Hemp "Attractive" for Biodiesel, Researchers Say

Researchers at the University of Connecticut reported last week that the fiber crop cannabis sativa, also known as industrial hemp, has several qualities that make it an attractive feedstock for producing biodiesel, a sustainable diesel fuel made from renewable plant resources.

Industrial hemp can grow in infertile soils and does not require lots of water, fertilizer, or high-grade inputs to flourish, said researchers led by Dr. Richard Parnas, a professor of chemical, materials, and biomolecular engineering. It produces strong fibers that, until the advent of synthetic fibers in the 1950s, made it the premier product used in making rope and clothing around the world.

Currently, much biodiesel feedstock comes from crops that could otherwise be used for human food consumption, such as soybeans, peanuts, olives, and rapeseed. Similar problems face the production of ethanol, which diverts corn that could have been used for cattle feed (and ultimately consumed as meat by humans) into the fuel production market.

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

Parnas pointed out that much of the world still relies on hemp as a primary fiber, mainly because of its ability to "grow like a weed." But in fiber production, hemp seeds are often discarded, and, the researcher said, this waste product could be put to good use by using it as a fuel.

"If someone is already growing hemp," he said, "they might be able to produce enough fuel to power their whole farm with the oil from the seeds they produce."

Parnas and his team used virgin hemp seed oil to create biodiesel using a process called transesterification and achieved a high conversion efficiency with 97% of the hemp oil being converted to biodiesel. The university holds a patent on a biodiesel reactor system that could be customized to make biodiesel from a range of feedstocks, including hemp.

"Our research data could make buying a reactor system with our technology more attractive," says Parnas. "If we have data for the production of many different feedstocks, we can tailor the system to meet the company's needs."

Industrial hemp is grown in Canada, China, and European countries, among other places. But the DEA has barred its production in the US, leading to a bizarre situation in which American farmers have to sit idly by while industrial hemp products are imported from other countries. A number of states have passed legislation authorizing hemp research or production, but they are blocked by the DEA, which refuses to recognize any difference between high-fiber, low-THC hemp and low-fiber, high-THC marijuana.