Will We Ever See Hemp Cars on the Road?

 Key Points

Hemp has anywhere between 25,000 and 50,000 uses, depending on who you believe. Hempcrete is beginning to impact the construction industry, while the plant could also play a massive role in textile manufacturing.

Despite the weird and wonderful uses for hemp, one of the most intriguing is the almost mythical hemp car. Indeed, it has been the source of much speculation since Henry Ford’s proposed hemp plastic vehicle in 1941.

Major automobile manufacturers use hemp in relatively small quantities, but can they create an entire car from hemp? This article attempts to answer this question and looks into the story behind Ford’s hemp car. First, however, let’s take a look at why we should use hemp to create cars in the first place.

The Climate Change Specter

In 2018, a Pew Research Center poll surveyed people from 26 nations, asking them if they believed climate change was a major threat to their country. The median percentage who said “yes” was 68%. In the United States, that figure was 59%.

According to NASA, humans have increased atmospheric CO2 concentration by almost 50% since the beginning of the Industrial Revolution. In 2021, the global average atmospheric CO2 level was 416 parts per million (ppm). This is a staggering rise from the 320ppm figure recorded in 1960. Consequences include:

As we lurch towards an environmental catastrophe (many scientists say we’re already there), it is worth noting that scientists have known about this issue for a very long time.

Warnings from History

In the early 1800s, Alexander Humboldt predicted climate change induced by humans. During a long journey of scientific exploration in Latin America in 1814, he wrote about destroyed forests and dried-up springs caused by humans.

Then, in 1896, Svante Arrhenius, a Swedish scientist, warned that fossil fuel combustion might ultimately lead to global warming. He proposed a relationship between atmospheric CO2 concentrations and atmospheric temperature.

According to Arrhenius, a fall of 50% in CO2 levels would lead to a 4–5-degree Celsius drop in the Earth’s temperature. He also said that an increase of 50% could increase the world’s average temperature by 5-6 degrees.

In 1938, Guy Callendar showed that the temperature of the Earth was increasing due to rising CO2 levels. He calculated that average global temperatures had increased by 0.3 degrees Celsius in the previous half-century. Unfortunately, his work was ignored or largely dismissed.

Nonetheless, it is against this background that Henry Ford wanted to create a unique automobile.

Henry Ford’s Vision

Hemp cars have an array of advantages. Hemp is biodegradable and renewable. It is extremely durable and is now legal to grow on American soil. Moreover, a hemp car would produce far fewer emissions than standard vehicles. A Greenpeace report in 2018 said that the automobile industry was responsible for 9% of the world’s total carbon footprint!

Henry Ford was already aware of the potential damage caused by cars in his era and intended to do something about it.

In 1925, he spoke to the New York Times, stating that the future of fuel would come from fruit, weeds, sawdust, almost anything. Ford said there was fuel in every bit of vegetable matter that could be fermented.

He also pointed out that there was enough alcohol in a year’s yield of an acre of potatoes to drive the machinery needed to cultivate fields for a century. After all, refining fossil fuels and biomass requires the same basic thermochemical decomposition process.

Ford believed that if he could create plastic cars from farm products, he could create safer and more affordable vehicles. The process would also benefit agriculture. The goal was to create an all-plastic car up to 300 pounds lighter than steel models. Moreover, these cars would have up to ten times the impact resistance of steel. In fact, his car weighed 2,000 pounds; steel cars weighed 3,000 pounds at the time.

Did Ford Really Create a Hemp Car?

The suggestion is that Ford unveiled a prototype car made primarily from hemp in the early 1940s. Ford was a big supporter of agriculture and wanted to help farmers during the Great Depression. He was acutely aware that the popularity of automobiles was increasing markedly.

In a February 1941 interview with the New York Times, Ford said his test car would be lighter, safer, and more affordable than other vehicles. While Ford used plastic for much of the car, he used strong fibers such as hemp and ramie. The car ran on ethanol made from hemp and other agricultural waste.

The Reality

Unfortunately, claims that at least 70% of the car was made from hemp are false. In reality, Ford’s chemists created a plastic consisting of 70% cellulose fiber and 30% resin binder. The cellulose consisted of 10% hemp. Therefore, the body of the car was only around 7% hemp.

Ford unveiled his invention in Dearborn, Michigan, at the town’s annual festival on August 13, 1941. It was a Ford 60 made almost exclusively from plastic, which came almost entirely from plants. According to the New York Times, Ford had asked 29 scientists to perform research for 12 years concerning using agricultural products in industry. Indeed, there was a possibility of plastic cars being sold to consumers by 1943.

However, Ford’s dream never got off the ground. Hemp was already illegal to grow due to the 1937 Marihuana Tax Act. Lobbyists representing industries such as plastics, oil, and paper could see hemp was a threat and acted accordingly. Hemp enjoyed a brief revival during WWII. However, the last federally legal crop was grown in 1957.

In Fordlandia, there is a suggestion that Ford decided not to proceed because of the strong smell of formaldehyde that failed to subside over time. He realized that cars smelling like a morgue probably wouldn’t sell too well!

Also, America was in the process of preserving metal for a possible war effort, so plastic manufacture became a priority briefly. However, the United States soon joined WWII, and factories shifted their focus accordingly. This killed any momentum that plastic had.

Bruce Dietzen’s “Cannabis Car”

There are a few automobiles that used cannabis and hemp in their development.

Hemp is around 70% cellulose, making it ideal for plastic creation. Manufacturers extract cellulose from hemp and fabricate it via methods used to make traditional plastics. They can mix cellulose with pre-existing materials to create hybrids.

Bruce Dietzen made a valiant attempt to get hemp car production off the ground. The former Dell executive spent $200,000 to create his unique sports convertible in 2016 and said he probably incurred another $200,000 worth of expenses.

It is made with 100 pounds of woven hemp and the chassis of a Mazda. According to Dietzen, its body is at least ten times more dent resistant than steel. Therefore, in theory, it wouldn’t need huge repairs after minor accidents.

At the time, hemp was illegal to grow in Florida, where Dietzen lived. As a result, he had to import the woven material from China. The vehicle runs on biofuel from recycled agricultural waste. It probably has an even lower carbon footprint than electric vehicles.

However, his plan to create the Renew Sports Car did not come to fruition as his Cannabis Car concept officially never reached production. He had aimed to offer three configurations by 2025 at $100,000 per vehicle. However, Dietzen confirmed that he aims to bring advanced versions of the hemp fabric to market for electric vehicle companies to use and help decrease their carbon footprint.

Do Any Car Manufacturers Use Hemp to Create Their Machines?

The answer is “yes,” but in very limited quantities. Apart from Dietzen’s attempt, cars made with hemp typically consist of a small percentage of the plant.

HempFlax is a global leader in hemp production and says its hemp is used in indoor panels for BMW, Bugatti, Bentley, and Mercedes cars. Usually, car door panels are made from plastic and glass fiber. However, hemp is about 30 times lighter than glass fiber, thus reducing fuel costs. Also, producing hemp requires about 10% of the energy.

Aperta Motors of San Diego has begun production of the Paradigm, a solar-power car capable of traveling up to 1,000 miles a day on a full charge. The car’s body is made from Kevlar, carbon, and hemp.

Motive Industries Inc. was supposed to release the Kestrel Hemp Biocomposite Electric Car, with the idea first brought to public attention in 2010. The car’s gross vehicle weight was just 1,874 pounds, including the weight of the batteries that powered it. Its range was 99 miles, and it had a top speed of 84mph. However, Motive had no interest in automaking, so the car never made it to market.

Recently, a group of Italian companies combined to create parts for the M1RA, a touring car with some parts made of hemp fabric. It is a racing car with 680 HP.

With so many reasons to create hemp cars, why isn’t the road filled with them?

High Cost

At present, manufacturing hemp cars is still more expensive than their standard counterparts. Perhaps the price will go down now that hemp is legal to grow. Even so, most automobile manufacturers have the cost-cutting process down to a fine art to enhance profits.

Making hemp into a composite for structural use is expensive. It would ultimately cost more than steel at scale. Why? This is down to high labor costs. Steel, in contrast, is cheaper to produce, and it is far easier to use when making millions of cars each year.

If hemp is used in the automobile industry more regularly, manufacturers will surely find ways to reduce costs. Whether it can become cheaper to mass-produce than steel is another matter.

Lack of Tensile Strength

Much is made of the fact that hemp is apparently stronger than steel. However, there remain concerns over the tensile strength of hemp fibers. In contrast, car manufacturers continually find new ways to add high tensile strength steel to their creations.

Tensile strength relates to the capacity to withstand tension. The pressure something can withstand before breaking, cracking, or tearing is its tensile strength.

Advanced High Strength Steel (AHSS) has a minimum tensile strength of 500 megapascals (MPa). Ultra-High Strength Steel (UHSS) has a tensile strength of at least 780 MPa. In 2011, Mazda announced that it had developed vehicle components using 1,800 MPa steel.

How Does Hemp Compare?

A 2013 study published in Advances in Materials Science and Engineering sought to determine hemp fibers’ physical and mechanical properties. The researchers found something very interesting. The smaller the diameter of synthetic fibers, the fewer the flaws and the higher the tensile strength. Hemp fibers seem to be the same.

Hemp fibers with a diameter of 4 micrometers have a tensile strength of 4200 MPa. However, hemp fibers with a diameter of 66 micrometers have a tensile strength of just 250 MPa. At 800 micrometers, the tensile strength of the fibers falls to just 10MPa.

Another study, published in Composites Part B: Engineering in 2013, looked at the mechanical properties of chemically-treated hemp fiber reinforced sandwich composites. The researchers found that hemp’s tensile strength was around 50MPa, with around the same strength and stiffness as non-reinforced polyester resin. Furthermore, the hemp fibers didn’t reinforce the composites and did little but add cost and complexity.

Car manufacturers now use fiberglass and carbon fibers to make car bodies, and both materials have at least 30 times the tensile strength of hemp. Fiberglass composites are 20 times stiffer than their hemp counterparts, whereas carbon fiber composites are 50-150 times stiffer.

Ultimately, while Dietzen’s car could be more dent resistant than steel cars, it doesn’t mean his vehicle will hold up better in a serious accident. Moreover, a car made mainly from hemp would be heavier than existing automobiles, more expensive to make, and have a lower level of performance.

Hemp fiber’s properties are good enough to use as a composite material reinforcement. However, issues such as high moisture content of fibers, poor fiber/matrix interfacial strength, and variability in fiber composites can reduce the efficiency with which these fibers can be utilized.