Is biofuel really a benefit?

The setting of net-zero targets around the world is leading to the exploration of alternative sources of energy. It has become increasingly clear that no single technology will be a silver bullet in the race to hold global temperatures in check. Wind, solar, hydrogen, geothermal and smart grids are among many other technologies that have all been proposed as possible solutions. Another possible solution that is increasingly coming to light is biodiesel. Although it represents only a fraction of the total diesel consumed worldwide, there has been an increasing interest in biodiesel production in recent years. Production in the United States alone has increased by over 150%?over the past 10 years.

One of the main advantages of biodiesel is that it can be produced from renewable feedstock, including plant oils and animal fat, as well as lower vehicle emissions when using biodiesel rather than petro-diesel.?Biodiesel is also lower in sulfur, which reduces the need for additional refining.

But its great advantage is also a cause for concern. To meet the demand for biodiesel and replace more traditional fuel sources, large quantities of crops would be required -- crops that would not be used to feed populations. Take, for example, the province of Ontario in Canada, which has an annual diesel consumption of approximately five billion liters.?According to the Ontario Ministry of Agriculture, Food and Rural Affairs, the 5-year average soybean production in the area was 3.1 million tons, and the 5-year average canola production was 59,860 tons (2009-13). If these crops were converted to biodiesel, they would replace just 12% of the province’s diesel consumption for on-road applications.

The availability of feedstock can also vary, impacting the production of biofuel. There may be plastics present in feedstock from a meat processing plant which must be removed prior to converting the fat to oil.

There are also many precautions that must be taken when producing biofuels, and process safety engineers play an important role in ensuring they can be produced safely. The typical process involves converting fat to oil in a?transesterification?chemical reaction with the use of catalysts. The final product can then be further processed to remove contaminants such as alcohol and glycerin. Biodiesel shares many of the same hazards as petro-diesel, such as the potential for fires and explosions. Thus, expertise and experience in the production and refining of conventional petrochemicals are very much applicable to biodiesel. This includes the use of traditional safeguarding methods such as control systems with shutdowns and pressure relief valves. Despite these issues, processes can be made safe if risk assessments such as hazard and operability studies (HAZOP) are performed, and appropriate safeguards are implemented.

Despite concerns over biofuel efficiency, it is important to remember it is still a technology that is growing. This is because only additional funding and research will allow the current issues to be resolved. Overall, biodiesel production shows promise as one of many elements as we move forward toward net zero. According to the US Energy Information Administration, in 2019, world consumption of biodiesel rose to more than 255,000 barrels. In the US alone,?production has increased by over 150%?in the past decade.

If you wish to know more about the pros and cons of biofuel, you can read this Elsevier Engineering blog post.