The global push towards utilizing a greater amount of sustainable resources in an effort to reduce our dependence on polluting energy sources such as fossil fuels has led to an increasing amount of research devoted on alternative energy sources. Commonly known alternative energy sources include solar, wind, hydroelectric, geothermal and biomass energy.
Plants possess a number of biomass components that have been transformed into currently used fuel sources. Additionally, plants also possess a wide variety of phytochemicals that are shown to successfully mimic liquid fuels and therefore potentially substitute petrochemicals.
One plant of interest for similar alternative fuel purposes is Cannabis sativa L., which is more commonly referred to as hemp. Hemp is a multi-purpose and fast growing crop that has been extensively studied for its use in the pharmaceutical and constructions sectors, however its potential use as a biodiesel fuel is worth investigating as well.
Plants and Biofuels
Almost any type of plant or organic material can be converted to fuel, and the advantages that these alternative fuel sources have over fossil fuels are huge. Below are some of the advantages:
- Plants contain little to no sulfur components or other contaminants that are commonly found in gasoline. These contaminants are associated with causing air pollution and the subsequent promotion of acid rain.
- Photosynthesis is the process by which plants convert water and carbon dioxide (CO2) into carbohydrates and oxygen. The production of biomass recycles CO2, a major contributor of global warming, back into the fuel source, which is also beneficial for the environment.
- No mining, strip-mining or drilling is required to harvest plants, as compared to those processes that are used for the extraction of oil1.
Converting Hemp to Fuel
As a crop, hemp exhibits a good resistance to drought and pests, a well-developed root system that is resistant to soil erosion, as well as a much lower water requirement as compared to other crops like cotton. Hemp is therefore a highly versatile fiber crop that is particularly unique for its possession of both a high percentage of useful oil and biomass components.
Historically, hemp biomass has been used for energy purposes, however its use for this purpose was traditionally limited to the use of oil that was pressed from hemp seed to provide lighting for some applications.
In 2011, Dr. Thomas Prade of the Swedish University of Agricultural Sciences investigated the energy yield of hemp for its potential application as both a solid biofuel and biogas, and comparing this data to other commonly used energy crops in northern Europe.
In his work, Prade determined that industrial hemp exhibits a high energy yield per hectare, as well as a good specific methane yield that could be increased through the pretreatment of biogas2.
Additionally, a group of researchers from the University of Connecticut have also confirmed that physical and chemical properties of biodiesel derived from unrefined hemp soil meets the standards set by the American Society for Testing and Materials for biodiesel fuel2.
Future Research Directions
Despite the potential benefits associated with converting hemp to an energy crop, the cultivation of industrial help is still prohibited in a majority of industrial countries such as Norway and the United States.
Although governments are concerned of the potential abuse that could result from the cultivation of these plants for their desired psychoactive effects, the industrial growth of hemp would exhibit an insignificant concentration of the compounds that induce these effects.
Future research must therefore be conducted on the sustainability of hemp as a potential energy crop in large-scale bioenergy carrier production. Additionally, any potential environmental, economical and social impacts must also be further examined.
By: Benedette Cuffari, AZO Clean Tech