The impacts of climate change on our fragile planet are both increasingly obvious and increasingly disastrous. Fossil fuels are unquestionably one of the biggest contributors; the race to find a sustainable substitute for these finite and ever-diminishing resources is on. Biofuel is one of the suggestions, but how viable is it? And is hemp the best biofuel?
It’s a common misconception among hemp and cannabis proponents that simply switching from fossil fuels to hemp biofuel would, in one fell swoop, would solve the world’s frankly terrifying fossil fuel conundrum. Far from being the planet-saving solution that they are all too often presented as, biofuels as a whole bring their own set of issues that create more problems than they solve.
Nothing exists in isolation. It’s vital to look at the domino effect that replacing fossil fuels with biofuels would have on the planet as a whole. However, when comparing hemp to other biofuel feedstocks, there are some advantages to be seen.
Biodiesel and ethanol can both be made from hemp
There are two types of biofuel: biodiesel and ethanol. Ethanol is made from grains (corn, barley, wheat, etc) or sugar cane, but can also be made from the inedible parts of most plants. It is frequently used as a biofuel, but usually blended with petrol.
Cars designed to run on petrol can only tolerate a 10% addition of ethanol to petrol; flexible fuel cars can use an up to 80% ethanol mix. In Brazil, where vast amounts of sugar cane are grown for biofuel, some cars can run on 100% ethanol.
Biodiesel is made by refining oils and fats from plants or animals, most commonly from vegetable oil, and requires methanol. Regular diesel is often blended with biodiesel at a ratio of 4:1 respectively, but blends can range from 2% – 100% biodiesel. A practical advantage of biodiesel is that any diesel car can run on it.
Hemp, if grown as a biofuel feedstock, would be able to produce both biofuels. Hempseed is comprised of 30-35% oil by weight, giving it a fuel yield of roughly 780 litres per hectare (207 gallons per hectare). This is considerably lower than palm oil and coconut, but over twice that of rapeseed, peanut, and sunflower, and four times that of soybean. The remainder of the plant can be made into ethanol using fermentation under low oxygen levels.
Natural consequences of biofuel production
The most common feedstocks used for biofuel are soybeans and corn (US), sugar cane and sugar beet (South America), palm oil (Southeast and East Asia), and rapeseed (Europe). All of these require significant amounts of fertile land in order to flourish.
Great swathes of rainforest have been destroyed to create space for oil palms and deforestation is occurring on an alarming and unprecedented scale in all of these areas. This has obliterated the habitat of numerous species, many of which (such as the orangutan) are already endangered.
These feedstocks are also grown on arable land formerly used to farm crops for human consumption, driving the prices of these crops up and out of the reach of the poor. In addition, what is known as ‘secondary deforestation’ is taking place as more land is needed to farm crops for food.
Biofuel targets set by various governments around the world might be doing more harm than good in terms of both climate change and food supply. It is the developing countries that are being hit the hardest by these problems rather than affluent ones.
What advantages does hemp have as a biofuel feedstock?
Hemp has the advantage of being able to grow in less fertile soil, and its ability to grow on what is referred to as ‘marginal land’ is highly praised by many. ‘Marginal land’ is fundamentally an economic term, denoting a piece of land that costs more to farm than it can profit from. This can refer to land with poor soil quality, pollution from previous industrial activities or lands with particularly difficult terrain challenges for farming, such as steep sloping mountainsides.
However, in real terms, it produces the most seed when grown on fertile land under optimum conditions. Should its use as a biofuel feedstock catch on, it is very likely that arable land would be devoted to hemp in the same way that it is to rival feedstocks now, with the same negative impact on the price of food.
The other problems with marginal land are that firstly, it often supports species and processes that are a valuable part of the ecosystem. Secondly, by its very nature, it tends to be in places that are impractical to farm, such as mountainsides.
The issue of how to harvest hemp in hard to reach places, and how to transport it to a biofuel processing facility, cannot be ignored. Since both activities generate CO2 by burning fossil fuels, this must be factored into its efficacy as a carbon-neutral crop. This applies to all biofuel feedstock crops, on all land, not just hemp on marginal land. The carbon cost of ploughing, sowing, harvesting, transportation and processing is higher than that of producing fossil fuels.
Although this means that switching to hemp fuel for all motor vehicles will neither solve the energy crisis nor halt climate change, there could be a smaller-scale, yet still helpful application. If farms are able to grow and process hemp on-site to make biofuels for farm vehicles and machinery, they may be able to create a self-sustaining and low-carbon-emitting ‘loop’. This can, on a small scale, help to end their dependency on fossil fuels. Hemp could be introduced as a rotation crop in existing food crop cultivation, lessening the impact on both food prices and fossil fuel use.
There is also the fact that hemp is currently very much a ‘niche market’ food crop, so there is not the same dependence on it as there is on corn, for example. However, this currently renders it cost-ineffective for large-scale biofuel production.
Minimal fertilizer and water is needed to grow hemp
Another area that requires scrutiny when looking at biofuels is the fertilizers needed to farm them. These fertilizers are basically nitrates from oil and gas – yes, fossil fuels – using the energy-intensive Haber-Bosch process to produce ammonia, which in turn is used as feedstock for all other nitrogen fertilizers.
Once introduced to land, they don’t just sit in the soil. Either they get washed into watercourses where they disturb the ecosystem, kill fish, and pollute drinking water supplies; or enter the atmosphere, becoming nitrous oxide. Nitrous oxide is a greenhouse gas worse than carbon dioxide. They also enter the atmosphere and become the mono-nitrogen oxides NO and NO₂, which contribute to ground level ozone (another health hazard).
Hemp requires soil fertility roughly equivalent to that of corn to grow well. However, around 70% of its nutrient requirements will be returned to the soil during and after the growth cycle. Plus, a small amount of nutrient gives a large yield response. This drastically reduces the amount of fertilisers it needs over the long term. This is a definite advantage over all other biofuel feedstocks.
The same can be said of its water requirements. One of the biggest problems with biofuels is that their production requires more water than fossil fuels, anywhere from twice to 48 times as much. Hemp requires about 30 – 40 cm (12-15 in) water per growing season or equivalent rainfall to produce a crop, whereas corn requires around 56 cm (22 inches).
The entire plant can be used
Perhaps one of the biggest advantages of hemp as a biofuel is the potential for using every part of the plant. Once oil is pressed from the seeds, the remaining hulls and seed matter can be compressed into ‘cakes’ for nutritious animal feed. Trim from harvesting and leaves that fall off during growth return to the soil, along with the roots, replenishing it for the next crop. The bast fibres and hurds are used for fibre, paper and building materials, to name but a few products.
Developments in biofuel research and its application to hemp
The process of pyrolysis is relatively new to the application of hemp biofuel. Pyrolysis involves subjective fibrous cellulose-containing plant matter (technically known as lignocellulosic biomass) to intense heat in order to obtain fuel-grade oils. The process is extremely economically feasible as basically waste biomass can be used in the process. The technique can be applied to hemp, and even to the enormous amount of biomass already produced by worldwide hemp and marijuana cultivation.
This development ties into the ways that the whole plant can be used, even simply the waste produced by the cannabis industry as a whole. For example, Washington alone produced 1.7 million pounds of cannabis plant waste in the first three years after legalization (2014).
Since this time, many European countries have legalized hemp cultivation and so has the USA, so the amount of waste is only expected to increase. California has been facing a cannabis waste problem for a long time. Pyrolysis offers a possible avenue through which to capitalize on cannabis and hemp waste and use it to make biofuel without confronting the already demanding issue of where to cultivate it.
There are still obstacles to discovering whether or not hemp is the best biofuel. Currently, the biggest obstacle to using hemp as biofuel is that so little of it is grown. Legislation has loosened over the last couple of years, especially in the USA, where hemp cultivation has been legalized.
However, most hemp cultivated in Europe, China and the USA is used in the production of food products, CBD products, cosmetics and research. Some of it is used in the manufacture of specialty spun products such as hemp paper and hemp rope.
Many advantages of hemp as a biofuel remain theoretical because so little of it has been used for biofuel on a commercial scale. It is to be fervently hoped that this does not remain the case for much longer.
- Disclaimer:Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.