TechnologyCould hemp fuel be the key to a sustainable...

Could hemp fuel be the key to a sustainable future?


Ever since Earth Day of this year, folks have been discussing hemp’s potential influence as a crop that could improve sustainability practices worldwide. Here are a few reasons why it could dramatically improve our chances of reducing the impacts of a rapidly changing climate, particularly in the form of hemp fuel. 

What is hemp fuel? 

Hemp fuel” is a collective term applied to various alternative fuel types derived from the industrial hemp plant. Currently, there are two types. These include hemp biodiesel and hemp ethanol or methanol. What separates the two is the part of the plant it comes from. The former comes from the pressed hemp seed. The oil extracted from the pressing process goes directly toward the production of hemp biodiesel. 

On the other hand, hemp ethanol comes from the stalk of the hemp plant. Instead of being pressed, it’s fermented to make fuel. Further, methanol comes from the plant’s woody pulp matter. Manufacturers can make both these types through a process known as “gasification.” 

Gasification is a technological process that can covert any carbon-based material into synthesis gas, or “syngas.” This is another name for the fuel gas we people use to run their cars. The process essentially exposes the hemp plant material to extremely high temperatures and pressures until a string of chemical reactions occurs, ultimately converting it into gaseous fuel. 

The idea of using hemp this way arose way back in 1895 when the idea of using vegetable oil as fuel started rising in popularity. After Dr. Rudolf Diesel pulled it off that year, word started spreading about the potential of there being an alternate fuel source. The interest persisted through 1900 when Diesel demonstrated peanut oil’s efficiency as fuel in Paris. 

Is hemp a good biofuel? 

Industrial hemp is a highly reliable and eco-friendly fuel alternative. Even as a crop alone, apart from its potential as hemp biofuel, the plant can grow where typical crops can’t. In fact, it takes so well to poor-quality soil that farmers around the world use it to restore their agricultural lands to health. 

According to Richard Parnas, a University of Connecticut professor of chemical materials and biomolecular engineering, the hemp plant has a remarkable ability to thrive in soils deemed infertile. Because of this, farmers can maximize their land’s use, dedicating more space to food instead. 

“For sustainable fuels, often it comes down to a question of food versus fuel,” Parnas told UConn Today. “It’s equally important to make fuel from plants that are not food but also won’t need the high-quality land.” 

Further, it demands far less of farmers and their resources than most other crops around the world. For example, you can grow hemp without having to give it much water or fertilizer. It doesn’t take much to grow a healthy crop. As Parnas pointed out, a farmer who’s already cultivating hemp could produce enough fuel to power their entire farm using the hemp seeds alone. 

Plus, the scientist also found that the production of hemp is extraordinarily efficient. Over 97% of the hemp oil they harvested was successfully converted to hemp biodiesel. Parnas has so much faith in this plant as a sustainable fuel source that he and his colleagues are developing a reactor system driven by hemp power. 

With the $1.8 million granted to them by the U.S. Department of Energy, Parnas, his graduate student Si-Yu Li, and colleagues Dr. Yi Li and Dr. James Stuart, they’re gearing up to construct a pilot biodiesel production facility in two years. 

In addition to fueling vehicles and other machines, hemp biofuel could also be the ideal energy source for heating in cold climates, such as the northeastern United States. Experts suggest this use for pelleting industrial hemp, specifically. Hemp pellets made from harvested straw can be used for incineration and even for making bedding or litter for animals

With all that said, hemp is an excellent biofuel. It has an impressively high conversion level and the source crop doesn’t demand too many resources for cultivation. Plus, hemp hurd (the cellulose-rich fibers that comprise 75% of the plant’s stalk) can be used for so much more than fuel production, offering a versatile solution to mitigating many climate challenges. 

How much hemp biodiesel is in an acre of industrial hemp? 

Hemp farmers can grow an amazing amount of biodiesel per acre of hemp. They can harvest it in two different ways: in pelleted form, discussed above, or torrefied. Each of these categories of hemp biofuel yields varying amounts per acre. Below are some examples of how much hemp straw you can expect to get from a pellet vs. torrefied gross yield per two acres, which can then be made into fuel:

  • The pellet yield of hemp per two acres, with harvest moistures* ranging from 30-80%, is 889-3,111 lbs/acre. 
  • The torrefied yield of hemp per two acres according to the same parameters is 636-2,227.

*This term refers to the hemp straw’s moisture content when it was harvested. 

Ultimately, this means that a single acre of industrial hemp can be used to make 22 gallons of oil in 70-140 days, based on an average of 5,300 lbs of straw per acre. Some experts are not so optimistic about the amount of hemp fuel produced per acre. Penn State agronomy professor Greg Roth stated that it’s “not likely to be cost competitive as a feedstock for biodiesel” based on the university’s trials back in 2017.

Still, others recognize the substantial amount of potential. For example, a member of Hemp Car Transmaerica, Gray Sigler, told the Chicago Tribune, “If we raised hemp on 6% of the land in the US, we could provide all of the fuel we need for power generation and transportation.” 

This estimate may not sound like a lot. Yet, when you compare it in hectares to other popular sources of energy, it’s clear that engineers should take a long, hard look at the cannabis plant for future “green” hemp-derived power:

  • Soybean: ~56 gal/ha
  • Sunflower: 82 gal/ha
  • Peanut: 90 gal/ha
  • Rapeseed: 102 gal/ha
  • Coconut: 230 gal/ha 
  • Hemp: 207 gal/ha
  • Oil palm: 508 gallons of fuel per hectare (gal/ha)

To get an idea of why the two variations of the plant might create more or less hemp biofuel, you should first understand the differences in how fuel makers produce and extract the substance. 


Torrefaction is the process of pyrolysis of biomass. In other words, it’s the breakdown of biological material at high temperatures, between 225-300֯C. The different compounds in hemp start to degrade at different heat levels. The three types and their associated degradation temperatures are listed below:

  • Hemicellulose: These are the most reactive chemical compounds in woody plant material. They start to decompose at 225-325֯C. 
  • Lignin: Another major component of wood. It has a much wider range of temperatures that lead to its degradation, starting as low as 225֯C, far past hemicellulose’s maximum, stopping at 500֯C. 
  • Cellulose: This is essentially a chain of sugar molecules responsible for woody plant material’s strength. This particular compound is what makes hemp such a good alternative for paper and fiber production. Cellulose decomposes between 305-375֯C. This is the threshold makers consider for torrefaction. 

Pelletizing hemp

To create a hemp pellet, also known as a “briquette,” a maker doesn’t need to use heat hardly at all. Instead, the process depends exclusively on subjecting the plant material to high pressures. This results in small cylindrical sticks or rods made up of compressed hemp stalk and/or straw. A machine is necessary to produce these pellets successfully. 

In some cases, this could be a better choice than torrefied hemp. Take the torrefaction of tree wood, for example. The higher the temperature of the pellet production process, the more chance there is to volatize chemical contaminants, meaning these harmful compounds could turn into vapor. 

When industrial hemp is used as a fuel, these chemicals could present challenges to flue gas cleaning. If the same happens to hemp, it could potentially defeat the entire purpose of turning to hemp as a primary fuel alternative. 

This is because flue gas cleaning systems are responsible for removing gas pollutants from flue gases, thereby improving the world’s air quality and safety. (Flue gases are the gases exiting the pipes or channels, such as the exhaust from a furnace.) 

Making this cleaning process more difficult would weaken the systems’ ability to clear the air of harmful compounds, slowing down any progress in mitigating related climate change effects from greenhouse gases (GHGs).  

Can hemp biodiesel replace fossil fuels? 

There seem to be high hopes for hemp’s potential to replace prominent fossil fuel energy sources like petroleum diesel. After all, that’s the entire motivation behind researching hemp as an alternative fuel source, to begin with. However, the only way this potential can be realized is for the crop to be more widely adopted by fuel makers. 

There are several reasons why it should be eyed as a prime source of fuel, especially as climate-related challenges mount by the day. 

Even prominent activist platforms such as Nation of Change believe that there is significant chance humanity could wean itself off fossil fuels by replacing the resource with hemp instead. Michael T. Hertz wrote in 2019 that leftist politicians should “make hemp a centerpiece of their fight against fossil fuels and climate change.” 

It can produce the same amount of biomass in a 20-year period as 4.1 acres of trees. Further, some estimates say that each dry ton of that rapidly produced biomass can yield 80 gal of fuel. This gives it the capacity to replace petroleum diesel as our go-to source of energy. 

As long as the energy industry is willing to progress with the times and do what it takes to preserve degrading environments, there is great potential for hemp to become the newly preferred material for fuel production. 


Scientists are catching on to the incomparable versatility of the hemp plant. There are many reasons why hemp might be one of the best options for making energy consumption more sustainable. However, its potential for making hemp biofuel is among the most important. 

Results are promising on hemp’s potential to replace petroleum as the world’s preferred source of fuel. It outperforms many other popular sources, too, second only to oil palm. Because of the high yield and relative ease of cultivation, you just might be filling your car with hemp biodiesel sooner than you think. 

Jazmin Murphy
Jazmin Murphy is a trained science writer & reporter who has covered a breadth of topics. She is also a strong supporter and advocate of cannabis for recreational, wellness, and medical purposes.


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