can used for biodiesel and hemp fibres in the construction of homes. 

A weed smoking car?

In 2001 a car drove 10 000 miles around the US and Canada entirely powered by hemp oil. No mention of the impact on the engine itself was made on the website. In 2007 a study was carried out on the potential of hemp oil as a biofuel and this found some difficulty.


The German Nova Institute found in a comparative trial of rapeseed and hemp oil that though hemp would beat most pollution regulations (and thus is cleaner than most other fuels) “the coke residue of hemp oil is twice as high as that of rapeseed oil. This will negatively affect the operation of the engine.” Essentially, unless you put in additives you will coke up your engine if using pure hemp oil.

The research argued that the drawback was due to one of the reasons it is good to eat – “The lower oxidation stability of hemp oil in comparison with rapeseed oil results from the high content of polyunsaturated fatty acids.” These fatty acids could replace your need to eat fish every week – they include Omega 3 – but burned in an engine could block up your injector nozzles. Blocked nozzles = poor performance, if it drove at all!

The research looked at mixing hemp oil with another readily available and green fuel – rapeseed oil. “By adding 80% of rapeseed oil to refined hemp oil, the demands on oxidation stability according to [German pollution regulations] could be fulfilled.” As ever the researchers were cautious in their conclusions and could only suggest further research is done.

The chief problem that the Nova Institute found was in the cost. Contrary to popular belief, hemp produces less oil than rape. As a result, even at a high scale production rate, hemp would cost more to produce. Higher production costs = higher cost at the pump. The paper suggested that “Coming from small-scale production that is common today, hemp oil costs at least 2.34 [per litre] (in case of good valorisation of the press cake), totally ruling out the use as fuel. Under large area cultivation and with hot pressing, the minimum price of hemp oil could decrease to 0.91 /[per litre].”

Compare the projected costs of hempseed oil to rapeseed? Rapeseed was found to cost much less: “The minimum prices of rapeseed oil as calculated in the three scenarios range between 0.58 and 0.78 [per litre]”.

Diesel was first envisaged as a biofuel until people discovered mineral oils under Texas and made enough money to influence government into banning hemp, or so some argue!  If America turned from corn bioethanol to hemp? Several million acres of oilseed plantation and at the rate the plant grows? Who knows – such a radical move could wrench us off our addiction to that noxious stuff under Texas…

Build a doobie home?

The modern world has two major polluting habits – energy and housing. It is widely understood that cement takes a tonne of carbon for every tonne of product made. Just building the Freedom Tower in Manhattan is putting several hundred thousand tonnes of carbon into the air!

A video of an ABC news report went online recently how a new home in South Africa was built using hemp and lime mortar. It seems that you can build an energy efficient home with a very low carbon footprint by turning hemp fibres into bricks. Being fibrous the bricks are insulating, and thus you are basically building your home out of insulation from the start!

House made of hemp / cannabis

A house made of hemp.


A UK website suggests sums up the potential of hempcrete: “Cast around a timber frame, Hempcrete is unique in its ability to provide excellent thermal and acoustic insulation as well as thermal mass and storage all in a single structurally sound building system”.



Green usually costs, as we have seen with hempseed biodiesel above. Hempcrete homes however, are comparable in cost to traditionally built homes.  The website suggests: “The costs of Hemp-Lime building are comparable to those of conventional construction and in many cases, due to the lightweight structure requiring less substantial foundations, Hempcrete has been a more cost effective alternative.”

In 1999 a home was built in Bury St Edmunds which got headline writers scrabbling for pot jokes. Built of hemp bricks, it was done as an experiment to see how good such a home could be. A report by the Building Research Establishment concluded “there was significant heat loss through the external walls and windows from the traditionally built Masonry house by comparison with the Hemp House”. In a world where energy bills cripple families, a highly energy efficient home is a serious draw – you will live in a home that is pretty much built of insulation!

Unlike the US, growing hemp is legal in the UK. Bureaucracy is fierce and a lot of hurdles are there to make it difficult to grow here. Apart from anything, one imagines that farmers worry about stoners from miles around descending on a budding field in the hope they’ve found a “secret government cannabis farm”. Yet, as you will understand you couldn’t get a buzz off a 10 foot joint of hemp, let alone a normal doobie …

Could hemp change the world? Through the two primary energy bugaboos of modern society, it could be an answer. Trees take 30 years to turn from seed to newspaper. Hemp? A few months. Mineral oil takes millions of years to turn from trees into diesel. Hemp? Months. Building homes? 100 acres of hemp to build a more energy efficient home than carbon costly brick. The production values certainly stand up – will we see Barratt boxes made of hemp in future? Not in the short term. Too many powerful conservatives make too much money from raping the resources of the world for something like this to change the world soon… The world does change by a few degrees at a time, and a few people making a small difference can result in large scale change. Will you take the leap?

Richard Shrubb

Richard Shrubb is a freelance journalist with a specific interest in medical science and sailing, for more info about Richard, see his web site and you can follow Richard on Twitter #Shrubberz


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    • i think the video said ‘just a few acres’ ? which i thought was quite impressive, given that it’s not just the structural components of the house, but the furnishings, carpets etc!

  1. Since a young teen or B4 [ idk if 12 is teen yet] But I used cannabis for the next decade eve an all day. More than using I always tried to educate myself. Mostly 4 grow but for uses to to make arugments for pot. I have reffered to Cannabis as a merical plant for the properties it has, all it could be used for, and all the Great things it can be substuited for. While growing up, learning about a eve/ anything I wanted to know I belive I no why the Cannabis Plant is not used other than the effects it causes. aka [ the high] Beliving that the few Real Reasons for Goverments around the world Not Allowing its Use are. The Oil companys dont want it because Hemp makes fule, fule that Does Not consume. The Fact that Hemp makes better quility ideams that will last far longer. I belive surly Goverments think tax revaune will decreas because the Population will not have to rebuy [exmp] a shirt, socks, or jeans again 6 months may hav the shirt, socks, or jeans for many years. What I belive they do not consider with tat thinking is the Population is still going to Spend $$$ as they do now so I dont belive Tax rev would go down. They want use were we are, keeping low men low an in there place. Just a form of controle to keep the population in its classes.

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